Examine individual changes

'{{about|[[ischemia]] of the small bowel|ischemia of the large bowel|ischemic colitis}} {{Infobox medical condition (new) | name = Mesenteric ischemia | image = Ischemicbowel.PNG | caption = [[Computer tomography]] (CT) showing dilated loops of small bowel with thickened walls (black arrow), findings characteristic of ischemic bowel due to [[thrombosis]] of the [[superior mesenteric vein]]. | synonyms = Mesenteric ischaemia, mesenteric vascular disease | field = [[Gastroenterology]] | symptoms = '''Acute''': [[Pain out of proportion|sudden severe pain]]<ref name=Surg2013/><br>'''Chronic''': [[abdominal pain]] after eating, [[unintentional weight loss]], [[vomiting]]<ref name=Ye2014/><ref name=Surg2013/> | complications = | onset = > 60 years old<ref name=Britt2012/> | duration = | types = Acute, chronic<ref name=Surg2013/> | causes = | risks = [[Atrial fibrillation]], [[heart failure]], [[chronic renal failure]], being [[thrombophilia|prone to forming blood clots]], previous [[myocardial infarction]]<ref name=Ye2014/> | diagnosis = [[Angiography]], [[computer tomography]]<ref name=Surg2013/> | differential = | prevention = | treatment = [[Stent]]ing, [[thrombolytics|medications to break down the clot]], surgery<ref name=Surg2013/><ref name=Ye2014/> | medication = | prognosis = ~80% risk of death<ref name=Britt2012/> | frequency = '''Acute''': 5 per 100,000 per year (developed world)<ref name=Geo2012/><br>'''Chronic''': 1 per 100,000<ref name=Gus2014/> | deaths = }} <!-- Definition and symptoms --> '''Mesenteric ischemia''' is a medical condition in which injury of the [[small intestine]] occurs due to not enough [[blood]] supply.<ref name=Ye2014>{{cite book|last1=Yelon|first1=Jay A.|title=Geriatric Trauma and Critical Care|date=2014|publisher=Springer Verlag|location=New York|isbn=9781461485018|page=182|edition=Aufl. 2014|url=https://books.google.com/books?id=Uoi4BAAAQBAJ&pg=PA182|deadurl=no|archiveurl=https://web.archive.org/web/20170908171423/https://books.google.com/books?id=Uoi4BAAAQBAJ&pg=PA182|archivedate=2017-09-08|df=}}</ref> It can come on suddenly, known as acute mesenteric ischemia, or gradually, known as chronic mesenteric ischemia.<ref name=Surg2013/> Acute disease often presents with sudden severe pain.<ref name=Surg2013>{{cite journal|last1=Bobadilla|first1=JL|title=Mesenteric ischemia.|journal=The Surgical clinics of North America|date=August 2013|volume=93|issue=4|pages=925–40, ix|pmid=23885938|doi=10.1016/j.suc.2013.04.002}}</ref> Symptoms may come on more slowly in those with acute on chronic disease.<ref name=Ye2014/> Signs and symptoms of chronic disease include [[abdominal pain]] after eating, [[unintentional weight loss]], [[vomiting]], and being afraid of eating.<ref name=Surg2013/><ref name=Ye2014/> <!-- Cause and diagnosis --> Risk factors include [[atrial fibrillation]], [[heart failure]], [[chronic renal failure]], being [[thrombophilia|prone to forming blood clots]], and previous [[myocardial infarction]].<ref name=Ye2014/> There are four mechanisms by which poor blood flow occurs: a [[arterial embolism|blood clot from elsewhere getting lodged in an artery]], a [[arterial thrombosis|new blood clot forming in an artery]], a blood clot forming in the [[superior mesenteric vein]], and insufficient blood flow due to [[hypotension|low blood pressure]] or [[vasoconstriction|spasms of arteries]].<ref name=Britt2012/><ref>{{cite book|last1=Creager|first1=Mark A.|title=Vascular medicine : a companion to Braunwald's heart disease|date=2013|publisher=Elsevier/Saunders|location=Philadelphia, PA|isbn=9781437729306|pages=323–324|edition=2nd|url=https://books.google.com/books?id=TrstW0MKDA4C&pg=PA323|deadurl=no|archiveurl=https://web.archive.org/web/20170908171423/https://books.google.com/books?id=TrstW0MKDA4C&pg=PA323|archivedate=2017-09-08|df=}}</ref> Chronic disease is a risk factor for acute disease.