endemic goiter

endemic goiter,

an enlargement of the thyroid gland caused by the intake of inadequate amounts of dietary iodine. Iodine deprivation leads to diminished production and secretion of thyroid hormone by the gland. The pituitary gland, operating on a negative feedback system, senses the deficiency and secretes increased amounts of thyroid-stimulating hormone, causing hyperplasia and hypertrophy of the thyroid gland. The goiter may grow during the winter months and shrink during the summer months when the person eats more iodine-containing fresh vegetables. Initially the goiter is diffuse; later it becomes multinodular. Endemic goiter occurs occasionally in adolescents at puberty and widely in population groups in geographic areas in which limited amounts of iodine are present in soil, water, and food. The use of iodized salt is a prophylactic treatment. Desiccated thyroid given orally may prevent further growth of adult goiters and may reduce the size of diffuse goiters. A large goiter may cause dysphagia, dyspnea, tracheal deviation, and cosmetic problems. Also called colloid nodular goiter.

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goiter (goi´tur),

n an enlargement of the thyroid gland.

goiter, colloid,

n (endemic goiter, iodine deficiency goiter, simple goiter) a visible enlargement of the thyroid gland without obvious signs of hypofunction or hyperfunction of the gland resulting from inadequate intake or from an increased demand for iodine.

goiter, endemic,

n See goiter, colloid.

goiter, exophthalmic,

n a disease of the thyroid gland consisting of hyperthyroidism, exophthalmos, and goiterous enlargement of the thyroid gland. A diffuse primary hyperplasia of the thyroid gland of obscure origin; may occur at any age. It produces nervousness, muscular weakness, heat intolerance, tremor, loss of weight, lid lag, and absence of winking and may lead to thyrotoxic heart disease and thyroid crisis.

goiter, iodine deficiency,

n See goiter, colloid.

goiter, nodular, nontoxic,

n the recurrent episodes of hyperplasia and involution of colloid goiter, which result in a multinodular goiter. Symptoms are related to pressure.

goiter, simple,

n See goiter, colloid.