What is the thyroid?
The thyroid is a butterfly-shaped gland in the lower front part of the neck. Glands are organs located in different parts of the body. Glands make and release hormones, substances that aid body function and growth. The thyroid gland helps regulate your body temperature and control your heart rate and metabolism (the process that turns the food you eat into energy).
What is hyperthyroidism?
Hyperthyroidism is an overactivity of the thyroid. This means that your thyroid produces and releases more hormones than your body needs. This can affect your body and the way it functions.
What are the symptoms of hyperthyroidism?
Symptoms of hyperthyroidism can include the following:
- Rapid heartbeat
- Feeling shaky, nervous
- Weight loss
- Increased appetite
- Diarrhea
- Double vision
- Thin skin
- Menstrual changes
- Intolerance to heat and excessive sweating
- Swelling and enlargement of the neck from an enlarged thyroid gland (goiter)
- Bulging of the eyes (seen with Graves’ disease)
- Muscle weakness
What are the causes of hyperthyroidism?
There are several causes of hyperthyroidism:
- Graves’ disease: This is a disorder in which the immune system attacks the thyroid, causing it to make too much thyroid hormone. Graves disease is a hereditary condition (affects several members of the family) and more commonly occurs in women than in men. Graves’ disease is the most common form of hyperthyroidism and accounts for 85% of cases.
- Thyroid nodules: A thyroid nodule is a lump or growth of cells (which may be cancerous or non-cancerous) in the thyroid gland that can cause it to produce more hormones than your body needs.
- Thyroiditis: This is a general term that refers to an inflammation (swelling) of the thyroid caused by an infection or a problem with the immune system. It causes the thyroid gland to leak hormones, resulting in more than your body needs. This condition can occur after the delivery of a baby (postpartum thyroiditis) or from taking the drugs interferon and amiodarone.
Who is affected by hyperthyroidism?
Both men and women can have hyperthyroidism, but it occurs most often in women aged 20-40.
How is hyperthyroidism diagnosed?
Your doctor will do a physical examination and take a blood sample to measure your hormone levels. When you have hyperthyroidism, levels of the thyroid hormones T3 and T4 are above normal, and thyroid stimulating hormone (TSH) is lower than normal. Your doctor may also want to perform a thyroid scan, a picture of your thyroid to check its shape and to see if there are any nodules.
How is hyperthyroidism treated?
There are many treatments for hyperthyroidism. Your doctor will help you determine what type of treatment is best for you. Treatments include the following:
- Anti-thyroid drugs methimazole (Tapazole) or propylthioracil (PTU): These drugs block the ability of the thyroid to make hormones. They offer rapid control of the thyroid.
- Radioactive iodine: Radioactive iodine is taken by mouth and absorbed by the overactive thyroid cells. The iodine damages these cells, and causes the thyroid to shrink and thyroid hormone levels to go down. This usually leads to permanent destruction of the thyroid, which will cure hyperthyroidism. Most patients who receive this treatment have to take thyroid hormone drugs for the rest of their lives to maintain normal hormone levels.
- Surgery: The doctor may remove the thyroid gland through surgery (thyroidectomy). This will usually cause hypothyroidism (an underactive thyroid). Patients who have a thyroidectomy have to take thyroid supplements to keep hormone levels normal.
- Beta blockers: These drugs block the action of thyroid hormones on the body. They do not change the amount of hormones in your blood, but they can help control the rapid heartbeat, nervousness, and shakiness caused by hyperthyroidism.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. For additional written health information, please contact the Health Information Center at the Cleveland Clinic 216.444.3771 or toll-free 800.223.2273 extension 43771 or visit www.clevelandclinic.org/health/. This document was last reviewed on: 3/26/2008...index#14129