<ref>{{cite journal|last1=Sreenarasimhaiah|first1=J|title=Chronic mesenteric ischemia.|journal=Best practice & research. Clinical gastroenterology|date=April 2005|volume=19|issue=2|pages=283–95|pmid=15833694|doi=10.1016/j.bpg.2004.11.002}}</ref> The best method of diagnosis is [[angiography]], with [[computer tomography]] (CT) being used when that is not available.<ref name=Surg2013/> <!-- Treatment and prognosis --> Treatment of acute ischemia may include [[stent]]ing or [[thrombolytics|medications to break down the clot]] provided at the site of obstruction by [[interventional radiology]].<ref name=Surg2013/> [[Open surgery]] may also be used to remove or bypass the obstruction and may be required to remove any intestines that may have died.<ref name=Ye2014/> If not rapidly treated outcomes are often poor.<ref name=Surg2013/> Among those affected even with treatment the risk of death is 70% to 90%.<ref name=Britt2012>{{cite book|last1=Britt|first1=L.D.|title=Acute care surgery|date=2012|publisher=Wolters Kluwer Health/Lippincott Williams & Wilkins|location=Philadelphia|isbn=9781608314287|page=621|edition=1st|url=https://books.google.com/books?id=7GRnoeg6aZEC&pg=PA621|deadurl=no|archiveurl=https://web.archive.org/web/20170908171423/https://books.google.com/books?id=7GRnoeg6aZEC&pg=PA621|archivedate=2017-09-08|df=}}</ref> In those with chronic disease [[vascular bypass|bypass surgery]] is the treatment of choice.<ref name=Surg2013/> Those who have thrombosis of the vein may be treated with [[anticoagulation]] such as [[heparin]] and [[warfarin]], with surgery used if they do not improve.<ref name=Ye2014/><ref>{{cite book|last1=Liapis|first1=C.D.|title=Vascular surgery|date=2007|publisher=Springer|location=Berlin|isbn=9783540309567|page=420|url=https://books.google.com/books?id=FRW3mzt2dZ4C&pg=PA420|deadurl=no|archiveurl=https://web.archive.org/web/20170908171423/https://books.google.com/books?id=FRW3mzt2dZ4C&pg=PA420|archivedate=2017-09-08|df=}}</ref> <!-- Epidemiology and history --> Acute mesenteric ischemia affects about five per hundred thousand people per year in the developed world.<ref name=Geo2012>{{cite book|author1=Geoffrey D. Rubin|title=CT and MR Angiography: Comprehensive Vascular Assessment|date=2012|publisher=Lippincott Williams & Wilkins|isbn=9781469801834|page=318|url=https://books.google.com/books?id=xPwG17yFkzcC&pg=PA318|deadurl=no|archiveurl=https://web.archive.org/web/20170908171423/https://books.google.com/books?id=xPwG17yFkzcC&pg=PA318|archivedate=2017-09-08|df=}}</ref> Chronic mesenteric ischemia affects about one per hundred thousand people.<ref name=Gus2014>{{cite book|author1=Gustavo S. Oderich|title=Mesenteric Vascular Disease: Current Therapy|date=2014|publisher=Springer|isbn=9781493918478|page=105|url=https://books.google.com/books?id=nL2PBQAAQBAJ&pg=PA105|deadurl=no|archiveurl=https://web.archive.org/web/20170908171423/https://books.google.com/books?id=nL2PBQAAQBAJ&pg=PA105|archivedate=2017-09-08|df=}}</ref> Most people affected are over 60 years old.<ref name=Britt2012/> Rates are about equal in males and females of the same age.<ref name=Britt2012/> Mesenteric ischemia was first described in 1895.