most common type of goiter, encountered chiefly in geo-graphic regions where
the natural supply of iodine is deficient (eg, the Great Lakes areas of the United
States), is the so-called sim-ple or colloid goiter. In addition to being
caused by an iodine de-ficiency, simple goiter may be caused by an intake of
large quantities of goitrogenic substances in patients with unusually
susceptible glands. These substances include excessive amounts of iodine or
lithium, which is used in treating bipolar disorders.
goiter represents a compensatory hypertrophy of the thyroid gland, caused by
stimulation by the pituitary gland. The pituitary gland produces thyrotropin or
TSH, a hormone that controls the release of thyroid hormone from the thyroid
gland. Its production increases if there is subnormal thyroid activity, as when
insufficient iodine is available for production of the thyroid hormone. Such
goiters usually cause no symptoms, except for the swelling in the neck, which
may result in tracheal compression when excessive.
goiters of this type recede after iodine imbalance is cor-rected. Supplementary
iodine, such as SSKI, is prescribed to sup-press the pituitaryâ€™s
thyroid-stimulating activity. When surgery is recommended, the risk for
postoperative complications is mini-mized by ensuring a preoperative euthyroid
state by treatment with antithyroid medications and iodide to reduce the size
and vascularity of the goiter.
children in iodine-poor regions with iodine com-pounds can prevent simple or
endemic goiter. If the mean iodine intake is less than 40 fg/day, the thyroid
gland hypertrophies. The World Health Organization recommends that salt be iodized
to a concentration of 1 part in 100,000, which is adequate for the pre-vention
of endemic goiter. In the United States, salt is iodized to 1 part in 10,000.
The introduction of iodized salt has been the sin-gle most effective means of
preventing goiter in at-risk populations.