What is Hyperthyroidism?

Hyperthyroidism is when the thyroid gland is overactive and produces excess of a thyroid hormone (thyroxine), the hormone that regulates metabolism. There are several causes of hyperthyroidism, including Graves’ disease, toxic nodular goiter and thyroiditis. Common symptoms of hyperthyroidism include:

  • Nervousness
  • Irritability
  • Perspiration
  • Fine, brittle hair
  • Weak muscles and shaky hands
  • Fast heartbeat and high blood pressure
  • Difficulty sleeping and fatigue
  • Weight loss
  • Increased bowel movements
  • Confusion
  • Irregular menstrual cycle

Graves’ disease is an autoimmune disorder that causes hyperthyroidism. Many patients with Graves’ disease also show signs of Graves’ ophthalmopathy, including prominent or bulging eyes, light sensitivity, double vision, red or inflamed eyes, and puffy eyelids.

Toxic nodular goiter is a condition in which one or more thyroid nodules become overactive, but it does not produce the bulging eyes or skin problems that occur with Graves’ disease.

Thyroiditis causes temporary hyperthyroidism followed by hypothyroidism (underactive thyroid).

If left untreated, hyperthyroidism can cause pregnancy complications, heart rhythm disorders that may lead to congestive heart failure, and osteoporosis. In rare cases, hyperthyroidism due to Graves’ disease can cause thyroid storm, which is a sudden increase in thyroid hormones causing fever, sweating and an irregular heartbeat. Thyroid storm can be life-threatening.

The Northwestern Medicine Comprehensive Thyroid and Endocrine Surgery Program can diagnose all causes of hyperthyroidism by taking blood tests, conducting physical exams, using imaging tests and measuring radioactive iodine uptake. Initial treatment of hyperthyroidism is focused on beta blockers to treat the symptoms of hyperthyroidism and anti-thyroid drugs to slow the production of thyroid hormones. Other treatment options are radioactive iodine therapy to ablate the thyroid gland or surgery to remove the thyroid gland.

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