<ref name=Surg2013/> ==Signs and symptoms== Three progressive phases of mesenteric ischemia have been described:<ref>{{cite journal |author=Boley, SJ, Brandt, LJ, Veith, FJ |year=1978 |title=Ischemic disorders of the intestines |journal=Curr Probl Surg |volume=15 |pages=1–85 |doi=10.1016/S0011-3840(78)80018-5 |issue=4 |pmid=365467}}</ref><ref>{{cite journal |vauthors=Hunter G, Guernsey J | title = Mesenteric ischemia | journal = Med Clin North Am | volume = 72 | issue = 5 | pages = 1091–115 | year = 1988 | pmid = 3045452}}</ref> *A ''hyper active'' stage occurs first, in which the primary symptoms are severe abdominal pain and the passage of bloody stools. Many patients get better and do not progress beyond this phase. *A ''paralytic'' phase can follow if ischemia continues; in this phase, the abdominal pain becomes more widespread, the belly becomes more tender to the touch, and bowel [[peristalsis|motility]] decreases, resulting in abdominal bloating, no further bloody stools, and absent bowel sounds on exam. *Finally, a ''shock'' phase can develop as fluids start to leak through the damaged colon lining. This can result in [[Shock (circulatory)|shock]] and [[metabolic acidosis]] with [[dehydration]], [[hypotension|low blood pressure]], [[tachycardia|rapid heart rate]], and confusion. Patients who progress to this phase are often critically ill and require [[intensive care]]. ===Clinical findings=== Symptoms of mesenteric ischemia vary and can be acute (especially if embolic),<ref name="pmid15159262">{{cite journal |vauthors=Oldenburg WA, Lau LL, Rodenberg TJ, Edmonds HJ, Burger CD |title=Acute mesenteric ischemia: a clinical review |journal=Arch. Intern. Med. |volume=164 |issue=10 |pages=1054–62 |year=2004 |pmid=15159262 | doi=10.1001/archinte.164.10.1054}}</ref> subacute, or chronic.<ref name="pmid2691119">{{cite journal |vauthors=Font VE, Hermann RE, Longworth DL |title=Chronic mesenteric venous thrombosis: difficult diagnosis and therapy |journal=Cleveland Clinic journal of medicine |volume=56 |issue=8 |pages=823–8 |year=1989 |pmid=2691119 |doi=10.3949/ccjm.56.8.823}}</ref> Case series report prevalence of clinical findings and provide the best available, yet biased, estimate of the sensitivity of clinical findings.<ref name="pmid2321134">{{cite journal |vauthors=Levy PJ, Krausz MM, Manny J |title=Acute mesenteric ischemia: improved results--a retrospective analysis of ninety-two patients |journal=Surgery |volume=107 |issue=4 |pages=372–80 |year=1990 |pmid=2321134}}</ref><ref name="pmid11877691">{{cite journal |author=Park WM, Gloviczki P, Cherry KJ, Hallett JW, Bower TC, Panneton JM, Schleck C, [[Duane Ilstrup|Ilstrup D]], Harmsen WS, Noel AA |title=Contemporary management of acute mesenteric ischemia: Factors associated with survival |journal=J. Vasc. Surg. |volume=35 |issue=3 |pages=445–52 |year=2002 |pmid=11877691|doi=10.1067/mva.2002.120373 }}</ref> In a series of 58 patients with mesenteric ischemia due to mixed causes:<ref name="pmid11877691"/> * [[abdominal pain]] was present in 95% (median of 24 hours duration). The other three patients presented with shock and [[metabolic acidosis]]. * [[nausea]] in 44% * [[vomiting]] in 35% * [[diarrhea]] in 35% * [[heart rate]] > 100 in 33% * '[[Rectal bleeding|blood per rectum]]' in 16% (not stated if this number also included occult blood – presumably not) * [[constipation]] in 7% ===Diagnostic heuristics=== In the absence of adequate quantitative studies to guide diagnosis, various heuristics help guide diagnosis: * Mesenteric ischemia "''should be suspected when individuals, especially those at high risk for acute mesenteric ischemia, develop severe and persisting abdominal pain that is disproportionate to their abdominal findings''".<ref name=AGA2000>{{cite journal|title=American Gastroenterological Association Medical Position Statement: guidelines on intestinal ischemia.