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 is an autoimmune disorder. The body's 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.
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Hyperthyroidism and thyrotoxicosis. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T116479/Hyperthyroidism-and-thyrotoxicosis. Updated March 21, 2016. Accessed October 4, 2016.
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Primary hyperthyroidism. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: http://www.niddk.nih.gov/health-information/health-topics/endocrine/primary-hyperparathyroidism/Pages/fact-sheet.aspx. Updated August 2012. Accessed December 11, 2015.
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Last reviewed December 2015 by Kim A. Carmichael, MD
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