What causes hyperthyroidism?

Some common causes of hyperthyroidism include:

  • Graves’ Disease
  • Functioning adenoma and toxic multinodular goiter (TMNG)
  • Excessive intake of thyroid hormones
  • Abnormal secretion of TSH
  • Thyroiditis (inflammation of the thyroid gland)
  • Excessive iodine intake

Graves’ disease

Graves’ disease, which is caused by a generalized overactivity of the thyroid gland, and is the most common cause of hyperthyroidism. In this condition, the thyroid gland usually has lost the ability to respond to the normal control by the pituitary gland via TSH (renegade). Graves’ disease is hereditary and is up to five times more common among women than men.

Graves’ disease is thought to be an autoimmune disease, and antibodies that are characteristic of the illness may be found in the blood. These antibodies include thyroid stimulating immunoglobulin (TSI antibodies), thyroid peroxidase antibodies (TPO), and TSH receptor antibodies.

Graves’ disease symptoms and signs

Signs and symptoms of Graves’ disease include those of hyperthyroidism; however, Graves’ disease may be associated with eye disease (Graves’ opthalmopathy) and skin lesions (dermopathy). Opthalmopathy can occur before, after, or at the same time as the hyperthyroidism. Early on, it may cause sensitivity to light and a feeling of “sand in the eyes.” The eyes may be reddened and produce excess tears. Swelling behind the eyeballs causes the eyes to protrude, and double vision can occur. The degree of opthalmopathy is worsened in those who smoke.

In addition to the symptoms of hyperthyroidism mentioned above, Graves’ disease may be associated with eye disease (Graves’ opthalmopathy) and skin lesions (dermopathy). Opthalmopathy can occur before, after, or at the same time as the hyperthyroidism. Early on, it may cause sensitivity to light and a feeling of “sand in the eyes.” The eyes may be reddened and produce excess tears. Swelling behind the eyeballs causes the eyes to protrude, and double vision can occur. The degree of opthalmopathy is worsened in those who smoke.

The course of the eye disease is often independent of the thyroid disease, and steroid medications may be necessary to control the inflammation that causes the opthalmopathy. In addition, surgical intervention may be required. The skin condition (dermopathy) is rare and causes a painless, red, lumpy skin rash on the front of the legs.

Graves’ disease triggers

The triggers for Graves’ disease include:

Graves’ disease can be diagnosed by a standard, nuclear medicine thyroid scan, which shows diffusely increased uptake of a radioactively labeled iodine. In addition, a blood test may reveal elevated TSI levels.