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{{short description|Inflammation of the liver}}
{{Infobox disease
{{Redirect|Hepatite|the mineral of that name|Baryte}}
|Name = Hepatitis
{{Infobox medical condition (new)
|Image = Alcoholic_hepatitis.jpg
| name = Hepatitis
|Caption = [[Alcoholic liver disease|Alcoholic hepatitis]] evident by fatty change, cell [[necrosis]], [[Mallory bodies]]
| image = Alcoholic_hepatitis.jpg
|ICD10 = {{ICD10|K|75|9|k|70}}
| caption = [[Alcoholic hepatitis]] as seen with a microscope, showing fatty changes (white circles), remnants of dead liver cells, and [[Mallory bodies]] (twisted-rope shaped inclusions within some liver cells). ([[H&E stain]])
|ICD9 = {{ICD9|573.3}}
| field = [[Infectious disease (medical specialty)|Infectious disease]], [[gastroenterology]], [[hepatology]]
|DiseasesDB = 20061
| pronounce =
|MedlinePlus = 001154
| symptoms = [[jaundice|Yellowish skin]], poor appetite, abdominal pain<ref name=MedLine2016/><ref name=WHO2016QA/>
|eMedicineSubj =
| complications = [[cirrhosis|Scarring of the liver]], [[liver failure]], [[liver cancer]]<ref name=NIH2016/>
|eMedicineTopic =
| onset =
|MeshID = D006505
| duration = Short term or long term<ref name=MedLine2016/>
| causes = [[Viruses]], [[ethanol|alcohol]], toxins, autoimmune<ref name=WHO2016QA/><ref name=NIH2016/>
| risks =
| diagnosis =
| differential =
| prevention = Vaccination (for viral hepatitis),<ref name=WHO2016QA/> avoiding excessive alcohol
| treatment = Medication, [[liver transplant]]<ref name=MedLine2016/><ref name=Trans2012/>
| medication =
| frequency = > 500 million cases<ref name=NIH2016/>
| deaths = > One million a year<ref name=NIH2016/>
}}
}}
'''Hepatitis''' (plural: '''hepatitides''') is a [[medical condition]] defined by the inflammation of the [[liver]] and characterized by the presence of [[inflammation|inflammatory]] [[cell (biology)|cell]]s in the [[Tissue (biology)|tissue]] of the organ. The name is from the Greek ''hepar'' (ἧπαρ), the root being ''hepat''- (ἡπατ-), meaning ''liver'', and suffix ''-itis'', meaning "inflammation" (c. 1727).<ref>{{cite web|url=http://www.etymonline.com/index.php?search=hepatitis&searchmode=none |title=Online Etymology Dictionary |publisher=Etymonline.com |date= |accessdate=2012-08-26}}</ref> The condition can be self-limiting (healing on its own) or can progress to [[fibrosis]] (scarring) and [[cirrhosis]].


'''Hepatitis''' is [[inflammation]] of the [[liver parenchyma|liver tissue]].<ref name=NIH2016>{{cite web|title=Hepatitis|url=https://www.niaid.nih.gov/diseases-conditions/hepatitis|website=NIAID|access-date=2 November 2016|url-status=live|archive-url=https://web.archive.org/web/20161104002228/https://www.niaid.nih.gov/diseases-conditions/hepatitis|archive-date=4 November 2016}}</ref><ref name="MedlinePlus 2020">{{cite web | title=Hepatitis | website=MedlinePlus | date=2020-05-20 | url=https://medlineplus.gov/hepatitis.html | access-date=2020-07-19 | quote=Your liver is the largest organ inside your body. It helps your body digest food, store energy, and remove poisons. Hepatitis is an inflammation of the liver.}}</ref> Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes ([[jaundice]]), [[Anorexia (symptom)|poor appetite]], [[vomiting]], [[fatigue (medicine)|tiredness]], [[abdominal pain]], and [[diarrhea]].<ref name=MedLine2016/><ref name=WHO2016QA/> Hepatitis is ''[[acute (medicine)|acute]]'' if it resolves within six months, and ''[[chronic condition|chronic]]'' if it lasts longer than six months.<ref name=MedLine2016>{{cite web|title=Hepatitis|url=https://medlineplus.gov/hepatitis.html|website=MedlinePlus|access-date=10 November 2016|url-status=live|archive-url=https://web.archive.org/web/20161111061624/https://medlineplus.gov/hepatitis.html|archive-date=11 November 2016}}</ref><ref>{{cite web|title=Hepatitis (Hepatitis A, B, and C) {{!}} ACG Patients|url=http://patients.gi.org/topics/viral-hepatitis/|website=patients.gi.org|url-status=live|archive-url=https://web.archive.org/web/20170223163352/http://patients.gi.org/topics/viral-hepatitis/|archive-date=2017-02-23}}</ref> Acute hepatitis can [[self-limiting (biology)|resolve on its own]], progress to chronic hepatitis, or (rarely) result in [[acute liver failure]].<ref>{{cite journal |author1=Bernal W. |author2=Wendon J. | year = 2013 | title = Acute Liver Failure | journal = New England Journal of Medicine | volume = 369 | issue = 26| pages = 2525–2534 | doi=10.1056/nejmra1208937| pmid=24369077|s2cid=205116503 | doi-access = free }}</ref> Chronic hepatitis may progress to scarring of the liver ([[cirrhosis]]), [[liver failure]], and [[liver cancer]].<ref name=NIH2016/><ref>{{Cite web |title=Esto es la hepatitis: Conócela, enfréntate a ella |url=https://www.infoterio.com/2022/08/Esto-es-la-hepatitis-Conocela-enfrentate-a-ella.html |access-date=2023-02-12 |website=Infoterio Noticias {{!}} Ciencia y Tecnología |date=8 August 2022 |language=es}}</ref>
Hepatitis may occur with limited or no symptoms, but often leads to [[jaundice]], [[Anorexia (symptom)|anorexia]] (poor appetite) and [[malaise]]. Hepatitis is acute when it lasts less than six months and chronic when it persists longer. Worldwide, [[Viral hepatitis|hepatitis viruses]] are the most common cause of the condition, but hepatitis can be caused by other infections, toxic substances (notably [[Ethanol|alcohol]], certain [[medication]]s, some industrial organic solvents and plants), and [[Autoimmune hepatitis|autoimmune diseases]]..


Hepatitis is most commonly caused by the virus ''[[hepatovirus A]]'', ''[[hepatitis B virus|B]]'', ''[[hepatitis C virus|C]]'', ''[[hepatitis D virus|D]]'', and ''[[hepatitis E virus|E]]''.<ref name=WHO2016QA>{{cite web|title=What is hepatitis?|url=https://www.who.int/features/qa/76/en/|website=WHO|access-date=10 November 2016|date=July 2016|url-status=live|archive-url=https://web.archive.org/web/20161107003115/http://www.who.int/features/qa/76/en/|archive-date=7 November 2016}}</ref><ref name=NIH2016/> Other [[Viral hepatitis|viruses can also cause liver inflammation]], including [[cytomegalovirus]], [[Epstein–Barr virus]], and [[Yellow fever|yellow fever virus]]. Other common causes of hepatitis include [[alcoholism|heavy alcohol use]], certain medications, toxins, other infections, [[autoimmune diseases]],<ref name=WHO2016QA/><ref name=NIH2016/> and [[non-alcoholic steatohepatitis]] (NASH).<ref name=NASH2014>{{cite web|title=Fatty Liver Disease (Nonalcoholic Steatohepatitis) |url=https://www.niddk.nih.gov/health-information/health-topics/liver-disease/nonalcoholic-steatohepatitis/pages/facts.aspx |website=NIDDK |access-date=10 November 2016 |date=May 2014 |archive-url=https://web.archive.org/web/20161111061658/https://www.niddk.nih.gov/health-information/health-topics/liver-disease/nonalcoholic-steatohepatitis/pages/facts.aspx |archive-date=11 November 2016 |url-status=dead }}</ref> Hepatitis A and E are mainly spread by contaminated food and water.<ref name=NIH2016/> Hepatitis B is mainly [[sexually transmitted infection|sexually transmitted]], but may also be [[vertically transmitted infection|passed from mother to baby]] during [[pregnancy]] or [[childbirth]] and spread through infected [[blood]].<ref name=NIH2016/> Hepatitis C is commonly spread through infected blood such as may occur during [[needle sharing]] by [[drug injection|intravenous drug users]].<ref name=NIH2016/> Hepatitis D can only infect people already infected with hepatitis B.<ref name=NIH2016/>
== Signs and symptoms ==
[[File:Jaundice08.jpg|thumb|A person with jaundice]]


Hepatitis A, B, and D are [[vaccine-preventable diseases|preventable]] with [[immunization]].<ref name=WHO2016QA/> Medications may be used to treat chronic viral hepatitis.<ref name=MedLine2016/> Antiviral medications are recommended in all with chronic hepatitis C, except those with conditions that limit their life expectancy.<ref name="AASLD-IDSA">{{Cite journal|last=AASLD/IDSA HCV Guidance Panel|date=2015-09-01|title=Hepatitis C guidance: AASLD-IDSA recommendations for testing, managing, and treating adults infected with hepatitis C virus|journal=Hepatology|volume=62|issue=3|pages=932–954|doi=10.1002/hep.27950|issn=1527-3350|pmid=26111063|doi-access=free}}</ref> There is no specific treatment for NASH; physical activity, a [[healthy diet]], and [[weight loss]] are recommended.<ref name=NASH2014/> [[Autoimmune hepatitis]] may be treated with [[immunosuppressants|medications to suppress the immune system]].<ref>{{cite web|title=Autoimmune Hepatitis|url=https://www.niddk.nih.gov/health-information/health-topics/liver-disease/autoimmune-hepatitis/Pages/facts.aspx|website=NIDDK|access-date=10 November 2016|date=March 2014|url-status=dead|archive-url=https://web.archive.org/web/20161111061856/https://www.niddk.nih.gov/health-information/health-topics/liver-disease/autoimmune-hepatitis/Pages/facts.aspx|archive-date=11 November 2016}}</ref> A [[liver transplant]] may be an option in both acute and chronic liver failure.<ref name=Trans2012>{{cite web|title=Liver Transplant|url=https://www.niddk.nih.gov/health-information/health-topics/liver-disease/liver-transplant/Pages/facts.aspx|website=NIDDK|access-date=10 November 2016|date=April 2012|url-status=dead|archive-url=https://web.archive.org/web/20161111061924/https://www.niddk.nih.gov/health-information/health-topics/liver-disease/liver-transplant/Pages/facts.aspx|archive-date=11 November 2016}}</ref>
=== Acute ===
Initial features are of nonspecific flu-like symptoms, common to almost all acute [[viral infections]] and may include [[malaise]], [[myalgia|muscle]] and [[arthralgia|joint aches]], [[fever]], [[nausea]] or [[vomiting]], [[diarrhea]], and [[headache]]. More specific [[symptom]]s, which can be present in acute hepatitis from any cause, are: profound [[Anorexia (symptom)|loss of appetite]], aversion to [[smoking]] among [[Tobacco smoking|smokers]], [[choluria|dark urine]], yellowing of the eyes and skin ([[jaundice]]) and abdominal discomfort. Physical findings are usually minimal, apart from [[jaundice]], tender [[hepatomegaly]] (swelling of the liver), [[lymphadenopathy]] (enlarged lymph nodes, in 5%), and [[splenomegaly]] (enlargement of the [[spleen]]. Acute viral hepatitis is more likely to be asymptomatic in children. Symptomatic individuals may present after a convalescent stage of 7 to 10 days, with the total illness lasting weeks.<ref name="Ryder S, Beckingham I 2001 151–153">{{cite journal |author=Ryder S, Beckingham I |title=Acute hepatitis |journal=BMJ |volume=322 |issue=7279 |pages=151–153 |year=2001 |pmid = 11159575 |doi=10.1136/bmj.322.7279.151 |pmc=1119417}}</ref>


Worldwide in 2015, hepatitis A occurred in about 114 million people, chronic hepatitis B affected about 343 million people and chronic hepatitis C about 142 million people.<ref>{{cite journal|title=Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015|journal=The Lancet|date=October 2016|volume=388|issue=10053|pages=1545–1602|doi=10.1016/S0140-6736(16)31678-6|pmid=27733282|pmc=5055577|last1=Vos|first1=Theo|last2=Allen|first2=Christine|last3=Arora|first3=Megha|last4=Barber|first4=Ryan M.|last5=Bhutta|first5=Zulfiqar A.|last6=Brown|first6=Alexandria|last7=Carter|first7=Austin|last8=Casey|first8=Daniel C.|last9=Charlson|first9=Fiona J.|last10=Chen|first10=Alan Z.|last11=Coggeshall|first11=Megan|last12=Cornaby|first12=Leslie|last13=Dandona|first13=Lalit|last14=Dicker|first14=Daniel J.|last15=Dilegge|first15=Tina|last16=Erskine|first16=Holly E.|last17=Ferrari|first17=Alize J.|last18=Fitzmaurice|first18=Christina|last19=Fleming|first19=Tom|last20=Forouzanfar|first20=Mohammad H.|last21=Fullman|first21=Nancy|last22=Gething|first22=Peter W.|last23=Goldberg|first23=Ellen M.|last24=Graetz|first24=Nicholas|last25=Haagsma|first25=Juanita A.|last26=Hay|first26=Simon I.|last27=Johnson|first27=Catherine O.|last28=Kassebaum|first28=Nicholas J.|last29=Kawashima|first29=Toana|last30=Kemmer|first30=Laura|display-authors=29}}</ref> In the United States, NASH affects about 11 million people and [[alcoholic hepatitis]] affects about 5 million people.<ref name=NASH2014/><ref>{{cite journal|last1=Basra|first1=Sarpreet|title=Definition, epidemiology and magnitude of alcoholic hepatitis|journal=World Journal of Hepatology|date=2011|volume=3|issue=5|pages=108–13|doi=10.4254/wjh.v3.i5.108|pmid=21731902|pmc=3124876 |doi-access=free }}</ref> Hepatitis results in more than a million deaths a year, most of which occur indirectly from liver scarring or liver cancer.<ref name=NIH2016/><ref>{{cite journal|title=Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980–2015: a systematic analysis for the Global Burden of Disease Study 2015|journal=The Lancet|date=October 2016|volume=388|issue=10053|pages=1459–1544|doi=10.1016/S0140-6736(16)31012-1|pmid=27733281|pmc=5388903|last1=Wang|first1=Haidong|last2=Naghavi|first2=Mohsen|last3=Allen|first3=Christine|last4=Barber|first4=Ryan M.|last5=Bhutta|first5=Zulfiqar A.|last6=Carter|first6=Austin|last7=Casey|first7=Daniel C.|last8=Charlson|first8=Fiona J.|last9=Chen|first9=Alan Zian|last10=Coates|first10=Matthew M.|last11=Coggeshall|first11=Megan|last12=Dandona|first12=Lalit|last13=Dicker|first13=Daniel J.|last14=Erskine|first14=Holly E.|last15=Ferrari|first15=Alize J.|last16=Fitzmaurice|first16=Christina|last17=Foreman|first17=Kyle|last18=Forouzanfar|first18=Mohammad H.|last19=Fraser|first19=Maya S.|last20=Fullman|first20=Nancy|last21=Gething|first21=Peter W.|last22=Goldberg|first22=Ellen M.|last23=Graetz|first23=Nicholas|last24=Haagsma|first24=Juanita A.|last25=Hay|first25=Simon I.|last26=Huynh|first26=Chantal|last27=Johnson|first27=Catherine O.|last28=Kassebaum|first28=Nicholas J.|last29=Kinfu|first29=Yohannes|last30=Kulikoff|first30=Xie Rachel|display-authors=29}}</ref> In the United States, hepatitis A is estimated to occur in about 2,500 people a year and results in about 75 deaths.<ref>{{cite web|title=Statistics & Surveillance Division of Viral Hepatitis CDC|url=https://www.cdc.gov/hepatitis/statistics/index.htm|website=CDC|access-date=10 November 2016|url-status=live|archive-url=https://web.archive.org/web/20161111012229/http://www.cdc.gov/hepatitis/Statistics/index.htm|archive-date=11 November 2016}}</ref> The word is derived from the [[Ancient Greek|Greek]] ''hêpar'' ({{lang|grc|[[wikt:ἧπαρ|ἧπαρ]]}}), meaning "liver", and ''[[wikt:-itis|-itis]]'' ({{lang|grc|-ῖτις}}), meaning "inflammation".<ref>{{cite web |url=http://www.etymonline.com/index.php?search=hepatitis&searchmode=none |title=Online Etymology Dictionary |publisher=Etymonline.com |access-date=2012-08-26 |url-status=live |archive-url=https://web.archive.org/web/20121020195733/http://www.etymonline.com/index.php?search=hepatitis&searchmode=none |archive-date=2012-10-20 }}</ref>
A small proportion of people with acute hepatitis progress to [[acute liver failure]], in which the liver is unable to remove harmful substances from the blood (leading to confusion and coma due to [[hepatic encephalopathy]]) and produce blood proteins (leading to [[peripheral edema]] and bleeding).<ref name="Ryder S, Beckingham I 2001 151–153"/>
{{TOC limit|3}}


=== Chronic ===
== Signs and symptoms ==
[[File:Jaundice eye.jpg|thumb|upright=1.3|Jaundiced eyes]]
Chronic hepatitis may cause nonspecific symptoms such as malaise, tiredness and weakness, and often leads to no symptoms at all. It is commonly identified on [[blood test]]s performed either for [[screening (medicine)|screening]] or to evaluate nonspecific symptoms. The presence of [[jaundice]] indicates advanced liver damage. On physical examination there may be enlargement of the liver.<ref name=MerckHome>{{MerckHome|10|137|c||Chronic hepatitis}}</ref>
Hepatitis has a broad spectrum of presentations that range from a complete lack of symptoms to severe&nbsp;[[liver failure]].<ref name="Harrison's Principles, chapter 360 (Acute Viral)">{{Cite book|title=Harrison's Principles of Internal Medicine, 19e|last=Dienstag|first=JL|publisher=McGraw-Hill|year=2015|isbn=978-0-07-180215-4|editor-last=Kasper|editor-first=D|location=New York, NY|chapter=Chapter 360: Acute Viral Hepatitis|editor-last2=Fauci|editor-first2=A|editor-last3=Hauser|editor-first3=S|editor-last4=Longo|editor-first4=D|editor-last5=Jameson|editor-first5=J|editor-last6=Loscalzo|editor-first6=J}}</ref><ref name="CURRENT Diagnosis & Treatment">{{Cite book|title=CURRENT Diagnosis & Treatment: Gastroenterology, Hepatology, & Endoscopy, 3e|last1=Rutherford|first1=A|last2=Dienstag|first2=JL|publisher=McGraw-Hill|year=2016|isbn=978-0-07-183772-9|editor-last=Greenberger|editor-first=NJ|location=New York, NY|chapter=Chapter 40: Viral Hepatitis|editor-last2=Blumberg|editor-first2=RS|editor-last3=Burakoff|editor-first3=R}}</ref><ref name="Khalili & Burman">{{Cite book|title=Pathophysiology of Disease: An Introduction to Clinical Medicine, 7e|last1=Khalili|first1=M|last2=Burman|first2=B|publisher=McGraw-Hill|year=2013|isbn=978-1-25-925144-3|editor-last=Hammer|editor-first=GD|chapter=Chapter 14: Liver Disease|editor-last2=McPhee|editor-first2=SJ}}</ref> The acute form of hepatitis, generally caused by viral infection, is characterized by&nbsp;[[constitutional symptoms]]&nbsp;that are typically self-limiting.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="CURRENT Diagnosis & Treatment" /> Chronic hepatitis presents similarly, but can manifest [[medical sign|signs]] and symptoms specific to liver dysfunction with long-standing inflammation and damage to the organ.<ref name="Khalili & Burman" /><ref name="Harrison's Principles, chapter 362 (Chronic)">{{Cite book|title=Harrison's Principles of Internal Medicine, 19e|last=Dienstag|first=JL|publisher=McGraw-Hill|year=2015|isbn=978-0-07-180215-4|editor-last=Kasper|editor-first=D|location=New York, NY|chapter=Chapter 362: Chronic Hepatitis|editor-last2=Fauci|editor-first2=A|editor-last3=Hauser|editor-first3=S|editor-last4=Longo|editor-first4=D|editor-last5=Jameson|editor-first5=J|editor-last6=Loscalzo|editor-first6=J}}</ref>


=== Acute hepatitis ===
Extensive damage to and scarring of liver (i.e. cirrhosis) leads to weight loss, easy bruising and bleeding, [[peripheral edema]] (swelling of the legs) and accumulation of [[ascites]] (fluid in the abdomen). Eventually, cirrhosis may lead to various complications: [[esophageal varices]] (enlarged veins in the wall of the esophagus that can cause life-threatening bleeding), [[hepatic encephalopathy]] (confusion and coma) and [[hepatorenal syndrome]] (kidney dysfunction).
Acute viral hepatitis follows three distinct phases:
# The initial [[Prodrome|prodromal phase]] (preceding symptoms) involves [[non-specific]] and [[flu-like]] symptoms common to many acute viral infections. These include [[Fatigue (medical)|fatigue]], [[nausea]], [[vomiting]], poor appetite, joint pain, and headaches.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="CURRENT Diagnosis & Treatment" /> Fever, when present, is most common in cases of hepatitis A and E.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Late in this phase, people can experience liver-specific symptoms, including [[choluria]] (dark urine) and clay-colored stools.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="CURRENT Diagnosis & Treatment" />
# [[Jaundice|Yellowing of the skin and whites of the eyes]] follow the prodrome after about 1–2 weeks and can last for up to 4 weeks.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="CURRENT Diagnosis & Treatment" /> The non-specific symptoms seen in the prodromal typically resolve by this time, but people will develop an [[hepatomegaly|enlarged liver]] and right upper abdominal pain or discomfort.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> 10–20% of people will also experience an [[Splenomegaly|enlarged spleen]], while some people will also experience a mild unintentional weight loss.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Khalili & Burman" />
# The recovery phase is characterized by resolution of the clinical symptoms of hepatitis with persistent elevations in [[Liver function tests|liver lab values]] and potentially a persistently enlarged liver.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> All cases of hepatitis A and E are expected to fully resolve after 1–2 months.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Most hepatitis B cases are also self-limiting and will resolve in 3–4 months. Few cases of hepatitis C will resolve completely.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />
Both [[drug-induced hepatitis]] and [[autoimmune hepatitis]] can present very similarly to acute viral hepatitis, with slight variations in symptoms depending on the cause.<ref name="Fontana & Hayashi">{{Cite journal|last1=Fontana|first1=Robert|last2=Hayashi|first2=Paul|date=2014-05-01|title=Clinical Features, Diagnosis, and Natural History of Drug-Induced Liver Injury|journal=Seminars in Liver Disease|language=en|volume=34|issue=2|pages=134–144|doi=10.1055/s-0034-1375955|pmid=24879979|doi-access=free}}</ref><ref name="Manns Lohse Vergani">{{Cite journal|last1=Manns|first1=Michael P.|last2=Lohse|first2=Ansgar W.|last3=Vergani|first3=Diego|title=Autoimmune hepatitis – Update 2015|journal=Journal of Hepatology|volume=62|issue=1|pages=S100–S111|doi=10.1016/j.jhep.2015.03.005|pmid=25920079|year=2015|doi-access=free}}</ref> Cases of drug-induced hepatitis can manifest with systemic signs of an allergic reaction including rash, fever, [[serositis]] (inflammation of membranes lining certain organs), elevated [[Eosinophil granulocyte|eosinophils]] (a type of white blood cell), and [[Bone marrow suppression|suppression of bone marrow activity]].<ref name="Fontana & Hayashi" />


=== Fulminant hepatitis ===
[[Acne]], abnormal [[menstruation]], [[lung scarring]], inflammation of the [[thyroid gland]] and [[kidney]]s may be present in [[women]] with [[autoimmune hepatitis]].<ref name=MerckHome/>
Fulminant hepatitis, or massive hepatic [[necrosis|cell death]], is a rare and life-threatening complication of acute hepatitis that can occur in cases of hepatitis B, D, and E, in addition to drug-induced and autoimmune hepatitis.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Fontana & Hayashi" /><ref name="Manns Lohse Vergani" /> The complication more frequently occurs in instances of hepatitis B and D co-infection at a rate of 2–20% and in pregnant women with hepatitis E at rate of 15–20% of cases.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="CURRENT Diagnosis & Treatment" /> In addition to the signs of acute hepatitis, people can also demonstrate signs of [[coagulopathy]] (abnormal coagulation studies with easy bruising and bleeding) and [[encephalopathy]] (confusion, disorientation, and [[somnolence|sleepiness]]).<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="CURRENT Diagnosis & Treatment" /> Mortality due to fulminant hepatitis is typically the result of various complications including [[cerebral edema]], [[gastrointestinal bleeding]], [[sepsis]], [[respiratory failure]], or [[kidney failure]].<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />

=== Chronic hepatitis ===
Acute cases of hepatitis are seen to be resolved well within a six-month period. When hepatitis is continued for more than six months it is termed chronic hepatitis.<ref>{{cite book|last1=Munjal|first1=Y. P.|last2=Sharm|first2=Surendra K.|title=API Textbook of Medicine, Ninth Edition, Two Volume Set|date=2012|publisher=JP Medical Ltd|isbn=9789350250747|page=870|url=https://books.google.com/books?id=L7pW3yGjj7kC&pg=PA870|language=en|url-status=live|archive-url=https://web.archive.org/web/20170910162730/https://books.google.com/books?id=L7pW3yGjj7kC&pg=PA870|archive-date=2017-09-10}}</ref> Chronic hepatitis is often asymptomatic early in its course and is detected only by liver laboratory studies for [[Screening (medicine)|screening]] purposes or to evaluate non-specific symptoms.<ref name="Khalili & Burman" /><ref name="Harrison's Principles, chapter 362 (Chronic)" /> As the inflammation progresses, patients can develop constitutional symptoms similar to acute hepatitis, including fatigue, nausea, vomiting, poor appetite, and joint pain.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Jaundice can occur as well, but much later in the disease process and is typically a sign of advanced disease.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Chronic hepatitis interferes with hormonal functions of the liver which can result in acne, [[hirsutism]] (abnormal hair growth), and [[Amenorrhoea|amenorrhea]] (lack of menstrual period) in women.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Extensive damage and scarring of the liver over time defines [[cirrhosis]], a condition in which the liver's ability to function is permanently impeded.<ref name="Khalili & Burman" /> This results in jaundice, weight loss, coagulopathy, [[ascites]] (abdominal fluid collection), and [[peripheral edema]] (leg swelling).<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Cirrhosis can lead to other life-threatening complications such as [[hepatic encephalopathy]], [[esophageal varices]], [[hepatorenal syndrome]], and [[Hepatocellular carcinoma|liver cancer]].<ref name="Khalili & Burman" />


== Causes ==
== Causes ==
Causes of hepatitis can be divided into the following major categories: infectious, metabolic, ischemic, autoimmune, genetic, and other. Infectious agents include viruses, bacteria, and parasites. Metabolic causes include prescription medications, toxins (most notably [[Alcoholic liver disease|alcohol]]), and [[non-alcoholic fatty liver disease]]. [[Autoimmune hepatitis|Autoimmune]] and genetic causes of hepatitis involve genetic predispositions and tend to affect characteristic populations.<ref>[https://www.vinmec.com/vi/tieu-hoa-gan-mat/thong-tin-suc-khoe/viem-gan-tu-mien-la-gi/ Viêm gan tự miễn.] Phần nội dung "Yếu tố nguy cơ mắc bệnh viêm gan tự miễn". Bệnh viện đa khoa quốc tế Vinmec. Truy cập 28/12/2023</ref>


=== Infectious ===
[[Viral hepatitis]] is the most common cause of hepatitis worldwide.<ref>{{cite web|title=Hepatitis|url=http://www.who.int/topics/hepatitis/en/|publisher=World Health Organization|accessdate=25 November 2013|author=World Health Organization}}</ref> The most common causes of viral hepatitis are the five unrelated hepatotropic viruses [[hepatitis A]], [[hepatitis B]], [[hepatitis C]], [[hepatitis D]] (which requires hepatitis B to cause disease), and [[hepatitis E]]. Other common causes of non-viral hepatitis include [[Hepatotoxicity|toxic and drug-induced]], [[Alcoholic hepatitis|alcoholic]], [[Autoimmune hepatitis|autoimmune]], [[Non-alcoholic fatty liver disease|fatty liver]], and [[Inborn error of metabolism|metabolic disorders]].<ref>{{cite book|title=Harrison's Principles of Internal Medicine.|year=2012|publisher=McGraw-Hill|location=New York|url=http://www.accessmedicine.com/content.aspx?aID=9134248|edition=18th|editor=Longo, DL|format=Onlline|chapter=Chapter 306. Chronic Hepatitis}}</ref> Less commonly some bacterial, parasitic, fungal, mycobacterial and protozoal infections can cause hepatitis.<ref name="McGraw-Hill">{{cite book|title=Harrison's Principles of Internal Medicine.|year=2012|publisher=McGraw-Hill|location=New York|url=http://www.accessmedicine.com/content.aspx?aID=9134248|edition=18th|editor=Longo, DL|format=Onlline|chapter=Chapter 305. Acute Viral Hepatitis}}</ref><ref>{{cite book|title=Schiff's Diseases of the Liver|year=2011|publisher=Wiley-Blackwell|location=Oxford, UK|url=http://onlinelibrary.wiley.com/doi/10.1002/9781119950509.ch39/summary|author=Dunn, MA|editor=Schiff ER, Maddrey WC, Sorrell MF|accessdate=25 November 2013|format=Online|chapter=Chapter 39. Parasitic Disease}}</ref> Additionally, certain [[complications of pregnancy]] and [[ischemic hepatitis|decreased blood flow]] to the liver can induce hepatitis.<ref name="McGraw-Hill"/><ref>{{cite book|title=Schiff's Diseases of the Liver|year=2011|publisher=Wiley-Blackwell|location=Oxford, UK|url=http://onlinelibrary.wiley.com/doi/10.1002/9781119950509.ch11/summary|author=Bacq Y|editor=Schiff ER, Maddrey WC, Sorrell MF|accessdate=25 November 2013|format=Online|chapter=Chapter 11. The Liver in Pregnancy}}</ref> [[Cholestasis]] (obstruction of [[bile]] flow) due to [[hepatocyte|hepatocellular]] dysfunction, [[biliary tract]] obstruction, or [[biliary atresia]] can result in liver damage and hepatitis.<ref>{{cite journal|last=Santos|first=JK|coauthors=Choquette M, Bezerra JA|title=Cholestatic liver disease in children|journal=Curr Gastroenterol Rep|date=Feb 2010|volume=12|issue=1|pages=30–39|doi=10.1007/s11894-009-0081-8|pmid=20425482|pmc=2882095}}</ref><ref>{{cite book|last=Geller|first=DA|title=Schwartz's principles of surgery|year=2010|publisher=McGraw-Hill, Medical Pub. Division|location=New York|isbn=978-0071547697|edition=9th|editor=Brunicardi F|accessdate=4 December 2013|chapter=Chapter 31 Liver}}</ref>


=== Alcoholic hepatitis ===
==== Viral hepatitis ====
{{Main|Viral hepatitis}}
[[Viral hepatitis]] is the most common type of hepatitis worldwide, especially in Asia and Africa.<ref>{{cite web|url=https://www.who.int/topics/hepatitis/en/|title=Hepatitis|publisher=World Health Organization|access-date=25 November 2013|author=World Health Organization|url-status=live|archive-url=https://web.archive.org/web/20131202223841/http://www.who.int/topics/hepatitis/en/|archive-date=2 December 2013}}</ref> Viral hepatitis is caused by five different viruses (hepatitis A, B, C, D, and E).<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> [[Hepatitis A]] and [[hepatitis E]] behave similarly: they are both transmitted by the [[fecal–oral route]], are more common in developing countries, and are self-limiting illnesses that do not lead to chronic hepatitis.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref>{{Cite web|url=https://www.cdc.gov/hepatitis/hav/afaq.htm|title=Hepatitis A Questions and Answers for the Public {{!}} Division of Viral Hepatitis {{!}} CDC|website=www.cdc.gov|access-date=2016-03-14|url-status=live|archive-url=https://web.archive.org/web/20160312094721/http://www.cdc.gov/hepatitis/hav/afaq.htm|archive-date=2016-03-12}}</ref><ref>{{Cite web|url=https://www.who.int/mediacentre/factsheets/fs280/en/|title=Hepatitis E|website=World Health Organization|language=en-GB|access-date=2016-03-14|url-status=live|archive-url=https://web.archive.org/web/20160312074914/http://www.who.int/mediacentre/factsheets/fs280/en/|archive-date=2016-03-12}}</ref>

[[Hepatitis B]], [[hepatitis C]], and [[hepatitis D]] are transmitted when blood or [[mucous membrane]]s are exposed to infected blood and body fluids, such as semen and vaginal secretions.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Viral particles have also been found in saliva and breastmilk. Kissing, sharing utensils, and breastfeeding do not lead to transmission unless these fluids are introduced into open sores or cuts.<ref>{{Cite web|url=https://www.cdc.gov/hepatitis/HBV/PDFs/HepBWhenSomeoneClose.pdf|title=When Someone Close to You Has Hepatitis|last=Centers for Disease Control & Prevention|date=June 2010|access-date=March 14, 2016|url-status=live|archive-url=https://web.archive.org/web/20160306084204/http://www.cdc.gov/hepatitis/HBV/PDFs/HepBWhenSomeoneClose.pdf|archive-date=March 6, 2016}}</ref> Many families who do not have safe drinking water or live in unhygienic homes have contracted hepatitis because saliva and blood droplets are often carried through the water and blood-borne illnesses spread quickly in unsanitary settings.<ref>{{Cite web |title=Hepatitis A |url=https://www.who.int/news-room/fact-sheets/detail/hepatitis-a |access-date=2023-05-07 |website=www.who.int |language=en}}</ref>

Hepatitis B and C can present either acutely or chronically.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Hepatitis D is a defective virus that requires hepatitis B to replicate and is only found with hepatitis B co-infection.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> In adults, hepatitis B infection is most commonly self-limiting, with less than 5% progressing to chronic state, and 20 to 30% of those chronically infected developing cirrhosis or liver cancer.<ref name="WHO Hepatitis B" /> Infection in infants and children frequently leads to chronic infection.<ref name="WHO Hepatitis B" />

Unlike hepatitis B, most cases of hepatitis C lead to chronic infection.<ref name="CDC FAQ on Hepatitis C">{{Cite web|url=https://www.cdc.gov/hepatitis/hcv/cfaq.htm|title=Hepatitis C FAQs for the Public {{!}} Division of Viral Hepatitis {{!}} CDC|website=www.cdc.gov|access-date=2016-03-14|url-status=live|archive-url=https://web.archive.org/web/20160315151117/http://www.cdc.gov/hepatitis/hcv/cfaq.htm|archive-date=2016-03-15}}</ref> Hepatitis C is the second most common cause of cirrhosis in the US (second to alcoholic hepatitis).<ref name="Friedman 55e">{{Cite book|title=Current Medical Diagnosis & Treatment 2016 55e|last=Friedman|first=Lawrence S.|publisher=McGraw Hill|year=2015|isbn=978-0071845090|editor-last=Papadakis, M |editor2=McPhee, SJ |editor3=Rabow, MW|chapter=Chapter 16: Liver, Biliary Tract, & Pancreas Disorders}}</ref> In the 1970s and 1980s, blood transfusions were a major factor in spreading hepatitis C virus.<ref name="CDC FAQ on Hepatitis C" /> Since widespread screening of blood products for hepatitis C began in 1992, the risk of acquiring hepatitis C from a blood transfusion has decreased from approximately 10% in the 1970s to 1 in 2 million currently.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />

==== Parasitic hepatitis ====
[[File:Echinococcus granulosus.JPG|thumb|Echinococcus granulosus]]
[[Parasites of humans|Parasites]] can also infect the liver and activate the immune response, resulting in symptoms of acute hepatitis with increased serum [[Immunoglobulin E|IgE]] (though chronic hepatitis is possible with chronic infections).<ref name="Harder & Mehlhorn">{{Cite book|title=Comparative Hepatitis|url=https://archive.org/details/comparativehepat00webe|url-access=limited|author1=Harder, A |author2=Mehlhorn, H |publisher=Birkhauser|year=2008|isbn=978-3764385576|editor1=Weber, O |editor2=Protzer, U |pages=[https://archive.org/details/comparativehepat00webe/page/n171 161]–216|chapter=Diseases Caused by Adult Parasites or Their Distinct Life Cycle Stages}}</ref> Of the [[protozoa]]ns, [[Trypanosoma cruzi]], [[Leishmaniasis|Leishmania]] species, and the [[malaria]]-causing [[Plasmodium]] species all can cause liver inflammation.<ref name="Harder & Mehlhorn" /> Another protozoan, [[Entamoeba histolytica]], causes hepatitis with distinct liver abscesses.<ref name="Harder & Mehlhorn" />

Of the worms, the [[Cestode infection|cestode]] [[Echinococcus granulosus]], also known as the dog tapeworm, infects the liver and forms characteristic hepatic [[Echinococcosis|hydatid cysts]].<ref name="Harder & Mehlhorn" /> The liver [[Fluke (parasite)|flukes]] [[Fasciola hepatica]] and [[Clonorchis sinensis]] live in the bile ducts and cause progressive hepatitis and liver fibrosis.<ref name="Harder & Mehlhorn" />

==== Bacterial hepatitis ====
Bacterial infection of the liver commonly results in [[pyogenic liver abscess]]es, acute hepatitis, or [[granuloma]]tous (or chronic) liver disease.<ref name="Wisplinghoff & Appleton">{{Cite book|title=Comparative Hepatitis|url=https://archive.org/details/comparativehepat00webe|url-access=limited|author1=Wisplinghoff, H |author2=Appleton, DL |publisher=Birkhauser|year=2008|isbn=978-3764385576|editor1=Weber, O |editor2=Protzer, U |pages=[https://archive.org/details/comparativehepat00webe/page/n153 143]–160|chapter=Bacterial Infections of the Liver}}</ref> Pyogenic abscesses commonly involve [[enteric]] bacteria such as ''[[Escherichia coli]]'' and ''[[Klebsiella pneumoniae]]'' and are composed of multiple bacteria up to 50% of the time.<ref name="Wisplinghoff & Appleton" /> Acute hepatitis is caused by ''[[Neisseria meningitidis]]'', ''[[Neisseria gonorrhoeae]]'', ''[[Bartonella henselae]]'', ''[[Borrelia burgdorferi]]'', [[salmonella]] species, [[brucella]] species and [[campylobacter]] species.<ref name="Wisplinghoff & Appleton" /> Chronic or granulomatous hepatitis is seen with infection from [[Mycobacterium|mycobacteria]] species, ''[[Tropheryma whipplei]]'', ''[[Treponema pallidum]]'', ''[[Coxiella burnetii]]'', and [[rickettsia]] species.<ref name="Wisplinghoff & Appleton" />

=== Metabolic ===

==== Alcoholic hepatitis ====
{{Main|Alcoholic hepatitis}}
{{Main|Alcoholic hepatitis}}
Excessive alcohol consumption is a significant cause of hepatitis and is the most common cause of cirrhosis in the U.S.<ref name="Friedman 55e" /> Alcoholic hepatitis is within the spectrum of [[alcoholic liver disease]]. This ranges in order of severity and reversibility from [[Alcoholic fatty liver|alcoholic steatosis]] (least severe, most reversible), [[alcoholic hepatitis]], cirrhosis, and liver cancer (most severe, least reversible).<ref name="Friedman 55e" /> Hepatitis usually develops over years-long exposure to alcohol, occurring in 10 to 20% of alcoholics.<ref name="Harrison's Principles chapter 363 (Alcohol)">{{Cite book|title=Harrison's Principles of Internal Medicine 19e|author1=Mailliard, ME |author2=Sorrell, MF |publisher=McGraw-Hill|year=2015|isbn=978-0-07-180215-4|editor1=Kasper, D |editor2=Fauci, A |editor3=Hauser, S |editor4=Longo, D |editor5=Jameson, J |editor6=Loscalzo, J |chapter=Chapter 363: Alcoholic Liver Disease}}</ref> The most important risk factors for the development of alcoholic hepatitis are quantity and duration of alcohol intake.<ref name="Harrison's Principles chapter 363 (Alcohol)" /> Long-term alcohol intake in excess of 80 grams of alcohol a day in men and 40 grams a day in women is associated with development of alcoholic hepatitis (1 beer or 4 ounces of wine is equivalent to 12g of alcohol).<ref name="Friedman 55e" /> Alcoholic hepatitis can vary from asymptomatic [[hepatomegaly]] (enlarged liver) to symptoms of acute or chronic hepatitis to liver failure.<ref name="Friedman 55e" />


==== Toxic and drug-induced hepatitis ====
Excessive [[alcohol]] consumption is a significant cause of hepatitis and liver damage ([[cirrhosis]]). Alcoholic hepatitis usually develops over years-long exposure to alcohol. Alcohol intake in excess of 80 grams of alcohol a day in men and 40 grams a day in women is associated with development of alcoholic hepatitis. Alcoholic hepatitis can vary from mild asymptomatic disease to severe liver inflammation and [[liver failure]]. Symptoms and physical exam findings are similar to other causes of hepatitis. Laboratory findings are significant for [[elevated transaminases]], usually with elevation of [[aspartate transaminase]] (AST) in a 2 to 1 ratio to [[alanine transaminase]] (ALT).<ref>{{cite book|last=Longo|first=Dan|title=Alcoholic Liver Disease in Harrison's principles of internal medicine.|publisher=McGraw-Hill|location=New York|isbn=978-0-07174889-6|edition=18th}}</ref><ref>{{cite book|last=Papadaikis|first=Maxine|title=Alcoholic Liver Disease in Current medical diagnosis and treatment 2014.|year=2014|publisher=Mcgraw-Hill|isbn=978-0-07-180633-6}}</ref>
Many chemical agents, including medications, industrial toxins, and herbal and dietary supplements, can cause hepatitis.<ref name="Harrison's Principles chapter 361 (Toxic and Drug-Induced)">{{Cite book|title=Harrison's Principles of Internal Medicine 19e|author1=Lee, WM |author2=Dienstag, JL |publisher=McGraw-Hill|year=2015|isbn=978-0-07-180215-4|editor1=Kasper, D |editor2=Fauci, A |editor3=Hauser, S |editor4=Longo, D |editor5=Jameson, J |editor6=Loscalzo, J |chapter=Chapter 361: Toxic and Drug-Induced Hepatitis}}</ref><ref name="Occupational exposure to solvents" /> The spectrum of drug-induced liver injury varies from acute hepatitis to chronic hepatitis to acute liver failure.<ref name="Harrison's Principles chapter 361 (Toxic and Drug-Induced)" /> Toxins and medications can cause liver injury through a variety of mechanisms, including direct [[cell damage]], disruption of cell metabolism, and causing structural changes.<ref>{{cite journal|last=Lee|first=William M.|title=Drug-Induced Hepatotoxicity|journal=New England Journal of Medicine|date=31 July 2003|volume=349|issue=5|pages=474–485|doi=10.1056/NEJMra021844|pmid=12890847}}</ref> Some drugs such as [[paracetamol]] exhibit predictable dose-dependent liver damage while others such as [[isoniazid]] cause idiosyncratic and unpredictable reactions that vary by person.<ref name="Harrison's Principles chapter 361 (Toxic and Drug-Induced)" /> There are wide variations in the mechanisms of liver injury and [[latency period]] from exposure to development of clinical illness.<ref name="Friedman 55e" />


Many types of drugs can cause liver injury, including the [[analgesic]] paracetamol; [[antibiotic]]s such as isoniazid, [[nitrofurantoin]], [[Amoxicillin/clavulanic acid|amoxicillin-clavulanate]], [[erythromycin]], and [[Trimethoprim/sulfamethoxazole|trimethoprim-sulfamethoxazole]]; [[anticonvulsant]]s such as [[valproate]] and [[phenytoin]]; cholesterol-lowering [[statin]]s; [[steroid]]s such as [[Oral contraceptive pill|oral contraceptives]] and [[anabolic steroid]]s; and [[Highly Active Anti-Retroviral Therapy|highly active anti-retroviral therapy]] used in the treatment of [[HIV/AIDS]].<ref name="Friedman 55e" /> Of these, amoxicillin-clavulanate is the most common cause of drug-induced liver injury, and [[paracetamol toxicity]] the most common cause of acute liver failure in the United States and Europe.<ref name="Harrison's Principles chapter 361 (Toxic and Drug-Induced)" />
Alcoholic hepatitis may lead to cirrhosis and is more common in patients with long-term alcohol consumption and those infected with [[hepatitis C]].<ref>{{cite journal|last=Corrao|first=G|coauthors=Aricò, S|title=Independent and combined action of hepatitis C virus infection and alcohol consumption on the risk of symptomatic liver cirrhosis|journal=Hepatology (Baltimore, Md.)|date=April 1998|volume=27|issue=4|pages=914–9|pmid=9537428|doi=10.1002/hep.510270404}}</ref> Patients who drink alcohol to excess are also more often than others found to have hepatitis C.<ref>{{cite journal|pmid=8633498|year=1996|last1=Rosman|first1=AS|last2=Waraich|first2=A|last3=Galvin|first3=K|last4=Casiano|first4=J|last5=Paronetto|first5=F|last6=Lieber|first6=CS|title=Alcoholism is associated with hepatitis C but not hepatitis B in an urban population|volume=91|issue=3|pages=498–505|journal=The American journal of gastroenterology}}</ref> The combination of hepatitis C and alcohol consumption accelerates the development of cirrhosis.<ref>{{cite web|last=Lieber|first=Charles|title=Alcohol and Hepatitis C|url=http://pubs.niaaa.nih.gov/publications/arh25-4/245-254.htm|publisher=National Institute on Alcohol Abuse and Alcoholism|accessdate=18 November 2013}}</ref>


[[Herb|Herbal remedies]] and [[dietary supplement]]s are another important cause of hepatitis; these are the most common causes of drug-induced hepatitis in Korea.<ref>{{cite journal|last=Suk|first=Ki Tae|year=2012|title=Drug-induced liver injury: present and future|journal=Clinical and Molecular Hepatology|volume=18|issue=3|pages=249–57|doi=10.3350/cmh.2012.18.3.249|pmc=3467427|pmid=23091804|author2=Kim, Dong Joon}}</ref> The United States–based [http://www.dilin.org/ Drug Induced Liver Injury Network] linked more than 16% of cases of hepatotoxicity to herbal and dietary supplements.<ref name="NIH - herbal supplements">{{Cite journal|url=http://livertox.nih.gov/Herbals_and_Dietary_Supplements.htm|title=Herbals_and_Dietary_Supplements|website=livertox.nih.gov|date=2012 |pmid=31643176 |access-date=2016-03-14|url-status=live|archive-url=https://web.archive.org/web/20160508234736/http://livertox.nih.gov/Herbals_and_Dietary_Supplements.htm|archive-date=2016-05-08}}</ref> In the United States, herbal and dietary supplements – unlike [[pharmaceutical drug]]s – are unregulated by the [[Food and Drug Administration]].<ref name="NIH - herbal supplements" /> The [[National Institutes of Health]] maintains the [https://livertox.nlm.nih.gov LiverTox] {{Webarchive|url=https://web.archive.org/web/20190724165846/https://livertox.nlm.nih.gov/ |date=2019-07-24 }} database for consumers to track all known prescription and non-prescription compounds associated with liver injury.<ref>{{Cite news|url=https://www.nih.gov/news-events/news-releases/nih-launches-free-database-drugs-associated-liver-injury|title=NIH launches free database of drugs associated with liver injury|date=2015-09-30|work=National Institutes of Health (NIH)|access-date=2018-09-18|language=en}}</ref>
=== Toxic and drug-induced hepatitis ===
{{Main|Hepatotoxicity}}


Exposure to other [[hepatotoxin]]s can occur accidentally or intentionally through ingestion, inhalation, and skin absorption. The industrial toxin [[carbon tetrachloride]] and the wild mushroom [[Amanita phalloides]] are other known hepatotoxins.<ref name="Harrison's Principles chapter 361 (Toxic and Drug-Induced)" /><ref name="Occupational exposure to solvents">{{cite journal|last1=Malaguarnera|first1=Giulia|last2=Cataudella|first2=E|last3=Giordano|first3=M|last4=Nunnari|first4=G|last5=Chisari|first5=G|last6=Malaguarnera|first6=M|year=2012|title=Toxic hepatitis in occupational exposure to solvents|journal=World Journal of Gastroenterology|volume=18|issue=22|pages=2756–66|doi=10.3748/wjg.v18.i22.2756|pmc=3374978|pmid=22719183 |doi-access=free }}</ref><ref>{{cite book|chapter-url=http://www.accessmedicine.com/content.aspx?aID=6361074|title=Tintinalli's Emergency Medicine: A Comprehensive Study Guide.|publisher=McGraw-Hill|year=2011|edition=7th|location=New York|chapter=Chapter 83. Hepatic Disorders, Jaundice, and Hepatic Failure|chapter-format=Online|vauthors=O'Mara SR, Gebreyes K|veditors=Cydulka RK, Meckler GD|access-date=26 November 2013|url-status=live|archive-url=https://web.archive.org/web/20131202233459/http://www.accessmedicine.com/content.aspx?aID=6361074|archive-date=2 December 2013}}</ref>
A large number of medications and other chemical agents can cause hepatitis. In the United States [[acetaminophen]], [[antibiotics]], and [[central nervous system]] medications are among the most common causes of drug-induced hepatitis. Acetaminophen, also known as paracetamol, is the leading cause of acute liver failure in the United States.<ref>{{cite journal|title=Acute Liver Failure including Acetaminophen Overdose|author=R. Fontana|journal=Med Clin North Am.|pages=761–794|month=July|year=2008|volume=4|pmc=2504411}}</ref> Herbal remedies and dietary supplements may also cause hepatitis, and these are the most common causes of drug-induced hepatitis in Korea.<ref>{{cite journal|last=Suk|first=Ki Tae|coauthors=Kim, Dong Joon|title=Drug-induced liver injury: present and future|journal=Clinical and Molecular Hepatology|year=2012|volume=18|issue=3|pages=249–57|doi=10.3350/cmh.2012.18.3.249|pmid=23091804|pmc=3467427}}</ref> Risk factors for drug-induced hepatitis include: increasing age, female sex, and previous drug-induced hepatitis. Genetic variability is increasingly understood as a key predisposing risk factor to drug-induced hepatitis.<ref>{{cite journal|last=Ghabril|first=Marwan|coauthors=Chalasani, Naga; Björnsson, Einar|title=Drug-induced liver injury: a clinical update|journal=Current Opinion in Gastroenterology|date=May 2010|volume=26|issue=3|pages=222–226|doi=10.1097/MOG.0b013e3283383c7c|pmid=20186054|pmc=3156474}}</ref><ref name="Navarro 731–739">{{cite journal|last=Navarro|first=Victor J.|coauthors=Senior, John R.|title=Drug-Related Hepatotoxicity|journal=New England Journal of Medicine|date=16 February 2006|volume=354|issue=7|pages=731–739|doi=10.1056/NEJMra052270|pmid=16481640}}</ref>


==== Non-alcoholic fatty liver disease ====
Toxins and medications can cause liver injury through a variety of mechanisms, including direct [[cell damage]], disrupting cell metabolism, and inducing structural changes.<ref>{{cite journal|last=Lee|first=William M.|title=Drug-Induced Hepatotoxicity|journal=New England Journal of Medicine|date=31 July 2003|volume=349|issue=5|pages=474–485|doi=10.1056/NEJMra021844|pmid=12890847}}</ref> Some medications, like acetaminophen, cause predictable [[Dose–response relationship|dose-related]] liver damage, whereas others cause [[Idiosyncratic drug reaction|idiosyncratic reactions]] that vary among individuals.<ref name="Navarro 731–739"/>
{{Main|Non-alcoholic fatty liver disease}}


Non-alcoholic hepatitis is within the spectrum of non-alcoholic liver disease (NALD), which ranges in severity and reversibility from [[non-alcoholic fatty liver disease]] (NAFLD) to non-alcoholic steatohepatitis (NASH) to cirrhosis to liver cancer, similar to the spectrum of alcoholic liver disease.<ref name="Harrison's Principles chapter 364 (Nonalcoholic)">{{Cite book|title=Harrison's Principles of Internal Medicine 19e|author1=Abdelmalek, MF |author2=Diehl AM |publisher=McGraw-Hill|year=2015|isbn=978-0-07-180215-4|editor1=Kasper, D |editor2=Fauci, A |editor3=Hauser, S |editor4=Longo, D |editor5=Jameson, J |editor6=Loscalzo, J |chapter=Chapter 364: Nonalcoholic Liver Diseases and Nonalcoholic Steatohepatitis}}</ref>
Exposure to other hepatotoxins can occur accidentally or intentionally through ingestion, inhalation, and skin absorption. [[Occupational exposure limit|Occupational exposure]] may occur in many work fields and can present acutely or insidiously.<ref>{{cite journal|last=Malaguarnera|first=Giulia|title=Toxic hepatitis in occupational exposure to solvents|journal=World Journal of Gastroenterology|year=2012|volume=18|issue=22|pages=2756–66|doi=10.3748/wjg.v18.i22.2756|pmid=22719183|first2=E|first3=M|first4=G|first5=G|first6=M|pmc=3374978}}</ref> [[Mushroom poisoning]] is a common toxic exposure that may result in hepatitis.<ref>{{cite book|title=Tintinalli's Emergency Medicine: A Comprehensive Study Guide.|year=2011|publisher=McGraw-Hill|location=New York|url=http://www.accessmedicine.com/content.aspx?aID=6361074|author=O'Mara SR, Gebreyes K|edition=7th|editor=Cydulka RK, Meckler GD|accessdate=26 November 2013|format=Online|chapter=Chapter 83. Hepatic Disorders, Jaundice, and Hepatic Failure}}</ref>

Non-alcoholic liver disease occurs in people with little or no history of alcohol use, and is instead strongly associated with [[metabolic syndrome]], obesity, [[insulin resistance]] and [[Diabetes mellitus type 2|diabetes]], and hypertriglyceridemia.<ref name="Friedman 55e" /> Over time, non-alcoholic fatty liver disease can progress to non-alcoholic [[steatohepatitis]], which additionally involves liver cell death, liver inflammation and possible fibrosis.<ref name="Friedman 55e" /> Factors accelerating progression from NAFLD to NASH are obesity, older age, non-African American ethnicity, female gender, diabetes mellitus, hypertension, higher [[Alanine transaminase|ALT]] or [[Aspartate transaminase|AST]] level, higher AST/ALT ratio, low platelet count, and an [http://www.nature.com/ijo/journal/v28/n10/fig_tab/0802734t1.html ultrasound steatosis score].<ref name="Friedman 55e" />

In the early stages (as with NAFLD and early NASH), most patients are asymptomatic or have mild [[Quadrant (abdomen)|right upper quadrant]] pain, and diagnosis is suspected on the basis of abnormal [[liver function tests]].<ref name="Friedman 55e" /> As the disease progresses, symptoms typical of chronic hepatitis may develop.<ref name="National Digestive Diseases Information Clearinghouse NDDIC">{{cite web|url=http://digestive.niddk.nih.gov/ddiseases/pubs/nash/index.aspx|title=Nonalcoholic Steatohepatitis|publisher=National Digestive Diseases Information Clearinghouse (NDDIC)|access-date=27 November 2013|author=National Digestive Diseases Information Clearinghouse (NDDIC)|url-status=live|archive-url=https://web.archive.org/web/20131202231555/http://digestive.niddk.nih.gov/ddiseases/pubs/nash/index.aspx|archive-date=2 December 2013}}</ref> While imaging can show fatty liver, only [[liver biopsy]] can demonstrate inflammation and fibrosis characteristic of NASH.<ref name="Masuoka 2013 106–122">{{cite journal|last=Masuoka|first=Howard C.|author2=Chalasani, Naga|title=Nonalcoholic fatty liver disease: an emerging threat to obese and diabetic individuals|journal=Annals of the New York Academy of Sciences|date=April 2013|volume=1281|issue=1|pages=106–122|doi=10.1111/nyas.12016|bibcode=2013NYASA1281..106M|pmid=23363012|pmc=3646408}}</ref> 9 to 25% of patients with NASH develop cirrhosis.<ref name="Friedman 55e" /> NASH is recognized as the third most common cause of liver disease in the United States.<ref name="National Digestive Diseases Information Clearinghouse NDDIC" />


=== Autoimmune ===
=== Autoimmune ===
{{Main|Autoimmune hepatitis}}
{{Main|Autoimmune hepatitis}}


Autoimmune hepatitis is a chronic disease caused by an abnormal [[Immune system|immune response]] against [[hepatocyte|liver cells]].<ref>{{cite web|title=Autoimmune Hepatitis|url=http://digestive.niddk.nih.gov/ddiseases/pubs/autoimmunehep/|publisher=National Digestive Diseases Information Clearinghouse (NDDIC)|accessdate=27 November 2013|author=National Digestive Diseases Information Clearinghouse (NDDIC)}}</ref> The disease is thought to have a [[genetic predisposition]] as it is associated with certain [[human leukocyte antigen]]s.<ref>{{cite journal|last=Teufel|first=Andreas|title=Update on autoimmune hepatitis|journal=World Journal of Gastroenterology|year=2009|volume=15|issue=9|pages=1035–41|doi=10.3748/wjg.15.1035|pmid=19266594|first2=PR|first3=S|pmc=2655176}}</ref> The symptoms of autoimmune hepatitis are similar to other hepatitides and may have a fluctuating course from mild to very severe. Women with the disease may have abnormal menstruation or become [[amenorrhea|amenorrheic]]. The disease occurs in people of all ages but most commonly in young women. Many people with autoimmune hepatitis have other [[autoimmune disease]]s.<ref>{{cite journal|last=Krawitt|first=Edward-L|title=Clinical features and management of autoimmune hepatitis|journal=World Journal of Gastroenterology|year=2008|volume=14|issue=21|pages=3301–5|doi=10.3748/wjg.14.3301|pmid=18528927|pmc=2716584}}</ref>
Autoimmune hepatitis is a chronic disease caused by an abnormal immune response against liver cells.<ref>{{cite web|url=http://digestive.niddk.nih.gov/ddiseases/pubs/autoimmunehep/|title=Autoimmune Hepatitis|publisher=National Digestive Diseases Information Clearinghouse (NDDIC)|access-date=27 November 2013|author=National Digestive Diseases Information Clearinghouse (NDDIC)|url-status=dead|archive-url=https://web.archive.org/web/20100915033205/http://digestive.niddk.nih.gov/ddiseases/pubs/autoimmunehep/|archive-date=15 September 2010}}</ref> The disease is thought to have a genetic predisposition as it is associated with certain [[human leukocyte antigen]]s involved in the immune response.<ref>{{cite journal|last1=Teufel|first1=Andreas|last2=Galle|first2=PR|last3=Kanzler|first3=S|year=2009|title=Update on autoimmune hepatitis|journal=World Journal of Gastroenterology|volume=15|issue=9|pages=1035–41|doi=10.3748/wjg.15.1035|pmc=2655176|pmid=19266594 |doi-access=free }}</ref> As in other autoimmune diseases, circulating [[Autoantibody|auto-antibodies]] may be present and are helpful in diagnosis.<ref name="Czaja Autoimmune">{{Cite journal|last=Czaja|first=Albert J|title=Diagnosis and Management of Autoimmune Hepatitis: Current Status and Future Directions|journal=Gut and Liver|volume=10|issue=2|doi=10.5009/gnl15352|pmc=4780448|pmid=26934884|pages=177–203|year=2016}}</ref> Auto-antibodies found in patients with autoimmune hepatitis include the [[Sensitivity and specificity|sensitive but less specific]] [[Anti-nuclear antibody|anti-nuclear antibody (ANA)]], smooth muscle antibody (SMA), and [[Anti-neutrophil cytoplasmic antibody|atypical perinuclear antineutrophil cytoplasmic antibody (p-ANCA)]].<ref name="Czaja Autoimmune" /> Other autoantibodies that are less common but more specific to autoimmune hepatitis are the antibodies against liver kidney microsome 1 (LKM1) and soluble liver antigen (SLA).<ref name="Czaja Autoimmune" /> Autoimmune hepatitis can also be triggered by drugs (such as [[nitrofurantoin]], [[hydralazine]], and [[methyldopa]]), after liver transplant, or by viruses (such as hepatitis A, [[Epstein–Barr virus|Epstein-Barr virus]], or [[measles]]).<ref name="Friedman 55e" />


Autoimmune hepatitis can present anywhere within the spectrum from asymptomatic to acute or chronic hepatitis to fulminant liver failure.<ref name="Friedman 55e" /> Patients are asymptomatic 25–34% of the time, and the diagnosis is suspected on the basis of abnormal liver function tests.<ref name="Czaja Autoimmune" /> Some studies show between 25% and 75% of cases present with signs and symptoms of acute hepatitis.<ref name="Friedman 55e" /><ref name=":0">{{Cite journal|last=Czaja|first=Albert J.|date=2016-03-15|title=Diagnosis and Management of Autoimmune Hepatitis: Current Status and Future Directions|journal=Gut and Liver|volume=10|issue=2|pages=177–203|doi=10.5009/gnl15352|issn=1976-2283|pmc=4780448|pmid=26934884}}</ref> As with other autoimmune diseases, autoimmune hepatitis usually affects young females (though it can affect patients of either sex of any age), and patients can exhibit classic signs and symptoms of autoimmunity such as fatigue, anemia, anorexia, [[Amenorrhoea|amenorrhea]], acne, arthritis, [[pleurisy]], [[thyroiditis]], [[ulcerative colitis]], [[nephritis]], and [[maculopapular rash]].<ref name="Friedman 55e" /> Autoimmune hepatitis increases the risk for cirrhosis, and the risk for liver cancer is increased by about 1% for each year of the disease.<ref name="Friedman 55e" />
=== Non-alcoholic fatty liver disease ===

{{Main|Non-alcoholic fatty liver disease}}
Many people with autoimmune hepatitis have other [[autoimmune disease]]s.<ref>{{cite journal|last=Krawitt|first=Edward-L|title=Clinical features and management of autoimmune hepatitis|journal=World Journal of Gastroenterology|year=2008|volume=14|issue=21|pages=3301–5|doi=10.3748/wjg.14.3301|pmid=18528927|pmc=2716584 |doi-access=free }}</ref> Autoimmune hepatitis is distinct from the other autoimmune diseases of the liver, [[primary biliary cirrhosis]] and [[primary sclerosing cholangitis]], both of which can also lead to scarring, fibrosis, and cirrhosis of the liver.<ref name="Friedman 55e" /><ref name="Czaja Autoimmune" />

=== Genetic ===
Genetic causes of hepatitis include [[Alpha 1-antitrypsin deficiency|alpha-1-antitrypsin deficiency]], [[HFE hereditary haemochromatosis|hemochromatosis]], and [[Wilson's disease]].<ref name="Friedman 55e" /> In alpha-1-antitrypsin deficiency, a [[Co-dominant expression|co-dominant]] mutation in the gene for alpha-1-antitrypsin results in the abnormal accumulation of the mutant AAT protein within liver cells, leading to liver disease.<ref>{{Cite journal|last=Teckman|first=Jeffrey H.|date=2013-03-07|title=Liver Disease in Alpha-1 Antitrypsin Deficiency: Current Understanding and Future Therapy|journal=COPD: Journal of Chronic Obstructive Pulmonary Disease|volume=10|issue=sup1|pages=35–43|doi=10.3109/15412555.2013.765839|pmid=23527737|s2cid=35451941|issn=1541-2555}}</ref> Hemochromatosis and Wilson's disease are both [[autosomal recessive]] diseases involving abnormal storage of minerals.<ref name="Friedman 55e" /> In hemochromatosis, excess amounts of iron accumulate in multiple body sites, including the liver, which can lead to cirrhosis.<ref name="Friedman 55e" /> In Wilson's disease, excess amounts of copper accumulate in the liver and brain, causing cirrhosis and dementia.<ref name="Friedman 55e" />


When the liver is involved, alpha-1-antitrypsin deficiency and Wilson's disease tend to present as hepatitis in the neonatal period or in childhood.<ref name="Friedman 55e" /> Hemochromatosis typically presents in adulthood, with the onset of clinical disease usually after age 50.<ref name="Friedman 55e" />
Non-alcoholic fatty liver disease (NAFLD) is the occurrence of [[fatty liver]] in people who have little or no history of alcohol use. In the early stage there are usually no symptoms, as the disease progresses symptoms typical of chronic hepatitis may develop.<ref name="National Digestive Diseases Information Clearinghouse NDDIC">{{cite web|title=Nonalcoholic Steatohepatitis|url=http://digestive.niddk.nih.gov/ddiseases/pubs/nash/index.aspx|publisher=National Digestive Diseases Information Clearinghouse (NDDIC)|accessdate=27 November 2013|author=National Digestive Diseases Information Clearinghouse (NDDIC)}}</ref> NAFLD is associated with [[metabolic syndrome]], [[obesity]], [[diabetes]] and [[hyperlipidemia]].<ref>{{cite book|title=CURRENT Diagnosis & Treatment: Gastroenterology, Hepatology, & Endoscopy|year=2012|publisher=McGraw-Hill|location=New York|url=http://www.accessmedicine.com/content.aspx?aID=55961163|author=Cohen DE, Anania FA|edition=2nd|editor=Blumberg RS, Burakoff R|accessdate=27 November 2013|format=Online|chapter=Chapter 43. Nonalcoholic Fatty Liver Disease}}</ref> Severe NAFLD leads to inflammation, fibrosis, and cirrhosis, a state referred to as [[steatohepatitis|non-alcoholic steatohepatitis]] (NASH). Diagnosis requires excluding other causes of hepatitis, including excessive alcohol intake.<ref>{{cite journal|last=Chalasani|first=Naga|coauthors=Younossi, Zobair; Lavine, Joel E.; Diehl, Anna Mae; Brunt, Elizabeth M.; Cusi, Kenneth; Charlton, Michael; Sanyal, Arun J.|title=The diagnosis and management of non-alcoholic fatty liver disease: Practice Guideline by the American Association for the Study of Liver Diseases, American College of Gastroenterology, and the American Gastroenterological Association|journal=Hepatology|date=June 2012|volume=55|issue=6|pages=2005–2023|doi=10.1002/hep.25762|url=http://www.guideline.gov/content.aspx?id=37629|accessdate=27 November 2013|pmid=22488764}}</ref> While [[Medical imaging|imaging]] can show fatty liver, only [[liver biopsy]] can demonstrate inflammation and fibrosis characteristic of NASH.<ref name="Masuoka 2013 106–122">{{cite journal|last=Masuoka|first=Howard C.|coauthors=Chalasani, Naga|title=Nonalcoholic fatty liver disease: an emerging threat to obese and diabetic individuals|journal=Annals of the New York Academy of Sciences|date=April 2013|volume=1281|issue=1|pages=106–122|doi=10.1111/nyas.12016}}</ref> NASH is recognized as the third most common cause of liver disease in the United States.<ref name="National Digestive Diseases Information Clearinghouse NDDIC"/>


=== Ischemic hepatitis ===
=== Ischemic hepatitis ===
{{Main|Ischemic hepatitis}}
{{Main|Ischemic hepatitis}}
[[Ischemic hepatitis]] (also known as shock liver) results from reduced blood flow to the liver as in shock, heart failure, or vascular insufficiency.<ref name="Hepatic ischemia">{{cite web|title=Hepatic ischemia|url=https://www.nlm.nih.gov/medlineplus/ency/article/000214.htm|publisher=National Library of Medicine|access-date=4 December 2013|author=Medline Plus|date=2012-08-10|url-status=live|archive-url=https://web.archive.org/web/20131208021441/http://www.nlm.nih.gov/medlineplus/ency/article/000214.htm|archive-date=8 December 2013}}</ref> The condition is most often associated with [[heart failure]] but can also be caused by [[Shock (circulatory)|shock]] or [[sepsis]]. [[Blood testing]] of a person with ischemic hepatitis will show very high levels of [[Elevated transaminases|transaminase enzymes]] ([[Aspartate transaminase|AST]] and [[Alanine transaminase|ALT]]). The condition usually resolves if the underlying cause is treated successfully. Ischemic hepatitis rarely causes permanent liver damage.<ref>{{cite book|title=Sleisenger and Fordtran's Gastrointestinal and Liver Disease|year=2010|publisher=Saunders|isbn=978-1416061892|chapter-url=http://www.mdconsult.com/books/page.do?eid=4-u1.0-B978-1-4160-6189-2..00083-4--s0085&isbn=978-1-4160-6189-2&type=bookPage&from=content&uniqId=431734887-1227|editor1=Feldman, Friedman |editor2=Feldman, Brandt|access-date=4 December 2013|chapter-format=Online|chapter=Chapter 83 Vascular Diseases of the Liver|url-status=live|archive-url=https://web.archive.org/web/20160304110546/http://www.mdconsult.com/books/page.do?eid=4-u1.0-B978-1-4160-6189-2..00083-4--s0085&isbn=978-1-4160-6189-2&type=bookPage&from=content&uniqId=431734887-1227|archive-date=4 March 2016}}</ref>