|journal=Gastroenterology|date=May 2000|volume=118|issue=5|pages=951–3|pmid=10784595|doi=10.1016/s0016-5085(00)70182-x}}</ref> * Regarding mesenteric arterial thrombosis or embolism: "''...early symptoms are present and are relative mild in 50% of cases for three to four days before medical attention is sought''".<ref name="isbn9780195175455"> {{cite book| last = Cope| first = Zachary| authorlink = Zachary Cope| last2 = Silen| first2 = William|date=April 2005| title = Cope's Early Diagnosis of the Acute Abdomen| publisher = [[Oxford University Press]]| location = New York| edition = 21st| isbn = 978-0-19-517545-5| oclc = 56324163| url = https://books.google.com/?id=u30XbrHvyowC| lccn = 2004058138}}</ref> * Regarding mesenteric arterial thrombosis or embolism: "''Any patient with an arrhythmia such as atrial fibrillation who complains of abdominal pain is highly suspected of having embolization to the superior mesenteric artery until proved otherwise''".<ref name="isbn9780195175455"/> * Regarding nonocclusive intestinal ischemia: "''Any patient who takes digitalis and diuretics and who complains of abdominal pain must be considered to have nonocclusive ischemia until proved otherwise''".<ref name="isbn9780195175455"/> ==Diagnosis== It is difficult to diagnose mesenteric ischemia early.<ref>{{cite journal |vauthors=Evennett NJ, Petrov MS, Mittal A, Windsor JA |title=Systematic review and pooled estimates for the diagnostic accuracy of serological markers for intestinal ischemia |journal=World J Surg |volume=33 |issue=7 |pages=1374–83 |date=July 2009 |pmid=19424744 |doi=10.1007/s00268-009-0074-7 |url=}}</ref> One must also differentiate [[ischemic colitis]], which often resolves on its own, from the more immediately life-threatening condition of acute mesenteric ischemia of the [[small bowel]]. ===Blood tests=== In a series of 58 patients with mesenteric ischemia due to mixed causes:<ref name="pmid11877691"/> * [[White blood cell count]] >10.5 in 98% (probably an overestimate as only tested in 81% of patients) * [[Lactic acid]] elevated 91% (probably an overestimate as only tested in 57% of patients) ===During endoscopy=== A number of devices have been used to assess the sufficiency of oxygen delivery to the colon. The earliest devices were based on tonometry, and required time to equilibrate and estimate the pHi, roughly an estimate of local CO₂ levels. The first device approved by the U.S. FDA (in 2004) used visible light spectroscopy to analyze capillary oxygen levels. Use during aortic aneurysm repair detected when colon oxygen levels fell below sustainable levels, allowing real-time repair. In several studies, specificity has been 83% for chronic mesenteric ischemia and 90% or higher for acute colonic ischemia, with a sensitivity of 71%-92%. This device must be placed using endoscopy, however.<ref>{{cite journal |vauthors=Lee ES, Bass A, Arko FR, etal | title = Intraoperative colon mucosal oxygen saturation during aortic surgery | volume = 136 | issue = 1 | pages = 19–24 | year = 2006| pmid = 16978651 | doi = 10.1016/j.jss.2006.05.014 | journal = The Journal of surgical research}}</ref><ref>{{cite journal |vauthors=Friedland S, Benaron D, Coogan S, etal | title = Diagnosis of chronic mesenteric ischemia by visible light spectroscopy during endoscopy | journal = Gastrointest Endosc | volume = 65| issue = 2 | pages = 294–300 | year = 2007| pmid = 17137857 | doi = 10.1016/j.gie.2006.05.007 }}</ref><ref>{{cite journal |vauthors=Lee ES, Pevec WC, Link DP, etal | title = Use of T-stat to Predict Colonic Ischemia during and after Endovascular Aneurysm Repair: A case report | journal = J Vasc Surg | volume = 47| issue = 3 | pages = 632–634 | year = 2008| pmid = 18295116 | doi = 10.1016/j.jvs.2007.09.037 | pmc = 2707776}}</ref> ===Plain X-ray=== Plain [[X-ray]]s are often normal or show non-specific findings.