Hyperthyroidism: What It Is and How to Treat It What is hyperthyroidism? The thyroid gland, located in your neck, produces hormones that control your body's ability to create and use energy (metabolism). Hyperthyroidism (say: hy-per-thy-royd-iz-um) occurs when the thyroid produces too many of these hormones. This can speed up your body's metabolism by as much as 100 percent. What causes hyperthyroidism? Many things can cause hyperthyroidism. One of the most common causes of hyperthyroidism is Grave's disease, an autoimmune disorder. Your immune system uses antibodies to protect you against disease and infection. But if you have Grave's disease, your antibodies attack your thyroid gland by mistake. This makes it produce  too many hormones. This type of hyperthyroidism tends to run in families and occurs more often in women. Hyperthyroidism can also occur when noncancerous lumps grow in your thyroid gland. These lumps can increase the production of hormones and lead to hyperthyroidism. Thyroiditis (say: thi-royd-eye-tis) is another possible cause of hyperthyroidism. Thyroiditis is an inflammation of your thyroid gland, and it also leads to an overproduction of hormones. Thyroiditis usually goes away on its own.   Possible signs of hyperthyroidism Sudden weight loss Fatigue and muscle weakness Nervousness and anxiety Increased sweating Fast heartbeat Tremors Wider, swollen or red eyes How can my doctor find out if I have hyperthyroidism? Many other health problems can cause the same symptoms as hyperthyroidism. Your doctor will exam you and possibly do some tests to find out what is causing your symptoms. Your doctor may ask you to swallow while he or she feels your thyroid gland for any growths. He or she may test your reflexes and look for unusual eye changes. Blood tests can measure the levels of hormones in your blood. If a blood test shows signs of hyperthyroidism, your doctor want to do some additional tests to confirm the diagnosis. How is hyperthyroidism treated? There are different treatments for hyperthyroidism. Your doctor will help decide which treatment is right for you. Some of the things your doctor will consider are the cause of your hyperthyroidism, your age, the size of your thyroid gland and your overall health. The following are some possible treatments for hyperthyroidism: If you have thyroiditis, your doctor may give you a kind of medicine called a beta blocker. Beta blockers don't reduce your thyroid hormone levels, but they may help you feel better if you have shakiness or a fast heartbeat. Radioactive iodine (RAI) is a common, safe and effective treatment for hyperthyroidism. This medicine is taken by mouth. It helps reduce the size of the thyroid gland, as well as the symptoms of hyperthyroidism. Women who are pregnant or breastfeeding cannot use RAI. Antithyroid drugs (ATDs) make the thyroid gland stop producing too many hormones. They usually relieve the symptoms of hyperthyroidism in 6 to 8 weeks. Treatment with ATDs usually continues for a year or more, and there's a chance that your hyperthyroidism will come back after you stop taking the drugs. Surgery to remove the thyroid gland is an option if your thyroid gland is very large and is pressing on other parts of your neck. It may also be an option if you can't use ATDs. Talk to your doctor about the risks and benefits of each treatment. Even if treatment relieves your symptoms, your doctor will want to check your thyroid regularly to make sure that your hyperthyroidism does not come back.