Cause

Graves' disease is the most common cause of hyperthyroidism. In Graves' disease, the body's natural defense (immune) system attacks the thyroid gland. This causes the thyroid to make too much thyroid hormone. Graves' disease often runs in families.

Other common causes include:

• Thyroid nodules. These are abnormal growths in the thyroid gland. They cause the thyroid gland to make too much thyroid hormone.
• Thyroiditis. This condition occurs when your body makes antibodies that damage your thyroid gland. You can also get thyroiditis from a viral or bacterial infection. At first, thyroiditis may cause your thyroid levels to rise as hormone leaks out from the damaged gland. Later, levels may be low (hypothyroidism) until the gland repairs itself.

Uncommon causes of hyperthyroidism include tumors or eating foods or taking medicines that contain large amounts of iodine.

Learn more

Symptoms

You may have no symptoms of hyperthyroidism. 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.

Some people have irregular menstrual cycles or stop having periods altogether. And hyperthyroidism can also cause overdevelopment of the male breast.

The symptoms of hyperthyroidism are not the same for everyone. Your symptoms depend on how much hormone your thyroid gland is making, how long you have had the condition, and your age.

People with Graves' disease often have other symptoms, such as a goiter and bulging, reddened eyes.

What Happens

Graves' ophthalmopathy, also called thyroid eye disease, can be a problem caused by hyperthyroidism. It can occur before, after, or at the same time as symptoms of hyperthyroidism.

Thyroid eye disease can include eyes that bulge, are red, and are sensitive to light, and blurring or double vision. People who smoke are more likely to have these problems.

Thyroid eye disease may get worse for a time if you have radioactive iodine treatment. But the condition may get better if you take antithyroid medicine.

In rare cases, hyperthyroidism can cause a condition called thyroid storm, which can cause death if not treated right away. This happens when the thyroid gland releases large amounts of thyroid hormones in a short period of time. Certain things make this more likely to happen, including trauma, surgery, or an infection.

Without treatment, hyperthyroidism can lead to:

• Weight loss. This is because your body's metabolism is faster.
• Heart problems. For example, you may have a rapid heart rate, atrial fibrillation, or heart failure.
• Bone loss and osteoporosis.

Learn more

When to Call a Doctor

The most serious problem linked to hyperthyroidism is a life-threatening condition called thyroid storm .

Call 911 or other emergency services immediately if you have serious signs of thyroid storm such as shock or delirium .

Call your doctor now if you have been diagnosed with hyperthyroidism and:

• You feel very irritable.
• You have unusually high or low blood pressure compared to your normal blood pressure.
• You feel nauseated, are throwing up, or have diarrhea.
• Your heart is beating very fast or you have chest pain.
• You have a fever.
• You are confused or feel sleepy.
• You can't breathe well, or you feel very tired. These can be symptoms of heart failure.

You should also call your doctor if:

• You develop symptoms of Graves ophthalmopathy, such as bulging, reddened eyes.
• You feel very tired or weak.
• You are losing weight even though you are eating normally or more than usual.
• Your throat is swollen or you are having trouble swallowing.

Watchful waiting

Watchful waiting is a wait-and-see approach. If you think you have symptoms of hyperthyroidism, watchful waiting is not a good idea. Call your doctor if you think you may have hyperthyroidism. Early treatment may reduce your chances of having more serious problems.

Exams and Tests

To diagnose hyperthyroidism, your doctor will ask questions about your past health and your symptoms and will do a physical exam.

If your doctor thinks you may have hyperthyroidism, they may order:

• A thyroid-stimulating hormone (TSH) test. This blood test measures your levels of TSH. If your TSH level is low, your doctor will want to do more tests.
• Thyroid hormone tests. These blood tests measure your levels of two types of thyroid hormones, called T3 and T4. If your levels are high, you have hyperthyroidism.

When you are being treated for this condition, your doctor will test your TSH and thyroid hormones several times a year to see how well your treatment is working.

Your doctor may also do tests that can help find the cause of your condition. These can include an antithyroid antibody test, a thyroid scan, and a radioactive iodine uptake test.

Learn more

Watch

Treatment Overview

Your doctor may give you pills called beta-blockers. These can help control some symptoms until your thyroid levels improve with treatment. These symptoms include a fast heartbeat, shakiness, and feeling nervous.

Treatment for hyperthyroidism includes:

• Antithyroid medicines. 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 or surgery.
• Radioactive iodine therapy. Most people are cured after taking one dose. It destroys part or most of your thyroid gland, but it does not harm any other parts of your body. Radioactive iodine is not used if:
  • You are pregnant or you want to become pregnant within 6 months of treatment.
  • You are breastfeeding.
  • You have thyroid cancer or your doctor suspects you have thyroid cancer.
  • You have thyroiditis or another kind of hyperthyroidism that is often temporary.
• Surgery. This removes part or all of the thyroid gland. Surgery is usually a cure for hyperthyroidism, but it is not used as often as other treatment options and has more risks. Surgery is recommended if:
  • Your thyroid gland is so big that you have a hard time swallowing or breathing.
  • You have a nodule that could be thyroid cancer.
  • You have lots of side effects from antithyroid medicines and radioactive iodine is not an option for you.