=== Other ===
Injury to liver cells due to insufficient blood or oxygen results in ischemic hepatitis (or shock liver).<ref>{{cite web|title=Hepatic ischemia|url=http://www.nlm.nih.gov/medlineplus/ency/article/000214.htm|publisher=National Library of Medicine|accessdate=4 December 2013|author=Medline Plus|date=8/10/2012}}</ref> The condition is most often associated with [[heart failure]] but can also be caused by [[Shock (circulatory)|shock]] or [[sepsis]]. [[Blood testing]] of a person with ischemic hepatitis will show very high levels of [[Elevated transaminases|transaminase enzymes]] ([[Aspartate transaminase|AST]] and [[Alanine transaminase|ALT]]). The condition usually resolves if the underlying cause is treated successfully. Ischemic hepatitis rarely causes permanent liver damage.<ref>{{cite book|title=Sleisenger and Fordtran's Gastrointestinal and Liver Disease|year=2010|publisher=Saunders|isbn=978-1416061892|url=http://www.mdconsult.com/books/page.do?eid=4-u1.0-B978-1-4160-6189-2..00083-4--s0085&isbn=978-1-4160-6189-2&type=bookPage&from=content&uniqId=431734887-1227|editor=Feldman, Friedman and Brandt|accessdate=4 December 2013|format=Online|chapter=Chapter 83 Vascular Diseases of the Liver}}</ref>
{{Main|Neonatal hepatitis}}
Hepatitis can also occur in neonates and is attributable to a variety of causes, some of which are not typically seen in adults.<ref name="Biliary disease in infancy">{{cite journal |author1=Samyn, M |author2=Mieli-Vergani, G |date=November 2015 |title=Liver and Biliary Disease in Infancy |journal=Medicine |volume=43 |issue=11 |pages=625–630 |doi= 10.1016/j.mpmed.2015.08.008}}</ref> Congenital or perinatal infection with the hepatitis viruses, [[Toxoplasma gondii|toxoplasma]], [[rubella]], [[cytomegalovirus]], and [[syphilis]] can cause neonatal hepatitis.<ref name="Biliary disease in infancy" /> Structural abnormalities such as [[biliary atresia]] and [[choledochal cysts]] can lead to [[Cholestasis|cholestatic liver injury]] leading to neonatal hepatitis.<ref name="Biliary disease in infancy" /> [[Inborn error of metabolism|Metabolic diseases]] such as [[Glycogen storage disease|glycogen storage disorders]] and [[Lysosomal storage disease|lysosomal storage disorders]] are also implicated.<ref name="Biliary disease in infancy" /> Neonatal hepatitis can be [[Idiopathy|idiopathic]], and in such cases, biopsy often shows large multinucleated cells in the liver tissue.<ref>{{cite journal |last=Roberts |first=Eve A. |date=2003-10-01 |title=Neonatal hepatitis syndrome |journal=Seminars in Neonatology |volume=8 |issue=5 |pages=357–374 |doi=10.1016/S1084-2756(03)00093-9 |issn=1084-2756 |pmid=15001124}}</ref> This disease is termed giant cell hepatitis and may be associated with viral infection, autoimmune disorders, and drug toxicity.<ref>{{cite book |last1=Sokol |first1=Ronald J. |last2=Narkewicz |first2=Michael R. |chapter=Chapter 22: Liver & Pancreas |editor1-last=Hay |editor1-first=William W. |display-editors=etal |title=Current diagnosis & treatment: pediatrics |edition=21st |location=New York |publisher=McGraw-Hill Medical |isbn=978-0-07-177970-8 |chapter-url=http://www.accessmedicine.com/content.aspx?aID=56821699 |access-date=2 December 2013 |url-status=live |archive-url=https://web.archive.org/web/20131210093945/http://www.accessmedicine.com/content.aspx?aID=56821699 |archive-date=10 December 2013 |date=2012-06-21 }}</ref><ref>{{cite journal |last=Alexopoulou |first=Alexandra |author2=Deutsch, Melanie |author3=Ageletopoulou, Johanna |author4=Delladetsima, Johanna K. |author5=Marinos, Evangelos |author6=Kapranos, Nikiforos |author7=Dourakis, Spyros P. |date=May 2003 |title=A fatal case of postinfantile giant cell hepatitis in a patient with chronic lymphocytic leukaemia |journal=European Journal of Gastroenterology & Hepatology |volume=15 |issue=5 |pages=551–555 |doi=10.1097/01.meg.0000050026.34359.7c |pmid=12702915}}</ref>


== Mechanism ==
=== Giant cell hepatitis ===


The specific mechanism varies and depends on the underlying cause of the hepatitis. Generally, there is an initial insult that causes liver injury and activation of an inflammatory response, which can become chronic, leading to progressive [[fibrosis]] and [[cirrhosis]].<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />
Giant cell hepatitis is a rare form of hepatitis that predominantly occurs in [[neonate|newborns]] and children. Diagnosis is made on the basis of the presence of [[multinucleated]] hepatocyte [[giant cells]] on liver biopsy.<ref>{{cite journal|last=Raj|first=S.|coauthors=Stephen, T.; Debski, R. F.|title=Giant Cell Hepatitis With Autoimmune Hemolytic Anemia: A Case Report and Review of Pediatric Literature|journal=Clinical Pediatrics|date=23 March 2011|volume=50|issue=4|pages=357–359|doi=10.1177/0009922810379501|pmid=21436150}}</ref> The cause of giant cell hepatitis is unknown but the condition is associated with viral infection, autoimmune disorders, and drug toxicity.<ref>{{cite journal|last=Alexopoulou|first=Alexandra|coauthors=Deutsch, Melanie; Ageletopoulou, Johanna; Delladetsima, Johanna K.; Marinos, Evangelos; Kapranos, Nikiforos; Dourakis, Spyros P.|title=A fatal case of postinfantile giant cell hepatitis in a patient with chronic lymphocytic leukaemia|journal=European Journal of Gastroenterology & Hepatology|date=May 2003|volume=15|issue=5|pages=551–555|doi=10.1097/01.meg.0000050026.34359.7c}}</ref><ref>{{cite book|last=al.]|first=edited by William W. Hay ... [et|title=Current diagnosis & treatment : pediatrics|publisher=McGraw-Hill Medical|location=New York|isbn=978-0-07-177970-8|url=http://www.accessmedicine.com/content.aspx?aID=56821699|edition=21st|accessdate=2 December 2013|chapter=Chpt 22 Liver & Pancreas}}</ref>


== Mechanism ==
=== Viral hepatitis ===


[[File:Stages of Liver disease NIDDK NIH.gif|thumb|upright=1.3|Stages of liver disease]]
The specific mechanism varies and depends on the underlying cause for the condition. In viral hepatitis, the presence of the virus in the liver cells causes the immune system to attack the liver, resulting in inflammation and impaired function.<ref>{{cite journal|author=Nakamoto Y, Kaneko S|journal=Curr Mol Med.|year=2003|month=Sep|volume=3(6)|pages=537–44|pmid=14527085|issue=6|title=Mechanisms of viral hepatitis induced liver injury.}}</ref> In autoimmune hepatitis, the immune system attacks the liver due to the autoimmune disease.<ref>{{cite journal|journal=Pediatr Transplant.|year=2004|month=Dec|volume=8(6)|pages=589–93|pmid=15598331|doi=10.1111/j.1399-3046.2004.00288.x}}</ref> Some hepatitis, often including hepatitis caused by alcoholism, fat deposits accumulate in the liver, resulting in fatty liver disease, also called [[steatohepatitis]].<ref name=Inaba04>{{cite book |last2=Cohen |first2=William B. |last1=Inaba |first1=Darryl |title=Uppers, downers, all arounders: physical and mental effects of psychoactive drugs |publisher=CNS Publications |location=Ashland, Or |year=2004 |isbn=0-926544-27-6 |edition=5th |ref=harv}}</ref>
The pathway by which hepatic viruses cause [[viral hepatitis]] is best understood in the case of hepatitis B and C.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> The viruses do not directly activate [[apoptosis]] (cell death).<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Nakamoto & Kaneko">{{Cite journal|last1=Nakamoto|first1=Yasunari|last2=Kaneko|first2=Shuichi|date=2003-09-01|title=Mechanisms of viral hepatitis induced liver injury|journal=Current Molecular Medicine|volume=3|issue=6|pages=537–544|issn=1566-5240|pmid=14527085|doi=10.2174/1566524033479591}}</ref> Rather, infection of liver cells activates the [[Innate immune system|innate]] and [[Adaptive immune system|adaptive]] arms of the [[immune system]] leading to an inflammatory response which causes cellular damage and death, including viral-induced apoptosis via the induction of the death receptor-mediated signaling pathway.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Nakamoto & Kaneko" /><ref>{{Cite journal|last1=Lin|first1=Shaoli|last2=Zhang|first2=Yan-Jin|date=August 2017|title=Interference of Apoptosis by Hepatitis B Virus|journal=Viruses|language=en|volume=9|issue=8|page=230|doi=10.3390/v9080230|pmid=28820498|pmc=5580487|doi-access=free}}</ref><ref>{{Cite journal|last1=Cao|first1=Lei|last2=Quan|first2=Xi-Bing|last3=Zeng|first3=Wen-Jiao|last4=Yang|first4=Xiao-Ou|last5=Wang|first5=Ming-Jie|date=2016|title=Mechanism of Hepatocyte Apoptosis|journal=Journal of Cell Death|language=en|volume=9|pages=19–29|doi=10.4137/JCD.S39824|pmid=28058033|pmc=5201115}}</ref> Depending on the strength of the immune response, the types of immune cells involved and the ability of the virus to evade the body's defense, infection can either lead to clearance (acute disease) or persistence (chronic disease) of the virus.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> The chronic presence of the virus within liver cells results in multiple waves of [[inflammation]], injury and [[wound healing]] that over time lead to scarring or [[fibrosis]] and culminate in [[hepatocellular carcinoma]].<ref name="Nakamoto & Kaneko" /><ref>{{Cite journal|last=Wong|first=Grace Lai-Hung|date=2014-09-01|title=Prediction of fibrosis progression in chronic viral hepatitis|journal=Clinical and Molecular Hepatology|volume=20|issue=3|pages=228–236|doi=10.3350/cmh.2014.20.3.228|issn=2287-285X|pmc=4197170|pmid=25320725}}</ref> People with impaired immune response are at greater risk of developing chronic infection.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> [[Natural killer cell]]s are the primary drivers of the initial innate response and create a [[cytokine]] environment that results in the recruitment of [[T helper cell|CD4 T-helper]] and [[Cytotoxic T cell|CD8 cytotoxic T-cells]].<ref name="Rehermann Killer Cells">{{Cite journal|last=Rehermann|first=Barbara|date=2015-11-01|title=Natural Killer Cells in Viral Hepatitis|journal=Cellular and Molecular Gastroenterology and Hepatology|volume=1|issue=6|pages=578–588|doi=10.1016/j.jcmgh.2015.09.004|issn=2352-345X|pmc=4678927|pmid=26682281}}</ref><ref name="Heim & Thimme">{{Cite journal|last1=Heim|first1=Markus H.|last2=Thimme|first2=Robert|date=2014-11-01|title=Innate and adaptive immune responses in HCV infections|journal=Journal of Hepatology|volume=61|issue=1 Suppl|pages=S14–25|doi=10.1016/j.jhep.2014.06.035|issn=1600-0641|pmid=25443342|doi-access=free}}</ref> [[Interferon type I|Type I interferons]] are the cytokines that drive the antiviral response.<ref name="Heim & Thimme" /> In chronic Hepatitis B and C, natural killer cell function is impaired.<ref name="Rehermann Killer Cells" />


== Diagnosis ==
=== Steatohepatitis ===
Diagnosis is made by assessing an individual's symptoms, physical exam, and medical history, in conjunction with [[blood test]]s, [[liver biopsy]], and [[medical imaging|imaging]]. Blood testing includes [[Clinical chemistry|blood chemistry]], [[Liver function tests|liver enzymes]], [[serology]] and [[nucleic acid testing]]. Abnormalities in blood chemistry and enzyme results may be indicative of certain etiologies or stages of hepatitis.<ref>{{cite journal|last=Green|first=RM|coauthors=Flamm, S|title=AGA technical review on the evaluation of liver chemistry tests|journal=Gastroenterology|date=October 2002|volume=123|issue=4|pages=1367–84|pmid=12360498|doi=10.1053/gast.2002.36061}}</ref><ref>{{cite journal|last=Pratt|first=DS|coauthors=Kaplan, MM|title=Evaluation of abnormal liver-enzyme results in asymptomatic patients|journal=The New England Journal of Medicine|date=Apr 27, 2000|volume=342|issue=17|pages=1266–71|pmid=10781624|doi=10.1056/NEJM200004273421707}}</ref> Imaging can identify [[steatosis]] of the liver but liver biopsy is required to demonstrate [[fibrosis]] and [[cirrhosis]].<ref name="Masuoka 2013 106–122"/> A biopsy is not necessary if the clinical, laboratory, and radiologic data suggests cirrhosis. Furthermore, there is a small but significant risk to liver biopsy, and cirrhosis itself predisposes for complications caused by [[liver biopsy]].<ref>{{cite journal |last=Grant |first=A |coauthors=Neuberger J |year=1999 | title=Guidelines on the use of liver biopsy in clinical practice |journal=Gut |volume=45 |issue=Suppl 4 |pages=1–11 |pmid=10485854 |url=http://gut.bmj.com/cgi/content/full/45/suppl_4/IV1|quote=The main cause of mortality after percutaneous liver biopsy is intraperitoneal haemorrhage as shown in a retrospective Italian study of 68 000 percutaneous liver biopsies in which all six patients who died did so from intraperitoneal haemorrhage. Three of these patients had had a laparotomy, and all had either cirrhosis or malignant disease, both of which are risk factors for bleeding. |doi=10.1136/gut.45.2008.iv1 |pmc=1766696 }}</ref>


[[Steatohepatitis]] is seen in both alcoholic and non-alcoholic liver disease and is the culmination of a cascade of events that began with injury. In the case of [[Non-alcoholic fatty liver disease|non-alcoholic steatohepatitis]], this cascade is initiated by changes in metabolism associated with obesity, insulin resistance, and lipid dysregulation.<ref name="Hardy Oakley Anstee Day">{{Cite journal|last1=Hardy|first1=Timothy|last2=Oakley|first2=Fiona|last3=Anstee|first3=Quentin M.|last4=Day|first4=Christopher P.|date=2016-03-03|title=Nonalcoholic Fatty Liver Disease: Pathogenesis and Disease Spectrum|journal=Annual Review of Pathology|doi=10.1146/annurev-pathol-012615-044224|issn=1553-4014|pmid=26980160|volume=11|pages=451–96|url=https://zenodo.org/record/3452754}}{{Dead link|date=February 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref name="Yoon & Cha Pathogenesis">{{Cite journal|last1=Yoon|first1=Hye-Jin|last2=Cha|first2=Bong Soo|date=2014-11-27|title=Pathogenesis and therapeutic approaches for non-alcoholic fatty liver disease|journal=World Journal of Hepatology|volume=6|issue=11|pages=800–811|doi=10.4254/wjh.v6.i11.800|issn=1948-5182|pmc=4243154|pmid=25429318 |doi-access=free }}</ref> In [[alcoholic hepatitis]], chronic excess alcohol use is the culprit.<ref name="Chayanupatkul & Liangpunsakul" /> Though the inciting event may differ, the progression of events is similar and begins with accumulation of free [[fatty acid]]s (FFA) and their breakdown products in the liver cells in a process called [[steatosis]].<ref name="Hardy Oakley Anstee Day" /><ref name="Yoon & Cha Pathogenesis" /><ref name="Chayanupatkul & Liangpunsakul" /> This initially reversible process overwhelms the [[hepatocyte]]'s ability to maintain lipid homeostasis leading to a toxic effect as fat molecules accumulate and are broken down in the setting of an [[Cellular stress response|oxidative stress response]].<ref name="Hardy Oakley Anstee Day" /><ref name="Yoon & Cha Pathogenesis" /><ref name="Chayanupatkul & Liangpunsakul" /> Over time, this abnormal lipid deposition triggers the [[immune system]] via [[Toll-like receptor|toll-like receptor 4]] (TLR4) resulting in the production of inflammatory [[cytokine]]s such as TNF that cause liver cell injury and death.<ref name="Hardy Oakley Anstee Day" /><ref name="Yoon & Cha Pathogenesis" /><ref name="Chayanupatkul & Liangpunsakul" /> These events mark the transition to [[steatohepatitis]] and in the setting of chronic injury, [[fibrosis]] eventually develops setting up events that lead to cirrhosis and hepatocellular carcinoma.<ref name="Hardy Oakley Anstee Day" /> Microscopically, changes that can be seen include steatosis with large and swollen hepatocytes ([[Ballooning degeneration|ballooning]]), evidence of cellular injury and cell death (apoptosis, necrosis), evidence of inflammation in particular in [[Liver|zone 3 of the liver]], variable degrees of fibrosis and [[Mallory body|Mallory bodies]].<ref name="Hardy Oakley Anstee Day" /><ref name="Definition, epidemiology, and magnitude">{{Cite journal|last1=Basra|first1=Sarpreet|last2=Anand|first2=Bhupinderjit S.|date=2011-05-27|title=Definition, epidemiology and magnitude of alcoholic hepatitis|journal=World Journal of Hepatology|volume=3|issue=5|pages=108–113|doi=10.4254/wjh.v3.i5.108|issn=1948-5182|pmc=3124876|pmid=21731902 |doi-access=free }}</ref><ref>{{Cite journal|last1=Haga|first1=Yuki|last2=Kanda|first2=Tatsuo|last3=Sasaki|first3=Reina|last4=Nakamura|first4=Masato|last5=Nakamoto|first5=Shingo|last6=Yokosuka|first6=Osamu|date=2015-12-14|title=Nonalcoholic fatty liver disease and hepatic cirrhosis: Comparison with viral hepatitis-associated steatosis|journal=World Journal of Gastroenterology|volume=21|issue=46|pages=12989–12995|doi=10.3748/wjg.v21.i46.12989|issn=2219-2840|pmc=4674717|pmid=26675364 |doi-access=free }}</ref>
{| class="wikitable"

== Diagnosis ==
{| class="wikitable" style = "float: right; margin-left:15px; text-align:center"
! scope="col" |Most elevated aminotransferase
! scope="col" |Cause
|-
|-
| rowspan="9" | ALT
! Liver chemistry test !! Clinical implication of abnormality
|Chronic hepatitis B, C, and D
|-
|-
|Nonalcoholic liver disease
| [[Alanine transaminase]] (ALT) || Hepatocellular damage
|-
|-
|Acute viral hepatitis
| [[Aspartate transaminase]] (AST) || Hepatocellular damage
|-
|-
|Medications/toxins
| [[Bilirubin]] || Cholestasis
|-
|-
|Autoimmune hepatitis
| [[Alkaline phosphatase]] || Cholestasis
|-
|-
|Wilson's disease
| [[Prothrombin time]] || Impaired [[Liver#Synthesis|synthetic function]]
|-
|-
|Alpha-1-antitrypsin deficiency
| [[Albumin]] || Impaired [[Liver#Synthesis|synthetic function]]
|-
|-
|Hemochromatosis
| [[Gamma-glutamyl transpeptidase]] (GGT) || Cholestasis
|-
|-
|''Ischemic hepatitis (severe elevation up to thousands)''
| [[Bile acids]] || Cholestasis
|-
|-
| rowspan="2" | AST
| [[Lactate dehydrogenase]] || Hepatocellular damage
|Alcoholic liver disease
|-
|Cirrhosis
|}
|}
[[File:Histopathology of acute hepatitis.jpg|thumb|Histopathology of acute hepatitis with lobular disarray and associated lymphocytic inflammation, acidophil body formation (arrow) and bilirubinostasis.]]
Diagnosis of hepatitis is made on the basis of some or all of the following: a person's signs and symptoms, medical history including sexual and substance use history, blood tests, [[Medical imaging|imaging]], and [[liver biopsy]].<ref name="Friedman 55e" /> In general, for viral hepatitis and other acute causes of hepatitis, the person's blood tests and clinical picture are sufficient for diagnosis.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Friedman 55e" /> For other causes of hepatitis, especially chronic causes, blood tests may not be useful.<ref name="Friedman 55e" /> In this case, liver biopsy is the [[Gold standard (test)|gold standard]] for establishing the diagnosis: [[Histopathology|histopathologic]] analysis is able to reveal the precise extent and pattern of inflammation and [[fibrosis]].<ref name="Friedman 55e" /> Biopsy is typically not the initial diagnostic test because it is invasive and is associated with a small but significant risk of bleeding that is increased in people with liver injury and cirrhosis.<ref>{{cite journal|last=Grant|first=A|year=1999|title=Guidelines on the use of liver biopsy in clinical practice|journal=Gut|volume=45|issue=Suppl 4|pages=1–11|doi=10.1136/gut.45.2008.iv1|pmc=1766696|pmid=10485854|quote=The main cause of mortality after percutaneous liver biopsy is intraperitoneal haemorrhage as shown in a retrospective Italian study of 68 000 percutaneous liver biopsies in which all six patients who died did so from intraperitoneal haemorrhage. Three of these patients had had a laparotomy, and all had either cirrhosis or malignant disease, both of which are risk factors for bleeding.|author2=Neuberger J}}</ref>

Blood testing includes [[Liver function tests|liver enzymes]], [[serology]] (i.e. for autoantibodies), [[nucleic acid test]]ing (i.e. for hepatitis virus DNA/RNA), [[Blood chemistry study|blood chemistry]], and [[complete blood count]].<ref name="Friedman 55e" /> Characteristic patterns of liver enzyme abnormalities can point to certain causes or stages of hepatitis.<ref>{{cite journal|last=Green|first=RM|date=October 2002|title=AGA technical review on the evaluation of liver chemistry tests|journal=Gastroenterology|volume=123|issue=4|pages=1367–84|doi=10.1053/gast.2002.36061|pmid=12360498|author2=Flamm, S|doi-access=free}}</ref><ref>{{cite journal|last=Pratt|first=DS|date=Apr 27, 2000|title=Evaluation of abnormal liver-enzyme results in asymptomatic patients|journal=The New England Journal of Medicine|volume=342|issue=17|pages=1266–71|doi=10.1056/NEJM200004273421707|pmid=10781624|author2=Kaplan, MM}}</ref> Generally, [[Aspartate transaminase|AST]] and [[Alanine transaminase|ALT]] are elevated in most cases of hepatitis regardless of whether the person shows any symptoms.<ref name="Friedman 55e" /> The degree of elevation (i.e. levels in the hundreds vs. in the thousands), the predominance for AST vs. ALT elevation, and the ratio between AST and ALT are informative of the diagnosis.<ref name="Friedman 55e" />

[[Medical ultrasound|Ultrasound]], [[CT scan|CT]], and [[Magnetic resonance imaging|MRI]] can all identify steatosis (fatty changes) of the liver tissue and nodularity of the liver surface suggestive of cirrhosis.<ref>{{Cite journal|last1=Ito|first1=Katsuyoshi|last2=Mitchell|first2=Donald G.|title=Imaging Diagnosis of Cirrhosis and Chronic Hepatitis|journal=Intervirology|volume=47|issue=3–5|pages=134–143|doi=10.1159/000078465|pmid=15383722|year=2004|s2cid=36112368}}</ref><ref>{{Cite journal|last1=Allan|first1=Richard|last2=Thoirs|first2=Kerry|last3=Phillips|first3=Maureen|date=2010-07-28|title=Accuracy of ultrasound to identify chronic liver disease|journal=World Journal of Gastroenterology|volume=16|issue=28|pages=3510–3520|doi=10.3748/wjg.v16.i28.3510|issn=1007-9327|pmc=2909550|pmid=20653059 |doi-access=free }}</ref> CT and especially MRI are able to provide a higher level of detail, allowing visualization and characterize such structures as vessels and tumors within the liver.<ref>{{Cite journal|last1=Sahani|first1=Dushyant V.|last2=Kalva|first2=Sanjeeva P.|date=2004-07-01|title=Imaging the Liver|journal=The Oncologist|language=en|volume=9|issue=4|pages=385–397|doi=10.1634/theoncologist.9-4-385|issn=1083-7159|pmid=15266092|doi-access=free}}</ref> Unlike steatosis and cirrhosis, no imaging test is able to detect liver inflammation (i.e. hepatitis) or fibrosis.<ref name="Friedman 55e" /> Liver biopsy is the only definitive diagnostic test that is able to assess inflammation and fibrosis of the liver.<ref name="Friedman 55e" />


=== Viral hepatitis ===
=== Viral hepatitis ===
{{Main|Viral hepatitis}}


Viral hepatitis is primarily diagnosed through blood tests for levels of viral [[antigen]]s (such as the [[HBsAg|hepatitis B surface]] or [[HBcAg|core]] antigen), anti-viral antibodies (such as the anti-hepatitis B surface antibody or anti-hepatitis A antibody), or viral DNA/RNA.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Friedman 55e" /> In early infection (i.e. within 1 week), [[Immunoglobulin M|IgM]] antibodies are found in the blood.<ref name="Friedman 55e" /> In late infection and after recovery, [[Immunoglobulin G|IgG]] antibodies are present and remain in the body for up to years.<ref name="Friedman 55e" /> Therefore, when a patient is positive for IgG antibody but negative for IgM antibody, he is considered [[Immunity (medical)|immune]] from the virus via either prior infection and recovery or prior vaccination.<ref name="Friedman 55e" />
{{Main|viral hepatitis}}


In the case of hepatitis B, blood tests exist for multiple virus antigens (which are different components of the [[:File:HBV.png|virion particle]]) and antibodies.<ref name="pmid26568915">{{cite journal |year=2015 |title=Update on hepatitis B and C virus diagnosis |journal=World Journal of Virology |volume=4 |issue=4 |pages=323–42 |doi=10.5501/wjv.v4.i4.323 |pmc=4641225 |pmid=26568915 |vauthors=Villar LM, Cruz HM, Barbosa JR, Bezerra CS, Portilho MM, Scalioni Lde P |doi-access=free }}</ref> The combination of antigen and antibody positivity can provide information about the stage of infection (acute or chronic), the degree of viral replication, and the infectivity of the virus.<ref name="pmid26568915" />
Viral hepatitis is mostly diagnosed through clinical laboratory testing. Some of these tests react with the virus or parts of the virus, such as the [[HBsAg|Hepatitis B surface antigen]] test or [[nucleic acid testing|nucleic acid tests]].<ref>{{cite web|url=http://www.fda.gov/downloads/BiologicsBloodVaccines/BloodBloodProducts/ApprovedProducts/LicensedProductsBLAs/BloodDonorScreening/InfectiousDisease/ucm092713.pdf|title=Genetic Systems HBsAg EIA 3.0 package insert|publisher=Bio-Rad Laboratories|accessdate=20Jan2014}}</ref><ref>{{cite web|url=http://www.fda.gov/downloads/biologicsbloodvaccines/bloodbloodproducts/approvedproducts/licensedproductsblas/blooddonorscreening/infectiousdisease/ucm092120.pdf|title=Chiron Procleix Assay package insert|publisher=Gen-Probe Incorporated|accessdate=20Jan2014}}</ref> Many of the tests are [[serology|serological tests]] that react to the [[antibodies]] formed by the [[immune system]]. For some major causes of viral hepatitis, such as Hepatitis B, there are multiple serological tests used that provide additional information for diagnosis.<ref>{{cite web|url=http://www.cdc.gov/hepatitis/hbv/pdfs/serologicchartv8.pdf|title=Interpretation of Hepatitis B Serologic Test Results|publisher=[[Centers for Disease Control and Prevention]]|accessdate=20Jan2014}}</ref>


=== Differential diagnosis ===
=== Alcoholic versus non-alcoholic ===
The most apparent distinguishing factor between [[Alcoholic hepatitis|alcoholic steatohepatitis]] (ASH) and [[Nonalcoholic Steatohepatitis|nonalcoholic steatohepatitis]] (NASH) is a history of excessive alcohol use.<ref name="Neuman, French, et al">{{Cite journal|last1=Neuman|first1=Manuela G.|last2=French|first2=Samuel W.|last3=French|first3=Barbara A.|last4=Seitz|first4=Helmut K.|last5=Cohen|first5=Lawrence B.|last6=Mueller|first6=Sebastian|last7=Osna|first7=Natalia A.|last8=Kharbanda|first8=Kusum K.|last9=Seth|first9=Devanshi|date=2014-12-01|title=Alcoholic and non-alcoholic steatohepatitis|journal=Experimental and Molecular Pathology|volume=97|issue=3|pages=492–510|doi=10.1016/j.yexmp.2014.09.005|pmc=4696068|pmid=25217800}}</ref> Thus, in patients who have no or negligible alcohol use, the diagnosis is unlikely to be alcoholic hepatitis. In those who drink alcohol, the diagnosis may just as likely be alcoholic or nonalcoholic hepatitis especially if there is concurrent obesity, diabetes, and metabolic syndrome. In this case, alcoholic and nonalcoholic hepatitis can be distinguished by the pattern of liver enzyme abnormalities; specifically, in alcoholic steatohepatitis AST>ALT with ratio of AST:ALT>2:1 while in nonalcoholic steatohepatitis ALT>AST with ratio of ALT:AST>1.5:1.<ref name="Neuman, French, et al" />


Liver biopsies show identical findings in patients with ASH and NASH, specifically, the presence of [[Granulocyte|polymorphonuclear]] infiltration, hepatocyte [[necrosis]] and [[apoptosis]] in the form of [[ballooning degeneration]], [[Mallory body|Mallory bodies]], and fibrosis around veins and sinuses.<ref name="Friedman 55e" />
Several diseases can present with signs, symptoms, and/or [[Liver function tests|liver function test]] abnormalities similar to hepatitis. In severe cases of [[alpha 1-antitrypsin deficiency]] (A1AD), excess [[protein]] in liver cells causes and inflammation and cirrhosis.<ref>{{cite journal|last=Stoller|first=James K|coauthors=Aboussouan, Loutfi S|title=α1-antitrypsin deficiency|journal=The Lancet|date=June 2005|volume=365|issue=9478|pages=2225–2236|doi=10.1016/S0140-6736(05)66781-5}}</ref> Some [[Inborn error of metabolism|metabolic disorders]] cause damage to the liver through a variety of mechanisms. In [[hemochromatosis]] and [[Wilson's disease]] toxic accumulation of [[dietary mineral]]s results in inflammation and cirrhosis.<ref>{{cite journal|last=Hansen|first=Keli|coauthors=Horslen, Simon|title=Metabolic liver disease in children|journal=Liver Transplantation|date=May 2008|volume=14|issue=5|pages=713–733|doi=10.1002/lt.21520|pmid=18433056}}</ref>


=== Pathology ===
== Virus screening ==
The purpose of screening for viral hepatitis is to identify people infected with the disease as early as possible, even before symptoms and transaminase elevations may be present. This allows for early treatment, which can both prevent disease progression and decrease the likelihood of transmission to others.<ref>{{Cite web |date=2021-08-13 |title=Hepatitis Testing |url=https://www.testing.com/hepatitis-testing/ |access-date=2023-05-12 |website=Testing.com |language=en-US}}</ref>


=== Hepatitis A ===
The liver, like all organs, responds to injury in a limited number of ways and a number of patterns have been identified. Liver biopsies are rarely performed for acute hepatitis and because of this the histology of chronic hepatitis is better known than that of acute hepatitis.
Hepatitis A causes an acute illness that does not progress to chronic liver disease. Therefore, the role of screening is to assess immune status in people who are at high risk of contracting the virus, as well as in people with known liver disease for whom hepatitis A infection could lead to liver failure.<ref>{{Cite web|url=https://www.cdc.gov/hepatitis/statistics/surveillanceguidelines.htm|title=Guidelines For Viral Hepatitis Surveillance And Case Management|website=www.cdc.gov|access-date=2016-03-12|url-status=live|archive-url=https://web.archive.org/web/20160310094046/http://www.cdc.gov/hepatitis/statistics/surveillanceguidelines.htm|archive-date=2016-03-10}}</ref><ref>{{Cite book|title=Harrison's Manual of Medicine|edition=18|chapter=Chapter 164: Chronic Hepatitis|last1=Harrison|first1=Tindsley Randolph|editor-last1=Longo|editor-first1=Dan L.|editor-last2=Fauci|editor-first2=Anthony S.|editor-link2=Anthony Fauci|editor-last3=Kasper|editor-first3=Dennis L.|editor-last4=Hauser|editor-first4=Stephen L.|editor-last5=Jameson|editor-first5=L. Jerry|editor-last6=Loscalzo|editor-first6=Jerry|publisher=McGraw-Hill|date=2013|location=New York, NY}}</ref> People in these groups who are not already immune can receive the [[hepatitis A vaccine]].{{cn|date=March 2023}}


Those at high risk and in need of screening include:<ref name="WHO Hep A Fact Sheet July 2015" /><ref name="Voise 2011" /><ref name="CDC Adult Vaccine">{{cite web|title=Adult Immunization Schedule by Vaccine and Age Group|url=https://www.cdc.gov/vaccines/schedules/hcp/child-adolescent.html|website=www.CDC.gov|access-date=March 7, 2016|url-status=live|archive-url=https://web.archive.org/web/20160305212647/http://www.cdc.gov/vaccines/schedules/hcp/child-adolescent.html|archive-date=March 5, 2016}}</ref>
==== Acute ====
* People in close contact (either living with or having sexual contact) with someone who has hepatitis A
* People traveling to an area with endemic hepatitis A
* People who do not have access to clean water
* People who use illicit drugs
* People with liver disease
* People with poor sanitary habits such as not washing hands after using the restroom or changing diapers


The presence of anti-hepatitis A [[Immunoglobulin G|IgG]] in the blood indicates past infection with the virus or prior vaccination.<ref>{{Cite book|title=Chapter 163: "Acute Hepatitis." Harrison's Manual of Medicine, 18e.|last=Longo, Dan L.|publisher=McGraw-Hill|year=2013|location=New York, NY|display-authors=etal}}</ref>
In acute hepatitis the lesions (areas of abnormal tissue) predominantly contain diffuse sinusoidal and portal mononuclear infiltrates ([[lymphocyte]]s, [[plasma cell]]s, [[Kupffer cell]]s) and swollen [[hepatocyte]]s. Acidophilic cells ([[Councilman body|Councilman bodies]]) are common. Hepatocyte regeneration and cholestasis (canalicular bile plugs) typically are present. Bridging hepatic [[necrosis]] (areas of necrosis connecting two or more portal tracts) may also occur. There may be some lobular disarray. Although aggregates of lymphocytes in portal zones may occur these are usually neither common nor prominent. The normal architecture is preserved. There is no evidence of [[fibrosis]] or [[cirrhosis]] (fibrosis plus regenerative nodules). In severe cases prominent hepatocellular necrosis around the central vein (zone 3) may be seen.


