Thyrotoxicosis; Overactive thyroid; Graves disease - hyperthyroidism; Thyroiditis - hyperthyroidism; Toxic goiter - hyperthyroidism; Thyroid nodules - hyperthyroidism; Thyroid hormone - hyperthyroidism
Hyperthyroidism is a condition in which the thyroid gland makes too much thyroid hormone. The condition is often called overactive thyroid.
The thyroid gland is an important organ of the endocrine system. It is located at the front of the neck just above where your collarbones meet. The gland makes the hormones that control the way every cell in the body uses energy. This process is called metabolism.
Many diseases and conditions can cause hyperthyroidism, including:
You're restless and nervous. You feel hungry all the time, but no matter how much you eat, you keep losing weight. You can't sleep or concentrate, and you feel hot and sweaty. If symptoms like these are putting you on edge, the problem may be an overactive thyroid gland, or hyperthyroidism. This little butterfly-shaped structure in your neck is your thyroid gland. It's job is to release the hormones that help control your body's energy levels, a process known as metabolism. When you have hyperthyroidism, that little gland goes into overdrive, releasing too much of its hormones. Having too much thyroid hormone is like putting your body in fast forward, everything speeds up. That's why you feel shaky, hungry, and your heart feels like it's pounding. So, what causes hyperthyroidism? You can develop an overactive thyroid because you've gotten too much iodine, an element the thyroid uses to make its hormones. Or, you might have a growth on your thyroid that's causing the excess hormone production. But many people with hyperthyroidism have an autoimmune disorder called Graves disease, which also makes their eyes bulge out. During an exam, your doctor may notice that your thyroid is larger than normal, and that you have high blood pressure, tremors, or a fast heart rate. These can all be signs of hypothyroidism. You'll probably have a blood test to check the levels of your thyroid hormones. If you do have an overactive thyroid, you may need to take medicine to slow down the gland and its hormone production. Or, your doctor may suggest having surgery to remove some or all of the thyroid, or taking radioactive iodine to destroy it. If you have surgery or radioactive iodine treatment, you'll probably need to take thyroid hormones for the rest of your life to replace the ones your body can no longer make. You can't prevent hyperthyroidism, but once you have it, it's usually pretty easy to treat. With the right treatment you can finally be free from its symptoms. While you're being treated, watch out for an emergency condition called thyroid crisis, or thyroid storm, which can set in if you've been under a lot of stress or have an infection. If you have a fever, fast and unsteady heartbeat, or you feel less alert than usual, call your emergency services number or go to the ER right away.
Common symptoms include:
Other symptoms that can occur with this disease:
The health care provider will do a physical exam. The exam may find the following:
Blood tests are also ordered to measure your thyroid hormones TSH, T3, and T4.
You may also have blood tests to check:
Imaging tests of the thyroid may also be needed, including:
Treatment depends on the cause and severity of symptoms. Hyperthyroidism is usually treated with one or more of the following:
If your thyroid is removed with surgery or destroyed with radioactive iodine, you must take thyroid hormone replacement pills for the rest of your life.
Medicines called beta-blockers may be prescribed to treat symptoms such as fast heart rate, tremor, sweating, and anxiety until the hyperthyroidism can be controlled.
Hyperthyroidism is treatable. Some causes may go away without treatment.
Hyperthyroidism caused by Graves disease usually gets worse over time. It has many complications, some of which are severe and affect quality of life.
Thyroid crisis (storm) is a sudden worsening of hyperthyroidism symptoms that may occur with infection or stress. Fever, decreased alertness, and abdominal pain may occur. People need to be treated in the hospital.
Other complications of hyperthyroidism include:
Surgery-related complications, including:
Call your provider if you have symptoms of hyperthyroidism. Go to an emergency room or call the local emergency number (such as 911) if you have:
Call your provider if you are being treated for hyperthyroidism and you develop symptoms of underactive thyroid, including:
Bahn RS, Burch HB, Cooper DS, et al. Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Endocr Pract. 2011;17(3):457-520. PMID: 21700562
Davies TF, Laurberg P, Bahn RS. Hyperthyroid disorders. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 13th ed. Philadelphia, PA: Elsevier; 2016:chap 12.
Duke WS, Terris DJ. Hyperthyroidism. In: Cameron JL, Cameron AM, eds. Current Surgical Therapy. 11th ed. Philadelphia, PA: Elsevier Saunders; 2014:652-658.
Ferri FF. Hyperthyroidism. In: Ferri FF, ed. Ferri's Clinical Advisor 2015. Philadelphia, PA: Elsevier Mosby; 2015:623-624.
Weiss RE, Refetoff S. Thyroid function testing. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 78.
Last reviewed on: 4/23/2015
Reviewed by: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Internal review and update on 07/24/2016 by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.