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A look at the causes and treatment options for this common cause of hyperthyroidism.

Your thyroid gland makes hormones that regulate how your body uses energy. Having too much thyroid hormone in the body is known as hyperthyroidism.

According to the American Thyroid Association (ATA), the most common cause of hyperthyroidism is a condition called Graves' disease, which occurs when the entire thyroid gland is overactive. The condition is named after Robert Graves, the Irish doctor who first described it.

Too many hormones

Graves' disease causes the immune system to produce antibodies that cause the thyroid to make more hormones than the body needs. This causes all of the body's functions to speed up.

Symptoms of Graves' disease can occur slowly or come on very suddenly. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), signs and symptoms of Graves' disease may include:

• An enlarged thyroid.
• Trouble sleeping.
• Irritability or nervousness.
• Sensitivity to heat and increased sweating.
• Hand tremors.
• Rapid heartbeat.
• Frequent bowel movements.
• Unexplained weight loss.
• Fatigue or muscle weakness.

In women, Graves' disease can result in lighter menstrual flows and less frequent periods.

Unlike other conditions associated with an overactive thyroid, Graves' disease may cause bulging or discomfort in one or both eyes that can affect vision. It also may cause reddening and thickening of the skin, often on the shins and tops of the feet.

Some people with Graves' disease don't experience any symptoms.

Risk factors

Graves' disease usually affects people who are older than age 30. But it can affect people of all ages.

According to NIDDK, you are at greater risk for Graves' disease if you:

• Are female. Women are seven to eight times more likely to get the disease than men.
• Have a family history of the disease.
• Are under severe emotional stress.
• Gave birth in the past 12 months.
• Have other health conditions, such as rheumatoid arthritis, type 1 diabetes or lupus.

Treating the disease

Without treatment, Graves' disease can cause serious conditions such as heart problems, weak and brittle bones, and even death.

Fortunately, treatment for the condition is safe and almost always successful, according to the ATA.

Treatment options include:

Antithyroid medicine. Your doctor can prescribe drugs that are designed to keep the thyroid from making too much thyroid hormone.

Radioactive iodine. A pill containing iodine can be taken to destroy thyroid cells so that less thyroid hormone is made.

Surgery. You can undergo a procedure where most or all of your thyroid is removed. After surgery, you will need to take thyroid hormone to replace the needed hormone your body can no longer make.

With any of these treatments, your doctor may also prescribe a beta blocker drug to help keep thyroid hormone from acting on your body. These drugs work within hours and can help control symptoms such as rapid heart rate, trembling and nervousness until other treatments can take effect.

After treatment

According to the ATA, people who have treatment for Graves' disease often develop low thyroid hormone levels (called hypothyroidism) later. Because of this, it's important to have frequent blood tests to measure thyroid hormone levels after treatment ends.

Reviewed 11/27/2023