If you have Graves' disease and have been taking antithyroid medicine but your hyperthyroidism has not improved, you can continue to take antithyroid medicine or you can try radioactive iodine therapy or surgery.

The kind of treatment you have depends on a number of things, including your age, what is causing your hyperthyroidism, how much thyroid hormone your body is making, and other medical conditions you may have. Some people need more than one kind of treatment. If it is not clear which treatment is best for you, ask your doctor to explain the pros and cons of each treatment.

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. So even if your symptoms are not bothering you, you still need treatment.

Problems with treatment

Sometimes treatment may cause hypothyroidism. Hypothyroidism is the opposite of hyperthyroidism. Instead of making too much thyroid hormone, your body is now making too little thyroid hormone. Hypothyroidism is most common after treatment with radioactive iodine. But it can also occur after surgery and sometimes after taking antithyroid medicine. If you do have hypothyroidism, you may need to take thyroid hormone medicine for the rest of your life.

Self-Care

• Take your medicines exactly as prescribed. You need to take the thyroid medicine at the same time each day. Ask your doctor what to do if you miss a dose. Call your doctor if you think you are having a problem with your medicine.
• Graves' disease can make your eyes sore. Use artificial tears, eye drops, and sunglasses to protect your eyes from dryness, wind, and sun. Raise your head with pillows at night to prevent your eyes from swelling. In some cases, taping your eyelids shut at night will keep your eyes from being dry in the morning.
• Make sure you get enough calcium. Foods that are rich in calcium include milk, yogurt, cheese, and dark green vegetables.
• If you need to gain weight, ask your doctor about special diets.
• Do not eat seaweed or kelp. These are high in iodine, which can make hyperthyroidism worse. Kelp and seaweed are commonly used in sushi and other Japanese foods. Limit how much iodized salt and seafood you eat. Try to eat healthy foods.
• Do not use caffeine and other stimulants. These can make symptoms worse, such as a fast heartbeat, nervousness, and problems focusing.
• Do not smoke. Smoking can make your condition worse and may lead to more serious eye problems. If you need help quitting, talk to your doctor about stop-smoking programs and medicines. These can increase your chances of quitting for good.
• Lower your stress. Learn to use biofeedback, guided imagery, meditation, or other methods to relax.
• Use creams or ointments for irritated skin. Ask your doctor which type to use.
• Tell all your doctors about your condition. They need to know because some medicines contain iodine.

Learn more

Watch

Medicines

Antithyroid medicine is often used for hyperthyroidism. It works faster than radioactive iodine therapy. And unlike radioactive iodine, it doesn't cause lasting thyroid damage.

You also may take this medicine before you have radioactive iodine treatment or surgery. Taking it may bring your metabolism to normal, make you feel better, or reduce the chances of more serious problems.

Antithyroid medicine controls hyperthyroidism in many people. But:

• You have to take the medicine for at least 1 year.
• Your symptoms may come back after you stop taking it. Then you have to start taking it again or try a different treatment.
• There are some side effects. These include a rash or hives and, in rare cases, liver injury and a low white blood cell count. A low white blood cell count can make it hard for your body to fight infection.

You may take beta-blockers or other medicines to treat symptoms such as a fast heartbeat or dry eyes until your thyroid improves.

When to use antithyroid medicine

Antithyroid medicine works best if:

• You have mild hyperthyroidism.
• Your thyroid gland is only swollen a little bit (small goiter).

The medicine may be used instead of radioactive iodine if you are pregnant, breastfeeding, or trying to become pregnant.

Children are treated with antithyroid medicine. That's because experts don't know if radioactive iodine treatment is safe for children.

Learn more

Watch

Surgery

Surgery for hyperthyroidism is called thyroidectomy. It removes part or all of the thyroid gland. Doctors rarely use this surgery to treat hyperthyroidism. It's riskier than other treatments.

Your doctor may recommend surgery if:

• Your thyroid gland is so big that it's hard for you to swallow or breathe.
• You have thyroid cancer.
• Your doctor suspects that you have thyroid cancer.
• You had serious side effects from taking antithyroid medicines, and radioactive iodine isn't an option for you.
• You have a large goiter that radioactive iodine treatment didn't shrink.
• You have a single, large thyroid nodule that makes too much thyroid hormone, and radioactive iodine didn't help with the nodule.

Your doctor will have you take antithyroid medicines if you have any surgery for the condition.

After surgery, your doctor will check your thyroid hormone levels regularly. That's because you could get hypothyroidism (too little thyroid hormone). If you do have hypothyroidism, you may need to take thyroid hormone medicine for the rest of your life.

Learn more

Watch

Radioactive Iodine Treatment

Radioactive iodine is given as a liquid or capsule that you swallow. The iodine is taken up by your thyroid gland. The radioactivity in the iodine kills most or all of the tissue in your thyroid gland. But it doesn't harm any other parts of your body.

Most people are cured of hyperthyroidism after one dose of the medicine.

Radioactive iodine damages your thyroid gland. Over time, most people who take it develop hypothyroidism (having too little thyroid hormone). If you have hypothyroidism, you can replace the thyroid hormone by taking thyroid hormone medicine for the rest of your life.

Radioactive iodine shouldn't be used by children. And it shouldn't be used if you:

• Are pregnant.
• Are breastfeeding.
• Want to become pregnant within 6 months of treatment.

Learn more