How hyperthyroidism affects your health

Your thyroid acts like a conductor, directing hormones that seep into every tissue in your body and affect many vital functions, including your heart rate and how fast you burn calories.

When your thyroid is "overactive," you could be diagnosed with hyperthyroidism. On the other hand, hypothyroidism occurs when your thyroid gland does not produce enough hormone.

"Hyperthyroidism is when your thyroid gland releases an overabundance of thyroid hormones," says Kara Hawkins, MD, a Sentara Healthcare endocrinologist. "When this happens, you can experience a rapid and irregular heartbeat, trouble sleeping and anxiety, among many other symptoms."

What is the thyroid?

Your thyroid is a butterfly-shaped gland located at the front of your neck, under your voice box. The two sides lie around your windpipe.

The thyroid gland produces hormones that control your metabolism. Your metabolic rate affects how your body uses energy, which can impact your weight. Thyroid hormones also play a role in the movement of the muscles in the digestive tract and how your body regulates temperature.

Your thyroid relies on iodine to help it work properly. Since the body doesn't make iodine, food must provide it. The pituitary gland and hypothalamus in your brain tell the thyroid gland whether to release hormones into the bloodstream. So, problems with your pituitary gland can also lead to thyroid issues.

"For your thyroid to work correctly, all of these pieces need to be in place working together," Dr. Hawkins says. "When the thyroid isn't producing the right amount of hormone, multiple organ systems can be affected."

What is hyperthyroidism?

If your thyroid produces too much hormone, you can feel a wide range of symptoms in just about every system in your body.

An overactive thyroid can lead to:

• Difficulty sleeping
• Fatigue
• Hand tremors
• Increased sweating
• Irritability
• Lighter or no periods for women
• More frequent bowel movements
• Nervousness
• Racing heart
• Thinning of your skin and fine, brittle hair
• Weakness in your muscles—especially in the upper arms and thighs
• Weight loss despite good appetite

"Many of these symptoms can be linked to other conditions, but if you are experiencing a number of these, it would be a good idea to see your health care provider, who can order blood tests to check your thyroid function."

In addition to evaluating your symptoms, your primary care provider or an endocrinologist can order blood tests that check thyroid hormone levels.

What causes hyperthyroidism?

The most common cause of hyperthyroidism is Graves' disease, an autoimmune disorder in which your immune system stimulates your thyroid gland to make too much hormone. Graves' disease can also involve the eyes, causing pain, redness, swelling and even bulging of the eyes.

Other causes of hyperthyroidism include noncancerous growths on the thyroid, inflammation of the thyroid, high levels of iodine or too much thyroid medication (overtreatment of hypothyroidism).

How is hyperthyroidism treated?

"We can treat hyperthyroidism in a few different ways, depending on the underlying cause, your age, the severity of your condition and whether any other medical conditions are also at play," Dr. Hawkins explains.

Treatment options include:

Anti-thyroid drugs - Reduce production of hormones by the thyroid. These do not cause permanent damage to the thyroid gland.

Radioactive iodine - You swallow a small capsule of radioactive iodine, which gets into your bloodstream and is absorbed by overactive thyroid cells and destroys them. The thyroid gland or thyroid nodules shrink in size over time. Depending on the underlying cause of hyperthyroidism and goals of treatment, the thyroid may be permanently rendered nonfunctional (requiring thyroid hormone treatment thereafter), or in some cases, thyroid function may remain.

Surgery - Surgical removal of all or most of your thyroid gland (after which treatment with thyroid hormone is required.)

Symptomatic treatment -medications are given on a temporary basis to help with symptoms in cases of self-limiting causes of an overactive thyroid (thyroiditis, or inflammation of the thyroid)

Your doctor will work with you to determine the best course of action to treat hyperthyroidism.