Reviewed by:  Dr. Robert Cooper, M.D., FACE

Hyperthyroidism occurs when your body produces too much thyroid hormone. A hyperactive thyroid can significantly increase the body’s metabolism. Most cases are attributed to Graves’ disease, an autoimmune condition where the body attacks its own cells and overproduces thyroid hormones. People with other autoimmune disorders or an inflamed thyroid (thyroiditis) are also at an increased risk for hyperthyroidism.

Common signs and symptoms include:

• Weight loss despite a possible increase in appetite and the amount of food consumed
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• Rapid or irregular heartbeat or a pounding heartbeat (palpitations)
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• Changes in bowel patterns. Usually an increase in the frequency of bowel movements.
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• Increased nervousness, irritability or anxiety attacks
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• Insomnia
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• Less tolerance to heat and increased sweating
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• Fine trembling in the hands and fingers
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• Enlarged thyroid (goiter); a goiter may appear as a swelling at the base of the neck
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• For women of child-bearing age, lighter periods or no period at all

Most of the symptoms listed can be caused by multiple conditions other than hyperthyroidism, so determining the source of the symptoms can take some time. If you experience any of these symptoms, call your doctor, who can test your thyroid levels with a blood test.

What's Next: Get Your Thyroid Tested

• Avoid the Risks of Thyroid Disease
• Signs of an Underactive Thyroid
• Lifestyle Tips for a Healthy Thyroid
• Check Your Neck
• Ask Your Doctor About Hypothyroidism
• Ask Your Doctor About Hyperthyroidism

Review Date: November 19, 2008