Encyclopedia Home / H / Hyperthyroidism


  • Alternative Names

    Overactive thyroid


    How the condition is treated depends on the cause and the severity of symptoms. Hyperthyroidism is usually treated with one or more of the following:

    • Antithyroid medications
    • Radioactive iodine (which destroys the thyroid and stops the excess production of hormones)
    • Surgery to remove the thyroid

    If the thyroid must be removed with surgery or destroyed with radiation, you must take thyroid hormone replacement pills for the rest of your life.

    Beta-blockers such as propranolol are used to treat some of the symptoms, including rapid heart rate, sweating, and anxiety until the hyperthyroidism can be controlled.

    Support Groups

    Expectations (prognosis)

    Hyperthyroidism is generally treatable and only rarely is life threatening. Some of its causes may go away without treatment.

    Hyperthyroidism caused by Graves disease usually gets worse over time. It has many complications, some of which are severe and affect quality of life.


    Thyroid crisis (storm), also called thyrotoxicosis, is a sudden worsening of hyperthyroidism symptoms that may occur with infection or stress. Fever, decreased mental alertness, and abdominal pain may occur. Immediate hospitalization is needed.

    Other complications related to hyperthyroidism include:

    • Heart-related complications including:
      • Rapid heart rate
      • Congestive heart failure
      • Atrial fibrillation
    • Increased risk for osteoporosis, if hyperthyroidism is present for a long time
    • Surgery-related complications, including:
      • Scarring of the neck
      • Hoarseness due to nerve damage to the voice box
      • Low calcium level due to damage to the parathyroid glands (located near the thyroid gland)
    • Treatments for hypothyroidism, such as radioactive iodine, surgery, and medications to replace thyroid hormones can have complications.

    Calling your health care provider

    Call your health care provider if you have symptoms that could be caused by too much thyroid hormone production. Go to an emergency room or call the local emergency number (such as 911), if you have:

    • Change in consciousness
    • Dizziness
    • Rapid, irregular heartbeat

    Call your health care provider if you are being treated for hyperthyroidism and you develop symptoms of underactive thyroid, including:

    • Depression
    • Mental and physical sluggishness
    • Weight gain