Thyrotoxicosis

Overview

Graves' disease is an inherited autoimmune disease in which the immune system attacks the thyroid gland, which then overproduces thyroid hormone. By far the most common cause of hyperthyroidism in Canada, it affects about one in every 100 people. It is far more common in women than in men. While its name may sound ominous, it has nothing to do with death or dying but rather was named after Robert Graves, the 19th century Irish doctor who first described the disorder. Graves' disease is rarely fatal, and people seldom get extremely ill because of it.

Causes

Graves' disease is an autoimmune disorder in which the body's own immune system mistakenly produces antibodies that bind to the surface of thyroid cells and then stimulate them to overproduce thyroid hormones. This has a dramatic impact on the body's metabolism, the process by which digested nutrients are converted into energy and used by cells to regulate the heart, the amount of calories burned while resting, energy level and other bodily functions. The disease is inherited, although not every member of an afflicted family will develop it.

While Graves' disease accounts for 90 per cent of hyperthyroidism, other causes include:

  • Thyroiditis, a viral infection of the thyroid gland in which thyroid hormones leak from the swollen, damaged gland;
  • "Silent" thyroiditis, a similar condition but without the painful swelling of the thyroid;
  • Multi-nodular or single nodular goiters which become self-directed.

Symptoms

The excess amount of thyroid hormone speeds up the body's metabolic process, which produces a variety of symptoms including:

  • rapid pulse
  • weight loss
  • nervousness
  • irritability
  • intolerance to hot weather
  • excessive sweating
  • shakiness
  • muscle weakness
  • loss of body fat and muscle
  • tremors in the fingers
  • hot, moist skin
  • enlargement of the thyroid gland (goiter)
  • bulging eyes
  • diarrhea

Treatment

There is no specific treatment for the underlying cause of Graves' disease, (the abnormality of the immune system). Treatment is, therefore, directed at the symptoms which are relatively easy to control. Anti-thyroid drugs can block thyroid hormone production, radioactive iodine can be used to destroy thyroid cells or part of the thyroid gland can be surgically removed (thyroidectomy). Your doctor can help you decide which treatment is best for you based on the extent of your condition, your age and your medical history.

Additional Resources

Thyroid Foundation of Canada