Hyperthyroidism
Definition
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. Your doctor may discover that you have hyperthyroidism while doing a test for another reason.
Hyperthyroidism is easily treated. With treatment, you can lead a healthy life. Hyperthyroidism generally does not go away on its own. Most people need treatment to make hyperthyroidism go away. After treatment, many people develop hypothyroidism (too little thyroid hormone).
Without treatment, hyperthyroidism can lead to serious heart problems, bone problems, and a dangerous condition called thyroid storm. In rare cases, thyroid storm develops when the thyroid gland releases large amounts of thyroid hormones in a short period of time. Thyroid storm usually happens after you have had a serious infection or you have been through a stressful time in your life.
Causes
If your thyroid gland makes too much thyroid hormone, you will have symptoms of hyperthyroidism. Most hyperthyroidism is caused by an immune system problem called Graves' Disease. 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.
You are more likely to have hyperthyroidism if:
- You are female. Women are more likely to develop hyperthyroidism than men.
- You have a family history of thyroid problems. People who have close relatives with Graves' Disease or other thyroid problems are more likely to develop hyperthyroidism.
- You have an autoimmune disease, such as Addison's Disease or type 1 diabetes.
- You smoke cigarettes. People who smoke are more likely to have Graves' Disease and are more likely to have Graves' ophthalmopathy.
- You have recently been through a stressful time such as a divorce or the loss of your job.
This web page focuses on hyperthyroidism caused by Graves' Disease.
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 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.
Diagnosis
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.
If your doctor thinks you may have hyperthyroidism, he or she may order:
- A thyroid-stimulating hormone (TSH) test, which is a blood test that measures your levels of TSH. If your TSH level is low, your doctor will want to do more tests.
- Thyroid hormone tests, which are blood tests to measure your levels of two types of thyroid hormones, called T3 and T4. If your thyroid hormone levels are high, you have hyperthyroidism.
When you are being treated for hyperthyroidism, your doctor will test your TSH and thyroid hormones several times a year to see how well your treatment is working.
After you are diagnosed with hyperthyroidism, your doctor may also want to do:
- An antithyroid antibody test to see if you have the kind of antibodies that attack thyroid tissue. This test can help diagnose Graves' Disease and autoimmune thyroidtis.
- A radioactive thyroid scan and radioactive iodine uptake tests, which use radiation and a special camera to determine the cause of your hyperthyroidism.
If you have Graves' ophthalmopathy, your doctor may also do an MRI and CT scan to look more closely at your eyes.
It is not clear whether people who do not have any risk factors and who do not have any symptoms of hyperthyroidism need to be tested regularly for thyroid problems. The American Thyroid Association recommends that adults, particularly women, be screened for thyroid problems every 5 years, beginning at age 35. But the U.S. Preventive Services Task Force does not think there is enough evidence to recommend either for or against regular thyroid testing. Talk to your doctor about whether you need to be tested for thyroid problems.
Treatment
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. Even if your symptoms do not bother you, you still need treatment, because hyperthyroidism can lead to more serious problems.
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 drinking 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—hypothyroidism, too little thyroid hormone. If this happens, you may need to take thyroid hormone pills for the rest of your life.
This infomation was taken from the University of Michigan Health System's Health Library.
