Hyperthyroidism, or an overactive thyroid gland, is typically diagnosed after the development of symptoms that can include weight loss, increased heart rate or palpitations, nervousness, difficulty sleeping, fatigue, intolerance to heat, warm skin, sweating or bulging of the eyes with Graves disease. Blood tests will show an elevated level of thyroid hormone (T3, T4) with a decreased level of thyroid-stimulating hormone (TSH), which is produced by the pituitary gland. The causes of hyperthyroidism include thyroiditis or inflammation of the thyroid gland, Graves disease, an overactive thyroid nodule, an overactive enlarged thyroid gland or goiter, and several other less common causes. Thyroiditis is an inflammation of the thyroid gland thought to be due to a viral illness and is typically self-limited over weeks to months. An overactive thyroid nodule is uncommon and can be diagnosed with a radioactive thyroid scan and ultrasound. Graves disease is the most common cause of hyperthyroidism, and it requires definitive treatment.
Graves disease is an autoimmune disorder of the thyroid gland in which patients develop antibodies to a receptor on the thyroid gland that then cause the gland to continuously overproduce thyroid hormone. Over time the thyroid gland enlarges and patients will develop a thyroid goiter. Patients with Graves disease can also develop swelling in the tissue behind the eyes which can cause bulging of the eyes and can lead to vision changes.
The symptoms of hyperthyroidism are readily treated by a number of different treatments depending on the cause of hyperthyroidism. Medications such as propothiourical (PTU) or methimazole are oral medications that decrease the amount of thyroid hormone produced by the thyroid gland and decrease the effects of increased thyroid hormone on the body. Other medications, such as propranolol or beta-blockers, can improve symptoms by blocking the effect of thyroid hormone on the cardiovascular system. Medications can be used as the primary treatment of thyroiditis until the inflammation resolves; however, when used for Graves disease or an overactive thyroid nodule or goiter, medications will decrease symptoms but will not treat the underlying disease.
The treatment of an overactive thyroid nodule is surgical removal. Your physician will begin medications to block the production of thyroid hormone to help relieve the symptoms of hyperthyroidism prior to surgery. Overactive or "hot" thyroid nodules are almost always benign in nature, and the remainder of the normal thyroid gland can be left in place to provide thyroid hormone production following surgery. Most patients will not need thyroid hormone replacement following removal of half of the thyroid gland.
The definitive treatment of Graves disease is either radioactive iodine therapy or surgical removal of the thyroid gland. Radioactive iodine therapy is the most common form of treatment for Graves disease and is administered as an oral form of radioactive iodine, which is absorbed by the thyroid gland. After its absorption the radioactivity destroys the thyroid gland. Because iodine is almost solely absorbed by the thyroid gland, there is relatively little radiation exposure outside of the thyroid gland. No previous studies have suggested that there is a significant increase in thyroid cancer following this treatment. After radioactive iodine treatment most patients will develop hypothyroid. These patients will require thyroid hormone replacement in the form of a thyroid hormone pill. Surgical removal of the thyroid gland is another definitive treatment for Graves disease or for thyroid goiter. Patients who cannot tolerate radioactive iodine or choose surgery as an alternative treatment can be cured almost immediately with removal of the entire thyroid gland. Most patients remain in the hospital for 24 hours following surgery and can return to normal activities a few days after surgery. There is a small amount of risk with thyroidectomy including bleeding, injury to nerves that can lead to hoarseness and damage to the parathyroid glands, which control the calcium level in the blood. Following removal of the entire thyroid gland, all patients will need thyroid hormone replacement in the form of oral thyroid hormone.