<ref>{{cite journal |vauthors=Smerud M, Johnson C, Stephens D | title = Diagnosis of bowel infarction: a comparison of plain films and CT scans in 23 cases | journal = AJR Am J Roentgenol | volume = 154 | issue = 1 | pages = 99–103 | year = 1990 | pmid = 2104734 | doi=10.2214/ajr.154.1.2104734}}</ref> ===Computed tomography=== [[Computed tomography]] (CT scan) is often used.<ref name="pmid3336673">{{cite journal |vauthors=Alpern M, Glazer G, Francis I | title = Ischemic or infarcted bowel: CT findings | journal = Radiology | volume = 166 | issue = 1 Pt 1 | pages = 149–52 | year = 1988 | pmid = 3336673 | doi=10.1148/radiology.166.1.3336673}}</ref><ref>{{cite journal | vauthors = Taourel P, Deneuville M, Pradel J, Régent D, Bruel J | title = Acute mesenteric ischemia: diagnosis with contrast-enhanced CT | journal = Radiology | volume = 199 | issue = 3 | pages = 632–6 | year = 1996 | pmid = 8637978 | doi = 10.1148/radiology.199.3.8637978 | url = http://radiology.rsnajnls.org/cgi/reprint/199/3/632.pdf | format = PDF | deadurl = no | archiveurl = https://web.archive.org/web/20080227142554/http://radiology.rsnajnls.org/cgi/reprint/199/3/632.pdf | archivedate = 2008-02-27 | df = }}</ref> The accuracy of the [[Computed tomography|CT scan]] depends on whether a small bowel obstruction (SBO) is present.<ref name="pmid15835585">{{cite journal |vauthors=Staunton M, Malone DE |title=Can acute mesenteric ischemia be ruled out using computed tomography? Critically appraised topic &#124; |journal=Canadian Association of Radiologists Journal |volume=56 |issue=1 |pages=9–12 |year=2005 |pmid=15835585 |url=http://search.ebscohost.com/login.aspx?direct=true&db=a9h&AN=16596241&site=ehost-live |deadurl=no |archiveurl=https://web.archive.org/web/20070927233441/http://search.ebscohost.com/login.aspx?direct=true&db=a9h&AN=16596241&site=ehost-live |archivedate=2007-09-27 |df= }}</ref> '''SBO absent''' * prevalence of mesenteric ischemia 23% * [[sensitivity (tests)|sensitivity]] 64% * [[specificity (tests)|specificity]] 92% * [[positive predictive value]] (at prevalence of 23%) 79% * [[negative predictive value]] (at prevalence of 23%) 95% '''SBO present''' * prevalence of mesenteric ischemia 62% * [[sensitivity (tests)|sensitivity]] 83% * [[specificity (tests)|specificity]] 93% * [[positive predictive value]] (at prevalence of 62%) 93% * [[negative predictive value]] (at prevalence of 62%) 61% Findings on [[Computed tomography|CT scan]] include: * Mesenteric edema<ref name="pmid3336673"/> * Bowel dilatation<ref name="pmid3336673"/> * Bowel wall thickening<ref name="pmid3336673"/> * Intramural gas<ref name="pmid3336673"/> * Mesenteric stranding<ref name="pmid15143223">{{cite journal |vauthors=Pereira JM, Sirlin CB, Pinto PS, Jeffrey RB, Stella DL, Casola G |title=Disproportionate fat stranding: a helpful CT sign in patients with acute abdominal pain |journal=Radiographics : a review publication of the Radiological Society of North America, Inc |volume=24 |issue=3 |pages=703–15 |year=2004 |pmid=15143223 |doi=10.1148/rg.243035084}}</ref> ===Angiography=== As the cause of the ischemia can be due to embolic or thrombotic occlusion of the mesenteric vessels or nonocclusive ischemia, the best way to differentiate between the etiologies is through the use of mesenteric angiography. Though it has serious risks, angiography provides the possibility of direct infusion of vasodilators in the setting of nonocclusive ischemia.<ref>Kao, Lillian S., and Tammy Lee. PreTest Surgery: PreTest Self-assessment and Review. New York: McGraw-Hill Medical, 2009.