=== Hepatitis B ===
In submassive necrosis&nbsp;– a rare presentation of acute hepatitis&nbsp;– there is widespread hepatocellular necrosis beginning in the [[hepatic lobule|centrizonal distribution]] and progressing towards [[portal tract]]s. The degree of [[parenchymal]] inflammation is variable and is proportional to duration of [[disease]].<ref>{{cite journal |author=Boyer JL, Klatskin G |title=Pattern of necrosis in acute viral hepatitis. Prognostic value of bridging (subacute hepatic necrosis) |journal=N. Engl. J. Med. |volume=283 |issue=20 |pages=1063–71 |year=1970 |pmid=4319402 |doi=10.1056/NEJM197011122832001}}</ref><ref name=Gimson1996>{{cite journal |author=Gimson AE |title=Fulminant and late onset hepatic failure |journal=Br J Anaesth |volume=77 |issue=1 |pages=90–8 |date=July 1996 |pmid=8703634 |url=http://bja.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=8703634 |doi=10.1093/bja/77.1.90}}</ref> Two distinct patterns of necrosis have been recognised: (1) zonal coagulative necrosis or (2) panlobular (nonzonal) necrosis.<ref name=Kirsch2009>{{cite journal |author=Kirsch R, Yap J, Roberts EA, Cutz E |title=Clinicopathologic spectrum of massive and submassive hepatic necrosis in infants and children |journal=Hum. Pathol. |volume=40 |issue=4 |pages=516–26 |date=April 2009 |pmid=19121848 |doi=10.1016/j.humpath.2008.07.018 |url=http://linkinghub.elsevier.com/retrieve/pii/S0046-8177(08)00447-4}}</ref> Numerous macrophages and lymphocytes are present. Necrosis and inflammation of the biliary tree occurs.<ref name=Nakanuma1994>{{cite journal |author=Nakanuma Y, Sasaki M, Terada T, Harada K |title=Intrahepatic peribiliary glands of humans. II. Pathological spectrum |journal=J. Gastroenterol. Hepatol. |volume=9 |issue=1 |pages=80–6 |year=1994 |pmid=8155873 |doi=10.1111/j.1440-1746.1994.tb01221.x }}</ref> Hyperplasia of the surviving biliary tract cells may be present. Stromal haemorrhage is common.
[[File:Hepatitis B virus v2.png|thumb|Hepatitis B virus v2]]
The [[Centers for Disease Control and Prevention|CDC]], [[World Health Organization|WHO]], [[United States Preventive Services Task Force|USPSTF]], and [[American Congress of Obstetricians and Gynecologists|ACOG]] recommend routine hepatitis B screening for certain high-risk populations.<ref name="CDC recommendations for Hepatitis B">{{Cite web|url=https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5708a1.htm#fig3|title=Recommendations for Identification and Public Health Management of Persons with Chronic Hepatitis B Virus Infection|website=www.cdc.gov|access-date=2016-03-11|url-status=live|archive-url=https://web.archive.org/web/20160306035320/http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5708a1.htm#fig3|archive-date=2016-03-06}}</ref><ref name="Screening for Hepatitis B">{{Cite book|url=https://www.ncbi.nlm.nih.gov/books/NBK208504/|title=Screening for Hepatitis B Virus Infection in Nonpregnant Adolescents and Adults: Systematic Review to Update the 2004 U.S. Preventive Services Task Force Recommendation|last1=Chou|first1=Roger|last2=Dana|first2=Tracy|last3=Bougatsos|first3=Christina|last4=Blazina|first4=Ian|last5=Zakher|first5=Bernadette|last6=Khangura|first6=Jessi|date=2014-01-01|publisher=Agency for Healthcare Research and Quality (US)|series=U.S. Preventive Services Task Force Evidence Syntheses, formerly Systematic Evidence Reviews|location=Rockville (MD)|pmid=24921112}}</ref><ref name="WHO guidelines for chronic Hepatitis B">{{Cite web|url=https://www.who.int/hiv/pub/hepatitis/hepatitis-b-guidelines/en/|title=Guidelines for the prevention, care and treatment of persons with chronic hepatitis B infection|website=World Health Organization|language=en-GB|access-date=2016-03-11|url-status=dead|archive-url=https://web.archive.org/web/20160220104219/http://www.who.int/hiv/pub/hepatitis/hepatitis-b-guidelines/en/|archive-date=2016-02-20}}</ref><ref name="ACOG Practice Bulletin">{{Cite web|url=http://www.acog.org/Resources-And-Publications/Practice-Bulletins/Committee-on-Practice-Bulletins-Obstetrics/Viral-Hepatitis-in-Pregnancy|title=ACOG Practice Bulletin: Clinical Management Guidelines for Obstetrician-Gynecologists: Viral Hepatitis in Pregnancy|website=www.acog.org|access-date=2016-03-12|archive-date=2020-08-07|archive-url=https://web.archive.org/web/20200807231110/https://www.acog.org/Resources-And-Publications/Practice-Bulletins/Committee-on-Practice-Bulletins-Obstetrics/Viral-Hepatitis-in-Pregnancy|url-status=dead}}</ref> Specifically, these populations include people who are:
* Beginning [[Immunosuppressive drug|immunosuppressive]] or [[Chemotherapy|cytotoxic therapy]]<ref name="CDC recommendations for Hepatitis B" />
* Blood, organ, or tissue donors<ref name="WHO guidelines for chronic Hepatitis B" />
* Born in countries where the prevalence of hepatitis B is high (defined as ≥2% of the population), whether or not they have been vaccinated<ref name="CDC recommendations for Hepatitis B" /><ref name="Screening for Hepatitis B" />
* Born in the United States whose parents are from countries where the prevalence of hepatitis B is very high (defined as ≥8% of the population), and who were not vaccinated<ref name="CDC recommendations for Hepatitis B" /><ref name="Screening for Hepatitis B" />
* Found to have elevated [[Liver function tests|liver enzymes]] without a known cause<ref name="CDC recommendations for Hepatitis B" />
* [[HIV/AIDS|HIV]] positive<ref name="CDC recommendations for Hepatitis B" /><ref name="Screening for Hepatitis B" /><ref name="WHO guidelines for chronic Hepatitis B" />
* In close contact with (i.e. live or have sex with) people known to have hepatitis B<ref name="CDC recommendations for Hepatitis B" /><ref name="Screening for Hepatitis B" /><ref name="WHO guidelines for chronic Hepatitis B" />
* Incarcerated<ref name="WHO guidelines for chronic Hepatitis B" />
* [[Intravenous drug users]]<ref name="CDC recommendations for Hepatitis B" /><ref name="Screening for Hepatitis B" /><ref name="WHO guidelines for chronic Hepatitis B" />
* [[Men who have sex with men]]<ref name="CDC recommendations for Hepatitis B" /><ref name="Screening for Hepatitis B" /><ref name="WHO guidelines for chronic Hepatitis B" />
* On [[hemodialysis]]<ref name="CDC recommendations for Hepatitis B" />
* Pregnant<ref name="CDC recommendations for Hepatitis B" /><ref name="Screening for Hepatitis B" /><ref name="ACOG Practice Bulletin" />
Screening consists of a blood test that detects hepatitis B surface antigen ([[HBsAg]]). If HBsAg is present, a second test – usually done on the same blood sample – that detects the antibody for the hepatitis B core antigen (anti-[[HBcAg]]) can differentiate between acute and chronic infection.<ref name="CDC recommendations for Hepatitis B" /><ref>{{Cite book|title=CURRENT Practice Guidelines in Primary Care 2015|author1=Esherick JS |author2=Clark DS |author3=Slater ED |publisher=McGraw-Hill|year=2015|location=New York, NY|display-authors=etal}}</ref> People who are high-risk whose blood tests negative for HBsAg can receive the [[hepatitis B vaccine]] to prevent future infection.<ref name="CDC recommendations for Hepatitis B" /><ref name="Screening for Hepatitis B" /><ref name="WHO guidelines for chronic Hepatitis B" /><ref name="ACOG Practice Bulletin" />


=== Hepatitis C ===
The histology may show some correlation with the cause:
[[File:HCV structure.png|thumb|HCV structure]]
[[File:ABHD5CGI-58-the-Chanarin-Dorfman-Syndrome-Protein-Mobilises-Lipid-Stores-for-Hepatitis-C-Virus-ppat.1005568.s014.ogv|thumb|ABHD5CGI-58-the-Chanarin-Dorfman-Syndrome-Protein-Mobilises-Lipid-Stores-for-Hepatitis-C-Virus-ppat.1005568.s014]]
The [[Centers for Disease Control and Prevention|CDC]], [[World Health Organization|WHO]], [[United States Preventive Services Task Force|USPSTF]], [[AASLD]], and [[American Congress of Obstetricians and Gynecologists|ACOG]] recommend screening people at high risk for hepatitis C infection.<ref name="ACOG Practice Bulletin" /><ref name="CDC - HCV prevention" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="Task Force">{{Cite web|url=https://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/hepatitis-c-screening|title=Final Recommendation Statement: Hepatitis C: Screening – US Preventive Services Task Force|website=www.uspreventiveservicestaskforce.org|access-date=2016-03-21|url-status=live|archive-url=https://web.archive.org/web/20160321180306/http://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/hepatitis-c-screening|archive-date=2016-03-21}}</ref><ref name="AASLD-IDSA" /> These populations include people who are:
* Adults in the United States born between 1945 and 1965<ref name="Task Force" /><ref name="AASLD-IDSA" />
* Blood or organ donors.<ref name="AASLD-IDSA" />
* Born to HCV-positive mothers<ref name="AASLD-IDSA" />
* HIV-positive<ref name="CDC - HCV prevention" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="Task Force" /><ref name="AASLD-IDSA" />
* Incarcerated, or who have been in the past<ref name="CDC - HCV prevention" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="Task Force" /><ref name="AASLD-IDSA" />
* Intranasal illicit drug users<ref name="CDC - HCV prevention" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="Task Force" /><ref name="AASLD-IDSA" />
* Intravenous drug users (past or current)<ref name="CDC - HCV prevention" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="Task Force" /><ref name="AASLD-IDSA" />
* Men who have sex with men<ref name="AASLD-IDSA" />
* On long-term hemodialysis, or who have been in the past<ref name="CDC - HCV prevention" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="Task Force" /><ref name="AASLD-IDSA" />
* Pregnant, and engaging in high-risk behaviors<ref name="ACOG Practice Bulletin" />
* Recipients of blood products or organs prior to 1992 in the United States<ref name="CDC - HCV prevention" /><ref name="Task Force" /><ref name="AASLD-IDSA" />
* Recipients of tattoos in an "unregulated setting"<ref name="Task Force" /><ref name="AASLD-IDSA" />
* Sex workers<ref name="Final Recommendation Statement: Hepatitis C: Screening" />
* Workers in a healthcare setting who have had a needlestick injury<ref name="AASLD-IDSA" />
For people in the groups above whose exposure is ongoing, screening should be periodic, though there is no set optimal screening interval.<ref name="Task Force" /> The AASLD recommends screening men who have sex with men who are HIV-positive annually.<ref name="AASLD-IDSA" /> People born in the US between 1945 and 1965 should be screened once (unless they have other exposure risks).<ref name="CDC - HCV prevention" /><ref name="Task Force" /><ref name="AASLD-IDSA" />


Screening consists of a blood test that detects anti-hepatitis C virus antibody. If anti-hepatitis C virus antibody is present, a confirmatory test to detect HCV RNA indicates chronic disease.<ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="AASLD-IDSA" />
*Zone 1 (periportal) occurs in [[phosphorus]] poisoning or [[eclampsia]].
*Zone 2 (midzonal) – rare – is seen in [[yellow fever]].
*Zone 3 (centrilobular) occurs with ischemic injury, toxic effects, carbon tetrachloride exposure or chloroform ingestion. Drugs such as acetaminophen may be metabolized in zone 1 to toxic compounds that cause necrosis in zone 3.


=== Hepatitis D ===
Where patients have recovered from this condition, biopsies commonly show multiacinar regenerative nodules (previously known as adenomatous hyperplasia).<ref name=Wanless1995>{{cite journal |author=Wanless IR |title=Terminology of nodular hepatocellular lesions |journal=Hepatology |volume=22 |issue=3 |pages=983–993 |date=September 1995 |doi=10.1002/hep.1840220341 |url=http://onlinelibrary.wiley.com/doi/10.1002/hep.1840220341/abstract |pmid=7657307}}</ref>
The [[Centers for Disease Control and Prevention|CDC]], [[World Health Organization|WHO]], [[United States Preventive Services Task Force|USPSTF]], [[AASLD]], and [[American Congress of Obstetricians and Gynecologists|ACOG]] recommend screening people at high risk for hepatitis D infection.<ref name="ACOG Practice Bulletin" /><ref name="CDC - HCV prevention" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="Task Force" /><ref name="AASLD-IDSA" /> These populations include people who are:
* Blood or organ donors.<ref name="AASLD-IDSA" />
* Incarcerated, or who have been in the past<ref name="CDC - HCV prevention" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="Task Force" /><ref name="AASLD-IDSA" />
* Intranasal illicit drug users<ref name="CDC - HCV prevention" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="Task Force" /><ref name="AASLD-IDSA" />
* Intravenous drug users (past or current)<ref name="CDC - HCV prevention" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="Task Force" /><ref name="AASLD-IDSA" />
* Sex workers<ref name="Final Recommendation Statement: Hepatitis C: Screening" />
* Workers in a healthcare setting who have had a needlestick injury<ref name="AASLD-IDSA" />


<blockquote>Hepatitis D is extremely rare. Symptoms include chronic diarrhea, anal and intestinal blisters, purple urine, and burnt popcorn scented breath.<ref name="CDC recommendations for Hepatitis B" /><ref name="Screening for Hepatitis B" /><ref name="WHO guidelines for chronic Hepatitis B" />
Massive hepatic necrosis is also known and is usually rapidly fatal. The pathology resembles that of submassive necrosis but is more markered in both degree and extent.


Screening consists of a blood test that detects the anti-hepitits D virus antibbody. If anti-hepitits D virus antibody is present, a confirmatory test to detect HDV RNA DNA indicates chronic disease.<ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="AASLD-IDSA" /></blockquote>
==== Chronic ====


== Prevention ==
Chronic hepatitis has been better studied and several conditions have been described.


=== Vaccines ===
Chronic hepatitis with piecemeal (periportal) necrosis (or interface hepatitis) with or without fibrosis<ref name=Gastroenterology1994>{{cite journal |author=Gastroenterology IWPotWCo |title=Terminology of chronic hepatitis, hepatic allograft rejection, and nodular lesions of the liver: summary of recommendations developed by an international working party, supported by the World Congresses of Gastroenterology, Los Angeles, 1994 |journal=Am. J. Gastroenterol. |volume=89 |issue=8 Suppl |pages=S177–81 |date=August 1994 |pmid=8048409 }}</ref> (formerly chronic active hepatitis) is any case of hepatitis occurring for more than 6 months with portal based inflammation, fibrosis, disruption of the terminal plate, and piecemeal necrosis. This term has now been replaced by the diagnosis of 'chronic hepatitis'.
==== Hepatitis A ====


{{Main|Hepatitis A vaccine}}
Chronic hepatitis without piecemeal necrosis (formerly called chronic persistent hepatitis) has no significant periportal necrosis or regeneration with a fairly dense mononuclear portal infiltrate. Councilman bodies are frequently seen within the lobule. Instead it includes persistent parenchymal focal hepatocyte necrosis ([[apoptosis]]) with mononuclear sinusoidal infiltrates.
[[File:Havrix-rokote.jpg|thumb|Havrix vaccine]]
The CDC recommends the [[hepatitis A vaccine]] for all children beginning at age one, as well as for those who have not been previously immunized and are at high risk for contracting the disease.<ref name="WHO Hep A Fact Sheet July 2015">{{cite web|title=Hepatitis A Fact sheet N°328|url=https://www.who.int/mediacentre/factsheets/fs328/en/|website=WHO Media Centre|access-date=March 7, 2016|url-status=live|archive-url=https://web.archive.org/web/20140221042107/http://www.who.int/mediacentre/factsheets/fs328/en/|archive-date=February 21, 2014}}</ref><ref name="Voise 2011">{{cite journal|last1=Voise|first1=Nathan|title=Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention. A shot at hepatitis prevention.|journal=J Am Osteopath Assoc|date=Oct 2011|volume=111|issue=10 Suppl 6|pages=S13–6|pmid=22086888}}<!--|access-date=March 7, 2016--></ref>


For children 12 months of age or older, the vaccination is given as a shot into the muscle in two doses 6–18 months apart and should be started before the age 24 months.<ref name="CDC Birth-18Y Immunizations">{{cite web|title=Birth-18 Years and Catchup Immunization Schedules for Providers.|url=https://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html|website=www.CDC.gov|access-date=March 7, 2016|url-status=live|archive-url=https://web.archive.org/web/20160306220930/http://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html|archive-date=March 6, 2016}}</ref> &nbsp;The dosing is slightly different for adults depending on the type of the vaccine. &nbsp;If the vaccine is for hepatitis A only, two doses are given 6–18 months apart depending on the manufacturer.<ref name="CDC Adult Vaccine"/> &nbsp;If the vaccine is [[Hepatitis A vaccine|combined hepatitis A and hepatitis B]], up to 4 doses may be required.<ref name="CDC Adult Vaccine"/>
The older terms have been [[deprecate]]d because the conditions are now understood as being able to alter over time so that what might have been regarded as a relatively benign lesion could still progress to cirrhosis. The simpler term ''chronic hepatitis'' is now preferred in association with the causative agent (when known) and a grade based on the degree of inflammation, piecemeal or bridging necrosis (interface hepatitis) and the stage of fibrosis. Several grading systems have been proposed but none have been adopted universally.


==== Hepatitis B ====
Cirrhosis is a diffuse process characterized by regenerative nodules that are separated from one another by bands of fibrosis. It is the end stage for many chronic liver diseases. The pathophysiological process that results in cirrhosis is as follows: hepatocytes are lost through a gradual process of hepatocellular injury and inflammation. This injury stimulates a regenerative response in the remaining hepatocytes. The fibrotic scars limit the extent to which the normal architecture can be reestablished as the scars isolate groups of hepatocytes. This results in nodules formation. Angiogenisis (new vessel formation) accompanies scar production which results in the formation of abnormal channels between the central hepatic veins and the portal vessels. This in turn causes shunting of blood around the regenerating parenchyma. Normal vascular structures including the sinusoidal channels may be obliterated by fibrotic tissue leading to portal hypertension. The overall reduction in hepatocyte mass, in conjunction with the portal blood shunting, prevents the liver from accomplishing its usual functions – the filtering of blood from the gastrointestinal tract and serum protein production. These changes give rise to the clinical manifestations of cirrhosis.
{{Main|Hepatitis B vaccine|l1=Hepatitis B vaccine}}
[[File:WHO-UNICEF estimates of hepatitis B vaccine (HepB-BD) coverage in countries from the European WHO region in the years 2000-2015.png|thumb|WHO-UNICEF estimates of hepatitis B vaccine (HepB-BD) coverage in countries from the European WHO region in the years 2000–2015]]
The CDC recommends the routine vaccination of all children under the age of 19 with the [[hepatitis B vaccine]].<ref name="CDC Update 1999">{{cite web|last1=Centers for Disease Control|title=Update: recommendations to prevent hepatitis B virus transmission—United States. MMWR 1999|date=1999|volume=48|pages=33–4|url=https://www.cdc.gov/mmwr/preview/mmwrhtml/00056293.htm|access-date=March 7, 2016|url-status=live|archive-url=https://web.archive.org/web/20160514225848/http://www.cdc.gov/mmwr/preview/mmwrhtml/00056293.htm|archive-date=May 14, 2016}}</ref> They also recommend it for those who desire it or are at high risk.<ref name="Voise 2011"/>


Routine vaccination for hepatitis B starts with the first dose administered as &nbsp;a shot into the muscle before the newborn is discharged from the hospital. An additional two doses should be administered before the child is 18 months.<ref name="CDC Birth-18Y Immunizations"/>
==== Specific causes ====

For babies born to a mother with hepatitis B surface antigen positivity, the first dose is unique – in addition to the vaccine, the hepatitis immune globulin should also be administered, both within 12 hours of birth. &nbsp;These newborns should also be regularly tested for infection for at least the first year of life.<ref name="CDC Birth-18Y Immunizations"/>

There is also a combination formulation that includes [[Hepatitis A vaccine|both hepatitis A and B vaccines]].<ref>{{Cite web|url=https://www.mayoclinic.org/drugs-supplements/hepatitis-a-and-hepatitis-b-vaccine-intramuscular-route/description/drg-20061965|title=Hepatitis A And Hepatitis B Vaccine (Intramuscular Route)|website=Mayo Clinic|access-date=25 January 2018}}</ref>

==== Other ====

There are currently no vaccines available in the United States for hepatitis C or E.<ref name="Final Recommendation Statement: Hepatitis C: Screening" /><ref name="WHO - Hepatitis E" /><ref name="WHO Hepatitis D" /> In 2015, a group in China published an article regarding the development of a [[vaccine for hepatitis E]].<ref>{{Cite journal|last=Zhang|date=March 5, 2015|title=Long-Term Efficacy of a Hepatitis E Vaccine|journal=NEJM|doi=10.1056/NEJMoa1406011|pmid=25738667|display-authors=etal|volume=372|issue=10|pages=914–22|doi-access=free}}</ref> As of March 2016, the United States government was in the process of recruiting participants for the [[Phases of clinical research|phase IV trial]] of the hepatitis E vaccine.<ref>{{Cite web|url=https://clinicaltrials.gov/ct2/show/NCT02189603|title=Phase IV Clinical Trial of Recombinant Hepatitis E Vaccine(Hecolin) - Full Text View - ClinicalTrials.gov|website=clinicaltrials.gov|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160309154410/https://clinicaltrials.gov/ct2/show/NCT02189603|archive-date=2016-03-09}}</ref>

=== Behavioral changes ===

==== Hepatitis A ====
Because hepatitis A is transmitted primarily through the [[Fecal-oral route|oral-fecal route]], the mainstay of prevention aside from vaccination is good hygiene, access to clean water and proper handling of sewage.<ref name="Voise 2011" />

==== Hepatitis B and C ====
As hepatitis B and C are transmitted through blood and multiple [[bodily fluids]], prevention is aimed at screening blood prior to [[Blood transfusion|transfusion]], abstaining from the use of injection drugs, safe needle and sharps practices in healthcare settings, and safe sex practices.<ref name="WHO Hepatitis B" /><ref name="Final Recommendation Statement: Hepatitis C: Screening" />

====Hepatitis D====
[[File:Hep D Epidemiology Figure 1.svg|thumb|350x350px|Worldwide prevalence of HDV among HBV carriers in 2015. Eight genotypes have been identified worldwide by comparative phylogenetic analysis. Genotype 1 is the most frequent and has variable pathogenicity, Genotypes 2 and 4 are found in East Asia causing relatively mild disease. Genotype 3 is found in South America in association with severe hepatitis. Genotypes 5, 6, 7, 8 have been found only in Africa.<ref>{{Cite journal|last=Rizzetto|first=Mario | name-list-style = vanc |date=2020|title=Epidemiology of the Hepatitis D virus|url=https://en.wikiversity.org/wiki/WikiJournal_of_Medicine/Epidemiology_of_the_Hepatitis_D_virus|journal=WikiJournal of Medicine|language=en|volume=7|pages=7|doi=10.15347/wjm/2020.001 |doi-access=free}}</ref>]]
The hepatitis D virus requires that a person first be infected with hepatitis B virus, so prevention efforts should focus on limiting the spread of hepatitis B. In people who have chronic hepatitis B infection and are at risk for [[superinfection]] with the hepatitis D virus, the preventive strategies are the same as for hepatitis B.<ref name="WHO Hepatitis D">{{Cite web|url=https://www.who.int/csr/disease/hepatitis/whocdscsrncs20011/en/index5.html|title=WHO {{!}} Hepatitis D|website=www.who.int|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160308152650/http://www.who.int/csr/disease/hepatitis/whocdscsrncs20011/en/index5.html|archive-date=2016-03-08}}</ref>

====Hepatitis E====

Hepatitis E is spread primarily through the oral-fecal route but may also be spread by blood and from mother to fetus. The mainstay of hepatitis E prevention is similar to that for hepatitis A (namely, good hygiene and clean water practices).<ref name="WHO - Hepatitis E">{{Cite web|url=https://www.who.int/mediacentre/factsheets/fs280/en/|title=Hepatitis E|website=World Health Organization|language=en-GB|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160306175719/http://www.who.int/mediacentre/factsheets/fs280/en/|archive-date=2016-03-06}}</ref>

====Alcoholic and metabolic hepatitis====

As excessive alcohol consumption can lead to hepatitis and cirrhosis, the following are maximal recommendations for alcohol consumption:<ref>{{Cite web|url=http://www.niaaa.nih.gov/alcohol-health/overview-alcohol-consumption/moderate-binge-drinking|title=Drinking Levels Defined {{!}} National Institute on Alcohol Abuse and Alcoholism (NIAAA)|website=www.niaaa.nih.gov|date=14 September 2011|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160323085131/http://www.niaaa.nih.gov/alcohol-health/overview-alcohol-consumption/moderate-binge-drinking|archive-date=2016-03-23}}</ref>
* Men – ≤ 4 drinks on any given day and ≤ 14 drinks per week
* Women – ≤ 3 drinks on any given day and ≤ 7 drinks per week
To prevent MAFLD it is recommended to maintain a normal weight, eat a healthy diet, avoid [[added sugar]], and exercise regularly.<ref>{{cite web |title=Preventing fatty liver disease before it's too late |url=https://wexnermedical.osu.edu/blog/fatty-liver-disease |website=wexnermedical.osu.edu |access-date=4 September 2023 |language=en |date=17 June 2020}}</ref><ref>{{cite web |title=Nonalcoholic Fatty Liver Disease (NAFLD) |url=https://liverfoundation.org/liver-diseases/fatty-liver-disease/nonalcoholic-fatty-liver-disease-nafld/ |website=liverfoundation.org |access-date=4 September 2023 |date=23 May 2022}}</ref>

=== Successes ===

====Hepatitis A====

In the United States, universal immunization has led to a two-thirds decrease in hospital admissions and medical expenses due to hepatitis A.<ref>{{Cite journal|last1=Franco|first1=Elisabetta|last2=Meleleo|first2=Cristina|last3=Serino|first3=Laura|last4=Sorbara|first4=Debora|last5=Zaratti|first5=Laura|date=2012-03-27|title=Hepatitis A: Epidemiology and prevention in developing countries|journal=World Journal of Hepatology|volume=4|issue=3|pages=68–73|doi=10.4254/wjh.v4.i3.68|issn=1948-5182|pmc=3321492|pmid=22489258 |doi-access=free }}</ref>

====Hepatitis B====

In the United States new cases of hepatitis B decreased 75% from 1990 to 2004.<ref>{{Cite web|url=https://www.cdc.gov/vaccines/pubs/pinkbook/hepb.html|title=Pinkbook {{!}} Hepatitis B {{!}} Epidemiology of Vaccine Preventable Diseases {{!}} CDC|website=www.cdc.gov|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160307091653/http://www.cdc.gov/vaccines/pubs/pinkbook/hepb.html|archive-date=2016-03-07}}</ref> &nbsp;The group that saw the greatest decrease was children and adolescents, likely reflecting the implementation of the 1999 guidelines.<ref name="Carroll chapter 35" />

====Hepatitis C====

Hepatitis C infections each year had been declining since the 1980s, but began to increase again in 2006.<ref>{{Cite web|url=https://www.cdc.gov/hepatitis/statistics/2013surveillance/commentary.htm|title=Commentary {{!}} U.S. 2013 Surveillance Data for Viral Hepatitis {{!}} Statistics & Surveillance &nbsp;{{!}} Division of Viral Hepatitis {{!}} CDC|website=www.cdc.gov|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160305151134/http://www.cdc.gov/hepatitis/statistics/2013surveillance/commentary.htm|archive-date=2016-03-05}}</ref> The data are unclear as to whether the decline can be attributed to [[needle exchange programme]]s.<ref>Wright NMJ, Millson CE, Tompkins CNE (2005). What is the evidence for the effectiveness of interventions to reduce hepatitis C infection and the associated morbidity? Copenhagen, WHO Regional Office for Europe (Health Evidence Network report; {{cite web |url=http://www.euro.who.int/document/E86159.pdf |title=WHO/Europe &#124; Home |access-date=2016-03-09 |url-status=live |archive-url=https://web.archive.org/web/20100501124733/http://www.euro.who.int/document/e86159.pdf |archive-date=2010-05-01 }}, accessed 9 Mar 2016).</ref>

====Alcoholic hepatitis====

[[File:Depiction of a liver failure patient.png|thumb|Depiction of a liver failure patient]]
Because people with alcoholic hepatitis may have no symptoms, it can be difficult to diagnose and the number of people with the disease is probably higher than many estimates.<ref>{{Cite journal|last1=Basra|first1=Sarpreet|last2=Anand|first2=Bhupinderjit S|date=2011-05-27|title=Definition, epidemiology and magnitude of alcoholic hepatitis|journal=World Journal of Hepatology|volume=3|issue=5|pages=108–113|doi=10.4254/wjh.v3.i5.108|issn=1948-5182|pmc=3124876|pmid=21731902 |doi-access=free }}</ref> Programs such as [[Alcoholics Anonymous]] have been successful in decreasing death due to [[cirrhosis]], but it is difficult to evaluate their success in decreasing the incidence of alcoholic hepatitis.<ref>{{Cite web|url=http://pubs.niaaa.nih.gov/publications/arh27-3/209-219.htm|title=The Epidemiology of Alcoholic Liver Disease|website=pubs.niaaa.nih.gov|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160303180417/http://pubs.niaaa.nih.gov/publications/arh27-3/209-219.htm|archive-date=2016-03-03}}</ref>

== Treatment ==
The treatment of hepatitis varies according to the type, whether it is acute or chronic, and the severity of the disease.
* Activity: Many people with hepatitis prefer bed rest, though it is not necessary to avoid all physical activity while recovering.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />
* Diet: A high-calorie diet is recommended.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Many people develop nausea and cannot tolerate food later in the day, so the bulk of intake may be concentrated in the earlier part of the day.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> In the acute phase of the disease, intravenous feeding may be needed if patients cannot tolerate food and have poor oral intake subsequent to nausea and vomiting.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />
* Drugs: People with hepatitis should avoid taking drugs metabolized by the liver.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> [[Glucocorticoid]]s are not recommended as a treatment option for acute viral hepatitis and may even cause harm, such as development of chronic hepatitis.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />
* Precautions: [[Universal precautions]] should be observed. Isolation is usually not needed, except in cases of hepatitis A and E who have fecal incontinence, and in cases of hepatitis B and C who have uncontrolled bleeding.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />

=== Hepatitis A ===
{{main|Hepatitis A}}

Hepatitis A usually does not progress to a chronic state, and rarely requires hospitalization.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="WHO Hep A Fact Sheet July 2015" /> Treatment is supportive and includes such measures as providing intravenous (IV) hydration and maintaining adequate nutrition.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="WHO Hep A Fact Sheet July 2015" />

Rarely, people with the hepatitis A virus can rapidly develop liver failure, termed ''fulminant hepatic failure'', especially the elderly and those who had a pre-existing liver disease, especially hepatitis C.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="WHO Hep A Fact Sheet July 2015" /> Mortality risk factors include greater age and chronic hepatitis C.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> In these cases, more aggressive supportive therapy and liver transplant may be necessary.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />

=== Hepatitis B ===
{{main|Hepatitis B}}

==== Acute ====
In healthy patients, 95–99% recover with no long-lasting effects, and antiviral treatment is not warranted.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Age and comorbid conditions can result in a more prolonged and severe illness. Certain patients warrant hospitalization, especially those who present with clinical signs of ascites, peripheral edema, and hepatic encephalopathy, and laboratory signs of [[hypoglycemia]], prolonged [[prothrombin time]], low serum [[Albumin human|albumin]], and very high serum [[bilirubin]].<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />

In these rare, more severe acute cases, patients have been successfully treated with antiviral therapy similar to that used in cases of chronic hepatitis B, with nucleoside analogues such as [[entecavir]] or [[Tenofovir disoproxil|tenofovir]]. As there is a dearth of clinical trial data and the drugs used to treat are prone to developing [[Drug resistance|resistance]], experts recommend reserving treatment for severe acute cases, not mild to moderate.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />

==== Chronic ====
Chronic hepatitis B management aims to control viral replication, which is correlated with progression of disease.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Seven drugs are approved in the United States:<ref name="Harrison's Principles, chapter 362 (Chronic)" />
* [[Adefovir dipivoxil]], a nucleotide analogue, has been used to supplement lamivudine in patients who develop resistance, but is no longer recommended as first-line therapy.<ref name="Harrison's Principles, chapter 362 (Chronic)" />
* [[Entecavir]] is safe, well tolerated, less prone to developing resistance, and the most potent of the existing hepatitis B antivirals; it is thus a first-line treatment choice.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> It is not recommended for lamivudine-resistant patients or as monotherapy in patients who are HIV positive.<ref name="Harrison's Principles, chapter 362 (Chronic)" />
* Injectable [[interferon alpha]] was the first therapy approved for chronic hepatitis B.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> It has several side effects, most of which are reversible with removal of therapy, but it has been supplanted by newer treatments for this indication.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> These include long-acting interferon bound to [[polyethylene glycol]] (pegylated interferon) and the oral nucleoside analogues.<ref name="Harrison's Principles, chapter 362 (Chronic)" />
* [[Lamivudine]] was the first approved oral nucleoside analogue.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> While effective and potent, lamivudine has been replaced by newer, more potent treatments in the Western world and is no longer recommended as first-line treatment.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> It is still used in areas where newer agents either have not been approved or are too costly.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Generally, the course of treatment is a minimum of one year with a minimum of six additional months of "consolidation therapy."<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Based on viral response, longer therapy may be required, and certain patients require indefinite long-term therapy.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Due to a less robust response in Asian patients, [[consolidation therapy]] is recommended to be extended to at least a year.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> All patients should be monitored for viral reactivation, which if identified, requires restarting treatment.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Lamivudine is generally safe and well tolerated.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Many patients develop resistance, which is correlated with longer treatment duration.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> If this occurs, an additional antiviral is added.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Lamivudine as a single treatment is contraindicated in patients coinfected with HIV, as resistance develops rapidly, but it can be used as part of a multidrug regimen.<ref name="Harrison's Principles, chapter 362 (Chronic)" />
* [[Pegylated interferon]] (PEG IFN) is dosed just once a week as a subcutaneous injection and is both more convenient and effective than standard interferon.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Although it does not develop resistance as do many of the oral antivirals, it is poorly tolerated and requires close monitoring.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> PEG IFN is estimated to cost about $18,000 per year in the United States, compared to $2,500–8,700 for the oral medications. Its treatment duration is 48 weeks, unlike oral antivirals which require indefinite treatment for most patients (minimum one year).<ref name="Harrison's Principles, chapter 362 (Chronic)" /> PEG IFN is not effective in patients with high levels of viral activity and cannot be used in immunosuppressed patients or those with cirrhosis.<ref name="Harrison's Principles, chapter 362 (Chronic)" />
* [[Telbivudine]] is effective but not recommended as first-line treatment; as compared to entecavir, it is both less potent and more resistance prone.<ref name="Harrison's Principles, chapter 362 (Chronic)" />
* [[Tenofovir disoproxil|Tenofovir]] is a nucleotide analogue and an antiretroviral drug that is also used to treat HIV infection.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> It is preferred to adefovir both in lamivudine-resistant patients and as initial treatment since it is both more potent and less likely to develop resistance.<ref name="Harrison's Principles, chapter 362 (Chronic)" />
First-line treatments currently used include PEG IFN, entecavir, and tenofovir, subject to patient and physician preference.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Treatment initiation is guided by recommendations issued by The American Association for the Study of Liver Diseases (AASLD) and the European Association for the Study of the Liver (EASL) and is based on detectable viral levels, [[HBeAg]] positive or negative status, [[Alanine transaminase|ALT]] levels, and in certain cases, family history of HCC and liver biopsy.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> In patients with compensated cirrhosis, treatment is recommended regardless of HBeAg status or ALT level, but recommendations differ regarding HBV DNA levels; AASLD recommends treating at DNA levels detectable above 2x10<sup>3</sup> IU/mL; EASL and WHO recommend treating when HBV DNA levels are detectable at any level.<ref name="Harrison's Principles, chapter 362 (Chronic)" /><ref name="WHO guidelines for chronic Hepatitis B" /> In patients with decompensated cirrhosis, treatment and evaluation for liver transplantation are recommended in all cases if HBV DNA is detectable.<ref name="Harrison's Principles, chapter 362 (Chronic)" /><ref name="WHO guidelines for chronic Hepatitis B" /> Currently, multidrug treatment is not recommended in treatment of chronic HBV as it is no more effective in the long term than individual treatment with entecavir or tenofovir.<ref name="Harrison's Principles, chapter 362 (Chronic)" />

