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´ter]

enlargement of the thyroid gland, causing a swelling in the front part of the neck; called also struma. adj., adj goit´rous. If there is evidence of pressure against the throat, or the possibility of a malignancy, the goiter may be removed surgically. Simple endemic goiter is usually caused by lack of iodine in the diet. In graves' disease, goiter is accompanied by excessive thyroid hormones in the blood and symptoms of hyperthyroidism.

aberrant goiter goiter of a supernumerary thyroid gland.

adenomatous goiter that caused by adenoma or multiple colloid nodules of the thyroid gland.

Basedow goiter a colloid goiter that has become hyperfunctioning after administration of iodine.

colloid goiter one that is large and soft and has distended spaces filled with colloid.

cystic goiter one with cysts formed by mucoid or colloid degeneration.

diffuse toxic goiter exophthalmic goiter.

endemic goiter goiter occurring widely in a geographic region where the food or water is deficient in iodine. Treatment consists of iodine replacement; although this will not cure the condition, it can stop it from enlarging, and iodine administered in advance will prevent development of goiter.

exophthalmic goiter any type accompanied by exophthalmos.

fibrous goiter goiter in which the thyroid capsule and stroma are hyperplastic.

follicular goiter parenchymatous goiter.

intrathoracic goiter one with part of the enlarged gland in the thoracic cavity.

iodide goiter that occurring in reaction to iodides at high concentrations, due to inhibition of iodide organification.

multinodular goiter one with circumscribed nodules within the gland.

nontoxic goiter that occurring sporadically and not associated with hyperthyroidism or hypothyroidism.

parenchymatous goiter one with increase in follicles and proliferation of epithelium.

perivascular goiter one that surrounds a large blood vessel.

retrovascular goiter one with processes behind a large blood vessel.

substernal goiter one whose lower part lies beneath the sternum.

suffocative goiter one that causes dyspnea due to pressure.

toxic multinodular goiter hyperthyroidism arising in a multinodular goiter, usually of long standing.

vascular goiter one due chiefly to dilatation of the blood vessels of the thyroid gland.

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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.