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The facts on overactive thyroid

Too much thyroid hormone can make you nervous, anxious and irritable, among other things.

Is your thyroid an overachiever?

If it produces more than enough hormones, the answer may be yes. And medical treatment may be needed to help it achieve the right balance.

All revved up

The thyroid is a small, butterfly-shaped gland that sits just below the Adam's apple. The gland makes hormones that control how fast your cells burn energy.

If your thyroid is overactive—a condition called hyperthyroidism—it makes too much thyroid hormone. The condition can make your entire body feel overactive.

Symptoms of hyperthyroidism can include:

  • Nervousness, anxiety or irritability.
  • Weight loss despite eating the same amount of food (or even more food than usual).
  • Increased perspiration.
  • Fast heart rate—often more than 100 beats per minute.
  • Trembling hands.
  • Difficulty sleeping.
  • More frequent bowel movements.
  • Intolerance of warm temperatures.
  • Fine, brittle hair or loss of scalp hair.
  • Muscular weakness, especially in the upper arms and thighs.
  • A goiter (enlargement of the thyroid) that may look or feel like a lump in the neck.

Behind the rush

So what provokes a thyroid to work overtime?

Most often, it's a problem with the immune system—a condition called Graves' disease, according to the American Thyroid Association (ATA).

Graves' disease causes antibodies, which are supposed to target and destroy germs, to instead bind to thyroid cells and stimulate them to overproduce hormones.

In addition to the symptoms listed above, Graves' disease may also cause eye problems, such as red, swollen or bulging eyes, or double vision.

Other causes of overactive thyroid include:

  • Nodules or lumps on the thyroid that produce excessive thyroid hormone.
  • Thyroiditis, an inflammatory condition that can cause the gland to leak thyroid hormone into the blood. Hyperthyroidism caused by thyroiditis is usually temporary and may be followed by a period when the thyroid is underactive (hypothyroidism).
  • Taking too much thyroid hormone in tablet form (to treat the opposite problem—an underactive thyroid).

Slowing down

Before modern treatments were discovered, the death rate from hyperthyroidism was as high as 50%, according to the ATA.

Today, however, doctors have several effective treatments from which to choose, and death from hyperthyroidism is rare. Treatment options include:

Antithyroid drugs. These medications are taken to slow or stop the production of thyroid hormone. The drugs are usually taken for several months to help normalize thyroid levels.

Radioactive iodine. Usually taken in capsule form, radioiodine gradually destroys hormone-making thyroid cells.

Surgery. An operation to remove the thyroid is rarely needed for hyperthyroidism. But sometimes surgery is necessary, such as to treat:

  • Pregnant women with severe hyperthyroidism, in whom other treatments could harm the baby.
  • People who have a suspicious lump, or nodule, on their thyroid.

Beta-blockers. These drugs can help reduce symptoms such as a racing heart, tremors and nervousness. But they do not change high levels of thyroid hormone in the blood.

Treatment depends on what's causing the hyperthyroidism, how severe it is, and any other medical conditions that a person may have, according to the American Thyroid Association.

If you think you may have an overactive thyroid, let your doctor know. A simple blood test may be all that's needed to find out what's causing your symptoms.

Reviewed 1/25/2021

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