Hyperthyroidism

What Is It?

Hyperthyroidism means having abnormally high levels of thyroid hormones. Thyroid hormones, which are made by the thyroid gland in the lower front of the neck, regulate the body's energy. When levels of thyroid hormones are unusually high, the body burns energy faster and many vital functions speed up.

In most cases, hyperthyroidism is caused by the thyroid gland producing too much thyroid hormone. The two most common reasons for this are:

• Graves' disease, an immune-system disorder that causes the thyroid to release too much thyroid hormone. Graves' disease typically affects young women between ages 20 and 40, although about 12% of patients are men. Because Graves' disease is an inherited disorder related to genetic factors, thyroid disease tends to affect several people in the same family.
• A benign (noncancerous) thyroid tumor that secrets increased amounts of thyroid hormones in an uncontrolled manner

Very rarely, hyperthyroidism may be caused by the pituitary gland making too much thyroid-stimulating hormone (TSH), which causes the thyroid gland to produce too much thyroid hormone.

Certain types of thyroid inflammation or viral thyroid infections can cause short-term hyperthyroidism.

In rare situations, excess thyroid hormone can come from a source outside the thyroid, including struma ovarii, an abnormal tissue growth in the ovary that secretes thyroid hormone. Symptoms of hyperthyroidism also can be caused by taking thyroid supplements when they aren't needed.

Symptoms

Hyperthyroidism causes the following symptoms:

• Nervousness
• Insomnia
• Dramatic emotional swings
• Sweating
• Tremors
• Increased heart rate
• Frequent bowel movements
• Unexplained weight loss, often despite an increased appetite
• Feeling warm or hot all the time
• Muscle weakness
• Shortness of breath and heart palpitations

In women, menstrual periods may either become less frequent or stop completely. Older people may develop heart failure or angina (chest pain).

When hyperthyroidism is caused by Graves' disease, you also may have swelling of tissues behind the eyes that causes a characteristic protruding, staring appearance. This condition is called exophthalmos.

Diagnosis

Your doctor will examine you, and will feel your thyroid for signs of enlargement and for abnormal lumps. He or she also may use a stethoscope to listen for signs of abnormal blood flow in the area of your thyroid gland. In other parts of your body, your doctor will check for additional signs of hyperthyroidism, including increased heart rate, a hand tremor, brisk response to tapping with a reflex hammer, excessive sweating, muscle weakness and protruding eyes.

If your doctor suspects that you have hyperthyroidism, he or she will order blood tests to check your levels of thyroid hormones. Other diagnostic tests may include blood tests to check levels of certain antibodies, an ultrasound of the thyroid and a thyroid scan.

Expected Duration

In people with hyperthyroidism caused by certain types of thyroid inflammation or viral thyroid infections, levels of thyroid hormones usually return to normal after several months. Most people with Graves' disease require long-term treatment, although the condition occasionally goes away on its own.

Prevention

Hyperthyroidism caused by taking too much thyroid medication can be prevented by following your doctor's instructions and periodically getting blood tests to check blood thyroid levels. Naturally occurring hyperthyroidism cannot be prevented.

Treatment

Hyperthyroidism is most often treated with anti-thyroid drug therapy, using propylthiouracil (sold as a generic drug) or methimazole (Tapazole, Thiamazole) to block the formation of thyroid hormones. Beta-blocker drugs, such as propranalol (Inderal) also may be used to control symptoms. Radioactive iodine, which destroys the thyroid, is a more permanent option for treating hyperthyroidism caused by Graves' disease. Another option that is rarely used today is surgery to remove part of the thyroid gland (subtotal thyroidectomy).

When To Call A Professional

Call your doctor if you have symptoms of hyperthyroidism.

Prognosis

Up to 50% of people treated with 12 to 24 months of anti-thyroid drugs have prolonged remissions of their illness. Radioactive iodine also is an effective treatment, although most people will develop an underactive thyroid (hypothyroidism) following this treatment. However, this condition is easily treated with a single pill of thyroid replacement medication daily.

Additional Info

Thyroid Foundation of America, Inc.

One Longfellow Place

Suite 1518

Boston, MA 02114

Toll-Free: 1-800-832-8321

Fax: 617-534-1515

Email: info@allthyroid.org

http://www.tsh.org/

American Thyroid Association, Inc.

6066 Leesburg Pike

Suite 650

Falls Church, VA 22041

Phone: 703-998-8890

Fax: 703-998-8893

Email: admin@thyroid.org

http://www.thyroid.org/