Congenital iodine deficiency syndrome

This article is about the medical term. For the Marxist political concept, see Parliamentary cretinism.

Congenital iodine deficiency syndrome
Specialty	Endocrinology

Cretinism is a condition of severely stunted physical and mental growth due to untreated congenital deficiency of thyroid hormones (congenital hypothyroidism) due to maternal nutritional deficiency of iodine.

Etymology and use of cretin

The term cretin describes a person so affected, but, like words such as spastic and lunatic, also is a word of abuse. Cretin became a medical term in the 18th century, from an Alpine French dialect prevalent in a region where persons with such a condition were especially common (see below); it saw wide medical use in the 19th and early 20th centuries, and then spread more widely in popular English as a markedly derogatory term for a person who behaves stupidly. Because of its pejorative connotations in popular speech, health-care workers have mostly abandoned cretin.

The etymology of cretin is uncertain. Several hypotheses exist. The most common derivation provided in English dictionaries is from the Alpine French dialect pronunciation of the word Chrétien ("(a) Christian"), which was a greeting there. According to the Oxford English Dictionary, the translation of the French term into "human creature" implies that the label "Christian" is a reminder of the humanity of the afflicted and beer drinking Motor cycle club, in contrast to brute beasts. Other sources suggest that Christian describes the person's "Christ-like" inability to sin, stemming, in such cases, from an incapacity to distinguish right from wrong.

Other speculative etymologies have been offered:

• From creta, Latin for chalk, because of the pallor of those affected.
• From "Crete", where iodine insufficiency (Hypothyroidism) was common prior to the modern era.[2]
• From cretira, Grisson-Romance creature, from Latin creatus.
• From cretine, French for alluvium (soil deposited by flowing water), an allusion to the affliction's suspected origin in inadequate soil.

Sporadic cretinism due to congenital hypothyroidism

Congenital hypothyroidism can be endemic, genetic, or sporadic. If untreated, it results in mild to severe impairment of both physical and mental growth and development.

Poor length growth is apparent as early as the first year of life. Adult stature without treatment ranges from 1 to 1.6 metres (3'4 to 5'3), depending on severity, sex and other genetic factors. Bone maturation and puberty are severely delayed. Ovulation is impeded and infertility is common.

Neurological impairment may be mild, with reduced muscle tone and coordination, or so severe that the person cannot stand or walk. Cognitive impairment may also range from mild to so severe that the person is nonverbal and dependent on others for basic care. Thought and reflexes are slower.

Other signs may include thickened skin, enlarged tongue, or a protruding abdomen.

Sporadic and genetic cretinism results from abnormal development or function of the foetal thyroid gland. This type of cretinism has been almost completely eliminated in developed countries by early diagnosis by newborn screening schemes followed by life long treatment with thyroxine (T4).

Thyroxine must be dosed as tablets only, even to newborns, as the liquid oral suspensions and compounded forms cannot be depended on for reliable dosing. In the case of dosing infants, the T4 tablets are generally crushed and mixed with breast milk, formula milk or water. If the medication is mixed with formulas containing iron or soya products, larger doses may be required, as these substances may alter the absorption of thyroid hormone from the gut. Frequent monitoring (every 2–3 weeks during the first months of life) is recommended to ensure that infants with congenital hypothyroidism remain within the high end of normal range, or euthyroid.

Epidemiology

Disability-adjusted life year for iodine deficiency per 100,000 inhabitants in 2002.

  no data

  less than 50

  50-100

  100-150

  150-200

  200-250

  250-300

  300-350

  350-400

  400-450

  450-500

  500-800

  more than 800

Cretinism arises from a diet deficient in iodine. It has affected many people worldwide and continues to be a major public health problem in many countries. Iodine is an essential trace element, necessary primarily for the synthesis of thyroid hormones. Although iodine is found in many foods, it is not universally present in all soils in adequate amounts. The soils of many inland areas on all continents are iodine deficient, and plants and animals grown there are correspondingly deficient. Populations living in those areas without outside food sources are most at risk of iodine deficiency diseases.

Iodine deficiency results in the impairments in varying degrees of physical and mental development. It also causes gradual enlargement of the thyroid gland, referred to as a goitre. It is being combated in many countries by public health campaigns of iodine administration.

History

Endemic cretinism was especially common in areas of southern Europe around the Alps and was described by ancient Roman writers, and often depicted by medieval artists. The earliest Alpine mountain climbers sometimes came upon whole villages of cretins. Alpine cretinism was described from a medical perspective by several travellers and physicians in the late eighteenth and early nineteenth centuries. At that time the cause was not known and it was often attributed to "stagnant air" in mountain valleys or "bad water." The proportion of people affected varied markedly throughout southern Europe and even within very small areas it might be common in one valley and not another. The number of severely affected persons was always a minority, and most persons were only affected to the extent of having a goitre and some degree of reduced cognition and growth. The majority of such cases were still socially functional in their pastoral villages.

Nineteenth century

More mildly affected areas of Europe and North America in the nineteenth century were referred to as "goiter belts". The degree of iodine deficiency was milder and manifested primarily as thyroid enlargement rather than severe mental and physical impairment. In Switzerland, for example, where soil is poor in iodine, cases of cretinism were very abundant and even considered genetically caused. As the variety of food sources dramatically increased in Europe and North America and the populations became less completely dependent on locally grown food, the prevalence of endemic goitre diminished.

Twentieth and twenty-first centuries

The early twentieth century saw the discovery of the relationships of sporadic cretinism with congenital hypothyroidism, and of endemic cretinism with hypothyroidism due to iodine deficiency. Both have been largely eliminated in the developed world.

There are recent suggestions that the skeletons supporting the existence of the human species Homo floresiensis are of individuals who suffered from cretinism.

See also

• Congenital hypothyroidism
• Iodine deficiency
• Moron

External links

• Network for Sustained Elimination of Iodine Deficiency
• Cretinism | Research in Mental Handicap

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