=== Hepatitis C ===
{{main|Hepatitis C}}
The American Association for the Study of Liver Diseases and the Infectious Diseases Society of America (AASLD-IDSA) recommend antiviral treatment for all patients with chronic hepatitis C infection except for those with additional chronic medical conditions that limit their life expectancy.<ref name="AASLD-IDSA"/>

Once it is acquired, persistence of the hepatitis C virus is the rule, resulting in chronic hepatitis C. The goal of treatment is prevention of hepatocellular carcinoma (HCC).<ref name="Messori Badiani Tripoli">{{Cite journal|last1=Messori|first1=Andrea|last2=Badiani|first2=Brigitta|last3=Trippoli|first3=Sabrina|date=2015-12-01|title=Achieving Sustained Virological Response in Hepatitis C Reduces the Long-Term Risk of Hepatocellular Carcinoma: An Updated Meta-Analysis Employing Relative and Absolute Outcome Measures|journal=Clinical Drug Investigation|volume=35|issue=12|pages=843–850|doi=10.1007/s40261-015-0338-y|issn=1179-1918|pmid=26446006|s2cid=41365729}}</ref> The best way to reduce the long-term risk of HCC is to achieve sustained virological response (SVR).<ref name="Messori Badiani Tripoli" /> SVR is defined as an undetectable viral load at 12 weeks after treatment completion and indicates a cure.<ref name="Revolution">{{Cite journal|last1=Thiagarajan|first1=Prarthana|last2=Ryder|first2=Stephen D.|date=2015-12-01|title=The hepatitis C revolution part 1: antiviral treatment options|journal=Current Opinion in Infectious Diseases|volume=28|issue=6|pages=563–571|doi=10.1097/QCO.0000000000000205|issn=1473-6527|pmid=26524328|s2cid=11926260}}</ref><ref name="Enhancing our understanding">{{Cite journal|last1=Gogela|first1=Neliswa A.|last2=Lin|first2=Ming V.|last3=Wisocky|first3=Jessica L.|last4=Chung|first4=Raymond T.|date=2015-03-01|title=Enhancing our understanding of current therapies for Hepatitis C virus (HCV)|journal=Current HIV/AIDS Reports|volume=12|issue=1|pages=68–78|doi=10.1007/s11904-014-0243-7|issn=1548-3568|pmc=4373591|pmid=25761432}}</ref> Currently available treatments include indirect and direct acting antiviral drugs.<ref name="Revolution"/><ref name="Enhancing our understanding"/> The indirect acting antivirals include [[pegylated interferon]] (PEG IFN) and [[ribavirin]] (RBV), which in combination have historically been the basis of therapy for HCV.<ref name="Revolution"/><ref name="Enhancing our understanding"/> Duration of and response to these treatments varies based on genotype.<ref name="Revolution"/><ref name="Enhancing our understanding"/> These agents are poorly tolerated but are still used in some resource-poor areas.<ref name="Revolution"/><ref name="Enhancing our understanding"/> In high-resource countries, they have been supplanted by direct acting antiviral agents, which first appeared in 2011; these agents target proteins responsible for viral replication and include the following three classes:<ref name="Revolution"/><ref name="Enhancing our understanding"/>
* [[NS3 (HCV)|NS3]] and [[NS4A (Hepacivirus)|NS4A]] [[Protease inhibitor (pharmacology)|protease inhibitor]]s, including [[telaprevir]], [[boceprevir]], [[simeprevir]], and others
* [[NS5A (hepacivirus)|NS5A]] inhibitors, including [[ledipasvir]], [[daclatasvir]], and others
* [[NS5B inhibitors]], including [[sofosbuvir]], [[dasabuvir]], and others
These drugs are used in various combinations, sometimes combined with ribavirin, based on the patient's [[genotype]], delineated as genotypes 1–6.<ref name="Enhancing our understanding"/> Genotype 1 (GT1), which is the most prevalent genotype in the United States and around the world, can now be cured with a direct acting antiviral regimen.<ref name="Enhancing our understanding"/> First-line therapy for GT1 is a combination of sofosbuvir and ledipasvir (SOF/LDV) for 12 weeks for most patients, including those with advanced fibrosis or cirrhosis.<ref name="Enhancing our understanding"/> Certain patients with early disease need only 8 weeks of treatment while those with advanced fibrosis or cirrhosis who have not responded to prior treatment require 24 weeks.<ref name="Enhancing our understanding"/> Cost remains a major factor limiting access to these drugs, particularly in low-resource nations; the cost of the 12-week GT1 regimen (SOF/LDV) has been estimated at US$94,500.<ref name="Revolution"/>

=== Hepatitis D ===
{{main|Hepatitis D}}
Hepatitis D is difficult to treat, and effective treatments are lacking. Interferon alpha has proven effective at inhibiting viral activity but only on a temporary basis.<ref name="Interferon alpha">{{cite journal|title=Interferon alpha for chronic hepatitis D|journal = Cochrane Database of Systematic Reviews|issue = 12|pages = CD006002|last2=Khan|first2=Muhammad Arsalan|last3=Salih|first3=Mohammad|last4=Jafri|first4=Wasim|date=2011-12-07|language=en|doi=10.1002/14651858.cd006002.pub2|pmid = 22161394|pmc = 6823236|last1=Abbas|first1=Zaigham| volume=2011 }}</ref>

=== Hepatitis E ===
{{main|Hepatitis E}}
[[File:Hepatitis E virus.jpg|thumb|Hepatitis E virus]]
Similar to hepatitis A, treatment of hepatitis E is supportive and includes rest and ensuring adequate nutrition and hydration.<ref name="CDC - HEV FAQ">{{Cite web|url=https://www.cdc.gov/hepatitis/hev/hevfaq.htm|title=HEV FAQs for Health Professionals {{!}} Division of Viral Hepatitis {{!}} CDC|website=www.cdc.gov|access-date=2016-03-17|url-status=live|archive-url=https://web.archive.org/web/20160308031004/http://www.cdc.gov/hepatitis/hev/hevfaq.htm|archive-date=2016-03-08}}</ref> Hospitalization may be required for particularly severe cases or for pregnant women.<ref name="CDC - HEV FAQ" />

=== Alcoholic hepatitis ===
First-line treatment of alcoholic hepatitis is treatment of alcoholism.<ref name="Harrison's Principles chapter 363 (Alcohol)" /> For those who abstain completely from alcohol, reversal of liver disease and a longer life are possible; patients at every disease stage have been shown to benefit by prevention of additional liver injury.<ref name="Harrison's Principles chapter 363 (Alcohol)" /><ref name="Chayanupatkul & Liangpunsakul" /> In addition to referral to psychotherapy and other treatment programs, treatment should include nutritional and psychosocial evaluation and treatment.<ref name="Harrison's Principles chapter 363 (Alcohol)" /><ref name="Chayanupatkul & Liangpunsakul" /><ref name="Comparative effectiveness - meta-analysis">{{Cite journal|last1=Singh|first1=Siddharth|last2=Murad|first2=Mohammad Hassan|last3=Chandar|first3=Apoorva K.|last4=Bongiorno|first4=Connie M.|last5=Singal|first5=Ashwani K.|last6=Atkinson|first6=Stephen R.|last7=Thursz|first7=Mark R.|last8=Loomba|first8=Rohit|last9=Shah|first9=Vijay H.|date=2015-10-01|title=Comparative Effectiveness of Pharmacological Interventions for Severe Alcoholic Hepatitis: A Systematic Review and Network Meta-analysis|journal=Gastroenterology|volume=149|issue=4|pages=958–970.e12|doi=10.1053/j.gastro.2015.06.006|issn=1528-0012|pmid=26091937}}</ref> Patients should also be treated appropriately for related signs and symptoms, such as ascites, hepatic encephalopathy, and infection.<ref name="Chayanupatkul & Liangpunsakul" />


Severe alcoholic hepatitis has a poor prognosis and is notoriously difficult to treat.<ref name="Harrison's Principles chapter 363 (Alcohol)" /><ref name="Chayanupatkul & Liangpunsakul" /><ref name="Comparative effectiveness - meta-analysis" /> Without any treatment, 20–50% of patients may die within a month, but evidence shows treatment may extend life beyond one month (i.e., reduce short-term mortality).<ref name="Harrison's Principles chapter 363 (Alcohol)" /><ref name="Comparative effectiveness - meta-analysis" /><ref name="STOPAH">{{Cite journal|last1=Thursz|first1=Mark|last2=Forrest|first2=Ewan|last3=Roderick|first3=Paul|last4=Day|first4=Christopher|last5=Austin|first5=Andrew|last6=O'Grady|first6=John|last7=Ryder|first7=Stephen|last8=Allison|first8=Michael|last9=Gleeson|first9=Dermot|date=2015-12-01|title=The clinical effectiveness and cost-effectiveness of STeroids Or Pentoxifylline for Alcoholic Hepatitis (STOPAH): a 2 × 2 factorial randomised controlled trial|journal=Health Technology Assessment|volume=19|issue=102|pages=1–104|doi=10.3310/hta191020|issn=2046-4924|pmid=26691209|pmc=4781103}}</ref> Available treatment options include [[pentoxifylline]] (PTX), which is a nonspecific [[TNF inhibitor]], [[corticosteroid]]s, such as [[prednisone]] or [[prednisolone]] (CS), corticosteroids with ''[[N-Acetylcysteine|N]]''[[N-Acetylcysteine|-acetylcysteine]] (CS with NAC), and corticosteroids with pentoxifylline (CS with PTX).<ref name="Comparative effectiveness - meta-analysis" /> Data suggest that CS alone or CS with NAC are most effective at reducing short-term mortality.<ref name="Comparative effectiveness - meta-analysis" /> Unfortunately, corticosteroids are contraindicated in some patients, such as those who have active gastrointestinal bleeding, infection, kidney failure, or pancreatitis.<ref name="Harrison's Principles chapter 363 (Alcohol)" /><ref name="Chayanupatkul & Liangpunsakul" /> In these cases PTX may be considered on a case-by-case basis in lieu of CS; some evidence shows PTX is better than no treatment at all and may be comparable to CS while other data show no evidence of benefit over placebo.<ref name="Comparative effectiveness - meta-analysis" /><ref name="STOPAH" /> Unfortunately, there are currently no drug treatments that decrease these patients' risk of dying in the longer term, at 3–12 months and beyond.<ref name="Comparative effectiveness - meta-analysis" />
Most of the causes of hepatitis cannot be distinguished on the basis of the pathology but some do have particular features that are suggestive of a particular diagnosis.


Weak evidence suggests [[Milk Thistle|milk thistle]] extracts may improve survival in alcoholic liver disease and improve certain liver tests (serum bilirubin and [[Gamma-glutamyl transpeptidase|GGT]]) without causing side effects, but a firm recommendation cannot be made for or against milk thistle without further study.<ref>{{Cite journal|title=Milk thistle for alcoholic and/or hepatitis B or C virus liver diseases|last1=Rambaldi|first1=Andrea|last2=Jacobs|first2=Bradly P|last3=Gluud|first3=Christian|date=2007-10-17|issn=1465-1858|language=en|doi=10.1002/14651858.cd003620.pub3|journal=Protocols|volume=2009 |pmid=17943794|pages=CD003620|issue=4|pmc=8724782 }}</ref>&nbsp;
The presence of micronodular cirrhosis, [[Mallory body|Mallory bodies]] and fatty change within a single biopsy are highly suggestive of alcoholic injury.<ref name=Baptista1981>{{cite journal |title=Alcoholic liver disease: morphological manifestations. Review by an international group |journal=Lancet |volume=1 |issue=8222 |pages=707–11 |date=March 1981 |pmid=6110925 }}</ref> Perivenular, pericellular fibrosis (known as 'chicken wire fibrosis' because of its appearance on [[trichrome]] or [[van Gieson stain]]s) with partial or complete obliteration of the central vein is also very suggestive of alcohol abuse.


The [[modified Maddrey's discriminant function]] may be used to evaluate the severity and prognosis in alcoholic hepatitis and evaluates the efficacy of using alcoholic hepatitis corticosteroid treatment.
Cardiac, ischemic and venous outflow obstruction all cause similar patterns.<ref name=Arcidi1981>{{cite journal |author=Arcidi JM, Moore GW, Hutchins GM |title=Hepatic morphology in cardiac dysfunction: a clinicopathologic study of 1000 subjects at autopsy |journal=Am. J. Pathol. |volume=104 |issue=2 |pages=159–66 |date=August 1981 |pmid=6455066 |pmc=1903755 }}</ref> The sinusoids are often dilated and filled with erythrocytes. The liver cell plates may be compressed. [[Coagulative necrosis]] of the hepatocytes can occur around the central vein. [[Hemosiderin]] and lipochrome laden [[macrophage]]s and inflammatory cells may be found. At the edge of the fibrotic zone cholestasis may be present. The portal tracts are rarely significantly involved until late in the course.
=== Metabolic hepatitis===
{{main|Non-alcoholic_fatty_liver_disease#Management}}
The main treatment of NASH is gradual weight loss and increased physical activity. In the United States, no medications have been approved to treat this disease.<ref>{{cite web |title=Treatment for NAFLD & NASH - NIDDK |url=https://www.niddk.nih.gov/health-information/liver-disease/nafld-nash/treatment |website=National Institute of Diabetes and Digestive and Kidney Diseases |access-date=4 September 2023}}</ref>
=== Autoimmune hepatitis ===


Autoimmune hepatitis is commonly treated by immunosuppressants such as the corticosteroids prednisone or prednisolone, the active version of prednisolone that does not require liver synthesis, either alone or in combination with azathioprine, and some have suggested the combination therapy is preferred to allow for lower doses of corticosteroids to reduce associated side effects,<ref name=":0" /> although the result of treatment efficacy is comparative.<ref>{{Cite journal|last1=Summerskill|first1=W. H.|last2=Korman|first2=M. G.|last3=Ammon|first3=H. V.|last4=Baggenstoss|first4=A. H.|date=1975-11-01|title=Prednisone for chronic active liver disease: dose titration, standard dose, and combination with azathioprine compared|journal=Gut|volume=16|issue=11|pages=876–883|doi=10.1136/gut.16.11.876|issn=0017-5749|pmc=1413126|pmid=1104411}}</ref>
Biliary tract disease including [[primary biliary cirrhosis]], [[sclerosing cholangitis]], inflammatory changes associated with idiopathic [[inflammatory bowel disease]] and duct obstruction have similar histology in their early stages. Although these diseases tend to primarily involve the biliary tract they may also be associated with chronic inflammation within the liver and difficult to distinguish on histological grounds alone. The fibrotic changes associated with these disease principally involve the portal tracts with cholangiole proliferation, portal tract inflammation with [[neutrophil]]s surrounding the cholangioles, disruption of the terminal plate by mononuclear inflammatory cells and occasional hepatocyte necrosis. The central veins are either not involved in the fibrotic process or become involved only late in the course of the disease. Consequently the central–portal relationships are minimally distorted. Where cirrhosis is present it tends to be in the form of a portal–portal bridging fibrosis.


Treatment of autoimmune hepatitis consists of two phases; an initial and maintenance phase. The initial phase consists of higher doses of corticosteroids which are tapered down over a number of weeks to a lower dose. If used in combination, azathioprine is given during the initial phase as well. Once the initial phase has been completed, a maintenance phase that consists of lower dose corticosteroids, and in combination therapy, azathioprine until liver blood markers are normalized. Treatment results in 66–91% of patients achieving normal liver test values in two years, with the average being 22 months.<ref name=":0" />
Hepatitis E causes different histological patterns that depend on the host's background.<ref name=Selves2010>{{cite journal |author=Selves J, Kamar N, Mansuy JM, Péron JM |title=[Hepatitis E virus: A new entity] |language=French |journal=Ann Pathol |volume=30 |issue=6 |pages=432–8 |date=December 2010 |pmid=21167429 |doi=10.1016/j.annpat.2010.10.003 |url=http://www.masson.fr/masson/S0242-6498(10)00317-2}}</ref> In immunocompetent patients the typical pattern is of severe intralobular necrosis and acute cholangitis in the portal tract with numerous neutrophils. This normally resolves without sequelae. Disease is more severe in those with preexisting liver disease such as cirrhosis. In the immunocompromised patients chronic infection may result with rapid progression to cirrhosis. The histology is similar to that found in hepatitis C virus with dense lymphocytic portal infiltrate, constant piecemeal necrosis and fibrosis.


== Prognosis ==
== Prognosis ==


=== Acute hepatitis ===
The outcome of hepatitis depends heavily on the disease or condition that is causing the symptoms. For some causes, such as subclinical Hepatitis A infection, the person may not experience any symptoms and will recover without any long term effects. For other causes hepatitis can result in irreparable damage to the liver and require a [[liver transplantation|liver transplant]].<ref name="Ryder S, Beckingham I 2001 151–153"/> A subset referred to in a 1993 classification as "hyperacute" liver failure can happen in less than a week.<ref>{{cite journal |author=O'Grady JG, Schalm SW, Williams R |title=Acute liver failure: redefining the syndromes |journal=Lancet |volume=342 |issue=8866 |pages=273–5 |year=1993 |pmid=8101303 |doi= 10.1016/0140-6736(93)91818-7|url=http://linkinghub.elsevier.com/retrieve/pii/0140-6736(93)91818-7}}</ref>
Nearly all patients with hepatitis A infections recover completely without complications if they were healthy prior to the infection. Similarly, acute hepatitis B infections have a favorable course towards complete recovery in 95–99% of patients.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Certain factors may portend a poorer outcome, such as co-morbid medical conditions or initial presenting symptoms of ascites, edema, or encephalopathy.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Overall, the mortality rate for acute hepatitis is low: ~0.1% in total for cases of hepatitis A and B, but rates can be higher in certain populations (super infection with both hepatitis B and D, pregnant women, etc.).<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />


In contrast to hepatitis A & B, hepatitis C carries a much higher risk of progressing to chronic hepatitis, approaching 85–90%.<ref>{{Cite book|title=Hepatitis C Virus: From Molecular Virology to Antiviral Therapy|publisher=Springer|year=2013|editor-last=Bartenschlager}}</ref> Cirrhosis has been reported to develop in 20–50% of patients with chronic hepatitis C.{{citation needed|date=March 2022}}
The liver can [[Liver#Regeneration and transplantation|regenerate]] damaged cells.<ref name=regen>{{cite book|title=Liver Regeneration|year=2011|publisher=De Gruyter|location=Berlin|isbn=9783110250794|page=1|url=http://books.google.co.za/books?id=RJEg-p-9iqsC&pg=PA1|editor=Dieter Häussinger}}</ref> Chronic damage to the liver can result in the formation of scar tissue called [[fibrosis]] and can result in [[Nodule (medicine)|nodules]] that block the liver from functioning properly; this condition is called [[cirrhosis]] and is not reversible.<ref>{{cite web|url=http://www.meddean.luc.edu/lumen/MedEd/orfpath/cirhosis.htm|title=Liver Cirrhosis|work=Review of Pathology of the Liver}}</ref> Cirrhosis may indicate a liver transplant is necessary. Another complication of chronic hepatitis is [[liver cancer]], specifically [[hepatocellular carcinoma]].<ref name=Robbins_2005>{{cite book | author = Kumar V, Fausto N, Abbas A (editors) | title = Robbins & Cotran Pathologic Basis of Disease | edition = 7th | pages= 914&ndash;7 | publisher = Saunders | year = 2003 | isbn = 978-0-7216-0187-8 }}</ref>


Other rare complications of acute hepatitis include [[pancreatitis]], [[aplastic anemia]], [[peripheral neuropathy]], and [[myocarditis]].<ref name="Harrison's Principles, chapter 360 (Acute Viral)" />
== Prevention ==


=== Vaccines ===
==== Fulminant hepatitis ====
Despite the relatively benign course of most viral cases of hepatitis, fulminant hepatitis represents a rare but feared complication. Fulminant hepatitis most commonly occurs in hepatitis B, D, and E. About 1–2% of cases of hepatitis E can lead to fulminant hepatitis, but pregnant women are particularly susceptible, occurring in up to 20% of cases.<ref>{{Cite journal|last=Khuroo|first=MS|date=1981|title=Incidence and severity of viral hepatitis in pregnancy|journal=Am J Med|doi=10.1016/0002-9343(81)90796-8 |pmid=6781338|volume=70|issue=2|pages=252–5}}</ref> Mortality rates in cases of fulminant hepatitis rise over 80%, but those patients that do survive often make a complete recovery. Liver transplantation can be life-saving in patients with fulminant liver failure.<ref>{{Cite journal|last=Gill|first=RQ|date=2001|title=Acute Liver Failure|journal=J Clin Gastroenterol|doi=10.1097/00004836-200109000-00005|pmid=11500606|volume=33|issue=3|pages=191–8}}</ref>


Hepatitis D infections can transform benign cases of hepatitis B into severe, progressive hepatitis, a phenomenon known as [[superinfection]].<ref>{{Cite journal|last1=Smedile|first1=A|display-authors=etal|date=1981|title=Infection with the delta agent in chronic HBsAg carriers|journal=Gastroenterology|doi= 10.1016/S0016-5085(81)80003-0|pmid=7286594|volume=81|issue=6|pages=992–7|url=https://www.gastrojournal.org/article/S0016-5085(81)80003-0/fulltext|doi-access=free}}</ref>
[[Vaccine|Vaccines]] are available to prevent hepatitis A and B. [[Hepatitis A]] [[immunity]] is achieved in 99-100% of persons receiving the two-dose inactivated virus vaccine. The hepatitis A vaccine is not approved for children under one year of age.<ref>{{cite journal|title=Hepatitis A Vaccines|journal=Weekly epidemiological record|date=4 February 2000|volume=75|pages=37-44|url=http://who.int/immunization/wer7505Hepatitis%20A_Feb00_position_paper.pdf|accessdate=20 February 2014|author=World Health Organization|publisher=World Health Organization|issn=0049-8114}}</ref> Vaccines to prevent [[hepatitis B]] have been available since 1986 and have been incorporated into at least 177 national immunization programs for children. Immunity is achieved in greater than 95% of children and young adults receiving the three-dose recombinant virus vaccine. Vaccination within 24 hours of birth can prevent transmission from an infected mother. Adults over 40 years of age have decreased immune response to the vaccine. The [[World Health Organization]] recommends vaccination of all children, particularly newborns in countries where hepatitis B is common to prevent [[vertical transmission|transmission from the mother to child]].<ref>{{cite journal|title=Hepatitis B Vaccines|journal=Weekly epidemiological review|date=2 October 2009|volume=84|pages=405-420|url=http://who.int/wer/2009/wer8440.pdf|accessdate=20 February 2014|author=World Health Organization|publisher=World Health Organization|issn=0049-8114}}</ref>

=== Chronic hepatitis ===
Acute hepatitis B infections become less likely to progress to chronic forms as the age of the patient increases, with rates of progression approaching 90% in vertically transmitted cases of infants compared to 1% risk in young adults.<ref name="Harrison's Principles, chapter 362 (Chronic)" /> Overall, the five-year survival rate for chronic hepatitis B ranges from 97% in mild cases to 55% in severe cases with cirrhosis.<ref name="Harrison's Principles, chapter 362 (Chronic)" />

Most patients who acquire hepatitis D at the same time as hepatitis B (co-infection) recover without developing a chronic infection. In people with hepatitis B who later acquire hepatitis D (superinfection), chronic infection is much more common at 80–90%, and liver disease progression is accelerated.<ref name="Interferon alpha" /><ref>{{cite journal |title=Interferon alpha versus any other drug for chronic hepatitis D |journal = Cochrane Database of Systematic Reviews|last1=Abbas |first1=Zaigham |last2=Ali |first2=Syed Salman |last3=Shazi |first3=Lubna |date=2015-06-02 |language=en |doi=10.1002/14651858.cd011727 | s2cid=70629280 }}</ref>

Chronic hepatitis C progresses towards cirrhosis, with estimates of cirrhosis prevalence of 16% at 20 years after infection.<ref>{{Cite journal|last1=Thein|first1=Hla-Hla|last2=Yi|first2=Qilong|last3=Dore|first3=Gregory J.|last4=Krahn|first4=Murray D.|date=2008-08-01|title=Estimation of stage-specific fibrosis progression rates in chronic hepatitis C virus infection: a meta-analysis and meta-regression|journal=Hepatology|volume=48|issue=2|pages=418–431|doi=10.1002/hep.22375|issn=1527-3350|pmid=18563841|s2cid=20771903|doi-access=free}}</ref> While the major causes of mortality in hepatitis C is end stage liver disease, hepatocellular carcinoma is an important additional long term complication and cause of death in chronic hepatitis.

Rates of mortality increase with progression of the underlying liver disease. Series of patients with compensated cirrhosis due to HCV have shown 3,5, and 10-year survival rates of 96, 91, and 79% respectively.<ref>{{Cite journal|last=Fattovich|first=G|date=1997|title=Morbidity and mortality in compensated cirrhosis type C: a retrospective follow-up study of 384 patients|journal=Gastroenterology|doi=10.1053/gast.1997.v112.pm9024300|pmid=9024300|volume=112|issue=2|pages=463–72}}</ref> The 5-year survival rate drops to 50% upon if the cirrhosis becomes decompensated.

== Epidemiology ==

=== Viral hepatitis ===

==== Hepatitis A ====
Hepatitis A is found throughout the world and manifests as large [[outbreak]]s and [[epidemic]]s associated with fecal contamination of water and food sources.<ref name="Carroll chapter 35">{{Cite book|title=Medical Microbiology|last=Carroll|first=Karen|publisher=McGraw-Hill|year=2015|isbn=978-0071824989|location=New York|chapter=Chapter 35: Hepatitis Viruses}}</ref> Hepatitis A viral infection is predominant in children ages 5–14 with rare infection of infants.<ref name="Carroll chapter 35" /> Infected children have little to no apparent clinical illness, in contrast to adults in whom greater than 80% are symptomatic if infected.<ref>{{Cite web|url=https://www.cdc.gov/hepatitis/hav/|title=Hepatitis A Information {{!}} Division of Viral Hepatitis {{!}} CDC|website=www.cdc.gov|access-date=2016-03-08|url-status=live|archive-url=https://web.archive.org/web/20160304081005/http://www.cdc.gov/hepatitis/hav/|archive-date=2016-03-04}}</ref> Infection rates are highest in low resource countries with inadequate public sanitation and large concentrated populations.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Aggarwal 488–496">{{Cite journal|last1=Aggarwal|first1=Rakesh|last2=Goel|first2=Amit|title=Hepatitis A|journal=Current Opinion in Infectious Diseases|volume=28|issue=5|pages=488–496|doi=10.1097/qco.0000000000000188|pmid=26203853|year=2015|s2cid=22340290}}</ref> In such regions, as much as 90% of children younger than 10 years old have been infected and are immune, corresponding both to lower rates of clinically symptomatic disease and outbreaks.<ref name="Carroll chapter 35" /><ref name="Aggarwal 488–496"/><ref>{{Cite web|url=https://www.who.int/mediacentre/factsheets/fs328/en/|title=WHO {{!}} Hepatitis A|website=www.who.int|access-date=2016-03-08|url-status=live|archive-url=https://web.archive.org/web/20140221042107/http://www.who.int/mediacentre/factsheets/fs328/en/|archive-date=2014-02-21}}</ref> The availability of a childhood [[vaccine]] has significantly reduced infections in the United States, with incidence declining by more than 95% as of 2013.<ref>{{Cite web|url=https://www.cdc.gov/hepatitis/hav/havfaq.htm#general|title=Hepatitis A Questions and Answers for Health Professionals {{!}} Division of Viral Hepatitis {{!}} CDC|website=www.cdc.gov|access-date=2016-03-08|url-status=live|archive-url=https://web.archive.org/web/20160306221037/http://www.cdc.gov/hepatitis/hav/havfaq.htm#general|archive-date=2016-03-06}}</ref> Paradoxically, the highest rates of new infection now occur in young adults and adults who present with worse clinical illness.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Specific populations at greatest risk include: travelers to endemic regions, men who have sex with men, those with occupational exposure to non-human primates, people with [[clotting disorder]]s who have received [[clotting factors]], people with history of [[chronic liver disease]] in whom co-infection with hepatitis A can lead to fulminant hepatitis, and intravenous drug users (rare).<ref name="Carroll chapter 35" />

==== Hepatitis B ====
{{main|Hepatitis B}}
[[File:HBV replication.png|thumb|HBV replication]]
[[Hepatitis B]] is the most common cause of viral hepatitis in the world with more than 240 million chronic carriers of the virus, 1 million of whom are in the United States.<ref name="WHO Hepatitis B">{{Cite web|url=https://www.who.int/mediacentre/factsheets/fs204/en/|title=Hepatitis B|website=World Health Organization|language=en-GB|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20141109161444/http://www.who.int/mediacentre/factsheets/fs204/en/|archive-date=2014-11-09}}</ref><ref name="Carroll chapter 35" /> In approximately two-thirds of patients who develop acute hepatitis B infection, no identifiable exposure is evident.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Of those acutely infected, 25% become lifetime carriers of the virus.<ref name="Carroll chapter 35" /> Risk of infection is highest among intravenous drug users, people with high-risk sexual behaviors, healthcare workers, people who had multiple transfusions, organ transplant patients, dialysis patients and newborns infected during the birthing process.<ref name="Carroll chapter 35" /> Close to 780,000 deaths in the world are attributed to hepatitis B.<ref name="WHO Hepatitis B" /> The most endemic regions are in sub-Saharan Africa and East Asia, where as many as 10% of adults are chronic carriers.<ref name="WHO Hepatitis B" /> Carrier rates in developed nations are significantly lower, encompassing less than 1% of the population.<ref name="WHO Hepatitis B" /> In endemic regions, transmission is thought to be associated with exposure during birth and close contact between young infants.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="WHO Hepatitis B" />

==== Hepatitis C ====
{{main|Hepatitis C}}
[[File:HepC replication.png|thumb|HepC replication]]
Chronic [[hepatitis C]] is a major cause of liver cirrhosis and hepatocellular carcinoma.<ref name="Rosen - Clinical Practice">{{Cite journal|last=Rosen|first=Hugo R.|date=2011-06-23|title=Clinical practice. Chronic hepatitis C infection| journal=The New England Journal of Medicine| volume=364| issue=25| pages=2429–2438| doi=10.1056/NEJMcp1006613|issn=1533-4406|pmid=21696309}}</ref> It is a common medical reason for liver transplantation due to its severe complications.<ref name="Rosen - Clinical Practice" /> It is estimated that 130–180 million people in the world are affected by this disease representing a little more than 3% of the world population.<ref name="Final Recommendation Statement: Hepatitis C: Screening">{{Cite web|url=https://www.who.int/mediacentre/factsheets/fs164/en/|title=Hepatitis C|website=World Health Organization|language=en-GB|access-date=2016-03-08|url-status=live|archive-url=https://web.archive.org/web/20160131041006/http://www.who.int/mediacentre/factsheets/fs164/en/|archive-date=2016-01-31}}</ref><ref name="Carroll chapter 35" /><ref name="Rosen - Clinical Practice" /> In the developing regions of Africa, Asia and South America, prevalence can be as high as 10% of the population.<ref name="Carroll chapter 35" /> In Egypt, rates of hepatitis C infection as high as 20% have been documented and are associated with [[Iatrogenesis|iatrogenic]] contamination related to [[schistosomiasis]] treatment in the 1950s–1980s.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Carroll chapter 35" /> Currently in the United States, approximately 3.5 million adults are estimated to be infected.<ref>{{Cite journal|last1=Edlin|first1=Brian R.|last2=Eckhardt|first2=Benjamin J.|last3=Shu|first3=Marla A.|last4=Holmberg|first4=Scott D.|last5=Swan|first5=Tracy|date=2015-11-01|title=Toward a more accurate estimate of the prevalence of hepatitis C in the United States|journal=Hepatology|language=en|volume=62|issue=5|pages=1353–1363|doi=10.1002/hep.27978|issn=1527-3350|pmc=4751870|pmid=26171595}}</ref> Hepatitis C is particularly prevalent among people born between 1945 and 1965, a group of about 800,000 people, with prevalence as high as 3.2% versus 1.6% in the general U.S. population.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> Most chronic carriers of hepatitis C are unaware of their infection status.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> The most common mode of transmission of hepatitis C virus is exposure to blood products via blood transfusions (prior to 1992) and intravenous drug injection.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Carroll chapter 35" /> A history of intravenous drug injection is the most important risk factor for chronic hepatitis C.<ref name="Rosen - Clinical Practice" /> Other susceptible populations include those engaged in high-risk sexual behavior, infants of infected mothers, and healthcare workers.<ref name="Carroll chapter 35" />

==== Hepatitis D ====
{{main|Hepatitis D}}
The [[hepatitis D]] virus causes chronic and fulminant hepatitis in the context of co-infection with the hepatitis B virus.<ref name="Carroll chapter 35" /> It is primarily transmitted via non-sexual contact and via needles.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Carroll chapter 35" /> Susceptibility to hepatitis D differs by geographic region.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Carroll chapter 35" /> In the United States and Northern Europe, populations at risk are intravenous drug users and people who receive multiple transfusions.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Carroll chapter 35" /> In the Mediterranean, hepatitis D is predominant among hepatitis B virus co-infected people.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="Carroll chapter 35" />

