Graves' disease is a disorder of the immune system that causes the thyroid gland to become overactive. It is an autoimmune disorder, which means the body's immune system mistakenly attacks the body's own cells instead of protecting them from outside invaders. In Graves' disease, the body's immune system makes abnormal chemicals called immunoglobulins that stimulate the thyroid gland to make too much thyroid hormone. This overactive thyroid state is called hyperthyroidism.
Doctors don't know what causes Graves' disease, but the fact that it tends to run in families indicates that the disease may have a genetic (inherited) component. It is possible that the abnormal production of immunoglobulins is triggered by some unknown factor in the environment, and the immune system fails to stop this overproduction because of an inherited defect.
Graves' disease affects women more than men. It most frequently strikes between the ages of 20 and 40 but can occur at any age.
Graves' disease can cause the following symptoms:
- Emotional swings
- Hand tremor
- Unexplained weight loss (often despite increased appetite)
- Sensitivity to warm temperatures (feeling hot all the time)
- Muscle weakness
- Shortness of breath
In women, menstrual periods may become less frequent or stop altogether. In older people, particularly people with heart disease, the disease may cause heart failure or heart-related chest pain called angina.
Graves' disease also may cause:
- Goiter. Goiter is a swelling in the lower front portion of the neck caused by an enlarged thyroid gland.
- Eye symptoms. Graves' disease can cause swelling of tissues around the eyes, which creates a characteristic "staring" or "frightened" appearance. The eyes bulge out and the eyelids appear to be pulled back. There is less blinking. The person may have double vision, itching and weeping.
- Skin symptoms. Rarely, there may be swelling of the feet and lower legs. Skin in this swollen area may appear thicker and darker than normal skin, and it may itch.
Your doctor will look for physical evidence of Graves' disease, including goiter, eye signs and skin signs. He or she also will ask you about recent weight loss, nervousness, tremors (shakes), increased sweating, palpitations, unusually frequent bowel movements, menstrual irregularities and whether you feel hot all the time.
During your physical examination, your doctor will feel your thyroid for abnormal nodules (lumps) and to see if it is enlarged. He or she also may use a stethoscope to listen for signs of abnormal blood flow near your thyroid gland. In other parts of your body, your doctor will check for additional signs of hyperthyroidism, including fast heart rate, irregular heart rhythm, hand tremor, fast reflexes when tendons are tapped with a soft hammer, and bulging eyes.
Your doctor will order blood tests to determine whether your thyroid is producing and releasing too much hormone. If your doctor is concerned about potential eye problems, he or she may order a computed tomography (CT) scan or magnetic resonance imaging (MRI) scan of your eyes. If your doctor thinks your heart is involved, an electrocardiogram (EKG) and/or other cardiac tests probably will be needed.
Almost all patients with Graves' need treatment, at least initially. Symptoms related to the high levels of circulating thyroid hormone will quickly improve with medications such as beta blockers and tranquilizers. It takes several weeks for the action of anti-thyroid medications to lower thyroid blood levels toward normal. Anti-thyroid medication is continued for at least one year unless another treatment is used.
There is no way to prevent Graves' disease.
Treatment focuses on two goals: rapidly improving the hyperthyroid symptoms, and slowing the thyroid's production of thyroid hormone.
Symptoms of palpitations, increased heart rate, tremor and nervousness are treated with a beta-blocker medication such as propanolol (Inderal). For anxiety and insomnia, your doctor may prescribe diazepam (Valium), lorazepam (Ativan) or a similar medication.
To stop the thyroid from producing too much hormone, there are three possible treatments: antithyroid medications, radioactive iodine and surgery.
Graves' disease is most often treated with the anti-thyroid drug methimazole (Tapazole, generic versions). Methimazole blocks the formation of thyroid hormones. Another anti-thyroid drug called propylthiouracil is also available. However, it should only be used in patients who cannot tolerate methimazole and in women just before and during their first trimester of pregnancy. Once thyroid hormone levels have reached normal, you and your doctor can decide whether to continue daily anti-thyroid medication or to choose radioactive iodine treatment.
Radioactive iodine is given by mouth. Most specialists recommend a large enough dose to completely stop the thyroid from producing thyroid hormone. You would then have to take thyroid medication daily for the rest of your life. Because people who receive radioactive iodine therapy temporarily store a small amount of radiation in their thyroid, they need to avoid prolonged contact with pregnant women and children for several days following treatment. Radioactive iodine is concentrated in breast milk and women must stop breast feeding if they choose this therapy.
Surgery for Graves' disease is rarely done today. However, people with very large goiters are less likely to respond well to anti-thyroid medication or radioactive iodine, and may have a better outcome if most of the thyroid gland is removed surgically (called subtotal thyroidectomy).
Patients with eye signs of Graves' disease may be given eye drops to keep the eyes moist and tinted eyeglasses to protect the eyes from sun, wind and dust. In people with severe eye symptoms, glucocorticoid medications may be necessary, either alone or together with radiation treatments to the muscles that control eye movement. Skin symptoms of Graves' disease may be treated with glucocorticoid creams and ointments.
Call your doctor if you have any of the symptoms of hyperthyroidism, including:
- Constant feelings of anxiety
- Difficulty sleeping
- Abnormal sweating or unusual sensitivity to warm temperatures
- Palpitations, shortness of breath or chest pain
- Weight loss, in spite of a normal or increased appetite
- Muscle weakness or wasting
Also call your doctor if you develop swelling or skin changes in your feet or lower legs, or if you notice a change in your eye appearance or eye function.
Many patients remain well after a single course of anti-thyroid drugs, but recurrence can happen at any time. Radioactive iodide is very effective, but often results in abnormally low levels of thyroid hormones (hypothyroidism). Surgery also can cause low levels of thyroid hormones.
The eye signs of Graves' disease tend to improve with anti-thyroid drug treatment. However, some element of the staring appearance often remains.
American Thyroid Association, Inc.
6066 Leesburg Pike
Falls Church, VA 22041