HYPOTHYROIDISM 409 



The mucous membranes may be thickened either per se or through 

 underlying myxedematous swellings. Frequently the palatine mucous 

 membrane is pleated into rugae. Vulvar and anal hypertrophies of the 

 mucous membranes may develop in young children. Rectal prolapse may 

 occur. 



The dentition is rather constantly abnormal. In athyrosis cases, the 

 milk teeth erupt quite late (after the first year). The permanent denti- 

 tion may quite fail to appear, the teeth remaining submerged in the gums 

 in a rudimentary state of development. In less severe cases, the second- 

 ary teeth often come in irregularly and their eruption dates are likewise 

 delayed. The crowns are often poorly facetted with defective enamel. 

 When hypothyroidism appears in adults, the teeth may loosen and fall out. 

 Owing to these factors dental caries, as in all endocrin disorders, is ex- 

 tremely often encountered. The teeth may exhibit a low resistance to 

 mechanical wear and grind off even to the gum's edge. Spacing of the 

 front incisors is emphasized by some. In the writer's experience, it is an 

 inconstant sign of hypothyroidism. The modern management of such cases 

 includes an accurate dental record of the eruption times of the teeth. It 

 is a considerable aid to diagnosis and treatment and should be kept by a 

 skilled dentist. 



Various skin diseases are regarded as expressions of hypothyroidism. 

 Such are scleroderma, psoriasis, eczema, ichthyosis, acne vulgaris (Morris), 

 as well as other cutaneous disorders. Occasionally brilliant cures are ap- 

 parently ascribable to thyroid medication. In these instances, we must 

 distinguish between a direct effect of thyroxin upon the diseased integu- 

 ment and an indirect effect resulting from the general stimulus to 

 metabolism caused by the thyroid hormone. Scleroderma particularly is 

 probably induced in some instances by subthyroid function as atrophic 

 and sclerotic thyroid glands have been found (Hektoen, Laredde and 

 Thomas, etc.). A number of cases of scleroderma exhibit hypothyroid 

 symptoms and yield to thyroid medication. In others, scleroderma is 

 associated with exophthalmic goiter. The relation of the thyroid gland 

 to scleroderma is ably discussed by Osier (6), most recently F. Wise. 



Central Nervous System. Mental abnormalities are an early and im- 

 portant manifestation of defective thyroid function. In the young, due 

 to failure of brain development, idiocy may be complete in the severest 

 cases. Even young hypothyroid infants very early betray mental back- 

 wardness. They fail to notice objects about them as do normal babies, 

 and learn to sit, creep, stand and walk at a later age. In this, however, 

 weakness of the locomotor organs plays a part. Mentality tests in older 

 children will often reveal surprising deficiencies even when quite unsus- 

 pected by the parents. Occasionally failure of a child to pass examinations 

 at school may be the first suggestion of developing hypothyroidism. Such 

 children may make pitiful efforts to keep up with their classes. Among 