==== Hepatitis E ====
{{main|Hepatitis E}}
Similar to Hepatitis A, [[hepatitis E]] manifests as large outbreaks and epidemics associated with fecal contamination of water sources.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /> It accounts for more than 55,000 deaths annually with approximately 20 million people worldwide thought to be infected with the virus.<ref name="WHO - Hepatitis E"/> It affects predominantly young adults, causing acute hepatitis.<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="HEV FAQs for Health Professionals">{{Cite web|url=https://www.cdc.gov/hepatitis/hev/hevfaq.htm#section1|title=HEV FAQs for Health Professionals {{!}} Division of Viral Hepatitis {{!}} CDC|website=www.cdc.gov|access-date=2016-03-09|url-status=live|archive-url=https://web.archive.org/web/20160308031004/http://www.cdc.gov/hepatitis/hev/hevfaq.htm#section1|archive-date=2016-03-08}}</ref> In infected pregnant women, Hepatitis E infection can lead to fulminant hepatitis with third trimester mortality rates as high as 30%.<ref name="Carroll chapter 35" /><ref name="HEV FAQs for Health Professionals" /> Those with weakened immune systems, such as organ transplant recipients, are also susceptible.<ref name="HEV FAQs for Health Professionals" /> Infection is rare in the United States but rates are high in the developing world (Africa, Asia, Central America, Middle East).<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="HEV FAQs for Health Professionals" /> Many genotypes exist and are differentially distributed around the world.<ref name="WHO - Hepatitis E" /> There is some evidence of hepatitis E infection of animals, serving as a reservoir for human infection.<ref name="Carroll chapter 35" />

=== Alcoholic hepatitis ===
[[Alcoholic hepatitis]] (AH) in its severe form has a one-month mortality as high as 50%.<ref name="Chayanupatkul & Liangpunsakul">{{Cite journal|last1=Chayanupatkul|first1=Maneerat|last2=Liangpunsakul|first2=Suthat|date=2014-05-28|title=Alcoholic hepatitis: a comprehensive review of pathogenesis and treatment|journal=World Journal of Gastroenterology|volume=20|issue=20|pages=6279–6286|doi=10.3748/wjg.v20.i20.6279|issn=2219-2840|pmc=4033465|pmid=24876748 |doi-access=free }}</ref><ref name="Definition, epidemiology, and magnitude" /><ref name="Singal Kamath Gores Shah">{{Cite journal|last1=Singal|first1=Ashwani K.|last2=Kamath|first2=Patrick S.|last3=Gores|first3=Gregory J.|last4=Shah|first4=Vijay H.|date=2014-04-01|title=Alcoholic hepatitis: current challenges and future directions|journal=Clinical Gastroenterology and Hepatology|volume=12|issue=4|pages=555–564; quiz e31–32|doi=10.1016/j.cgh.2013.06.013|issn=1542-7714|pmc=3883924|pmid=23811249}}</ref> Most people who develop AH are men but women are at higher risk of developing AH and its complications likely secondary to high body fat and differences in alcohol metabolism.<ref name="Definition, epidemiology, and magnitude" /> Other contributing factors include younger age <60, binge pattern drinking, poor nutritional status, obesity and hepatitis C co-infection.<ref name="Definition, epidemiology, and magnitude" /> It is estimated that as much as 20% of people with AH are also infected with hepatitis C.<ref name="Shoreibah, Bhupinderjit, Singal">{{Cite journal|last1=Shoreibah|first1=Mohamed|last2=Anand|first2=Bhupinderjit S.|last3=Singal|first3=Ashwani K.|date=2014-09-14|title=Alcoholic hepatitis and concomitant hepatitis C virus infection|journal=World Journal of Gastroenterology|volume=20|issue=34|pages=11929–11934|doi=10.3748/wjg.v20.i34.11929|issn=2219-2840|pmc=4161778|pmid=25232227 |doi-access=free }}</ref> In this population, the presence of hepatitis C virus leads to more severe disease with faster progression to cirrhosis, hepatocellular carcinoma and increased mortality.<ref name="Definition, epidemiology, and magnitude" /><ref name="Shoreibah, Bhupinderjit, Singal" /><ref>{{Cite journal|last1=Singal|first1=Ashwani K.|last2=Anand|first2=Bhupinder S.|date=2007-09-01|title=Mechanisms of synergy between alcohol and hepatitis C virus|journal=Journal of Clinical Gastroenterology|volume=41|issue=8|pages=761–772|doi=10.1097/MCG.0b013e3180381584|issn=0192-0790|pmid=17700425|s2cid=19482895}}</ref> Obesity increases the likelihood of progression to cirrhosis in cases of alcoholic hepatitis.<ref name="Definition, epidemiology, and magnitude" /> It is estimated that 70% of people who have AH will progress to cirrhosis.<ref name="Definition, epidemiology, and magnitude" />

=== Non-alcoholic steatohepatitis ===
Non-alcoholic steatohepatitis (NASH) is projected to become the top reason for [[liver transplantation]] in the United States by 2020, supplanting chronic liver disease due to hepatitis C.<ref name="From NAFLD to NASH">{{Cite journal|last1=Wree|first1=Alexander|last2=Broderick|first2=Lori|last3=Canbay|first3=Ali|last4=Hoffman|first4=Hal M.|last5=Feldstein|first5=Ariel E.|date=2013-11-01|title=From NAFLD to NASH to cirrhosis-new insights into disease mechanisms|journal=Nature Reviews. Gastroenterology & Hepatology|volume=10|issue=11|pages=627–636|doi=10.1038/nrgastro.2013.149|issn=1759-5053|pmid=23958599|s2cid=6899033}}</ref> About 20–45% of the U.S. population have NAFLD and 6% have NASH.<ref name="Friedman 55e" /><ref name="Harrison's Principles chapter 364 (Nonalcoholic)" /> The estimated prevalence of NASH in the world is 3–5%.<ref name="Weiß, Rau, Geier">{{Cite journal|last1=Weiß|first1=Johannes|last2=Rau|first2=Monika|last3=Geier|first3=Andreas|date=2014-06-27|title=Non-alcoholic fatty liver disease: epidemiology, clinical course, investigation, and treatment|journal=Deutsches Ärzteblatt International|volume=111|issue=26|pages=447–452|doi=10.3238/arztebl.2014.0447|issn=1866-0452|pmc=4101528|pmid=25019921}}</ref> Of NASH patients who develop [[cirrhosis]], about 2% per year will likely progress to [[hepatocellular carcinoma]].<ref name="Weiß, Rau, Geier" /> Worldwide, the estimated prevalence of hepatocellular carcinoma related to NAFLD is 15–30%.<ref name="NAFLD, NASH and liver cancer">{{Cite journal|last1=Michelotti|first1=Gregory A.|last2=Machado|first2=Mariana V.|last3=Diehl|first3=Anna Mae|date=2013-11-01|title=NAFLD, NASH and liver cancer|journal=Nature Reviews. Gastroenterology & Hepatology|volume=10|issue=11|pages=656–665|doi=10.1038/nrgastro.2013.183|issn=1759-5053|pmid=24080776|s2cid=22315274}}</ref> NASH is thought to be the primary cause of cirrhosis in approximately 25% of patients in the United States, representing 1–2% of the general population.<ref name="NAFLD, NASH and liver cancer" />

== History ==
=== Early observations ===
Initial accounts of a syndrome that we now think is likely to be hepatitis begin to occur around 3000 B.C. Clay tablets that served as medical handbooks for the ancient Sumerians described the first observations of jaundice. The Sumerians believed that the liver was the home of the soul, and attributed the findings of jaundice to the attack of the liver by a devil named [[Akhkhazu|Ahhazu]].<ref>{{cite journal |last1=Trepo |first1=Christian |date=February 2014 |title=A brief history of hepatitis milestones |journal=Liver International |volume=34 |issue=Supplement s1 |pages=29–37 |doi=10.1111/liv.12409|pmid=24373076 |s2cid=41215392 |doi-access=free }}</ref>

Around 400 B.C., [[Hippocrates]] recorded the first documentation of an epidemic jaundice, in particular noting the uniquely fulminant course of a cohort of patients who all died within two weeks. He wrote, "The bile contained in the liver is full of phlegm and blood, and erupts...After such an eruption, the patient soon raves, becomes angry, talks nonsense and barks like a dog."<ref>{{cite journal |date=July 2012 |title=Viral hepatitis—the silent killer. |journal=Annals of the Academy of Medicine, Singapore |volume=41 |issue=7 |pages=279–80 |pmid=22892603 |last1=Oon |first1=GC|doi=10.47102/annals-acadmedsg.V41N7p279 |s2cid=2757948 |doi-access=free }}</ref>

Given the poor sanitary conditions of war, infectious jaundice played a large role as a major cause of mortality among troops in the Napoleonic Wars, the American Revolutionary War, and both World Wars.<ref>{{cite book |title=Classic papers in viral hepatitis |editor1-last=Lee |editor1-first=Christine A. |editor2-last=Thomas |editor2-first=Howard C. |date=1988 |publisher=Science Press |isbn=978-1-870026-10-9 |location=London, England |others=Foreword by Dame Sheila Sherlock}}</ref> During World War II, estimates of soldiers affected by hepatitis were upwards of 10 million.

During World War II, soldiers received vaccines against diseases such as [[yellow fever]], but these vaccines were stabilized with human serum, presumably contaminated with hepatitis viruses, which often created epidemics of hepatitis.<ref>{{cite journal |date=April 1993 |title=The discovery of the hepatitis viruses. |journal=Gastroenterology |volume=104 |issue=4 |pages=955–63 |pmid=8385046 |last1=Purcell |first1=RH |doi=10.1016/0016-5085(93)90261-a}}</ref> It was suspected these epidemics were due to a separate infectious agent, and not due to the yellow fever virus itself, after noting 89 cases of jaundice in the months after vaccination out of a total 3,100 patients that were vaccinated. After changing the seed virus strain, no cases of jaundice were observed in the subsequent 8,000 vaccinations.<ref>{{cite journal |date=1946 |title=Homologous Serum Jaundice |journal=Proceedings of the Royal Society of Medicine |volume=39 |issue=10 |pages=649–654 |last1=Bradley |first1=WH|pmc=2181926 |pmid=19993376 |doi=10.1177/003591574603901012 }}</ref>

=== Willowbrook State School experiments ===
A New York University researcher named [[Saul Krugman]] continued this research into the 1950s and 1960s, most infamously with his experiments on mentally disabled children at the [[Willowbrook State School]] in New York, a crowded urban facility where hepatitis infections were highly endemic to the student body. Krugman injected students with gamma globulin, a type of antibody. After observing the temporary protection against infection this antibody provided, he then tried injected live hepatitis virus into students. Krugman also controversially took feces from infected students, blended it into milkshakes, and fed it to newly admitted children.<ref>{{Cite book|title=Intervention and Reflection: Basic Issues in Medical Ethics|last=Munson|first=Ronald|year=1996|pages=273–281}}</ref>

His research was received with much controversy, as people protested the questionable ethics surrounding the chosen target population. [[Henry K. Beecher|Henry Beecher]] was one of the foremost critics in an article in the ''New England Journal of Medicine'' in 1966, arguing that parents were unaware to the risks of consent and that the research was done to benefit others at the expense of children.<ref>{{Cite journal|last=Beecher|first=Henry|date=1966|title=Ethics and Clinical Research|journal=The New England Journal of Medicine|volume=274|issue=24|pages=1354–1360|doi=10.1056/nejm196606162742405|pmid=5327352|pmc=<!--none-->}}; Reprinted in {{cite journal |pmc=2566401 | pmid=11368058 | volume=79 | issue=4 | title=Ethics and clinical research. 1966 | year=2001 | author=Beecher HK | journal=Bull World Health Organ | pages=367–72}}</ref> Moreover, he argued that poor families with mentally disabled children often felt pressured to join the research project to gain admission to the school, with all of the educational and support resources that would come along with it.<ref name="ReferenceA">{{cite journal|date=April 1993|title=The discovery of the hepatitis viruses.|journal=Gastroenterology|volume=104|issue=4|pages=955–63|pmid=8385046|last1=Purcell|first1=RH|doi=10.1016/0016-5085(93)90261-a}}</ref> Others in the medical community spoke out in support of Krugman's research in terms of its widespread benefits and understanding of the hepatitis virus, and Willowbrook continues to be a commonly cited example in debates about medical ethics.<ref>{{Cite book|title=The Oxford Textbook of Clinical Research Ethics|last=Emanuel|first=Ezekiel|publisher=Oxford University Press|year=2008|pages=80–85}}</ref>

=== Australia antigen ===
The next insight regarding hepatitis B was a serendipitous one by [[Baruch Samuel Blumberg|Dr. Baruch Blumberg]], a researcher at the NIH who did not set out to research hepatitis, but rather studied lipoprotein genetics. He travelled across the globe collecting blood samples, investigating the interplay between disease, environment, and genetics with the goal of designing targeted interventions for at-risk people that could prevent them from getting sick.<ref>{{Cite book|title=Les Prix Nobel|last=Odelberg|first=Wilhelm|year=1976}}</ref> He noticed an unexpected interaction between the blood of a patient with [[Haemophilia|hemophilia]] that had received multiple transfusions and a protein found in the blood of an indigenous Australian person.<ref>{{Cite journal|last=Alter|first=Harvey J.|date=2014-01-01|title=The road not taken or how I learned to love the liver: A personal perspective on hepatitis history|journal=Hepatology|language=en|volume=59|issue=1|pages=4–12|doi=10.1002/hep.26787|pmid=24123147|issn=1527-3350|doi-access=free}}</ref> He named the protein the "Australia antigen" and made it the focus of his research. He found a higher prevalence of the protein in the blood of patients from developing countries, compared to those from developed ones, and noted associations of the antigen with other diseases like leukemia and Down Syndrome.<ref>{{Cite journal|last1=Blumberg BS|last2=Alter HJ|date=1965-02-15|title=A "new" antigen in leukemia sera|journal=JAMA|volume=191|issue=7|pages=541–546|doi=10.1001/jama.1965.03080070025007|issn=0098-7484|pmid=14239025}}</ref> Eventually, he came to the unifying conclusion that the Australia antigen was associated with viral hepatitis.

In 1970, [[David Dane]] first isolated the hepatitis B [[virion]] at London's Middlesex Hospital, and named the virion the 42-nm "Dane particle".<ref name="ReferenceA"/> Based on its association with the surface of the hepatitis B virus, the Australia antigen was renamed to "hepatitis B surface antigen" or [[HBsAg]].

Blumberg continued to study the antigen, and eventually developed the first hepatitis B vaccine using plasma rich in HBsAg, for which he received the [[Nobel Prize in Physiology or Medicine|Nobel Prize in Medicine]] in 1976.<ref>{{Cite web|url=https://www.nobelprize.org/prizes/medicine/1976/blumberg/biographical/|title=The Nobel Prize in Physiology or Medicine 1976|website=NobelPrize.org|language=en-US|access-date=2019-10-07}}</ref>

== Society and culture ==

=== Economic burden ===
Overall, hepatitis accounts for a significant portion of healthcare expenditures in both developing and developed nations, and is expected to rise in several developing countries.<ref name="Udompap, Kim & Kim">{{Cite journal|last1=Udompap|first1=Prowpanga|last2=Kim|first2=Donghee|last3=Kim|first3=W. Ray|date=2015-11-01|title=Current and Future Burden of Chronic Nonmalignant Liver Disease|journal=Clinical Gastroenterology and Hepatology|volume=13|issue=12|pages=2031–2041|doi=10.1016/j.cgh.2015.08.015|issn=1542-7714|pmc=4618163|pmid=26291665}}</ref><ref name="Reducing the neglected burden">{{Cite journal|last1=Lemoine|first1=Maud|last2=Eholié|first2=Serge|last3=Lacombe|first3=Karine|title=Reducing the neglected burden of viral hepatitis in Africa: Strategies for a global approach|journal=Journal of Hepatology|volume=62|issue=2|pages=469–476|doi=10.1016/j.jhep.2014.10.008|pmid=25457207|year=2015|doi-access=free}}</ref> While hepatitis A infections are self-limited events, they are associated with significant costs in the United States.<ref name="Current Childhood Vaccination Strategies">{{Cite journal|last1=Koslap-Petraco|first1=Mary Beth|last2=Shub|first2=Mitchell|last3=Judelsohn|first3=Richard|title=Hepatitis A: Disease Burden and Current Childhood Vaccination Strategies in the United States|journal=Journal of Pediatric Health Care|volume=22|issue=1|pages=3–11|doi=10.1016/j.pedhc.2006.12.011|pmid=18174084|year=2008}}</ref> It has been estimated that [[Direct cost|direct and indirect costs]] are approximately $1817 and $2459 respectively per case, and that an average of 27 work days is lost per infected adult.<ref name="Current Childhood Vaccination Strategies"/> A 1997 report demonstrated that a single hospitalization related to hepatitis A cost an average of $6,900 and resulted in around $500 million in total annual healthcare costs.<ref>{{Cite web|url=https://www.who.int/csr/disease/hepatitis/HepatitisA_whocdscsredc2000_7.pdf?ua=1|title=Hepatitis A|last1=Previsani|first1=Nicoletta|last2=Lavanchy|first2=Daniel|date=2000|website=World Health Organization Global Alert and Response|publisher=World Health Organization|access-date=March 5, 2016}}</ref> Cost effectiveness studies have found widespread vaccination of adults to not be feasible, but have stated that a combination hepatitis A and B vaccination of children and at risk groups (people from endemic areas, healthcare workers) may be.<ref>{{Cite journal|last1=Anonychuk|first1=Andrea M.|last2=Tricco|first2=Andrea C.|last3=Bauch|first3=Chris T.|last4=Pham|first4=Ba'|last5=Gilca|first5=Vladimir|last6=Duval|first6=Bernard|last7=John-Baptiste|first7=Ava|last8=Woo|first8=Gloria|last9=Krahn|first9=Murray|date=2008-01-01|title=Cost-effectiveness analyses of hepatitis A vaccine: a systematic review to explore the effect of methodological quality on the economic attractiveness of vaccination strategies|journal=PharmacoEconomics|volume=26|issue=1|pages=17–32|issn=1170-7690|pmid=18088156|doi=10.2165/00019053-200826010-00003|s2cid=46965673}}</ref>

Hepatitis B accounts for a much larger percentage of health care spending in endemic regions like Asia.<ref>{{Cite journal|last1=Chan|first1=Henry Lik-Yuen|last2=Jia|first2=Jidong|date=2011-01-01|title=Chronic hepatitis B in Asia—new insights from the past decade|journal=Journal of Gastroenterology and Hepatology|language=en|volume=26|pages=131–137|doi=10.1111/j.1440-1746.2010.06544.x|pmid=21199524|s2cid=23548529|issn=1440-1746|doi-access=free}}</ref><ref name="Economics of treating in Asia">{{Cite journal|last1=Dan|first1=Yock Young|last2=Aung|first2=Myat Oo|last3=Lim|first3=Seng Gee|date=2008-09-01|title=The economics of treating chronic hepatitis B in Asia|journal=Hepatology International|volume=2|issue=3|pages=284–295|doi=10.1007/s12072-008-9049-2|issn=1936-0533|pmc=2716880|pmid=19669256}}</ref> In 1997 it accounted for 3.2% of South Korea's total health care expenditures and resulted in $696 million in direct costs.<ref name="Economics of treating in Asia" /> A large majority of that sum was spent on treating disease symptoms and complications.<ref>{{Cite journal|last=Lavanchy|first=D.|date=2004-03-01|title=Hepatitis B virus epidemiology, disease burden, treatment, and current and emerging prevention and control measures|journal=Journal of Viral Hepatitis|volume=11|issue=2|pages=97–107|issn=1352-0504|pmid=14996343|doi=10.1046/j.1365-2893.2003.00487.x|s2cid=163757}}</ref> Chronic hepatitis B infections are not as endemic in the United States, but accounted for $357 million in hospitalization costs in the year 1990.<ref name="Udompap, Kim & Kim" /> That number grew to $1.5 billion in 2003, but remained stable as of 2006, which may be attributable to the introduction of effective drug therapies and vaccination campaigns.<ref name="Udompap, Kim & Kim" /><ref name="Reducing the neglected burden" />

People infected with chronic hepatitis C tend to be frequent users of the health care system globally.<ref name="Younossi, Kanwal, Saab, et al">{{Cite journal|last1=Younossi|first1=Z. M.|last2=Kanwal|first2=F.|last3=Saab|first3=S.|last4=Brown|first4=K. A.|last5=El-Serag|first5=H. B.|last6=Kim|first6=W. R.|last7=Ahmed|first7=A.|last8=Kugelmas|first8=M.|last9=Gordon|first9=S. C.|date=2014-03-01|title=The impact of hepatitis C burden: an evidence-based approach|journal=Alimentary Pharmacology & Therapeutics|language=en|volume=39|issue=5|pages=518–531|doi=10.1111/apt.12625|pmid=24461160|s2cid=21263906|issn=1365-2036|doi-access=free}}</ref> It has been estimated that a person infected with hepatitis C in the United States will result in a monthly cost of $691.<ref name="Younossi, Kanwal, Saab, et al" /> That number nearly doubles to $1,227 for people with compensated (stable) cirrhosis, while the monthly cost of people with decompensated (worsening) cirrhosis is almost five times as large at $3,682.<ref name="Younossi, Kanwal, Saab, et al" /> The wide-ranging effects of hepatitis make it difficult to estimate indirect costs, but studies have speculated that the total cost is $6.5 billion annually in the United States.<ref name="Udompap, Kim & Kim" /> In Canada, 56% of HCV related costs are attributable to cirrhosis and total expenditures related to the virus are expected to peak at CAD$396 million in the year 2032.<ref>{{Cite journal|last1=Myers|first1=Robert P.|last2=Krajden|first2=Mel|last3=Bilodeau|first3=Marc|last4=Kaita|first4=Kelly|last5=Marotta|first5=Paul|last6=Peltekian|first6=Kevork|last7=Ramji|first7=Alnoor|last8=Estes|first8=Chris|last9=Razavi|first9=Homie|date=2014-05-01|title=Burden of disease and cost of chronic hepatitis C infection in Canada|journal=Canadian Journal of Gastroenterology & Hepatology|volume=28|issue=5|pages=243–250|issn=2291-2797|pmc=4049256|pmid=24839620|doi=10.1155/2014/317623|doi-access=free}}</ref>

=== 2003 Monaca outbreak ===
The largest outbreak of hepatitis A virus in United States history occurred among people who ate at a now-defunct Mexican food restaurant located in Monaca, Pennsylvania in late 2003.<ref name="green onions">{{Cite journal|last=Centers for Disease Control and Prevention (CDC)|date=2003-11-28|title=Hepatitis A outbreak associated with green onions at a restaurant—Monaca, Pennsylvania, 2003|journal=MMWR. Morbidity and Mortality Weekly Report|volume=52|issue=47|pages=1155–1157|issn=1545-861X|pmid=14647018}}</ref> Over 550 people who visited the restaurant between September and October 2003 were infected with the virus, three of whom died as a direct result.<ref name="green onions" /> The outbreak was brought to the attention of health officials when local [[emergency medicine]] physicians noticed a significant increase in cases of hepatitis A in the county.<ref>{{Cite news|url=https://www.nytimes.com/2003/11/17/us/community-is-reeling-from-hepatitis-outbreak.html|title=Community Is Reeling From Hepatitis Outbreak|last=Polgreen|first=Lydia|date=November 16, 2003|work=[[The New York Times]]|access-date=March 10, 2016|url-status=live|archive-url=https://web.archive.org/web/20160322235231/http://www.nytimes.com/2003/11/17/us/community-is-reeling-from-hepatitis-outbreak.html|archive-date=March 22, 2016}}</ref> After conducting its investigation, the [[Centers for Disease Control and Prevention|CDC]] attributed the source of the outbreak to the use of contaminated raw [[Scallion|green onion]]. The restaurant was purchasing its green onion stock from farms in Mexico at the time.<ref name="green onions" /> It is believed that the green onions may have been contaminated through the use of contaminated water for crop irrigation, rinsing, or icing or by handling of the vegetables by infected people.<ref name="green onions" /> Green onion had caused similar outbreaks of hepatitis A in the southern United States prior to this, but not to the same magnitude.<ref name="green onions" /> The CDC believes that the restaurant's use of a large communal bucket for chopped raw green onion allowed non-contaminated plants to be mixed with contaminated ones, increasing the number of vectors of infection and amplifying the outbreak.<ref name="green onions" /> The restaurant was closed once it was discovered to be the source, and over 9,000 people were given hepatitis A [[Antibody|immune globulin]] because they had either eaten at the restaurant or had been in close contact with someone who had.<ref name="green onions" />

== Special populations ==

=== HIV co-infection ===
Persons infected with HIV have a particularly high burden of [[Hepatitis C and HIV coinfection|HIV-HCV co-infection]].<ref name="HIV co-infection">{{Cite journal|last1=Jordan|first1=Ashly E.|last2=Perlman|first2=David C.|last3=Neurer|first3=Joshua|last4=Smith|first4=Daniel J.|last5=Des Jarlais|first5=Don C.|last6=Hagan|first6=Holly|date=2016-01-28|title=Prevalence of hepatitis C virus infection among HIV+ men who have sex with men: a systematic review and meta-analysis|journal=International Journal of STD & AIDS|volume=28|issue=2|pages=145–159|doi=10.1177/0956462416630910|issn=1758-1052|pmid=26826159|pmc=4965334}}</ref><ref name="Platt, Easterbrook et al">{{Cite journal|last1=Platt|first1=Lucy|last2=Easterbrook|first2=Philippa|last3=Gower|first3=Erin|last4=McDonald|first4=Bethan|last5=Sabin|first5=Keith|last6=McGowan|first6=Catherine|last7=Yanny|first7=Irini|last8=Razavi|first8=Homie|last9=Vickerman|first9=Peter|date=2016-02-24|title=Prevalence and burden of HCV co-infection in people living with HIV: a global systematic review and meta-analysis|journal=The Lancet. Infectious Diseases|doi=10.1016/S1473-3099(15)00485-5|issn=1474-4457|pmid=26922272|volume=16|issue=7|pages=797–808|url=http://researchonline.lshtm.ac.uk/2532806/1/PLATT%20Lancet%20Inf%20Dis%20250116%20final%20accepted.pdf |archive-url=https://web.archive.org/web/20180719062234/http://researchonline.lshtm.ac.uk/2532806/1/PLATT%20Lancet%20Inf%20Dis%20250116%20final%20accepted.pdf |archive-date=2018-07-19 |url-status=live}}</ref> In a recent study by the [[World Health Organization|WHO]], the likelihood of being infected with hepatitis C virus was six times greater in those who also had HIV.<ref name="Platt, Easterbrook et al" /> The prevalence of HIV-HCV co-infection worldwide was estimated to be 6.2% representing more than 2.2 million people.<ref name="Platt, Easterbrook et al" /> Intravenous drug use was an independent risk factor for HCV infection.<ref name="Rosen - Clinical Practice" /> In the WHO study, the prevalence of HIV-HCV co-infection was markedly higher at 82.4% in those who injected drugs compared to the general population (2.4%).<ref name="Platt, Easterbrook et al" /> In a study of HIV-HCV co-infection among HIV positive men who have sex with men (MSM), the overall prevalence of anti-hepatitis C antibodies was estimated to be 8.1% and increased to 40% among HIV positive MSM who also injected drugs.<ref name="HIV co-infection" />

=== Pregnancy ===

==== Hepatitis B ====
[[Vertically transmitted infection|Vertical transmission]] is a significant contributor of new [[hepatitis B virus|HBV]] cases each year, with 35–50% of transmission from mother to neonate in endemic countries.<ref name="ACOG Practice Bulletin" /><ref name="mother-to-neonate">{{Cite book|title="Hepatic, Biliary, and Pancreatic Disorders." Williams Obstetrics, Twenty-Fourth Edition|last=Cunningham|first=F. Gary|publisher=McGraw-Hill|year=2013|location=New York, NY|display-authors=etal}}</ref> Vertical transmission occurs largely via a neonate's exposure to maternal blood and vaginal secretions during birth.<ref name="mother-to-neonate" /> While the risk of progression to chronic infection is approximately 5% among adults who contract the virus, it is as high as 95% among neonates subject to vertical transmission.<ref name="ACOG Practice Bulletin" /><ref>{{Cite journal|last=Tassopoulos|first=NC|display-authors=etal|date=June 1987|title=Natural history of acute hepatitis B surface antigen-positive hepatitis in Greek adults.|journal=Gastroenterology|volume=92|issue=6|pages=1844–50|doi=10.1016/0016-5085(87)90614-7|pmid=3569758}}<!--|access-date=March 16, 2016--></ref> The risk of viral transmission is approximately 10–20% when maternal blood is positive for HBsAg, and up to 90% when also positive for [[HBeAg]].<ref name="ACOG Practice Bulletin" />

Given the high risk of perinatal transmission, the [[Centre for Disease Control|CDC]] recommends screening all pregnant women for HBV at their first prenatal visit.<ref name="ACOG Practice Bulletin" /><ref>{{Cite web|url=https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5416a1.htm?s_cid=rr5416a1_e|title=A Comprehensive Immunization Strategy to Eliminate Transmission of Hepatitis B Virus Infection in the United States Recommendations of the Advisory Committee on Immunization Practices (ACIP) Part 1: Immunization of Infants, Children, and Adolescents|website=www.cdc.gov|access-date=2016-03-16|url-status=live|archive-url=https://web.archive.org/web/20160324191034/http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5416a1.htm?s_cid=rr5416a1_e|archive-date=2016-03-24}}</ref> It is safe for non-immune pregnant women to receive the HBV vaccine.<ref name="ACOG Practice Bulletin" /><ref name="mother-to-neonate" /> Based on the limited available evidence, the [[American Association for the Study of Liver Diseases]] (AASLD) recommends antiviral therapy in pregnant women whose viral load exceeds 200,000 IU/mL.<ref name="AASLD guidelines for chronic B">{{Cite journal|last1=Terrault|first1=Norah A.|last2=Bzowej|first2=Natalie H.|last3=Chang|first3=Kyong-Mi|last4=Hwang|first4=Jessica P.|last5=Jonas|first5=Maureen M.|last6=Murad|first6=M. Hassan|date=2016-01-01|title=AASLD guidelines for treatment of chronic hepatitis B|journal=Hepatology|volume=63|issue=1|pages=261–283|doi=10.1002/hep.28156|issn=1527-3350|pmid=26566064|pmc=5987259}}</ref> A growing body of evidence shows that antiviral therapy initiated in the third trimester significantly reduces transmission to the neonate.<ref name="mother-to-neonate" /><ref name="AASLD guidelines for chronic B" /> A systematic review of the Antiretroviral Pregnancy Registry database found that there was no increased risk of congenital anomalies with [[Tenofovir disoproxil|Tenofovir]]; for this reason, along with its potency and low risk of resistance, the AASLD recommends this drug.<ref name="AASLD guidelines for chronic B" /><ref>{{Cite journal|last1=Wang|first1=Liming|last2=Kourtis|first2=Athena P.|last3=Ellington|first3=Sascha|last4=Legardy-Williams|first4=Jennifer|last5=Bulterys|first5=Marc|date=2013-12-01|title=Safety of tenofovir during pregnancy for the mother and fetus: a systematic review|journal=Clinical Infectious Diseases|volume=57|issue=12|pages=1773–1781|doi=10.1093/cid/cit601|issn=1537-6591|pmid=24046310|doi-access=free}}</ref> A 2010 systematic review and meta-analysis found that [[Lamivudine]] initiated early in the third trimester also significantly reduced mother-to-child transmission of HBV, without any known adverse effects.<ref>{{Cite journal|last1=Shi|first1=Zhongjie|last2=Yang|first2=Yuebo|last3=Ma|first3=Lin|last4=Li|first4=Xiaomao|last5=Schreiber|first5=Ann|date=2010-07-01|title=Lamivudine in late pregnancy to interrupt in utero transmission of hepatitis B virus: a systematic review and meta-analysis|journal=Obstetrics and Gynecology|volume=116|issue=1|pages=147–159|doi=10.1097/AOG.0b013e3181e45951|issn=1873-233X|pmid=20567182|s2cid=41784922}}</ref>

The [[American Congress of Obstetricians and Gynecologists|ACOG]] states that the evidence available does not suggest any particular mode of delivery (i.e. [[Vaginal delivery|vaginal]] vs. [[Caesarean section|cesarean]]) is better at reducing vertical transmission in mothers with HBV.<ref name="ACOG Practice Bulletin" />

The [[World Health Organization|WHO]] and CDC recommend that neonates born to mothers with HBV should receive hepatitis B immune globulin ([[Hepatitis B immune globulin|HBIG]]) as well as the [[Hepatitis B vaccine|HBV vaccine]] within 12 hours of birth.<ref name="CDC recommendations for Hepatitis B" /><ref name="WHO guidelines for chronic Hepatitis B" /> For infants who have received HBIG and the HBV vaccine, breastfeeding is safe.<ref name="ACOG Practice Bulletin" /><ref name="mother-to-neonate" />

==== Hepatitis C ====
Estimates of the rate of [[hepatitis C virus|HCV]] vertical transmission range from 2–8%; a 2014 systematic review and meta-analysis found the risk to be 5.8% in HCV-positive, HIV-negative women.<ref name="ACOG Practice Bulletin" /><ref name="Benova - vertical transmission">{{cite journal |last1=Benova |first1=Lenka |last2=Mohamoud |first2=Yousra A. |last3=Calvert |first3=Clara |last4=Abu-Raddad |first4=Laith J. |date=2014-09-15 |title=Vertical transmission of hepatitis C virus: systematic review and meta-analysis |journal=Clinical Infectious Diseases |volume=59 |issue=6 |pages=765–773 |doi=10.1093/cid/ciu447 |issn=1537-6591 |pmc=4144266 |pmid=24928290}}</ref> The same study found the risk of vertical transmission to be 10.8% in HCV-positive, HIV-positive women.<ref name="Benova - vertical transmission" /> Other studies have found the risk of vertical transmission to be as high as 44% among HIV-positive women.<ref name="ACOG Practice Bulletin" /> The risk of vertical transmission is higher when the virus is detectable in the mother's blood.<ref name="Benova - vertical transmission" />

Evidence does not indicate that mode of delivery (i.e. vaginal vs. cesarean) has an effect on vertical transmission.<ref name="ACOG Practice Bulletin" />

For women who are HCV-positive and HIV-negative, breastfeeding is safe. CDC guidelines suggest avoiding it if a woman's nipples are cracked or bleeding to reduce the risk of transmission.<ref name="ACOG Practice Bulletin" /><ref name="CDC - HCV prevention">{{cite journal |date=October 16, 1998 |title=Recommendations for Prevention and Control of Hepatitis C Virus (HCV) Infection and HCV-Related Chronic Disease |url=https://www.cdc.gov/mmwr/preview/mmwrhtml/00055154.htm |journal=MMWR |pmid=9790221 |access-date=March 16, 2016 |volume=47 |issue=RR-19 |pages=1–39 |url-status=live |archive-url=https://web.archive.org/web/20160324082023/http://www.cdc.gov/mmwr/preview/mmwrhtml/00055154.htm |archive-date=March 24, 2016 }}</ref>

==== Hepatitis E ====
Pregnant women who contract [[Hepatitis E virus|HEV]] are at significant risk of developing fulminant hepatitis with maternal mortality rates as high as 20–30%, most commonly in the third trimester .<ref name="Harrison's Principles, chapter 360 (Acute Viral)" /><ref name="ACOG Practice Bulletin" /><ref name="mother-to-neonate" /> A 2016 systematic review and meta-analysis of 47 studies that included 3968 people found maternal [[Case fatality rate|case-fatality rates]] (CFR) of 20.8% and fetal CFR of 34.2%; among women who developed fulminant hepatic failure, CFR was 61.2%.<ref>{{Cite journal|last1=Jin|first1=H.|last2=Zhao|first2=Y.|last3=Zhang|first3=X.|last4=Wang|first4=B.|last5=Liu|first5=P.|date=2016-03-01|title=Case-fatality risk of pregnant women with acute viral hepatitis type E: a systematic review and meta-analysis|journal=Epidemiology & Infection|volume=FirstView|issue=10|pages=2098–2106|doi=10.1017/S0950268816000418|pmid=26939626|pmc=9150575 |issn=1469-4409|doi-access=free}}</ref>

