What are the causes of hyperthyroidism?

Graves' disease is the most common cause of hyperthyroidism. Graves' disease causes the thyroid gland to make too much thyroid hormone. Graves' disease, like many thyroid problems, often runs in families.

Other common causes include:

• Thyroid nodules. Thyroid nodules are abnormal growths in the thyroid gland that can make too much thyroid hormone.
• Thyroiditis. Thyroiditis occurs when your body makes antibodies that damage your thyroid gland. You can also get thyroiditis from a viral or bacterial infection. At first, thyroiditis may cause your thyroid levels to rise as hormone leaks out from the damaged gland. Later, levels may be low (hypothyroidism) until the gland repairs itself.

Uncommon causes of hyperthyroidism include tumors or eating foods or taking medicines that contain large amounts of iodine.

Hyperthyroidism can occur at any age but rarely affects children. It affects women more often than men. Graves' disease is the most common cause of hyperthyroidism.

Hyperthyroidism can have many different causes. The most common cause of hyperthyroidism is Grave's disease. Hyperthyroidism also could result from overtreating hypothyroidism or it could be due to Plummer's syndrome.

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Hyperthyroidism, or overactive thyroid, can be caused by a number of conditions affecting the thyroid. Common causes of hyperthyroidism include Graves disease, toxic nodule, toxic multinodular goiter, thyroiditis, excess TSH secretion, taking excess thyroid hormone, or excess iodine intake.

Graves disease is an autoimmune disorder characterized by generalized overactivity of the thyroid gland. It is more common in women and may be hereditary. Alternatively, the overactivity may be centered in areas of overgrowth, called nodules. When there is one or more overfunctioning nodules, this is called a toxic nodule or toxic multinodular goiter. Thyroiditis, or inflammation of the thyroid, may be associated with both hyper and hypothyroidism. Thyroiditis may occur following a viral infection or after pregnancy. Rarely, excess TSH secretion from the pituitary gland in the brain may cause hyperthyroidism. Excess iodine intake is also rare, and may be due to specific drugs, such as amiodarone.

For more information go the endocrinediseases.org: