Goiter

Alternative names:

euthyroid goiter; nontoxic diffuse goiter; nontoxic goiter; nontoxic nodular goiter; simple goiter

Definition:

An enlargement of the thyroid gland that is not associated with inflammation or cancer.

Causes, incidence, and risk factors:

A simple goiter occurs when the thyroid gland is unable to meet the metabolic demands of the body through sufficient hormone production. The thyroid gland compensates by enlarging, which usually overcomes mild deficiencies of thyroid hormone.

A simple goiter may be classified as an endemic (present continuously in a community) or sporadic goiter. Endemic (also known as colloid) goiters are usually caused by inadequate dietary intake of iodine in certain geographical areas with iodine depleted soil, usually areas away from the sea coast. In the US, the Great Lakes, Midwest, and Intermountain regions are known as the "goiter belt.". The use of iodized table salt prevents this deficiency. The incidence of iodine deficiency is now rare in the U.S. because of widespread distribution of foods from iodine sufficient areas and salt to which potassium iodide has been added.

Sporadic goiters are caused by swallowing of large amounts of certain foods or drugs and does not affect any particular segment of the population. Goitrogenic foods contain substances that decrease thyroid hormone production. Examples of these foods are rutabagas, cabbage, soybeans, peanuts, peaches, strawberries, spinach, and radishes. Drugs include lithium, cobalt, iodides, phenylbutazone, and others.

Hereditary factors may cause goiters. Excessive iodine intake is also a cause of goiter. Risk factors: female gender, over 40 years old, inadequate dietary intake of iodine, residence in an endemic area, ingestion of large amounts of goitrogenic foods or drugs, and a family history of goiters.