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Guide To Thyroid Disease
Less Common Sign:
Skin disease called pretibial myxedema on this woman's legs.
|What Is Graves Disease?
Graves disease is an autoimmune disorder that causes the thyroid gland to become overactive. It is the leading cause of hyperthyroidism in women. Signs of the disease usually start between the ages of 30 and 60 and it is characterized by the presence of hyperthyroidism, in addition to eye disease and skin problems. Most of the symptoms of Graves disease are the result of hyperthyroidism, which in turn is caused by an overactive thyroid. Doctors can tell the difference between hyperthyroid patients with Graves disease from other forms of hyperthyroidism because their blood tests reveal the presence of thyroid-stimulating antibodies. Graves disease is named after an Irish doctor called Robert Graves who first described the disorder over 150 years ago.
What Are The Symptoms?
Patients may display some of the common symptoms of hyperthyroidism, including:
• Unexplained weight loss (rarely, weight gain).
• Diarrhea or frequent bowel movements.
• Fatigue. See also, why am I so tired all the time?
• Insomnia or sleep apnea.
• Increased sweating.
• Irregular periods.
• Irregular heartbeat or heart palpitations.
• Increased appetite.
• Goiters (picture), but less frequently.
Clearer Signs: However, characteristic of Graves disease is the presence of eye disease and occasionally skin problems. In fact both conditions can be present long before symptoms of thyroid disease kick in. In about 5 percent of cases, eye and skin disorders can become progressively worse, even after the hyperthyroidism has been treated and controlled.
Eye Disease Symptoms
Nearly all patients with Graves disease suffer from inflammation of the eyes, a condition called ophthalmopathy or exopthalmus which causes the eyes to bulge (picture). Early signs include red or inflamed eyes, tears which form easily, sensitivity to bright light and pain like you have a dust particle in your eye. Double vision is rare unless the disorder has seriously progressed. An ultrasound scan or MRI scan of the eye will reveal if you have ophthalmopathy or not. Usually the condition is mild and comes under control when hyperthyroidism treatment begins. The severity of eye problems is not however an indication of how severely hyperthyroid the patient is. It should also be noted that eye disease tends to be worse in Graves patients who smoke.
Skin Disease Symptoms
Much more rarely, 1-2 percent of Graves patients will develop a skin disease called pretibial myxedema. Signs are raised patches of pink skin, which sometimes look raw and lumpy. It usually appears on the lower leg, and rarely on other parts of the body. It is usually mild, but severe cases can be painful. It may last for several months. It can be treated with steroids rubbed directly to the affected area. A 2002 study however found no difference in the 'cure' rate between patients treated with steroids and those who were not. Even more rarely a patient might develop a condition called thyroid acropachy. This is where the fingers or toes start to swell (known as clubbing) as bone lesions form. Although it is not painful, it can look unsightly and it can result in arthritic damage. There is no known treatment.
What Are The Causes Of Graves Disease?
About 10 percent of the world's population has thyroid autoantibodies (proteins in the body which attack the thyroid, we will call them antibodies for short). In the majority of cases, they never know it because the antibodies do not cause symptoms. However in some people the antibodies are triggered to either over stimulate the thyroid (causing Graves disease) or to suppress it causing Hashimoto's disease (a type of hypothyroidism). If you have Graves disease it means that the antibodies that stimulate the thyroid have taken over. It is thought that the same antibodies are responsible for causing eye disease. Exactly what triggers the creation of the antibodies or what causes them to attack the thyroid is still not clear. Possible theories include:
Stress: Some patients find a severely stressful event such as a death of a loved one can trigger Graves.
Virus: A virus could trigger the body to produce antibodies to fight the infection, and those antibodies may end up attacking the body as well.
Medications: Certain medications can change the body's immune system, in particular cytokines which are used to treat leukemia and hepatitis.
Genes: It may be that autoimmunity is passed down through the generations, particularly through the female line.
Iodine: People treated with radioactive iodine for hypothyroidism, sometimes end up 'over-treated' and hyperthyroid.
For more, see also causes of thyroid disease.
How Is It Diagnosed?
Your doctor will carry out a physical examination, measuring your heart rate, blood pressure and checking for any enlargement of the neck. Clues that you have Graves disease will include the presence of sore eyes (eye disease), an enlarged neck or thyroid gland, as well as a family history of autoimmune diseases. For example, a common sign of autoimmune problems is premature graying in the family (hair turning gray in your 20s). Other related problems include the presence of type 1 diabetes, pernicious anemia (related to lack of vitamin B12) and vitiligo (white patches of skin).
Laboratory blood tests will be necessary to make a clinical diagnosis (these are discussed in more detail in our article thyroid tests):
TSH Test: The levels of thyroid-stimulating hormone (TSH) in your blood will be measured.
T3 and T4: Your doctor may carry out this blood test to check your levels of thyroid hormone.
TSI or TRAb: This is a blood test to confirm the presence of thyroid stimulating antibodies which cause Graves disease.
How Is It Treated?
Graves disease is usually easily controlled and treatment is nearly always successful. Options include antithyroid medications, radioactive iodine and surgery. Each treatment has its pros and cons, and your doctor will explain these to you.
In Europe doctors tend to use thyroid drugs as a first line of treatment. While they take longer than iodine to have effect, unlike iodine or surgery, they are also beneficial in treating Graves eye disease. The two main drugs used are methimazole (Tapazole) and propylthiouracil (PTU) (and a third in Europe called carbimizole).
Also called radioiodine, this is the preferred first line of treatment in the United States. The patient drinks a solution of iodine which destroys part of or the entire thyroid gland. The dosage is varied according to the patient's age and severity of disease. It can be taken in one strong single dose or daily over a period of a few months. If the thyroid is completely destroyed, you will become hypothyroid and will need to take hormone replacement drugs for life. This procedure can make eye problems worse, even if hyperthyroidism is cured. In all cases, patients with eye disease will be given eye drops to treat inflammation. They may also need to tape their eyes closed at night to prevent dryness, and wear sun glasses during the day in sunlight. If the eye disease becomes progressively worse, they may be prescribed steroids to suppress the immune system.
The surgical removal of part or the entire thyroid gland is only usually considered if the first two options fail, or if the person has a goiter large enough to cause breathing or swallowing problems. If the entire thyroid is removed, you will become hypothyroid. Surgery is the main treatment for thyroid cancer. If you are pregnant, it is normally recommended to wait until after childbirth before going ahead with surgery. See also, thyroid disease and pregnancy.
Hyperthyroidism causes the body to speed up, which means your stores of vitamins and minerals are also used up faster than normal. For this reason you need to take extra care of your nutrition and ensure you eat a healthy balanced diet.
What Is The Prognosis?
Generally Graves disease responds well to treatment, although radioactive iodine and surgery usually lead to hypothyroidism. Also:
Surgery can damage your voice leading to permanent hoarseness.
Radioactive iodine can make eye disease worse in some cases.
Antithyroid drugs can in rare cases cause a reduction in white blood cell production and attack liver function. Your doctor should monitor this is you are on low-dose medications long-term.
As there is a natural tendency for hyperthyroid patients to turn hypothyroid within a few years of treatment, you should have blood tests at least once a year to check your thyroid. If you do end up with hypothyroidism, it is treated simply with one tablet a day (for the rest of your life). If you have been diagnosed with Graves disease, other members of the family should also be tested. It has a strong heredity link, a predisposition is sometimes revealed through genetic testing, before any changes can be detected in thyroid tests. However, it should be noted that just because you may be predisposed to a condition, does not mean you will develop it.