== Vaccine ==
An essential defense against hepatitis infections, especially those caused by Hepatitis A and B, is the hepatitis vaccination. The Hepatitis B vaccination is quite effective and frequently used. The frequency of hepatitis-related liver illnesses and fatalities has been considerably decreased by the immunization campaigns.<ref>{{Cite journal |last=McLean |first=Arlene A. |date=April 1985 |title=Hepatitis B vaccine: a review of the clinical data to date |url=https://linkinghub.elsevier.com/retrieve/pii/S0002817715300131 |journal=The Journal of the American Dental Association |language=en |volume=110 |issue=4 |pages=624–628 |doi=10.1016/S0002-8177(15)30013-1|pmid=3158685 }}</ref>


== See also ==
== See also ==
* [[Idiopathic granulomatous hepatitis]]
* [[World Hepatitis Day]]
* [[World Hepatitis Day]]


== References ==
== References ==
{{Reflist|30em}}
{{Reflist}}


== External links ==
== External links ==
{{Medical condition classification and resources
* [http://www.who.int/topics/hepatitis/en/ WHO fact sheet of hepatitis]
|ICD10 = {{ICD10|K|75|9|k|70}}
* [http://www.cdc.gov/ncidod/diseases/hepatitis/ Viral Hepatitis at the Centers for Disease Control]
|ICD9 = {{ICD9|573.3}}
|DiseasesDB = 20061
|MedlinePlus = 001154
|eMedicineSubj =
|eMedicineTopic =
|MeshID = D006505
}}
* [https://www.cdc.gov/ncidod/diseases/hepatitis/ Viral Hepatitis at the Centers for Disease Control]
* [https://www.who.int/topics/hepatitis/en/ WHO fact sheet of hepatitis]

{{Gastroenterology}}
{{Gastroenterology}}

{{Inflammation}}
{{Authority control}}


[[Category:Hepatitis| ]]
[[Category:Hepatitis| ]]
[[Category:Inflammations]]
[[Category:Inflammations]]
[[Category:Healthcare-associated infections]]
[[Category:Healthcare-associated infections]]
[[Category:Wikipedia medicine articles ready to translate]]
[[Category:Wikipedia infectious disease articles ready to translate]]
[[Category:Viral diseases]]
[[Category:Diseases of liver]]

Latest revision as of 20:39, 31 October 2024

Hepatitis
Alcoholic hepatitis as seen with a microscope, showing fatty changes (white circles), remnants of dead liver cells, and Mallory bodies (twisted-rope shaped inclusions within some liver cells). (H&E stain)
SpecialtyInfectious disease, gastroenterology, hepatology
SymptomsYellowish skin, poor appetite, abdominal pain[1][2]
ComplicationsScarring of the liver, liver failure, liver cancer[3]
DurationShort term or long term[1]
CausesViruses, alcohol, toxins, autoimmune[2][3]
PreventionVaccination (for viral hepatitis),[2] avoiding excessive alcohol
TreatmentMedication, liver transplant[1][4]
Frequency> 500 million cases[3]
Deaths> One million a year[3]

Hepatitis is inflammation of the liver tissue.[3][5] Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), poor appetite, vomiting, tiredness, abdominal pain, and diarrhea.[1][2] Hepatitis is acute if it resolves within six months, and chronic if it lasts longer than six months.[1][6] Acute hepatitis can resolve on its own, progress to chronic hepatitis, or (rarely) result in acute liver failure.[7] Chronic hepatitis may progress to scarring of the liver (cirrhosis), liver failure, and liver cancer.[3][8]

Hepatitis is most commonly caused by the virus hepatovirus A, B, C, D, and E.[2][3] Other viruses can also cause liver inflammation, including cytomegalovirus, Epstein–Barr virus, and yellow fever virus. Other common causes of hepatitis include heavy alcohol use, certain medications, toxins, other infections, autoimmune diseases,[2][3] and non-alcoholic steatohepatitis (NASH).[9] Hepatitis A and E are mainly spread by contaminated food and water.[3] Hepatitis B is mainly sexually transmitted, but may also be passed from mother to baby during pregnancy or childbirth and spread through infected blood.[3] Hepatitis C is commonly spread through infected blood such as may occur during needle sharing by intravenous drug users.[3] Hepatitis D can only infect people already infected with hepatitis B.[3]

Hepatitis A, B, and D are preventable with immunization.[2] Medications may be used to treat chronic viral hepatitis.[1] Antiviral medications are recommended in all with chronic hepatitis C, except those with conditions that limit their life expectancy.[10] There is no specific treatment for NASH; physical activity, a healthy diet, and weight loss are recommended.[9] Autoimmune hepatitis may be treated with medications to suppress the immune system.[11] A liver transplant may be an option in both acute and chronic liver failure.[4]

Worldwide in 2015, hepatitis A occurred in about 114 million people, chronic hepatitis B affected about 343 million people and chronic hepatitis C about 142 million people.[12] In the United States, NASH affects about 11 million people and alcoholic hepatitis affects about 5 million people.[9][13] Hepatitis results in more than a million deaths a year, most of which occur indirectly from liver scarring or liver cancer.[3][14] In the United States, hepatitis A is estimated to occur in about 2,500 people a year and results in about 75 deaths.[15] The word is derived from the Greek hêpar (ἧπαρ), meaning "liver", and -itis (-ῖτις), meaning "inflammation".[16]

Signs and symptoms

[edit]
Jaundiced eyes

Hepatitis has a broad spectrum of presentations that range from a complete lack of symptoms to severe liver failure.[17][18][19] The acute form of hepatitis, generally caused by viral infection, is characterized by constitutional symptoms that are typically self-limiting.[17][18] Chronic hepatitis presents similarly, but can manifest signs and symptoms specific to liver dysfunction with long-standing inflammation and damage to the organ.[19][20]

Acute hepatitis

[edit]

Acute viral hepatitis follows three distinct phases:

  1. The initial prodromal phase (preceding symptoms) involves non-specific and flu-like symptoms common to many acute viral infections. These include fatigue, nausea, vomiting, poor appetite, joint pain, and headaches.[17][18] Fever, when present, is most common in cases of hepatitis A and E.[17] Late in this phase, people can experience liver-specific symptoms, including choluria (dark urine) and clay-colored stools.[17][18]
  2. Yellowing of the skin and whites of the eyes follow the prodrome after about 1–2 weeks and can last for up to 4 weeks.[17][18] The non-specific symptoms seen in the prodromal typically resolve by this time, but people will develop an enlarged liver and right upper abdominal pain or discomfort.[17] 10–20% of people will also experience an enlarged spleen, while some people will also experience a mild unintentional weight loss.[17][19]
  3. The recovery phase is characterized by resolution of the clinical symptoms of hepatitis with persistent elevations in liver lab values and potentially a persistently enlarged liver.[17] All cases of hepatitis A and E are expected to fully resolve after 1–2 months.[17] Most hepatitis B cases are also self-limiting and will resolve in 3–4 months. Few cases of hepatitis C will resolve completely.[17]

Both drug-induced hepatitis and autoimmune hepatitis can present very similarly to acute viral hepatitis, with slight variations in symptoms depending on the cause.[21][22] Cases of drug-induced hepatitis can manifest with systemic signs of an allergic reaction including rash, fever, serositis (inflammation of membranes lining certain organs), elevated eosinophils (a type of white blood cell), and suppression of bone marrow activity.[21]

Fulminant hepatitis

[edit]

Fulminant hepatitis, or massive hepatic cell death, is a rare and life-threatening complication of acute hepatitis that can occur in cases of hepatitis B, D, and E, in addition to drug-induced and autoimmune hepatitis.[17][21][22] The complication more frequently occurs in instances of hepatitis B and D co-infection at a rate of 2–20% and in pregnant women with hepatitis E at rate of 15–20% of cases.[17][18] In addition to the signs of acute hepatitis, people can also demonstrate signs of coagulopathy (abnormal coagulation studies with easy bruising and bleeding) and encephalopathy (confusion, disorientation, and sleepiness).[17][18] Mortality due to fulminant hepatitis is typically the result of various complications including cerebral edema, gastrointestinal bleeding, sepsis, respiratory failure, or kidney failure.[17]

Chronic hepatitis

[edit]

Acute cases of hepatitis are seen to be resolved well within a six-month period. When hepatitis is continued for more than six months it is termed chronic hepatitis.[23] Chronic hepatitis is often asymptomatic early in its course and is detected only by liver laboratory studies for screening purposes or to evaluate non-specific symptoms.[19][20] As the inflammation progresses, patients can develop constitutional symptoms similar to acute hepatitis, including fatigue, nausea, vomiting, poor appetite, and joint pain.[20] Jaundice can occur as well, but much later in the disease process and is typically a sign of advanced disease.[20] Chronic hepatitis interferes with hormonal functions of the liver which can result in acne, hirsutism (abnormal hair growth), and amenorrhea (lack of menstrual period) in women.[20] Extensive damage and scarring of the liver over time defines cirrhosis, a condition in which the liver's ability to function is permanently impeded.[19] This results in jaundice, weight loss, coagulopathy, ascites (abdominal fluid collection), and peripheral edema (leg swelling).[20] Cirrhosis can lead to other life-threatening complications such as hepatic encephalopathy, esophageal varices, hepatorenal syndrome, and liver cancer.[19]

Causes

[edit]

Causes of hepatitis can be divided into the following major categories: infectious, metabolic, ischemic, autoimmune, genetic, and other. Infectious agents include viruses, bacteria, and parasites. Metabolic causes include prescription medications, toxins (most notably alcohol), and non-alcoholic fatty liver disease. Autoimmune and genetic causes of hepatitis involve genetic predispositions and tend to affect characteristic populations.[24]

Infectious

[edit]

Viral hepatitis

[edit]

Viral hepatitis is the most common type of hepatitis worldwide, especially in Asia and Africa.[25] Viral hepatitis is caused by five different viruses (hepatitis A, B, C, D, and E).[17] Hepatitis A and hepatitis E behave similarly: they are both transmitted by the fecal–oral route, are more common in developing countries, and are self-limiting illnesses that do not lead to chronic hepatitis.[17][26][27]

Hepatitis B, hepatitis C, and hepatitis D are transmitted when blood or mucous membranes are exposed to infected blood and body fluids, such as semen and vaginal secretions.[17] Viral particles have also been found in saliva and breastmilk. Kissing, sharing utensils, and breastfeeding do not lead to transmission unless these fluids are introduced into open sores or cuts.[28] Many families who do not have safe drinking water or live in unhygienic homes have contracted hepatitis because saliva and blood droplets are often carried through the water and blood-borne illnesses spread quickly in unsanitary settings.[29]

Hepatitis B and C can present either acutely or chronically.[17] Hepatitis D is a defective virus that requires hepatitis B to replicate and is only found with hepatitis B co-infection.[17] In adults, hepatitis B infection is most commonly self-limiting, with less than 5% progressing to chronic state, and 20 to 30% of those chronically infected developing cirrhosis or liver cancer.[30] Infection in infants and children frequently leads to chronic infection.[30]

Unlike hepatitis B, most cases of hepatitis C lead to chronic infection.[31] Hepatitis C is the second most common cause of cirrhosis in the US (second to alcoholic hepatitis).[32] In the 1970s and 1980s, blood transfusions were a major factor in spreading hepatitis C virus.[31] Since widespread screening of blood products for hepatitis C began in 1992, the risk of acquiring hepatitis C from a blood transfusion has decreased from approximately 10% in the 1970s to 1 in 2 million currently.[17]

Parasitic hepatitis

[edit]
Echinococcus granulosus

Parasites can also infect the liver and activate the immune response, resulting in symptoms of acute hepatitis with increased serum IgE (though chronic hepatitis is possible with chronic infections).[33] Of the protozoans, Trypanosoma cruzi, Leishmania species, and the malaria-causing Plasmodium species all can cause liver inflammation.[33] Another protozoan, Entamoeba histolytica, causes hepatitis with distinct liver abscesses.[33]

Of the worms, the cestode Echinococcus granulosus, also known as the dog tapeworm, infects the liver and forms characteristic hepatic hydatid cysts.[33] The liver flukes Fasciola hepatica and Clonorchis sinensis live in the bile ducts and cause progressive hepatitis and liver fibrosis.[33]

Bacterial hepatitis

[edit]

Bacterial infection of the liver commonly results in pyogenic liver abscesses, acute hepatitis, or granulomatous (or chronic) liver disease.[34] Pyogenic abscesses commonly involve enteric bacteria such as Escherichia coli and Klebsiella pneumoniae and are composed of multiple bacteria up to 50% of the time.[34] Acute hepatitis is caused by Neisseria meningitidis, Neisseria gonorrhoeae, Bartonella henselae, Borrelia burgdorferi, salmonella species, brucella species and campylobacter species.[34] Chronic or granulomatous hepatitis is seen with infection from mycobacteria species, Tropheryma whipplei, Treponema pallidum, Coxiella burnetii, and rickettsia species.[34]

Metabolic

[edit]

Alcoholic hepatitis

[edit]

Excessive alcohol consumption is a significant cause of hepatitis and is the most common cause of cirrhosis in the U.S.[32] Alcoholic hepatitis is within the spectrum of alcoholic liver disease. This ranges in order of severity and reversibility from alcoholic steatosis (least severe, most reversible), alcoholic hepatitis, cirrhosis, and liver cancer (most severe, least reversible).[32] Hepatitis usually develops over years-long exposure to alcohol, occurring in 10 to 20% of alcoholics.[35] The most important risk factors for the development of alcoholic hepatitis are quantity and duration of alcohol intake.[35] Long-term alcohol intake in excess of 80 grams of alcohol a day in men and 40 grams a day in women is associated with development of alcoholic hepatitis (1 beer or 4 ounces of wine is equivalent to 12g of alcohol).[32] Alcoholic hepatitis can vary from asymptomatic hepatomegaly (enlarged liver) to symptoms of acute or chronic hepatitis to liver failure.[32]

Toxic and drug-induced hepatitis

[edit]

Many chemical agents, including medications, industrial toxins, and herbal and dietary supplements, can cause hepatitis.[36][37] The spectrum of drug-induced liver injury varies from acute hepatitis to chronic hepatitis to acute liver failure.[36] Toxins and medications can cause liver injury through a variety of mechanisms, including direct cell damage, disruption of cell metabolism, and causing structural changes.[38] Some drugs such as paracetamol exhibit predictable dose-dependent liver damage while others such as isoniazid cause idiosyncratic and unpredictable reactions that vary by person.[36] There are wide variations in the mechanisms of liver injury and latency period from exposure to development of clinical illness.[32]

Many types of drugs can cause liver injury, including the analgesic paracetamol; antibiotics such as isoniazid, nitrofurantoin, amoxicillin-clavulanate, erythromycin, and trimethoprim-sulfamethoxazole; anticonvulsants such as valproate and phenytoin; cholesterol-lowering statins; steroids such as oral contraceptives and anabolic steroids; and highly active anti-retroviral therapy used in the treatment of HIV/AIDS.[32] Of these, amoxicillin-clavulanate is the most common cause of drug-induced liver injury, and paracetamol toxicity the most common cause of acute liver failure in the United States and Europe.[36]

Herbal remedies and dietary supplements are another important cause of hepatitis; these are the most common causes of drug-induced hepatitis in Korea.[39] The United States–based Drug Induced Liver Injury Network linked more than 16% of cases of hepatotoxicity to herbal and dietary supplements.[40] In the United States, herbal and dietary supplements – unlike pharmaceutical drugs – are unregulated by the Food and Drug Administration.[40] The National Institutes of Health maintains the LiverTox Archived 2019-07-24 at the Wayback Machine database for consumers to track all known prescription and non-prescription compounds associated with liver injury.[41]

Exposure to other hepatotoxins can occur accidentally or intentionally through ingestion, inhalation, and skin absorption. The industrial toxin carbon tetrachloride and the wild mushroom Amanita phalloides are other known hepatotoxins.[36][37][42]

Non-alcoholic fatty liver disease

[edit]

Non-alcoholic hepatitis is within the spectrum of non-alcoholic liver disease (NALD), which ranges in severity and reversibility from non-alcoholic fatty liver disease (NAFLD) to non-alcoholic steatohepatitis (NASH) to cirrhosis to liver cancer, similar to the spectrum of alcoholic liver disease.[43]

Non-alcoholic liver disease occurs in people with little or no history of alcohol use, and is instead strongly associated with metabolic syndrome, obesity, insulin resistance and diabetes, and hypertriglyceridemia.[32] Over time, non-alcoholic fatty liver disease can progress to non-alcoholic steatohepatitis, which additionally involves liver cell death, liver inflammation and possible fibrosis.[32] Factors accelerating progression from NAFLD to NASH are obesity, older age, non-African American ethnicity, female gender, diabetes mellitus, hypertension, higher ALT or AST level, higher AST/ALT ratio, low platelet count, and an ultrasound steatosis score.[32]

In the early stages (as with NAFLD and early NASH), most patients are asymptomatic or have mild right upper quadrant pain, and diagnosis is suspected on the basis of abnormal liver function tests.[32] As the disease progresses, symptoms typical of chronic hepatitis may develop.[44] While imaging can show fatty liver, only liver biopsy can demonstrate inflammation and fibrosis characteristic of NASH.[45] 9 to 25% of patients with NASH develop cirrhosis.[32] NASH is recognized as the third most common cause of liver disease in the United States.[44]

Autoimmune

[edit]

Autoimmune hepatitis is a chronic disease caused by an abnormal immune response against liver cells.[46] The disease is thought to have a genetic predisposition as it is associated with certain human leukocyte antigens involved in the immune response.[47] As in other autoimmune diseases, circulating auto-antibodies may be present and are helpful in diagnosis.[48] Auto-antibodies found in patients with autoimmune hepatitis include the sensitive but less specific anti-nuclear antibody (ANA), smooth muscle antibody (SMA), and atypical perinuclear antineutrophil cytoplasmic antibody (p-ANCA).[48] Other autoantibodies that are less common but more specific to autoimmune hepatitis are the antibodies against liver kidney microsome 1 (LKM1) and soluble liver antigen (SLA).[48] Autoimmune hepatitis can also be triggered by drugs (such as nitrofurantoin, hydralazine, and methyldopa), after liver transplant, or by viruses (such as hepatitis A, Epstein-Barr virus, or measles).[32]

Autoimmune hepatitis can present anywhere within the spectrum from asymptomatic to acute or chronic hepatitis to fulminant liver failure.[32] Patients are asymptomatic 25–34% of the time, and the diagnosis is suspected on the basis of abnormal liver function tests.[48] Some studies show between 25% and 75% of cases present with signs and symptoms of acute hepatitis.[32][49] As with other autoimmune diseases, autoimmune hepatitis usually affects young females (though it can affect patients of either sex of any age), and patients can exhibit classic signs and symptoms of autoimmunity such as fatigue, anemia, anorexia, amenorrhea, acne, arthritis, pleurisy, thyroiditis, ulcerative colitis, nephritis, and maculopapular rash.[32] Autoimmune hepatitis increases the risk for cirrhosis, and the risk for liver cancer is increased by about 1% for each year of the disease.[32]

Many people with autoimmune hepatitis have other autoimmune diseases.[50] Autoimmune hepatitis is distinct from the other autoimmune diseases of the liver, primary biliary cirrhosis and primary sclerosing cholangitis, both of which can also lead to scarring, fibrosis, and cirrhosis of the liver.[32][48]

Genetic

[edit]

Genetic causes of hepatitis include alpha-1-antitrypsin deficiency, hemochromatosis, and Wilson's disease.[32] In alpha-1-antitrypsin deficiency, a co-dominant mutation in the gene for alpha-1-antitrypsin results in the abnormal accumulation of the mutant AAT protein within liver cells, leading to liver disease.[51] Hemochromatosis and Wilson's disease are both autosomal recessive diseases involving abnormal storage of minerals.[32] In hemochromatosis, excess amounts of iron accumulate in multiple body sites, including the liver, which can lead to cirrhosis.[32] In Wilson's disease, excess amounts of copper accumulate in the liver and brain, causing cirrhosis and dementia.[32]

When the liver is involved, alpha-1-antitrypsin deficiency and Wilson's disease tend to present as hepatitis in the neonatal period or in childhood.[32] Hemochromatosis typically presents in adulthood, with the onset of clinical disease usually after age 50.[32]

Ischemic hepatitis

[edit]

Ischemic hepatitis (also known as shock liver) results from reduced blood flow to the liver as in shock, heart failure, or vascular insufficiency.[52] The condition is most often associated with heart failure but can also be caused by shock or sepsis. Blood testing of a person with ischemic hepatitis will show very high levels of transaminase enzymes (AST and ALT). The condition usually resolves if the underlying cause is treated successfully. Ischemic hepatitis rarely causes permanent liver damage.[53]

Other

[edit]

Hepatitis can also occur in neonates and is attributable to a variety of causes, some of which are not typically seen in adults.[54] Congenital or perinatal infection with the hepatitis viruses, toxoplasma, rubella, cytomegalovirus, and syphilis can cause neonatal hepatitis.[54] Structural abnormalities such as biliary atresia and choledochal cysts can lead to cholestatic liver injury leading to neonatal hepatitis.[54] Metabolic diseases such as glycogen storage disorders and lysosomal storage disorders are also implicated.[54] Neonatal hepatitis can be idiopathic, and in such cases, biopsy often shows large multinucleated cells in the liver tissue.[55] This disease is termed giant cell hepatitis and may be associated with viral infection, autoimmune disorders, and drug toxicity.[56][57]

Mechanism

[edit]

The specific mechanism varies and depends on the underlying cause of the hepatitis. Generally, there is an initial insult that causes liver injury and activation of an inflammatory response, which can become chronic, leading to progressive fibrosis and cirrhosis.[17]

Viral hepatitis

[edit]
Stages of liver disease

The pathway by which hepatic viruses cause viral hepatitis is best understood in the case of hepatitis B and C.[17] The viruses do not directly activate apoptosis (cell death).[17][58] Rather, infection of liver cells activates the innate and adaptive arms of the immune system leading to an inflammatory response which causes cellular damage and death, including viral-induced apoptosis via the induction of the death receptor-mediated signaling pathway.[17][58][59][60] Depending on the strength of the immune response, the types of immune cells involved and the ability of the virus to evade the body's defense, infection can either lead to clearance (acute disease) or persistence (chronic disease) of the virus.[17] The chronic presence of the virus within liver cells results in multiple waves of inflammation, injury and wound healing that over time lead to scarring or fibrosis and culminate in hepatocellular carcinoma.[58][61] People with impaired immune response are at greater risk of developing chronic infection.[17] Natural killer cells are the primary drivers of the initial innate response and create a cytokine environment that results in the recruitment of CD4 T-helper and CD8 cytotoxic T-cells.[62][63] Type I interferons are the cytokines that drive the antiviral response.[63] In chronic Hepatitis B and C, natural killer cell function is impaired.[62]

Steatohepatitis

[edit]

Steatohepatitis is seen in both alcoholic and non-alcoholic liver disease and is the culmination of a cascade of events that began with injury. In the case of non-alcoholic steatohepatitis, this cascade is initiated by changes in metabolism associated with obesity, insulin resistance, and lipid dysregulation.[64][65] In alcoholic hepatitis, chronic excess alcohol use is the culprit.[66] Though the inciting event may differ, the progression of events is similar and begins with accumulation of free fatty acids (FFA) and their breakdown products in the liver cells in a process called steatosis.[64][65][66] This initially reversible process overwhelms the hepatocyte's ability to maintain lipid homeostasis leading to a toxic effect as fat molecules accumulate and are broken down in the setting of an oxidative stress response.[64][65][66] Over time, this abnormal lipid deposition triggers the immune system via toll-like receptor 4 (TLR4) resulting in the production of inflammatory cytokines such as TNF that cause liver cell injury and death.[64][65][66] These events mark the transition to steatohepatitis and in the setting of chronic injury, fibrosis eventually develops setting up events that lead to cirrhosis and hepatocellular carcinoma.[64] Microscopically, changes that can be seen include steatosis with large and swollen hepatocytes (ballooning), evidence of cellular injury and cell death (apoptosis, necrosis), evidence of inflammation in particular in zone 3 of the liver, variable degrees of fibrosis and Mallory bodies.[64][67][68]

Diagnosis

[edit]
Most elevated aminotransferase Cause
ALT Chronic hepatitis B, C, and D
Nonalcoholic liver disease
Acute viral hepatitis
Medications/toxins
Autoimmune hepatitis
Wilson's disease
Alpha-1-antitrypsin deficiency
Hemochromatosis
Ischemic hepatitis (severe elevation up to thousands)
AST Alcoholic liver disease
Cirrhosis
Histopathology of acute hepatitis with lobular disarray and associated lymphocytic inflammation, acidophil body formation (arrow) and bilirubinostasis.

Diagnosis of hepatitis is made on the basis of some or all of the following: a person's signs and symptoms, medical history including sexual and substance use history, blood tests, imaging, and liver biopsy.[32] In general, for viral hepatitis and other acute causes of hepatitis, the person's blood tests and clinical picture are sufficient for diagnosis.[17][32] For other causes of hepatitis, especially chronic causes, blood tests may not be useful.[32] In this case, liver biopsy is the gold standard for establishing the diagnosis: histopathologic analysis is able to reveal the precise extent and pattern of inflammation and fibrosis.[32] Biopsy is typically not the initial diagnostic test because it is invasive and is associated with a small but significant risk of bleeding that is increased in people with liver injury and cirrhosis.[69]

Blood testing includes liver enzymes, serology (i.e. for autoantibodies), nucleic acid testing (i.e. for hepatitis virus DNA/RNA), blood chemistry, and complete blood count.[32] Characteristic patterns of liver enzyme abnormalities can point to certain causes or stages of hepatitis.[70][71] Generally, AST and ALT are elevated in most cases of hepatitis regardless of whether the person shows any symptoms.[32] The degree of elevation (i.e. levels in the hundreds vs. in the thousands), the predominance for AST vs. ALT elevation, and the ratio between AST and ALT are informative of the diagnosis.[32]

Ultrasound, CT, and MRI can all identify steatosis (fatty changes) of the liver tissue and nodularity of the liver surface suggestive of cirrhosis.[72][73] CT and especially MRI are able to provide a higher level of detail, allowing visualization and characterize such structures as vessels and tumors within the liver.[74] Unlike steatosis and cirrhosis, no imaging test is able to detect liver inflammation (i.e. hepatitis) or fibrosis.[32] Liver biopsy is the only definitive diagnostic test that is able to assess inflammation and fibrosis of the liver.[32]

Viral hepatitis

[edit]

Viral hepatitis is primarily diagnosed through blood tests for levels of viral antigens (such as the hepatitis B surface or core antigen), anti-viral antibodies (such as the anti-hepatitis B surface antibody or anti-hepatitis A antibody), or viral DNA/RNA.[17][32] In early infection (i.e. within 1 week), IgM antibodies are found in the blood.[32] In late infection and after recovery, IgG antibodies are present and remain in the body for up to years.[32] Therefore, when a patient is positive for IgG antibody but negative for IgM antibody, he is considered immune from the virus via either prior infection and recovery or prior vaccination.[32]

In the case of hepatitis B, blood tests exist for multiple virus antigens (which are different components of the virion particle) and antibodies.[75] The combination of antigen and antibody positivity can provide information about the stage of infection (acute or chronic), the degree of viral replication, and the infectivity of the virus.[75]

Alcoholic versus non-alcoholic

[edit]

The most apparent distinguishing factor between alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH) is a history of excessive alcohol use.[76] Thus, in patients who have no or negligible alcohol use, the diagnosis is unlikely to be alcoholic hepatitis. In those who drink alcohol, the diagnosis may just as likely be alcoholic or nonalcoholic hepatitis especially if there is concurrent obesity, diabetes, and metabolic syndrome. In this case, alcoholic and nonalcoholic hepatitis can be distinguished by the pattern of liver enzyme abnormalities; specifically, in alcoholic steatohepatitis AST>ALT with ratio of AST:ALT>2:1 while in nonalcoholic steatohepatitis ALT>AST with ratio of ALT:AST>1.5:1.[76]

Liver biopsies show identical findings in patients with ASH and NASH, specifically, the presence of polymorphonuclear infiltration, hepatocyte necrosis and apoptosis in the form of ballooning degeneration, Mallory bodies, and fibrosis around veins and sinuses.[32]

Virus screening

[edit]

The purpose of screening for viral hepatitis is to identify people infected with the disease as early as possible, even before symptoms and transaminase elevations may be present. This allows for early treatment, which can both prevent disease progression and decrease the likelihood of transmission to others.[77]

Hepatitis A

[edit]

Hepatitis A causes an acute illness that does not progress to chronic liver disease. Therefore, the role of screening is to assess immune status in people who are at high risk of contracting the virus, as well as in people with known liver disease for whom hepatitis A infection could lead to liver failure.[78][79] People in these groups who are not already immune can receive the hepatitis A vaccine.[citation needed]

Those at high risk and in need of screening include:[80][81][82]

  • People in close contact (either living with or having sexual contact) with someone who has hepatitis A
  • People traveling to an area with endemic hepatitis A
  • People who do not have access to clean water
  • People who use illicit drugs
  • People with liver disease
  • People with poor sanitary habits such as not washing hands after using the restroom or changing diapers

The presence of anti-hepatitis A IgG in the blood indicates past infection with the virus or prior vaccination.[83]

Hepatitis B

[edit]
Hepatitis B virus v2

The CDC, WHO, USPSTF, and ACOG recommend routine hepatitis B screening for certain high-risk populations.[84][85][86][87] Specifically, these populations include people who are:

Screening consists of a blood test that detects hepatitis B surface antigen (HBsAg). If HBsAg is present, a second test – usually done on the same blood sample – that detects the antibody for the hepatitis B core antigen (anti-HBcAg) can differentiate between acute and chronic infection.[84][88] People who are high-risk whose blood tests negative for HBsAg can receive the hepatitis B vaccine to prevent future infection.[84][85][86][87]

Hepatitis C

[edit]
HCV structure
ABHD5CGI-58-the-Chanarin-Dorfman-Syndrome-Protein-Mobilises-Lipid-Stores-for-Hepatitis-C-Virus-ppat.1005568.s014

The CDC, WHO, USPSTF, AASLD, and ACOG recommend screening people at high risk for hepatitis C infection.[87][89][90][91][10] These populations include people who are:

  • Adults in the United States born between 1945 and 1965[91][10]
  • Blood or organ donors.[10]
  • Born to HCV-positive mothers[10]
  • HIV-positive[89][90][91][10]
  • Incarcerated, or who have been in the past[89][90][91][10]
  • Intranasal illicit drug users[89][90][91][10]
  • Intravenous drug users (past or current)[89][90][91][10]
  • Men who have sex with men[10]
  • On long-term hemodialysis, or who have been in the past[89][90][91][10]
  • Pregnant, and engaging in high-risk behaviors[87]
  • Recipients of blood products or organs prior to 1992 in the United States[89][91][10]
  • Recipients of tattoos in an "unregulated setting"[91][10]
  • Sex workers[90]
  • Workers in a healthcare setting who have had a needlestick injury[10]

For people in the groups above whose exposure is ongoing, screening should be periodic, though there is no set optimal screening interval.[91] The AASLD recommends screening men who have sex with men who are HIV-positive annually.[10] People born in the US between 1945 and 1965 should be screened once (unless they have other exposure risks).[89][91][10]

Screening consists of a blood test that detects anti-hepatitis C virus antibody. If anti-hepatitis C virus antibody is present, a confirmatory test to detect HCV RNA indicates chronic disease.[90][10]

Hepatitis D

[edit]

The CDC, WHO, USPSTF, AASLD, and ACOG recommend screening people at high risk for hepatitis D infection.[87][89][90][91][10] These populations include people who are:

Hepatitis D is extremely rare. Symptoms include chronic diarrhea, anal and intestinal blisters, purple urine, and burnt popcorn scented breath.[84][85][86] Screening consists of a blood test that detects the anti-hepitits D virus antibbody. If anti-hepitits D virus antibody is present, a confirmatory test to detect HDV RNA DNA indicates chronic disease.[90][10]

Prevention

[edit]

Vaccines

[edit]

Hepatitis A

[edit]
Havrix vaccine

The CDC recommends the hepatitis A vaccine for all children beginning at age one, as well as for those who have not been previously immunized and are at high risk for contracting the disease.[80][81]

For children 12 months of age or older, the vaccination is given as a shot into the muscle in two doses 6–18 months apart and should be started before the age 24 months.[92]  The dosing is slightly different for adults depending on the type of the vaccine.  If the vaccine is for hepatitis A only, two doses are given 6–18 months apart depending on the manufacturer.[82]  If the vaccine is combined hepatitis A and hepatitis B, up to 4 doses may be required.[82]

Hepatitis B

[edit]
WHO-UNICEF estimates of hepatitis B vaccine (HepB-BD) coverage in countries from the European WHO region in the years 2000–2015

The CDC recommends the routine vaccination of all children under the age of 19 with the hepatitis B vaccine.[93] They also recommend it for those who desire it or are at high risk.[81]

Routine vaccination for hepatitis B starts with the first dose administered as  a shot into the muscle before the newborn is discharged from the hospital. An additional two doses should be administered before the child is 18 months.[92]

For babies born to a mother with hepatitis B surface antigen positivity, the first dose is unique – in addition to the vaccine, the hepatitis immune globulin should also be administered, both within 12 hours of birth.  These newborns should also be regularly tested for infection for at least the first year of life.[92]

There is also a combination formulation that includes both hepatitis A and B vaccines.[94]

Other

[edit]

There are currently no vaccines available in the United States for hepatitis C or E.[90][95][96] In 2015, a group in China published an article regarding the development of a vaccine for hepatitis E.[97] As of March 2016, the United States government was in the process of recruiting participants for the phase IV trial of the hepatitis E vaccine.[98]

Behavioral changes

[edit]

Hepatitis A

[edit]

Because hepatitis A is transmitted primarily through the oral-fecal route, the mainstay of prevention aside from vaccination is good hygiene, access to clean water and proper handling of sewage.[81]

Hepatitis B and C

[edit]

As hepatitis B and C are transmitted through blood and multiple bodily fluids, prevention is aimed at screening blood prior to transfusion, abstaining from the use of injection drugs, safe needle and sharps practices in healthcare settings, and safe sex practices.[30][90]

Hepatitis D

[edit]
Worldwide prevalence of HDV among HBV carriers in 2015. Eight genotypes have been identified worldwide by comparative phylogenetic analysis. Genotype 1 is the most frequent and has variable pathogenicity, Genotypes 2 and 4 are found in East Asia causing relatively mild disease. Genotype 3 is found in South America in association with severe hepatitis. Genotypes 5, 6, 7, 8 have been found only in Africa.[99]

The hepatitis D virus requires that a person first be infected with hepatitis B virus, so prevention efforts should focus on limiting the spread of hepatitis B. In people who have chronic hepatitis B infection and are at risk for superinfection with the hepatitis D virus, the preventive strategies are the same as for hepatitis B.[96]

Hepatitis E

[edit]

Hepatitis E is spread primarily through the oral-fecal route but may also be spread by blood and from mother to fetus. The mainstay of hepatitis E prevention is similar to that for hepatitis A (namely, good hygiene and clean water practices).[95]

Alcoholic and metabolic hepatitis

[edit]

As excessive alcohol consumption can lead to hepatitis and cirrhosis, the following are maximal recommendations for alcohol consumption:[100]

  • Men – ≤ 4 drinks on any given day and ≤ 14 drinks per week
  • Women – ≤ 3 drinks on any given day and ≤ 7 drinks per week

To prevent MAFLD it is recommended to maintain a normal weight, eat a healthy diet, avoid added sugar, and exercise regularly.[101][102]

Successes

[edit]

Hepatitis A

[edit]

In the United States, universal immunization has led to a two-thirds decrease in hospital admissions and medical expenses due to hepatitis A.[103]

Hepatitis B

[edit]

In the United States new cases of hepatitis B decreased 75% from 1990 to 2004.[104]  The group that saw the greatest decrease was children and adolescents, likely reflecting the implementation of the 1999 guidelines.[105]

Hepatitis C

[edit]

Hepatitis C infections each year had been declining since the 1980s, but began to increase again in 2006.[106] The data are unclear as to whether the decline can be attributed to needle exchange programmes.[107]

Alcoholic hepatitis

[edit]
Depiction of a liver failure patient

Because people with alcoholic hepatitis may have no symptoms, it can be difficult to diagnose and the number of people with the disease is probably higher than many estimates.[108] Programs such as Alcoholics Anonymous have been successful in decreasing death due to cirrhosis, but it is difficult to evaluate their success in decreasing the incidence of alcoholic hepatitis.[109]

Treatment

[edit]

The treatment of hepatitis varies according to the type, whether it is acute or chronic, and the severity of the disease.

