Question: What causes hyperthyroidism?
Answer: Hyperthyroidism -- an overactive thyroid that is producing too much thyroid hormone -- can be caused by a number of factors. Some of the more common but specific causes of hyperthyroidism include:
- Graves' disease, an autoimmune disease that can cause the thyroid to produce too much thyroid hormone
- Nodules on the thyroid, known as "toxic nodules," that produce excess thyroid hormone
- Excessive thyroid medication given to hypothyroid sufferers
- Excess intake of iodine
- Thyroiditis -- an inflammation of the thyroid most commonly caused by a virus
