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Johns Hopkins Symptoms and Remedies

Johns Hopkins Medicine

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Hyperthyroidism

What is it?

Hyperthyroidism is a disorder caused by excessive secretion of thyroid hormone by the thyroid, a gland in the neck that regulates body growth and metabolism. Normally, the pituitary gland, located at the base of the brain, produces a hormone (thyroid-stimulating hormone or TSH) that regulates the thyroid gland's output of thyroid hormone. Most often, hyperthyroidism is due to autonomous (unregulated by TSH) over production of thyroid hormone by an enlarged gland (Graves' disease). This is an autoimmune disorder. Less commonly, hyperthyroidism is caused by the growth of a single thyroid nodule that produces abnormally high amounts of thyroid hormone. Excess thyroid hormone speeds up all metabolic activity in the body (including the rate at which calories are burned) and may result in a myriad of symptoms; some can be mistaken as the result of stress or anxiety. While hyperthyroidism is eminently treatable, severe cases can be fatal if not adequately controlled. The disorder most commonly affects those between 30 and 40 years of age and is five times more frequent in women than men.

What Causes It?

  • Graves' disease is an autoimmune disorder, wherein an abnormal antibody is produced that stimulates a constant production of thyroid hormone.
  • Hyperthyroidism and other thyroid disorders run in families, although the exact genetic mechanisms are unknown.
  • An excessive amount of iodine in the diet and possibly, emotional stress may trigger the disorder in those predisposed to it.

Prevention

  • There is no way to prevent hyperthyroidism.

Diagnosis

  • Patient history and physical exam often point to the correct diagnosis. Indicators of hyperthyroidism include elevated heart rate, nervousness, tremor, sweating, appearance of goiter, and bulging eyes.
  • Blood tests show high levels of thyroid hor mones and low levels of TSH.
  • A thyroid scan is taken following the administration of radioactive iodine to determine the cause of hyperthyroidism.

How to Treat It

  • Orally administered radioactive iodine is now the preferred method of treatment. As the thyroid absorbs the iodine, radiation destroys parts of the gland, so that it produces less thyroid hormone.
  • Propylthiouracil or methimazole, two drugs that inhibit production of thyroid hormone, may be prescribed. Although symptoms often subside within several weeks, drug therapy must usually be continued for at least a year.
  • Surgery to remove a large portion of the thyroid may be recommended for some patients with extreme thyroid enlargement.
  • Hyperthyroid patients will require frequent medical supervision throughout their lives. One risk of radioactive iodine treatment or surgery is that the thyroid will end up producing too little thyroid hormone (hypothyroidism), which then requires lifelong supplemental therapy with thyroid hormone.

When to Call a Doctor

  • Contact your doctor if you experience the symptoms of hyperthyroidism.