</ref> ==Treatment== The treatment of mesenteric ischemia depends on the cause, and can be medical or surgical. However, if bowel has become necrotic, the only treatment is surgical removal of the dead segments of bowel. In [[Non-occlusive disease|non-occlusive mesenteric ischemia]], where there is no blockage of the arteries supplying the bowel, the treatment is medical rather than surgical. People are admitted to the hospital for resuscitation with intravenous fluids, careful monitoring of laboratory tests, and optimization of their cardiovascular function. NG tube decompression and heparin anticoagulation may also be used to limit stress on the bowel and optimize perfusion, respectively. Surgical revascularisation remains the treatment of choice for mesenteric ischaemia related to an occlusion of the vessels supplying the bowel, but thrombolytic medical treatment and vascular interventional radiological techniques have a growing role.<ref name="pmid12816826">{{cite journal |author=Sreenarasimhaiah J |title=Diagnosis and management of intestinal ischaemic disorders |journal=BMJ |volume=326 |issue=7403 |pages=1372–6 |year=2003 |pmid=12816826 | doi=10.1136/bmj.326.7403.1372 |pmc=1126251}}</ref> If the ischemia has progressed to the point that the affected intestinal segments are [[gangrene|gangrenous]], a [[bowel resection]] of those segments is called for. Often, obviously dead segments are removed at the first operation, and a second-look operation is planned to assess segments that are borderline that may be savable after revascularization.<ref>{{cite journal|last1=Meng|first1=X|last2=Liu|first2=L|last3=Jiang|first3=H|title=Indications and procedures for second-look surgery in acute mesenteric ischemia.|journal=Surgery today|date=August 2010|volume=40|issue=8|pages=700–5|pmid=20676851|doi=10.1007/s00595-009-4140-4}}</ref> ==Prognosis== The prognosis depends on prompt diagnosis (less than 12–24 hours and before gangrene)<ref name=AGA200b>{{cite journal |last1=Brandt |first1=LJ |last2=Boley |first2=SJ |title=AGA technical review on intestinal ischemia. American Gastrointestinal Association. |journal=Gastroenterology |date=May 2000 |volume=118 |issue=5 |pages=954–968 |pmid=10784596 |doi=10.1016/s0016-5085(00)70183-1}}</ref> and the underlying cause:<ref name="pmid">{{cite journal |vauthors=Schoots IG, Koffeman GI, Legemate DA, Levi M, van Gulik TM |title=Systematic review of survival after acute mesenteric ischaemia according to disease aetiology |journal=The British journal of surgery |volume=91 |issue=1 |pages=17–27 |year=2004 |pmid=14716789 |doi=10.1002/bjs.4459}}</ref> * venous thrombosis: 32% mortality * arterial embolism: 54% mortality * arterial thrombosis: 77% mortality * [[non-occlusive mesenteric ischemia|non-occlusive ischemia]]: 73% mortality. In the case of prompt diagnosis and therapy, acute mesenteric ischemia can be reversible.<ref>{{cite journal|last1=Nuzzo|first1=Alexandre|last2=Corcos|first2=Olivier|title=Reversible Acute Mesenteric Ischemia|journal=New England Journal of Medicine|date=13 October 2016|volume=375|issue=15|pages=e31|doi=10.1056/NEJMicm1509318}}</ref> ==History== Acute mesenteric ischemia was first described in 1895 while chronic disease was first described in the 1940s.<ref name=Surg2013/> Chronic disease was initially known as angina abdominis.<ref name=Surg2013/> ==References== {{Reflist}} ==External links== {{Medical resources | DiseasesDB = 29034 | ICD10 = {{ICD10|K|55|9|k|55}} | ICD9 = {{ICD9|557.9}} | ICDO = | OMIM = | MedlinePlus = 001156 | eMedicineSubj = radio | eMedicineTopic = 2726 }} {{Gastroenterology}} {{Hemodynamics}} [[Category:Diseases of intestines]] [[Category:Ischemia]] [[Category:RTT]] [[Category:RTTEM]]'