Hyperthyroidism is overactivity of the thyroid gland. This means the gland makes too much thyroid hormone. Too much hormone speeds up chemical reactions in the body. This causes mental and physical changes.
The thyroid gland is a small gland in the lower front of the neck. This gland takes iodine from the food you eat to make hormones called thyroxine (T4) and triiodothyronine (T3). The hormones control your metabolism (the chemical processes your body uses to turn the food you eat into energy). You need thyroid hormones to control body functions, such as temperature, heart rate, appetite, and digestion.
The most common form of hyperthyroidism is called Graves' disease. It occurs more often in women than men. It’s especially likely to affect women in their childbearing years between 20 and 40.
Possible causes of hyperthyroidism are:
Some thyroid gland problems may be inherited.
Some common symptoms include:
Your healthcare provider will ask about your medical history and symptoms and will examine you. You will have blood tests. These tests measure hormone levels and check thyroid gland function and your immune system. Additional tests may be done to check the thyroid gland:
Eye problems related to thyroid disease may require a CT scan or ultrasound to check the muscles that move the eye. Thyroid disease can make these muscles abnormally large.
Hyperthyroidism may be treated with medicine, radiation, or surgery. These treatments lower the amount of thyroid hormone in the body.
The 2 treatments used most often are antithyroid medicine and radioactive iodine.
Other medicines may be prescribed to help control your symptoms.
A third possible treatment is surgery to remove part or all of the thyroid gland or to remove a growth (tumor) in the gland. Surgery usually cures the disease. However, surgery has risks. Because there are so many important nerves and glands in the area of the thyroid gland, the surgery can have some serious complications. You can reduce the risk by choosing an experienced thyroid surgeon who does the surgery often. After surgery, you will need to take thyroid hormone for the rest of your life.
Your healthcare provider will keep checking your thyroid levels with blood tests for several weeks after radiation or surgical treatment. It may take several weeks to find the right dosage of thyroid medicine to keep your hormone level normal. Then your thyroid levels will need to be checked just every few months. If your thyroid levels get too low, they can be easily treated with thyroid hormone medicine.
Sometimes thyroid disease causes eye problems. Your eyes may dry out easily and need drops to keep them moist. Rarely, swelling of the tissues around the eye can threaten your vision. The swelling can put pressure on the nerves and blood vessels around the eye and eye muscles. Sometimes steroid medicine is used for the swelling and other eye problems. Surgery may be needed to treat problems with the eye muscles and eyelids, as well as crowding in the eye socket from swelling.
If you have hyperthyroidism and get pregnant, your condition should be followed closely by your healthcare provider. Most women with thyroid problems have few complications if their thyroid disorder is treated. If your thyroid hormone levels are not kept under control, they can cause problems for both you and baby. Very rarely medicines used to treat hyperthyroidism can affect a baby’s thyroid function. Ultrasound can help see if your baby is overreacting to your thyroid problem or medicines you are taking. Make sure all of your healthcare providers know about your pregnancy and any medicines you are taking. This will help you plan the best management of your pregnancy.
The effects of hyperthyroidism usually last as long as thyroid hormone levels are too high. Sometimes the disease gets better without treatment. However, sometimes it can cause heart failure and death if it is not treated.
Eye problems related to hyperthyroidism may continue even after the thyroid problem is treated. Sometimes treatment makes the eye problems worse.
Nonsmokers respond better to treatment of thyroid disease than smokers.
If you have a problem with your thyroid gland and are planning a pregnancy:
There is no known way to prevent hyperthyroidism.