What causes hyperthyroidism?
Graves' disease causes most hyperthyroidism. In Graves? disease, the body's natural defense (immune) system attacks the thyroid gland. The thyroid fights back by making too much thyroid hormone. Like many thyroid problems, it often runs in families.
Sometimes hyperthyroidism is caused by a swollen thyroid or small growths in the thyroid called thyroid nodules.
This topic focuses on hyperthyroidism caused by Graves' disease.
What are the symptoms?
You may have no symptoms at all. Or:
You may feel nervous, moody, weak, or tired.
Your hands may shake, your heart may beat fast, or you may have problems breathing.
You may be hot and sweaty or have warm, red, itchy skin.
You may have more bowel movements than usual.
You may have fine, soft hair that is falling out.
You may lose weight even though you eat the same or more than usual.
If you have any of these symptoms, call your doctor. Without treatment, hyperthyroidism can lead to heart problems, bone problems, and a dangerous condition called thyroid storm.