What is hyperthyroidism?

Hyperthyroidism is overactivity of the thyroid gland. Too much thyroid hormone is produced and released into the body. The excess thyroid hormone speeds up most chemical reactions in the body, causing mental and physical changes.

How does it occur?

The exact cause is unknown, but may include:

  • Your immune system may be involved.
  • Your body may be producing a substance that causes the thyroid gland to make more hormone than your body needs.
  • You have a growth(s) that makes the thyroid gland bigger.

Some thyroid gland problems may be inherited.

What are the symptoms?

Symptoms include:

  • anxiety, tiredness, or sleeplessness
  • feeling shaky, having tremors
  • feeling sweaty and hot, even though others around you are comfortable
  • shortness of breath
  • difficulty focusing your eyes
  • a bulging of one or both of your eyes
  • weight loss
  • faster heart rate
  • enlarged thyroid gland (goiter)
  • increased appetite
  • diarrhea.
How is it diagnosed?

Your health care provider will ask about your symptoms, examine you, and order lab tests. Some of these tests measure hormone levels and others check thyroid gland function. Your provider may order other tests such as a thyroid scan or an ultrasound.

How is it treated?

The options for treatment are medication, radiation, and surgery. These treatments lower the amount of thyroid hormone in your body.

Antithyroid drugs usually control hyperthyroidism in several weeks. You may need to keep taking these drugs for a year or longer.

A pill can deliver radiation to the thyroid. This method is commonly used to treat some types of hyperthyroidism, especially if you have had hyperthyroidism more than once. The main risk of this treatment is that your thyroid levels will become too low. A low level of thyroid hormone can be treated with drugs.

Surgery can be done to remove part or all of the thyroid gland or a growth in the gland. Surgery cures the disease 90% of the time. However, surgery has certain risks, including nerve damage and low thyroid levels.

How long will the effects last?

The effects of hyperthyroidism usually last as long as thyroid hormone levels are too high. Sometimes the disease improves without treatment. However, it can cause heart problems and death if it is not treated.

How can I help prevent hyperthyroidism?

There is no known way to prevent this condition.

How can I take care of myself?
  • Follow the full treatment prescribed by your health care provider.
  • Do not stop or change your thyroid medicine without first asking your health care provider.
  • Have regular checkups.
  • Contact your health care provider if you develop any symptoms that concern you.

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Published by iMcKesson Clinical Reference Products.
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Adapted from content provided by iMcKesson, LLC
Review Date: 6/9/2001