The thyroid is a small gland in the front of the neck that produces a hormone that is critical to the regulation of a variety of body functions. When the thyroid gland produces too much of this hormone, it can produce a variety of symptoms. Graves' disease is the most common form of hyperthyroidism, a condition in which the thyroid gland produces too much thyroid hormone.
Definition & Facts
Graves' disease was first described by a physician named Robert J. Graves in Ireland in 1835, who noticed distinctive symptoms in one of his patients. Much later, scientists determined that Graves' disease is an autoimmune disease that produces antibodies that affect hormone production. These antibodies, called thyroid-stimulating immunoglobulins, bind to thyroid cell receptors and “trick” the thyroid into producing more thyroid hormone.
Symptoms & Complaints
- Enlargement in the front of the throat (goiter)
- Excessive sweating and heat sensitivity
- Nervousness or irritability
- Tremors of the hands
- Increased heart rate
- Frequent bowel movements
- Muscle weakness
- Lighter menstrual periods or irregular menstruation
- Unintentional weight loss
- Thinning of skin or brittle hair
- Fertility problems
- Bulging eyes and vision problems
- Skin changes on the shins or feet
Individuals who have Graves’ disease may also have other immune system diseases, such as:
- Type 1 diabetes – a condition that prevents normal processing of blood sugar in the body
- Rheumatoid arthritis – a condition that damages the body’s joints
- Lupus– a condition that cause damage to joints, blood vessels, skin and other organs
- Vitiligo – a condition that prevents normal production of components that give skin its color
- Addison’s disease– a condition of adrenal glands in which insufficient hormone is produced, causing a number of symptoms
- Pernicious anemia – a condition in which the body cannot absorb vitamin B-12, which is needed to produce normal red blood cells.
Research indicates that Graves’ disease is caused by a malfunction in the body’s immune system. Normally, the immune system produces antibodies that fight viruses, bacteria, or other foreign substances in the bloodstream. When an individual has Graves’ disease, anti-thyroid autoantibodies are produced, which disrupt the normal regulation of the thyroid gland, overproducing thyroid hormones and causing unusual physical symptoms.
The antibodies cause an accumulation of carbohydrates in the skin, which appear to be attracted to the tissues around the eyes. This results in the changes in the eyes seen in Graves’ ophthalmopathy. It can also result in skin changes on the legs, called Graves’ dermopathy. Other symptoms caused by these antibodies can also occur.
No single gene causes Graves’ disease. The condition appears to be caused by both genetic factors and environmental factors. If one twin develops Graves’ disease, the other twin has a 20 percent chance of also developing it.
Smoking is associated with the development of eye disorders caused by the disease. Chronic stress appears to trigger Graves’ disease in individuals who are susceptible. Graves’ disease affects women much more frequently than it does men. Some scientists believe it is linked to infection by certain bacteria or viruses. Pregnancy can trigger the condition in some women.
Diagnosis & Tests
Your physician will take a thorough family history and do a complete physical examination to determine your general health and likelihood for having Graves’ disease. Blood tests can detect certain components that are associated with the condition, such as thyroid-stimulating hormone, triiodothyronine (T3) and thyroxine (T4). Blood tests can also detect levels of thyroid-stimulating immunoglobulin in the body, which indicates thyroid hormone in skin and eyes tissues. High readings of these components all indicate the patient has Graves’ disease.
A radioactive iodine uptake test uses a radioactive “pill” that is taken 4 to 6 hours before a scan of the thyroid gland is done. The thyroid absorbs iodine much faster than other parts of the body. The absorption of the iodine is then traced as it moves into the thyroid gland. Then, 24 hours later, another scan is done.
A high level of iodine in the thyroid indicates hyperthyroidism and possible Graves’ disease. In some cases, an ultrasound, CT scan, or MRI may be done to determine the effects of Graves’ disease on the eyes and surrounding muscles.
Treatment & Therapy
Treatment must focus on limiting the production of this hormone and block its effect on the body. A number of methods are employed to achieve this effect. Antithyroid agents, such as methimazole and propylthiouracil reduce the thyroid gland’s ability to produce hormones. These medications can produce side effects, such as heartburn, nausea, vomiting, muscle pain, joint pain, headache and problems with the sense of taste. They can also make the individual more vulnerable to infection.
Radioactive iodine is given as a capsule or in a water-based solution, which destroys thyroid tissue. The goal is to leave a small amount of tissue that will produce just enough of the hormone. However, in many cases, the individual will produce too little thyroid hormone, which then can be adjusted back to normal levels.
If antithyroid medications are not effective, or if the patient cannot take radioactive iodine, surgery may be recommended to remove all or part of the thyroid gland. If the entire thyroid gland is removed, the patients will need to take thyroid medications for the rest of their lives to replace the amount needed for normal body function.
Prevention & Prophylaxis
A healthy lifestyle of eating a good diet, regular exercise and periodic visits to your physician for physical exams can help to ensure your overall health, which can help to reduce the risk for Graves’ disease. These measures are especially important for people who have family members who have been diagnosed with Graves’ disease.