Graves' disease is an autoimmune disease -- one in which the immune system attacks certain tissues -- that causes overactivity of the thyroid gland (hyperthyroidism).

Located in the front of the neck just below the larynx (voicebox), the thyroid gland is an important organ of the endocrine system. The thyroid secretes the hormones thyroxine (T4) and triiodothyronine (T3), which control body metabolism. Regulation of metabolism is critical in controlling mood, weight and mental and physical energy levels.

Thyroid disorders caused by overproduction of thyroid hormones are called hyperthyroidism, and underproduction of these hormones is known as hypothyroidism.

Graves' disease is the most common cause of hyperthyroidism. The production of thyroid hormone is increased, causing a wide range of symptoms from anxiety and restlessness to insomnia and weight loss. In addition, the eyeballs may begin to protrude (exophthalmos) causing irritation and tearing.

Graves' disease is caused by innapropriate immune system activation that targets the thyroid gland and causes overproduction of thyroid hormones. Risk factors are being a woman over 20 years old, although the disorder may occur at any age and may affect men.

• Protruding eyes (less common in children)
• Weight loss
• Increased appetite
• Nervousness
• Restlessness
• Heat intolerance
• Increased sweating
• Fatigue
• Muscle weakness
• Double vision
• Eye irritation
• Breast enlargement in men (possible)
• Tremor
• Frequent bowel movements
• Menstrual irregularities in women
• Goiter (possible)

Physical examination shows an increased heart rate. Examination of the neck may show thyroid enlargement or goiter.

• Serum TSH is decreased
• Serum T3, free T4 are elevated
• Radioactive iodine uptake is usually high

• TSI
• Orbit CT scan

The purpose of treatment is to control the overactivity of the thyroid gland. Beta-blockers such as propranolol are often used to treat symptoms of rapid heart rate, sweating, and anxiety until the hyperthyroidism is controlled. Hyperthyroidism is treated with antithyroid medications, radioactive iodine or surgery.

Both radiation and surgery result in the need for lifelong use of replacement thyroid hormones, because these treatments destroy or remove the gland.

The eye problems related to Graves' disease usually resolve when the hyperthyroidism is effectively treated with medications, radiation or surgery. Sometimes use of prednisone (a steroid medication which suppresses the immune system) is required to reduce eye irritation and swelling.

Taping the eyes closed at night to prevent drying may sometimes be required. Sunglasses and eyedrops may lessen irritation of the eyes. Rarely, surgery may be needed to return the eyes to their normal position.

For most people, Graves' disease responds well to treatment. However, thyroid surgery or radioactive iodine will sometimes cause hypothyroidism, which can lead to weight gain, depression and mental and physical sluggishness. Antithyroid medications can also have serious side effects.

• Eye problems associated with the disease (called Graves' ophthalmopathy or exophthalmos)
• Cardiac complications including rapid heart rate, congestive heart failure (especially in the elderly) and atrial fibrillation
• Thyroid crisis or storm, a severe worsening of the symptoms of overactivity of the thyroid gland
• Increased risk for osteoporosis
• Inadequate levels of thyroid hormone medications following surgery or radiation, leading to fatigue, elevated cholesterol levels, mild weight gain, depression and mental and physical sluggishness
• Complications related to surgery, including visible scarring of the neck and hoarseness due to damage of the nerve to the voicebox, and low calcium levels due to damage to the parathyroid glands.

Call your health care provider if you have symptoms suggestive of Graves' disease. Also call if eye problems or general symptoms worsen (or do not improve) with treatment.

Go to the emergency room or call the local emergency number (such as 911) if symptoms of hyperthyroidism are associated with a rapid, irregular heart beat, fever, or a decrease in consciousness.