Endocrine System Home > Hyperthyroidism Causes
In the United States, Graves' disease is the most common cause of hyperthyroidism. However, there are a number of other reasons why a person might develop an overactive thyroid. Some of these -- such as thyroiditis or thyroid nodules -- occur within the thyroid gland, while others -- such as taking too much synthetic thyroid hormone -- occur in other places within the body.
What Causes Hyperthyroidism?A number of different conditions can cause hyperthyroidism. Some of these can occur within the thyroid gland itself, including:
- Graves' disease
- Thyroid nodules
- Consuming too much iodine (iodine-induced hyperthyroidism)
- Taking too much synthetic thyroid hormone
- A pituitary adenoma.