  • Activity: Many people with hepatitis prefer bed rest, though it is not necessary to avoid all physical activity while recovering.[17]
  • Diet: A high-calorie diet is recommended.[17] Many people develop nausea and cannot tolerate food later in the day, so the bulk of intake may be concentrated in the earlier part of the day.[17] In the acute phase of the disease, intravenous feeding may be needed if patients cannot tolerate food and have poor oral intake subsequent to nausea and vomiting.[17]
  • Drugs: People with hepatitis should avoid taking drugs metabolized by the liver.[17] Glucocorticoids are not recommended as a treatment option for acute viral hepatitis and may even cause harm, such as development of chronic hepatitis.[17]
  • Precautions: Universal precautions should be observed. Isolation is usually not needed, except in cases of hepatitis A and E who have fecal incontinence, and in cases of hepatitis B and C who have uncontrolled bleeding.[17]

Hepatitis A

[edit]

Hepatitis A usually does not progress to a chronic state, and rarely requires hospitalization.[17][80] Treatment is supportive and includes such measures as providing intravenous (IV) hydration and maintaining adequate nutrition.[17][80]

Rarely, people with the hepatitis A virus can rapidly develop liver failure, termed fulminant hepatic failure, especially the elderly and those who had a pre-existing liver disease, especially hepatitis C.[17][80] Mortality risk factors include greater age and chronic hepatitis C.[17] In these cases, more aggressive supportive therapy and liver transplant may be necessary.[17]

Hepatitis B

[edit]

Acute

[edit]

In healthy patients, 95–99% recover with no long-lasting effects, and antiviral treatment is not warranted.[17] Age and comorbid conditions can result in a more prolonged and severe illness. Certain patients warrant hospitalization, especially those who present with clinical signs of ascites, peripheral edema, and hepatic encephalopathy, and laboratory signs of hypoglycemia, prolonged prothrombin time, low serum albumin, and very high serum bilirubin.[17]

In these rare, more severe acute cases, patients have been successfully treated with antiviral therapy similar to that used in cases of chronic hepatitis B, with nucleoside analogues such as entecavir or tenofovir. As there is a dearth of clinical trial data and the drugs used to treat are prone to developing resistance, experts recommend reserving treatment for severe acute cases, not mild to moderate.[17]

Chronic

[edit]

Chronic hepatitis B management aims to control viral replication, which is correlated with progression of disease.[20] Seven drugs are approved in the United States:[20]

  • Adefovir dipivoxil, a nucleotide analogue, has been used to supplement lamivudine in patients who develop resistance, but is no longer recommended as first-line therapy.[20]
  • Entecavir is safe, well tolerated, less prone to developing resistance, and the most potent of the existing hepatitis B antivirals; it is thus a first-line treatment choice.[20] It is not recommended for lamivudine-resistant patients or as monotherapy in patients who are HIV positive.[20]
  • Injectable interferon alpha was the first therapy approved for chronic hepatitis B.[20] It has several side effects, most of which are reversible with removal of therapy, but it has been supplanted by newer treatments for this indication.[20] These include long-acting interferon bound to polyethylene glycol (pegylated interferon) and the oral nucleoside analogues.[20]
  • Lamivudine was the first approved oral nucleoside analogue.[20] While effective and potent, lamivudine has been replaced by newer, more potent treatments in the Western world and is no longer recommended as first-line treatment.[20] It is still used in areas where newer agents either have not been approved or are too costly.[20] Generally, the course of treatment is a minimum of one year with a minimum of six additional months of "consolidation therapy."[20] Based on viral response, longer therapy may be required, and certain patients require indefinite long-term therapy.[20] Due to a less robust response in Asian patients, consolidation therapy is recommended to be extended to at least a year.[20] All patients should be monitored for viral reactivation, which if identified, requires restarting treatment.[20] Lamivudine is generally safe and well tolerated.[20] Many patients develop resistance, which is correlated with longer treatment duration.[20] If this occurs, an additional antiviral is added.[20] Lamivudine as a single treatment is contraindicated in patients coinfected with HIV, as resistance develops rapidly, but it can be used as part of a multidrug regimen.[20]
  • Pegylated interferon (PEG IFN) is dosed just once a week as a subcutaneous injection and is both more convenient and effective than standard interferon.[20] Although it does not develop resistance as do many of the oral antivirals, it is poorly tolerated and requires close monitoring.[20] PEG IFN is estimated to cost about $18,000 per year in the United States, compared to $2,500–8,700 for the oral medications. Its treatment duration is 48 weeks, unlike oral antivirals which require indefinite treatment for most patients (minimum one year).[20] PEG IFN is not effective in patients with high levels of viral activity and cannot be used in immunosuppressed patients or those with cirrhosis.[20]
  • Telbivudine is effective but not recommended as first-line treatment; as compared to entecavir, it is both less potent and more resistance prone.[20]
  • Tenofovir is a nucleotide analogue and an antiretroviral drug that is also used to treat HIV infection.[20] It is preferred to adefovir both in lamivudine-resistant patients and as initial treatment since it is both more potent and less likely to develop resistance.[20]

First-line treatments currently used include PEG IFN, entecavir, and tenofovir, subject to patient and physician preference.[20] Treatment initiation is guided by recommendations issued by The American Association for the Study of Liver Diseases (AASLD) and the European Association for the Study of the Liver (EASL) and is based on detectable viral levels, HBeAg positive or negative status, ALT levels, and in certain cases, family history of HCC and liver biopsy.[20] In patients with compensated cirrhosis, treatment is recommended regardless of HBeAg status or ALT level, but recommendations differ regarding HBV DNA levels; AASLD recommends treating at DNA levels detectable above 2x103 IU/mL; EASL and WHO recommend treating when HBV DNA levels are detectable at any level.[20][86] In patients with decompensated cirrhosis, treatment and evaluation for liver transplantation are recommended in all cases if HBV DNA is detectable.[20][86] Currently, multidrug treatment is not recommended in treatment of chronic HBV as it is no more effective in the long term than individual treatment with entecavir or tenofovir.[20]

Hepatitis C

[edit]

The American Association for the Study of Liver Diseases and the Infectious Diseases Society of America (AASLD-IDSA) recommend antiviral treatment for all patients with chronic hepatitis C infection except for those with additional chronic medical conditions that limit their life expectancy.[10]

Once it is acquired, persistence of the hepatitis C virus is the rule, resulting in chronic hepatitis C. The goal of treatment is prevention of hepatocellular carcinoma (HCC).[110] The best way to reduce the long-term risk of HCC is to achieve sustained virological response (SVR).[110] SVR is defined as an undetectable viral load at 12 weeks after treatment completion and indicates a cure.[111][112] Currently available treatments include indirect and direct acting antiviral drugs.[111][112] The indirect acting antivirals include pegylated interferon (PEG IFN) and ribavirin (RBV), which in combination have historically been the basis of therapy for HCV.[111][112] Duration of and response to these treatments varies based on genotype.[111][112] These agents are poorly tolerated but are still used in some resource-poor areas.[111][112] In high-resource countries, they have been supplanted by direct acting antiviral agents, which first appeared in 2011; these agents target proteins responsible for viral replication and include the following three classes:[111][112]

These drugs are used in various combinations, sometimes combined with ribavirin, based on the patient's genotype, delineated as genotypes 1–6.[112] Genotype 1 (GT1), which is the most prevalent genotype in the United States and around the world, can now be cured with a direct acting antiviral regimen.[112] First-line therapy for GT1 is a combination of sofosbuvir and ledipasvir (SOF/LDV) for 12 weeks for most patients, including those with advanced fibrosis or cirrhosis.[112] Certain patients with early disease need only 8 weeks of treatment while those with advanced fibrosis or cirrhosis who have not responded to prior treatment require 24 weeks.[112] Cost remains a major factor limiting access to these drugs, particularly in low-resource nations; the cost of the 12-week GT1 regimen (SOF/LDV) has been estimated at US$94,500.[111]

Hepatitis D

[edit]

Hepatitis D is difficult to treat, and effective treatments are lacking. Interferon alpha has proven effective at inhibiting viral activity but only on a temporary basis.[113]

Hepatitis E

[edit]
Hepatitis E virus

Similar to hepatitis A, treatment of hepatitis E is supportive and includes rest and ensuring adequate nutrition and hydration.[114] Hospitalization may be required for particularly severe cases or for pregnant women.[114]

Alcoholic hepatitis

[edit]

First-line treatment of alcoholic hepatitis is treatment of alcoholism.[35] For those who abstain completely from alcohol, reversal of liver disease and a longer life are possible; patients at every disease stage have been shown to benefit by prevention of additional liver injury.[35][66] In addition to referral to psychotherapy and other treatment programs, treatment should include nutritional and psychosocial evaluation and treatment.[35][66][115] Patients should also be treated appropriately for related signs and symptoms, such as ascites, hepatic encephalopathy, and infection.[66]

Severe alcoholic hepatitis has a poor prognosis and is notoriously difficult to treat.[35][66][115] Without any treatment, 20–50% of patients may die within a month, but evidence shows treatment may extend life beyond one month (i.e., reduce short-term mortality).[35][115][116] Available treatment options include pentoxifylline (PTX), which is a nonspecific TNF inhibitor, corticosteroids, such as prednisone or prednisolone (CS), corticosteroids with N-acetylcysteine (CS with NAC), and corticosteroids with pentoxifylline (CS with PTX).[115] Data suggest that CS alone or CS with NAC are most effective at reducing short-term mortality.[115] Unfortunately, corticosteroids are contraindicated in some patients, such as those who have active gastrointestinal bleeding, infection, kidney failure, or pancreatitis.[35][66] In these cases PTX may be considered on a case-by-case basis in lieu of CS; some evidence shows PTX is better than no treatment at all and may be comparable to CS while other data show no evidence of benefit over placebo.[115][116] Unfortunately, there are currently no drug treatments that decrease these patients' risk of dying in the longer term, at 3–12 months and beyond.[115]

Weak evidence suggests milk thistle extracts may improve survival in alcoholic liver disease and improve certain liver tests (serum bilirubin and GGT) without causing side effects, but a firm recommendation cannot be made for or against milk thistle without further study.[117] 

The modified Maddrey's discriminant function may be used to evaluate the severity and prognosis in alcoholic hepatitis and evaluates the efficacy of using alcoholic hepatitis corticosteroid treatment.

Metabolic hepatitis

[edit]

The main treatment of NASH is gradual weight loss and increased physical activity. In the United States, no medications have been approved to treat this disease.[118]

Autoimmune hepatitis

[edit]

Autoimmune hepatitis is commonly treated by immunosuppressants such as the corticosteroids prednisone or prednisolone, the active version of prednisolone that does not require liver synthesis, either alone or in combination with azathioprine, and some have suggested the combination therapy is preferred to allow for lower doses of corticosteroids to reduce associated side effects,[49] although the result of treatment efficacy is comparative.[119]

Treatment of autoimmune hepatitis consists of two phases; an initial and maintenance phase. The initial phase consists of higher doses of corticosteroids which are tapered down over a number of weeks to a lower dose. If used in combination, azathioprine is given during the initial phase as well. Once the initial phase has been completed, a maintenance phase that consists of lower dose corticosteroids, and in combination therapy, azathioprine until liver blood markers are normalized. Treatment results in 66–91% of patients achieving normal liver test values in two years, with the average being 22 months.[49]

Prognosis

[edit]

Acute hepatitis

[edit]

Nearly all patients with hepatitis A infections recover completely without complications if they were healthy prior to the infection. Similarly, acute hepatitis B infections have a favorable course towards complete recovery in 95–99% of patients.[17] Certain factors may portend a poorer outcome, such as co-morbid medical conditions or initial presenting symptoms of ascites, edema, or encephalopathy.[17] Overall, the mortality rate for acute hepatitis is low: ~0.1% in total for cases of hepatitis A and B, but rates can be higher in certain populations (super infection with both hepatitis B and D, pregnant women, etc.).[17]

In contrast to hepatitis A & B, hepatitis C carries a much higher risk of progressing to chronic hepatitis, approaching 85–90%.[120] Cirrhosis has been reported to develop in 20–50% of patients with chronic hepatitis C.[citation needed]

Other rare complications of acute hepatitis include pancreatitis, aplastic anemia, peripheral neuropathy, and myocarditis.[17]

Fulminant hepatitis

[edit]

Despite the relatively benign course of most viral cases of hepatitis, fulminant hepatitis represents a rare but feared complication. Fulminant hepatitis most commonly occurs in hepatitis B, D, and E. About 1–2% of cases of hepatitis E can lead to fulminant hepatitis, but pregnant women are particularly susceptible, occurring in up to 20% of cases.[121] Mortality rates in cases of fulminant hepatitis rise over 80%, but those patients that do survive often make a complete recovery. Liver transplantation can be life-saving in patients with fulminant liver failure.[122]

Hepatitis D infections can transform benign cases of hepatitis B into severe, progressive hepatitis, a phenomenon known as superinfection.[123]

Chronic hepatitis

[edit]

Acute hepatitis B infections become less likely to progress to chronic forms as the age of the patient increases, with rates of progression approaching 90% in vertically transmitted cases of infants compared to 1% risk in young adults.[20] Overall, the five-year survival rate for chronic hepatitis B ranges from 97% in mild cases to 55% in severe cases with cirrhosis.[20]

Most patients who acquire hepatitis D at the same time as hepatitis B (co-infection) recover without developing a chronic infection. In people with hepatitis B who later acquire hepatitis D (superinfection), chronic infection is much more common at 80–90%, and liver disease progression is accelerated.[113][124]

Chronic hepatitis C progresses towards cirrhosis, with estimates of cirrhosis prevalence of 16% at 20 years after infection.[125] While the major causes of mortality in hepatitis C is end stage liver disease, hepatocellular carcinoma is an important additional long term complication and cause of death in chronic hepatitis.

Rates of mortality increase with progression of the underlying liver disease. Series of patients with compensated cirrhosis due to HCV have shown 3,5, and 10-year survival rates of 96, 91, and 79% respectively.[126] The 5-year survival rate drops to 50% upon if the cirrhosis becomes decompensated.

Epidemiology

[edit]

Viral hepatitis

[edit]

Hepatitis A

[edit]

Hepatitis A is found throughout the world and manifests as large outbreaks and epidemics associated with fecal contamination of water and food sources.[105] Hepatitis A viral infection is predominant in children ages 5–14 with rare infection of infants.[105] Infected children have little to no apparent clinical illness, in contrast to adults in whom greater than 80% are symptomatic if infected.[127] Infection rates are highest in low resource countries with inadequate public sanitation and large concentrated populations.[17][128] In such regions, as much as 90% of children younger than 10 years old have been infected and are immune, corresponding both to lower rates of clinically symptomatic disease and outbreaks.[105][128][129] The availability of a childhood vaccine has significantly reduced infections in the United States, with incidence declining by more than 95% as of 2013.[130] Paradoxically, the highest rates of new infection now occur in young adults and adults who present with worse clinical illness.[17] Specific populations at greatest risk include: travelers to endemic regions, men who have sex with men, those with occupational exposure to non-human primates, people with clotting disorders who have received clotting factors, people with history of chronic liver disease in whom co-infection with hepatitis A can lead to fulminant hepatitis, and intravenous drug users (rare).[105]

Hepatitis B

[edit]
HBV replication

Hepatitis B is the most common cause of viral hepatitis in the world with more than 240 million chronic carriers of the virus, 1 million of whom are in the United States.[30][105] In approximately two-thirds of patients who develop acute hepatitis B infection, no identifiable exposure is evident.[17] Of those acutely infected, 25% become lifetime carriers of the virus.[105] Risk of infection is highest among intravenous drug users, people with high-risk sexual behaviors, healthcare workers, people who had multiple transfusions, organ transplant patients, dialysis patients and newborns infected during the birthing process.[105] Close to 780,000 deaths in the world are attributed to hepatitis B.[30] The most endemic regions are in sub-Saharan Africa and East Asia, where as many as 10% of adults are chronic carriers.[30] Carrier rates in developed nations are significantly lower, encompassing less than 1% of the population.[30] In endemic regions, transmission is thought to be associated with exposure during birth and close contact between young infants.[17][30]

Hepatitis C

[edit]
HepC replication

Chronic hepatitis C is a major cause of liver cirrhosis and hepatocellular carcinoma.[131] It is a common medical reason for liver transplantation due to its severe complications.[131] It is estimated that 130–180 million people in the world are affected by this disease representing a little more than 3% of the world population.[90][105][131] In the developing regions of Africa, Asia and South America, prevalence can be as high as 10% of the population.[105] In Egypt, rates of hepatitis C infection as high as 20% have been documented and are associated with iatrogenic contamination related to schistosomiasis treatment in the 1950s–1980s.[17][105] Currently in the United States, approximately 3.5 million adults are estimated to be infected.[132] Hepatitis C is particularly prevalent among people born between 1945 and 1965, a group of about 800,000 people, with prevalence as high as 3.2% versus 1.6% in the general U.S. population.[17] Most chronic carriers of hepatitis C are unaware of their infection status.[17] The most common mode of transmission of hepatitis C virus is exposure to blood products via blood transfusions (prior to 1992) and intravenous drug injection.[17][105] A history of intravenous drug injection is the most important risk factor for chronic hepatitis C.[131] Other susceptible populations include those engaged in high-risk sexual behavior, infants of infected mothers, and healthcare workers.[105]

Hepatitis D

[edit]

The hepatitis D virus causes chronic and fulminant hepatitis in the context of co-infection with the hepatitis B virus.[105] It is primarily transmitted via non-sexual contact and via needles.[17][105] Susceptibility to hepatitis D differs by geographic region.[17][105] In the United States and Northern Europe, populations at risk are intravenous drug users and people who receive multiple transfusions.[17][105] In the Mediterranean, hepatitis D is predominant among hepatitis B virus co-infected people.[17][105]

Hepatitis E

[edit]

Similar to Hepatitis A, hepatitis E manifests as large outbreaks and epidemics associated with fecal contamination of water sources.[17] It accounts for more than 55,000 deaths annually with approximately 20 million people worldwide thought to be infected with the virus.[95] It affects predominantly young adults, causing acute hepatitis.[17][133] In infected pregnant women, Hepatitis E infection can lead to fulminant hepatitis with third trimester mortality rates as high as 30%.[105][133] Those with weakened immune systems, such as organ transplant recipients, are also susceptible.[133] Infection is rare in the United States but rates are high in the developing world (Africa, Asia, Central America, Middle East).[17][133] Many genotypes exist and are differentially distributed around the world.[95] There is some evidence of hepatitis E infection of animals, serving as a reservoir for human infection.[105]

Alcoholic hepatitis

[edit]

Alcoholic hepatitis (AH) in its severe form has a one-month mortality as high as 50%.[66][67][134] Most people who develop AH are men but women are at higher risk of developing AH and its complications likely secondary to high body fat and differences in alcohol metabolism.[67] Other contributing factors include younger age <60, binge pattern drinking, poor nutritional status, obesity and hepatitis C co-infection.[67] It is estimated that as much as 20% of people with AH are also infected with hepatitis C.[135] In this population, the presence of hepatitis C virus leads to more severe disease with faster progression to cirrhosis, hepatocellular carcinoma and increased mortality.[67][135][136] Obesity increases the likelihood of progression to cirrhosis in cases of alcoholic hepatitis.[67] It is estimated that 70% of people who have AH will progress to cirrhosis.[67]

Non-alcoholic steatohepatitis

[edit]

Non-alcoholic steatohepatitis (NASH) is projected to become the top reason for liver transplantation in the United States by 2020, supplanting chronic liver disease due to hepatitis C.[137] About 20–45% of the U.S. population have NAFLD and 6% have NASH.[32][43] The estimated prevalence of NASH in the world is 3–5%.[138] Of NASH patients who develop cirrhosis, about 2% per year will likely progress to hepatocellular carcinoma.[138] Worldwide, the estimated prevalence of hepatocellular carcinoma related to NAFLD is 15–30%.[139] NASH is thought to be the primary cause of cirrhosis in approximately 25% of patients in the United States, representing 1–2% of the general population.[139]

History

[edit]

Early observations

[edit]

Initial accounts of a syndrome that we now think is likely to be hepatitis begin to occur around 3000 B.C. Clay tablets that served as medical handbooks for the ancient Sumerians described the first observations of jaundice. The Sumerians believed that the liver was the home of the soul, and attributed the findings of jaundice to the attack of the liver by a devil named Ahhazu.[140]

Around 400 B.C., Hippocrates recorded the first documentation of an epidemic jaundice, in particular noting the uniquely fulminant course of a cohort of patients who all died within two weeks. He wrote, "The bile contained in the liver is full of phlegm and blood, and erupts...After such an eruption, the patient soon raves, becomes angry, talks nonsense and barks like a dog."[141]

Given the poor sanitary conditions of war, infectious jaundice played a large role as a major cause of mortality among troops in the Napoleonic Wars, the American Revolutionary War, and both World Wars.[142] During World War II, estimates of soldiers affected by hepatitis were upwards of 10 million.

During World War II, soldiers received vaccines against diseases such as yellow fever, but these vaccines were stabilized with human serum, presumably contaminated with hepatitis viruses, which often created epidemics of hepatitis.[143] It was suspected these epidemics were due to a separate infectious agent, and not due to the yellow fever virus itself, after noting 89 cases of jaundice in the months after vaccination out of a total 3,100 patients that were vaccinated. After changing the seed virus strain, no cases of jaundice were observed in the subsequent 8,000 vaccinations.[144]

Willowbrook State School experiments

[edit]

A New York University researcher named Saul Krugman continued this research into the 1950s and 1960s, most infamously with his experiments on mentally disabled children at the Willowbrook State School in New York, a crowded urban facility where hepatitis infections were highly endemic to the student body. Krugman injected students with gamma globulin, a type of antibody. After observing the temporary protection against infection this antibody provided, he then tried injected live hepatitis virus into students. Krugman also controversially took feces from infected students, blended it into milkshakes, and fed it to newly admitted children.[145]

His research was received with much controversy, as people protested the questionable ethics surrounding the chosen target population. Henry Beecher was one of the foremost critics in an article in the New England Journal of Medicine in 1966, arguing that parents were unaware to the risks of consent and that the research was done to benefit others at the expense of children.[146] Moreover, he argued that poor families with mentally disabled children often felt pressured to join the research project to gain admission to the school, with all of the educational and support resources that would come along with it.[147] Others in the medical community spoke out in support of Krugman's research in terms of its widespread benefits and understanding of the hepatitis virus, and Willowbrook continues to be a commonly cited example in debates about medical ethics.[148]

Australia antigen

[edit]

The next insight regarding hepatitis B was a serendipitous one by Dr. Baruch Blumberg, a researcher at the NIH who did not set out to research hepatitis, but rather studied lipoprotein genetics. He travelled across the globe collecting blood samples, investigating the interplay between disease, environment, and genetics with the goal of designing targeted interventions for at-risk people that could prevent them from getting sick.[149] He noticed an unexpected interaction between the blood of a patient with hemophilia that had received multiple transfusions and a protein found in the blood of an indigenous Australian person.[150] He named the protein the "Australia antigen" and made it the focus of his research. He found a higher prevalence of the protein in the blood of patients from developing countries, compared to those from developed ones, and noted associations of the antigen with other diseases like leukemia and Down Syndrome.[151] Eventually, he came to the unifying conclusion that the Australia antigen was associated with viral hepatitis.

In 1970, David Dane first isolated the hepatitis B virion at London's Middlesex Hospital, and named the virion the 42-nm "Dane particle".[147] Based on its association with the surface of the hepatitis B virus, the Australia antigen was renamed to "hepatitis B surface antigen" or HBsAg.

Blumberg continued to study the antigen, and eventually developed the first hepatitis B vaccine using plasma rich in HBsAg, for which he received the Nobel Prize in Medicine in 1976.[152]

Society and culture

[edit]

Economic burden

[edit]

Overall, hepatitis accounts for a significant portion of healthcare expenditures in both developing and developed nations, and is expected to rise in several developing countries.[153][154] While hepatitis A infections are self-limited events, they are associated with significant costs in the United States.[155] It has been estimated that direct and indirect costs are approximately $1817 and $2459 respectively per case, and that an average of 27 work days is lost per infected adult.[155] A 1997 report demonstrated that a single hospitalization related to hepatitis A cost an average of $6,900 and resulted in around $500 million in total annual healthcare costs.[156] Cost effectiveness studies have found widespread vaccination of adults to not be feasible, but have stated that a combination hepatitis A and B vaccination of children and at risk groups (people from endemic areas, healthcare workers) may be.[157]

Hepatitis B accounts for a much larger percentage of health care spending in endemic regions like Asia.[158][159] In 1997 it accounted for 3.2% of South Korea's total health care expenditures and resulted in $696 million in direct costs.[159] A large majority of that sum was spent on treating disease symptoms and complications.[160] Chronic hepatitis B infections are not as endemic in the United States, but accounted for $357 million in hospitalization costs in the year 1990.[153] That number grew to $1.5 billion in 2003, but remained stable as of 2006, which may be attributable to the introduction of effective drug therapies and vaccination campaigns.[153][154]

People infected with chronic hepatitis C tend to be frequent users of the health care system globally.[161] It has been estimated that a person infected with hepatitis C in the United States will result in a monthly cost of $691.[161] That number nearly doubles to $1,227 for people with compensated (stable) cirrhosis, while the monthly cost of people with decompensated (worsening) cirrhosis is almost five times as large at $3,682.[161] The wide-ranging effects of hepatitis make it difficult to estimate indirect costs, but studies have speculated that the total cost is $6.5 billion annually in the United States.[153] In Canada, 56% of HCV related costs are attributable to cirrhosis and total expenditures related to the virus are expected to peak at CAD$396 million in the year 2032.[162]

2003 Monaca outbreak

[edit]

The largest outbreak of hepatitis A virus in United States history occurred among people who ate at a now-defunct Mexican food restaurant located in Monaca, Pennsylvania in late 2003.[163] Over 550 people who visited the restaurant between September and October 2003 were infected with the virus, three of whom died as a direct result.[163] The outbreak was brought to the attention of health officials when local emergency medicine physicians noticed a significant increase in cases of hepatitis A in the county.[164] After conducting its investigation, the CDC attributed the source of the outbreak to the use of contaminated raw green onion. The restaurant was purchasing its green onion stock from farms in Mexico at the time.[163] It is believed that the green onions may have been contaminated through the use of contaminated water for crop irrigation, rinsing, or icing or by handling of the vegetables by infected people.[163] Green onion had caused similar outbreaks of hepatitis A in the southern United States prior to this, but not to the same magnitude.[163] The CDC believes that the restaurant's use of a large communal bucket for chopped raw green onion allowed non-contaminated plants to be mixed with contaminated ones, increasing the number of vectors of infection and amplifying the outbreak.[163] The restaurant was closed once it was discovered to be the source, and over 9,000 people were given hepatitis A immune globulin because they had either eaten at the restaurant or had been in close contact with someone who had.[163]

Special populations

[edit]

HIV co-infection

[edit]

Persons infected with HIV have a particularly high burden of HIV-HCV co-infection.[165][166] In a recent study by the WHO, the likelihood of being infected with hepatitis C virus was six times greater in those who also had HIV.[166] The prevalence of HIV-HCV co-infection worldwide was estimated to be 6.2% representing more than 2.2 million people.[166] Intravenous drug use was an independent risk factor for HCV infection.[131] In the WHO study, the prevalence of HIV-HCV co-infection was markedly higher at 82.4% in those who injected drugs compared to the general population (2.4%).[166] In a study of HIV-HCV co-infection among HIV positive men who have sex with men (MSM), the overall prevalence of anti-hepatitis C antibodies was estimated to be 8.1% and increased to 40% among HIV positive MSM who also injected drugs.[165]

Pregnancy

[edit]

Hepatitis B

[edit]

Vertical transmission is a significant contributor of new HBV cases each year, with 35–50% of transmission from mother to neonate in endemic countries.[87][167] Vertical transmission occurs largely via a neonate's exposure to maternal blood and vaginal secretions during birth.[167] While the risk of progression to chronic infection is approximately 5% among adults who contract the virus, it is as high as 95% among neonates subject to vertical transmission.[87][168] The risk of viral transmission is approximately 10–20% when maternal blood is positive for HBsAg, and up to 90% when also positive for HBeAg.[87]

Given the high risk of perinatal transmission, the CDC recommends screening all pregnant women for HBV at their first prenatal visit.[87][169] It is safe for non-immune pregnant women to receive the HBV vaccine.[87][167] Based on the limited available evidence, the American Association for the Study of Liver Diseases (AASLD) recommends antiviral therapy in pregnant women whose viral load exceeds 200,000 IU/mL.[170] A growing body of evidence shows that antiviral therapy initiated in the third trimester significantly reduces transmission to the neonate.[167][170] A systematic review of the Antiretroviral Pregnancy Registry database found that there was no increased risk of congenital anomalies with Tenofovir; for this reason, along with its potency and low risk of resistance, the AASLD recommends this drug.[170][171] A 2010 systematic review and meta-analysis found that Lamivudine initiated early in the third trimester also significantly reduced mother-to-child transmission of HBV, without any known adverse effects.[172]

The ACOG states that the evidence available does not suggest any particular mode of delivery (i.e. vaginal vs. cesarean) is better at reducing vertical transmission in mothers with HBV.[87]

The WHO and CDC recommend that neonates born to mothers with HBV should receive hepatitis B immune globulin (HBIG) as well as the HBV vaccine within 12 hours of birth.[84][86] For infants who have received HBIG and the HBV vaccine, breastfeeding is safe.[87][167]

Hepatitis C

[edit]

Estimates of the rate of HCV vertical transmission range from 2–8%; a 2014 systematic review and meta-analysis found the risk to be 5.8% in HCV-positive, HIV-negative women.[87][173] The same study found the risk of vertical transmission to be 10.8% in HCV-positive, HIV-positive women.[173] Other studies have found the risk of vertical transmission to be as high as 44% among HIV-positive women.[87] The risk of vertical transmission is higher when the virus is detectable in the mother's blood.[173]

Evidence does not indicate that mode of delivery (i.e. vaginal vs. cesarean) has an effect on vertical transmission.[87]

For women who are HCV-positive and HIV-negative, breastfeeding is safe. CDC guidelines suggest avoiding it if a woman's nipples are cracked or bleeding to reduce the risk of transmission.[87][89]

Hepatitis E

[edit]

Pregnant women who contract HEV are at significant risk of developing fulminant hepatitis with maternal mortality rates as high as 20–30%, most commonly in the third trimester .[17][87][167] A 2016 systematic review and meta-analysis of 47 studies that included 3968 people found maternal case-fatality rates (CFR) of 20.8% and fetal CFR of 34.2%; among women who developed fulminant hepatic failure, CFR was 61.2%.[174]

Vaccine

[edit]

An essential defense against hepatitis infections, especially those caused by Hepatitis A and B, is the hepatitis vaccination. The Hepatitis B vaccination is quite effective and frequently used. The frequency of hepatitis-related liver illnesses and fatalities has been considerably decreased by the immunization campaigns.[175]

See also

[edit]

References

[edit]
  1. ^ a b c d e f "Hepatitis". MedlinePlus. Archived from the original on 11 November 2016. Retrieved 10 November 2016.
  2. ^ a b c d e f g "What is hepatitis?". WHO. July 2016. Archived from the original on 7 November 2016. Retrieved 10 November 2016.
  3. ^ a b c d e f g h i j k l m "Hepatitis". NIAID. Archived from the original on 4 November 2016. Retrieved 2 November 2016.
  4. ^ a b "Liver Transplant". NIDDK. April 2012. Archived from the original on 11 November 2016. Retrieved 10 November 2016.
  5. ^ "Hepatitis". MedlinePlus. 2020-05-20. Retrieved 2020-07-19. Your liver is the largest organ inside your body. It helps your body digest food, store energy, and remove poisons. Hepatitis is an inflammation of the liver.
  6. ^ "Hepatitis (Hepatitis A, B, and C) | ACG Patients". patients.gi.org. Archived from the original on 2017-02-23.
  7. ^ Bernal W.; Wendon J. (2013). "Acute Liver Failure". New England Journal of Medicine. 369 (26): 2525–2534. doi:10.1056/nejmra1208937. PMID 24369077. S2CID 205116503.
  8. ^ "Esto es la hepatitis: Conócela, enfréntate a ella". Infoterio Noticias | Ciencia y Tecnología (in Spanish). 8 August 2022. Retrieved 2023-02-12.
  9. ^ a b c "Fatty Liver Disease (Nonalcoholic Steatohepatitis)". NIDDK. May 2014. Archived from the original on 11 November 2016. Retrieved 10 November 2016.
  10. ^ a b c d e f g h i j k l m n o p q r s t u v w x y AASLD/IDSA HCV Guidance Panel (2015-09-01). "Hepatitis C guidance: AASLD-IDSA recommendations for testing, managing, and treating adults infected with hepatitis C virus". Hepatology. 62 (3): 932–954. doi:10.1002/hep.27950. ISSN 1527-3350. PMID 26111063.
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