Hyperthyroidism (overactive thyroid)

The thyroid gland is a small butterfly shaped gland that is located in the lower front of the neck just under the Adam's apple. The thyroid gland produces hormones that control the body's organ functions and metabolism (how the body uses and stores energy from foods eaten). Hyperthyroidism describes an overactive thyroid that becomes enlarged and makes too much of the thyroid hormone for the body to maintain a healthy metabolism.

Most of the cases of hyperthyroidism result from Graves' disease, which is an autoimmune disease that causes over-stimulation of the thyroid gland. (An autoimmune disease occurs when the body's immune system becomes misdirected and attacks the very organs, cells, or tissues that it was designed to protect.)

A person with hyperthyroidism may feel anxious, irritable, restless, and nervous. There is an increase in sweating and feeling constantly overheated. There may be troubled with sleeping. Vision changes or eye irritation may occur. There may be muscle tremors and weakness and the heart may race or palpitate. Even though the appetite increases, there may be weight loss and frequent bowel movements or diarrhea. Menstrual changes may also be experienced.

Hyperthyroidism may be diagnosed with tests such as a blood test, a thyroid scan, or an ultrasound. Medical care may include medication, surgery, radioactive iodine, or a combination of these treatments. Antithyroid medication reduces the amount of thyroid hormone that the body is making. Additional medication known as beta-blockers may be necessary to control rapid heart beat. If these medications do not help, radioactive iodine may be used to destroy parts of the thyroid gland. Some cases require surgery to remove the thyroid gland.

Women are more likely than men to have thyroid problems. People with hyperthyroidism may require medical monitoring and follow-up for the rest of their lives.

Last Reviewed 2005

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

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