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Topic Overview

What is hyperthyroidism?

Hyperthyroidism means your thyroid makes too much thyroid hormone. Your thyroid is a gland in the front of your neck. It controls your metabolism, which is how your body turns food into energy. It also affects your heart, muscles, bones, and cholesterol.

Having too much thyroid hormone can make a lot of things in your body speed up. You may lose weight quickly, have a fast heartbeat, sweat a lot, or feel nervous and moody. Or you may have no symptoms at all. While your doctor is doing a test for another reason, he or she may discover that you have hyperthyroidism.

Hyperthyroidism is easily treated. With treatment, you can lead a healthy life. Without treatment, hyperthyroidism can lead to serious heart problems, bone problems, and a dangerous condition called thyroid storm.

What causes hyperthyroidism?

Graves' disease causes most hyperthyroidism. In Graves' disease, the body's natural defense (immune) system attacks the thyroid gland. The thyroid fights back by making too much thyroid hormone. Like many thyroid problems, it often runs in families.

Sometimes hyperthyroidism is caused by a swollen thyroid or small growths in the thyroid called thyroid nodules.

This topic focuses on hyperthyroidism caused by Graves' disease.

What are the symptoms?

You may have no symptoms at all. Or:

• You may feel nervous, moody, weak, or tired.
• Your hands may shake, your heart may beat fast, or you may have problems breathing.
• You may be hot and sweaty or have warm, red, itchy skin.
• You may have more bowel movements than usual.
• You may have fine, soft hair that is falling out.
• You may lose weight even though you eat the same or more than usual.

If you have any of these symptoms, call your doctor. Without treatment, hyperthyroidism can lead to heart problems, bone problems, and a dangerous condition called thyroid storm.

How is hyperthyroidism diagnosed?

Your doctor will ask you about your symptoms and do a physical exam. Then he or she will order blood tests to see how much thyroid hormone your body is making.

Sometimes hyperthyroidism is found while you are having a test for another reason. You may be surprised to find out that you have this problem.

How is it treated?

If your symptoms bother you, your doctor may give you pills called beta-blockers. These can help you feel better while you and your doctor decide what your treatment should be. Hyperthyroidism can lead to more serious problems. So even if your symptoms do not bother you, you still need treatment.

Radioactive iodine and antithyroid medicine are the treatments doctors use most often. The best treatment for you will depend on a number of things, including your age. Some people need more than one kind of treatment.

• Radioactive iodine is the most common treatment. Most people are cured after taking one dose. It destroys part of your thyroid gland, but it does not harm any other parts of your body.
• Antithyroid medicine works best if your symptoms are mild. These pills do not damage your thyroid gland. But they do not always work, and you have to take them at the same time every day. If they stop working, you may need to try radioactive iodine.

After treatment, you will need regular blood tests. These tests check to see if your hyperthyroidism has come back. They also check to see if you are making enough thyroid hormone. Sometimes treatment cures hyperthyroidism but causes the opposite problem—too little thyroid hormone. If this happens, you may need to take thyroid hormone pills for the rest of your life.

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