HYPOTHYEOIDISM 385 



toxemia induced in turn through an. unsanitay environment. Should this 

 viewpoint become general, we could possibly ascribe etiologic significance 

 to enteritis and other gastrointestinal diseases in the production of sporadic 

 hypothyroidism in children and adults. 



The role played by infectious diseases in the etiology of hypothyroidism 

 is probably greater than generally supposed but is difficult to demonstrate 

 as the thyroid injury sustained may exhibit itself clinically only many 

 months or years afterwards. Should the thyroid be hereditarily subfunc- 

 tional or be undergoing additional strain as during pregnancy, the inter- 

 currence of an infectious disease is more liable to lead to hypothyroidism. 

 A number of recent clinical and pathological observations have indicated 

 the considerable part played by infections in the etiology of hypothyroid- 

 ism. Among such diseases are usually included those of children, measles, 

 mumps, whooping-cough, scarlet fever and diphtheria. Archard's case quot- 

 ed by Crotti developed a myxedematous condition, in a child of ten years 

 of age following measles. This condition persisted until patient's death 

 forty-two years later when autopsy showed complete absence of the thyroid 

 gland. Nearly all ordinary infectious diseases of adults have been said 

 to have been followed by hypothyroidism. They need not be enumerated. 

 Typhoid fever seems but rarely followed by myxedema. McCarrison, how- 

 ever, suggests that the obesity ensuing after an attack of typhoid fever may 

 be thyrogenic. A few cases have succeeded the recent influenza epidemic 

 of 1918 (A. Lopez, etc.). Tuberculosis is not an important causal agent. 

 The thyroid is directly affected only in the general miliary form. Syphilis 

 has rarely been demonstrated as an etiological factor (Koehler, Pel, 

 Pospelow). Such cases improve on specific treatment. 



The chronic intoxications such as gout, lead poisoning, chronic alco- 

 holism and the cachexias are occasionally of importance. LaClcrc has 

 recently reported two cases of myxedematus children of alcoholic fathers. 

 Bedson's interesting experiments on the production of thyroid hyperplasia 

 and fibrosis from injections of the bodies of helminth worms substantiate 

 clinical observations of myxedema in hosts of these parasites. 



Psychic states of grief, anxiety, mental strain, etc., may precede hypo- 

 thyroidism, especially in predisposed subjects. 



Nutritional factors are probably more important than now recognized. 

 Marine and McCarrison observed both experimentally and clinically hypo- 

 thyroidism to be more common in the presence of undernutrition. Ac- 

 cording to Bensley's (c) observations, the thyroid in hibexnating animals 

 decreases much in size and in colloid. Probably the most important nutri- 

 tional factor is the presence or absence of iodin in the diet. The factor 

 has been more clearly proven for animals than man. An exclusive meat 

 diet not only sets an added strain upon the thyroid (hypertrophy of the 

 thyroid of opossums on meat ingestion, Bensley (a)) but also contains 

 almost no iodin, 



