Cretinism

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Overview
Cretinism is a condition of severely stunted physical and mental growth due to untreated congenital deficiency of thyroid hormones (hypothyroidism). The term cretin refers to a person so affected.

Etymology and usage of the term
The term cretin was brought into medical use 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 was used widely as a medical term in the 19th and early 20th centuries, but in recent decades has spread more widely in popular English as a markedly derogatory term for a person who exhibits stupid behaviour. Because of its pejorative connotations in popular speech, the term has been largely abandoned by physicians and health care workers.

The etymology of the word cretin is not known with certainty. Several hypotheses have been proposed. The most common derivation provided in English dictionaries is from the Alpine French dialect pronunciation of the word Chretien - (a) Christian, which functioned as a form of greeting in those parts. According to the Oxford English Dictionary, the translation of the Latin term into "human creature" implies that the label "Christian" is a reminder of the humanity of the afflicted, in contrast to brute beasts. Other sources have suggested "Christian" refers to the "Christ-like" inability of such a person to commit sin, because of an incapacity to distinguish right from wrong.

Other speculative etymologies have been offered:
 * 1) From creta, Latin for chalk, because of the pallor of those affected.
 * 2) From cretira, Grisson-Romance creature, from Latin creatus.
 * 3) From cretine, French for alluvium (soil deposited by flowing water), an allusion to the suspected origin from 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 meters, depending on severity, sex and other genetic factors. Bone maturation and puberty are severely delayed. Ovulation is impeded and infertility 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 and 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 programs followed by lifelong treatment with thyroxine.

Endemic Cretinism and Iodine Deficiency
Endemic cretinism arises from a diet deficient in iodine and has affected far more 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 it 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 for iodine deficiency diseases.

Iodine deficiency results in the impairments of varying degrees of physical and mental development. It also causes gradual enlargement of the thyroid gland, referred to as a Goitre. It is being combatted 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 Roman writers, and often depicted by medieval artists. Alpine cretinism was described from a medical perspective by several travellers and physicians in the late 18th and early 19th 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 affected by cretinism to the extent of having a goiter and some degree of reduced cognition and growth were still socially functional in their pastoral villages.

More mildly affected areas of Europe and North America in the 19th 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, the cases of cretinism were very abundant and even were considered to be 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 goiter diminished.

In the early 20th century the relationships of sporadic cretinism with congenital hypothyroidism, and endemic cretinism with hypothyroidism due to iodine deficiency were discovered and both have been largely eliminated in the developed world.