Cretinism

This article is about the medical condition. For other uses, see Cretin.

Congenital iodine-deficiency syndrome
Classification and external resources
ICD-10	E00
ICD-9	243
DiseasesDB	6612
eMedicine	ped/501
MeSH	C05.116.099.343.347

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

Etymology and use of cretin

The disused term cretin was a medical term which described a person so affected with the condition, but, as with words such as spastic and lunatic, it can also have a vulgar connotation and can be used disparagingly. Cretin became a medical term in the 18th century, from an Alpine French dialect; 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.^{[citation needed]}

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.^[1]
• 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.^[2]
• From "chretien," French for "Christian" or "Christlike," because those affected were so mentally handicapped that they were considered incapable of sinning ^[3]

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.^[4] 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.^[5]

  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. Iodine deficiency is the most common preventable cause of brain damage worldwide.^[6] Although iodine is found in many foods, it is not universally present in all soils in adequate amounts. Most iodine, in iodide form, is in the oceans where the iodide ions oxidize to elemental iodine, which then enters the atmosphere and falls to earth as rain, introducing iodine to soils. Earth deficient in iodine is most common inland and in mountainous areas and areas of frequent flooding, but can also occur in coastal regions owing to past glaciation, and leaching by snow, water and heavy rainfall, which removes iodine from the soil.^[7] Plants and animals grown in iodine deficient soils are correspondingly deficient. Populations living in those areas without outside food sources are most at risk of iodine deficiency diseases.^[8]

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.^[9] Alpine cretinism was described from a medical perspective by several travellers and physicians in the late 18th and early 19th centuries.^[10] 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 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 does not contain a large amount of 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 than completely dependent on locally grown food, the prevalence of endemic goitre diminished.

Twentieth and twenty-first centuries

The early 20th 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.

See also

• Congenital hypothyroidism
• Iodine deficiency
• Moron (psychology)

References

1. ^ Michalaki, Marina; Kyriazopoulou, Venetsana; Paraskevopoulou, Panagiota; Vagenakis, Apostolos G.; Markou, Kostas B. (2008). "The Odyssey of Nontoxic Nodular Goiter (NTNG) in Greece under Suppression Therapy, and after Improvement of Iodine Deficiency". Thyroid 18 (6): 641–5. doi:10.1089/thy.2007.0348. PMID 18578614. 
2. ^ Medvei, VC (1993). The History of Clinical Endocrinology. Pearl River, New York: Parthenon Publishing Group. 
3. ^ Robbins and Cotran - Pathologic basis of disease 8/E. Philadelphia, PA: Sauders Elsevier. 2004. 
4. ^ Chorazy PA, Himelhoch S, Hopwood NJ, Greger NG, Postellon DC (July 1995). "Persistent hypothyroidism in an infant receiving a soy formula: case report and review of the literature". Pediatrics 96 (1 Pt 1): 148–50. PMID 7596704. 
5. ^ "Mortality and Burden of Disease Estimates for WHO Member States in 2002" (xls). World Health Organization. 2002. http://www.who.int/entity/healthinfo/statistics/bodgbddeathdalyestimates.xls. 
6. ^ Chen, Zu-Pei; Hetzel, BS (February 2010). "Cretinism Revisited". Clinical Endocrinology and Metabolism 24 (1): 39–50. doi:10.1016/j.beem.2009.08.014. PMID 20172469. 
7. ^ Chapter 20. The Iodine Deficiency Disorders Thyroid Disease Manager. Retrieved: 2011-06-26.
8. ^ Gaitan E, Dunn JT (1992). "Epidemiology of iodine deficiency". Trends Endocrinol. Metab. 3 (5): 170–5. doi:10.1016/1043-2760(92)90167-Y. PMID 18407097. http://linkinghub.elsevier.com/retrieve/pii/1043-2760(92)90167-Y. 
9. ^ Fergus Fleming, Killing Dragons: The Conquest of the Alps, 2000, Grove Press, p. 179
10. ^ See, for example, William Coxe, "Account of the Vallais, and of the Goiters and Idiots of that Country," Universal Magazine of Knowledge & Pleasure, vol. 67, Dec. 2, 1780.

External links

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