Hyperthyroidism is a condition in which the body has too much thyroid hormone in the blood. Thyroid hormone is made by the thyroid gland, a butterfly-shaped gland in the front of the neck. It produces the hormones thyroxine (T4) and triiodothyronine (T3), which control metabolism. This affects:
The most common form of hyperthyroidism is Graves disease. Graves disease occurs when your own immune system produces antibodies that stimulate the thyroid gland to overproduce thyroid hormone. Hyperthyroidism can be the result of other conditions, such as:
Treatment of hyperthyroidism can lead to the opposite condition, hypothyroidism. This is a condition in which the thyroid gland produces too little thyroid hormone. It is easier to treat hypothyroidism long-term than hyperthyroidism. Treatment of hypothyroidism involves taking a pill of thyroid hormone.
It is estimated that 20 million Americans have thyroid disorders. These disorders affect more women than men—one in eight women will develop a thyroid disorder in her lifetime. Hyperthyroidism can occur at any age, but it is more common in people aged 60 and older.
American Association of Clinical Endocrinologists website. Available at: http://www.aace.com.
American Medical Women’s Association website. Available at: http://www.amwa-doc.org.
American Thyroid Association website. Available at: http://www.thyroid.org. Accessed November 30, 2009.
Hyperthyroidism. National Endocrine and Metabolic Diseases Information Service website. Available at: http://endocrine.niddk.nih.gov/pubs/Hyperthyroidism/. Updated April 2008. Accessed December 9, 2009.
Kasper DL, Harrison TR. Harrison's Principles of Internal Medicine. 16th ed. New York, NY: McGraw-Hill; 2005.
National Library of Medicine website. Available at: http://www.nlm.nih.gov.
Pearce EN. Diagnosis and management of thyrotoxicosis. Brit Med J. 2006;332:1369-1373.
Thyroid disorders. Healthy Women website. Available at: http://www.healthywomen.org/condition/thyroid-disorders. Updated November 2009. Accessed December 9, 2009.
Last reviewed November 2012 by Kim Carmichael, MD
Last Updated: 11/26/2012