Etiology.—Parenchymatous goitre, sometimes called also simple, or non-toxic goitre, is endemic in certain hilly districts in England—particularly Derbyshire and Gloucestershire—and in various parts of Scotland. It is exceedingly common in certain valleys in Switzerland. It is met with less frequently in men than in women, and it occurs chiefly during the child-bearing period of life. The toxic agent that causes goitre has been traced to certain mountain springs in goitrous districts; it has been observed that a patient with goitre may, through fæcal contamination apparently, infect the water supply, and that conscripts in order to avoid military service have drunk from goitrous springs with success. Children born in a goitrous district are liable to be cretins, while if goitrous parents move to a healthy district, the children are born healthy. If the water supply of a goitrous valley be changed to a healthy spring, goitre and cretinism disappear. Thorough boiling of the water rids it of its toxic properties.
Fig. 277.—Parenchymatous Goitre in a girl æt. 15.
(Mr. D. M. Greig's case.)
Morbid Anatomy.—Both the secreting and the fibrous elements share in the hyperplasia, and the gland as a whole becomes enlarged and forms a horseshoe-shaped swelling of moderate size in the neck. This swelling is soft and smooth on the surface, and is seldom quite symmetrical. In some cases the hypertrophy involves chiefly the isthmus. In others an outlying accessory lobule of thyreoid tissue constitutes the bulk of the swelling, and this may extend a considerable distance from the position of the normal thyreoid, reaching even behind the sternum into the thorax—infra-thoracic or retro-sternal goitre.
Fig. 278.—Larynx and Trachea surrounded by Goitre.
