Endemic goiter is one of a spectrum of iodine deficiency disorders and is characterized by thyroid gland enlargement. It can occur in any location where environmental iodine is limited but is rarely seen in developed countries as dietary iodine supplementation is routine. Goiters are often seen in inland and mountainous areas where iodine is leached from the soil and access to iodine-rich foods (ie, fish) is limited. Iodine deficiency disorders are common in widespread areas of Africa, Asia, and South America.
Patients with inadequate iodine in their diet have decreased T3 and T4 production and resultant increased pituitary thyroid-stimulating hormone (TSH) secretion. The thyroid becomes hyperplastic and enlarged; however, patients are typically euthyroid.
Management and Disposition
Prevention with dietary supplemental iodine is the mainstay of goiter management at the community level. Individual patients with goiter can be treated with potassium iodide solution or Lugol iodine, with iodized salt as a permanent solution. Surgical treatment can be indicated for massive goiter, particularly in the setting of tracheal or esophageal compression.
Goiters in developed countries are most likely to be caused by defects in thyroid hormone production, resulting in an increase in TSH.
Iodine deficiency is the most common cause of preventable mental retardation (endemic cretinism) in the world.
Some dietary staple items, such as cabbage, cassava, lima beans, and sweet potatoes, have a goitrogenic factor, which may be superimposed upon primary iodine deficiency.
Malignancy is not a common complication despite the massive size of many goiters, although it may interfere with detection.
In children, the goiter is usually diffuse; in adults, however, it is more commonly nodular since individual thyroid nodules proliferate at different rates.
Goiter. Easily visualized and palpable goiter. (Photo contributor: Seth W. Wright, MD.)
Goiter. Patient from mountainous inland region of Haiti with massive goiter. This island nation has a high rate of goiter due to the complex interaction of poverty, political instability, deforestation, and erosion of soil. (Photo contributor: Ian D. Jones, MD.)