AFFECTIONS CAUSED BY CONGENITAL OR ACQUIRED ABSENCE OF THE THYROID OR ITS FUNCTION The thyroid may either be absent at birth (thyreoplasia congenita), or may have been removed by surgical operation, or may have been obliterated by inflammatory, atrophy (athyreosis acquisita). Finally, there is athyreosis aequisita in goitre regions in which the gland is either absent or strumously degenerated: cretinism.
The clinical pictures vary, depending upon the commencing period of athyreosis, its imniediate or gradual onset, the descent of the child from a healthy family or one degenerated from long residence in a goitre region; and it is therefore advisable to distinguish, on the one hand, between congenital thyreoaplasia (thyreoaplasia or athyreosis congenita, congenital or infantile myxoedema, myxidiocy, myxredernatous idiocy, sporadic cretinism), and,on the other hand, acquired, athyreosis, cachexia operativa, and true endemic cretinism.
However, all these affections are homogeneous, inasniuch as they are attributable to the complete absence of the thyroid or its function, certain deviations occurring only in a few immaterial details.
Pathological Anatomy and presence or absence of the thyroid can be determined definitely only at autopsy. The demon stration of its presence, even when of normal size, is often impossible by palpation in the living; assumed positive findings have never been veri fied at autopsy in spite of the clinical picture of at hyreosis. In the place of the gland nothing is usually found reminding of the structure, rarely a slight cord of connective tissue, infiltrated sometimes by a few fat pearls. In the strumously degenerated thyroid of the true cretin the last vestige of functional gland tissue has disappeared, while in the genuine endemic cretin the thyroid is mostly absent altogether.
The manifestations of absent thyroids have been very laboriously investigated and collected, but they are of interest only for present pur poses in so far as the new-born and infants are concerned.
In the first place the physiological growth in length of all carti laginously preformed bones is impaired. Periosteal and enchondral processes of growth are almost entirely absent, resulting in dwarfish structure of the most pronounced type. The growth of the cranial bones
goes on unimpeded both as to length and thickness, with late closure of the fontanelles.
"Psychic dwarfism" is more pronounced in proportion to the early onset of the condition. Development, so far as already attained, is gravely interfered with or completely arrested. These nurslings, lying almost motionless, usually experience a rapid increase in weight as com pared to their growth in length, in spite of slight nutriment, the cause being impaired metabolism (Magnus-Levy).
Shapelessly bloated, they, exhibit the changes of the skin, mucous membranes, hair, and nails which are characteristic in myxoedema in the highest degree, undergoing marked physical and mental cachexia, which is the unavoidable consequence of every case of complete athyreosis. If cachexia occurs abruptly, as for instance after extirpation of the goitre in animal experiments, all manifestations of absent function occur with considerable energy-. Cachexia will develop only slowly if (1) the extir pated goitre has only quite gradually- led to a partial inhibition of the functional gland tissue; (2) there is adaptation to the thyroid function even if ever so slight ; (3) the remaining portion of the gland is only slowly destroyed; (4) the organ, after abscess formation, degenerates into Basedow's disease and inflammatory processes.
The highest degrees and the most repulsive and gravest manifesta tions are observed in congenital thyreoaplasia in typical cretin families living in a region of epidemic cretinism, when a child is attacked whose row of ancestors has been affected with goitre and cretinism for centuries. Since their occurrence became a matter of general knowledge through Virchow's classic investigations, they have at the present time practi cally become extinct, thanks to the recognition of the causative factors, to prophylaxis—vigorously instituted by Kocher (Berne)—and to organ ot herapy.
The most frequent of the etiologically different pathological pictures of athyreosis is