A simple goiter can occur without a known reason. It can occur when the thyroid gland is not able to make enough thyroid hormone to meet the body's needs. This can be due to a lack of iodine in a person's diet. To make up for the shortage of thyroid hormone, the thyroid gland grows larger.
Toxic nodular goiter is an enlarged thyroid gland that has a small, rounded growth or many growths called nodules. One or more of these nodules produce too much thyroid hormone.
The body needs iodine to produce thyroid hormone:
Simple goiters may occur in people who live in areas where the soil and water do not have enough iodine. People in these areas might not get enough iodine in their diet.
The use of iodized salt in many food products in the United States prevents a lack of iodine in the diet.
In many cases of simple goiter, the cause is unknown. Other than a lack of iodine, other factors that may lead to the condition include:
Certain medicines (lithium, amiodarone)
Certain foods (soy, peanuts, vegetables in the broccoli and cabbage family)
Simple goiters are also more common in:
Persons over age 40
People with a family history of goiter
The main symptom is an enlarged thyroid gland. The size may range from a single small nodule to a large neck lump.
A simple goiter may disappear on its own, or may become larger. Over time, the thyroid gland may stop making enough thyroid hormone. This condition is called hypothyroidism.
In some cases, a goiter becomes toxic and produces thyroid hormone on its own. This can cause high levels of thyroid hormone, a condition called hyperthyroidism.
When to Contact a Medical Professional
Call your health care provider if you experience any swelling in the front of your neck or any other symptoms of goiter.
Using iodized table salt prevents most simple goiters.
Kim M, Ladenson P. Thyroid. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 233.
Schlumberger MJ, Filetti S, Hay ID. Nontoxic diffuse and nodular goiter and thyroid neoplasia. In: Melmed S, Polonsky KS, et al., eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 14.
Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.