Hyperthyroidism (High Thyroid Level)

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KEY POINTS

• Hyperthyroidism means that your thyroid gland makes too much thyroid hormone.
• You may need medicine, radiation, or surgery.
• Make sure that you don’t stop taking your medicine or change the way you take it unless your provider tells you to change or stop taking the medicine.

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What is hyperthyroidism?

Hyperthyroidism is a condition that happens when your thyroid gland makes too much thyroid hormone.

Your thyroid gland is in the lower front of your neck. This gland takes iodine from the food you eat to make thyroid hormones. Thyroid hormones are chemicals that control the way your body turns the food you eat into energy. They also control body functions such as temperature, heart rate, appetite, and emotions.

Hyperthyroidism is more common in women and more common in people over age 60.

In older people, untreated hyperthyroidism can cause an irregular heartbeat that can lead to heart failure or a stroke. It can also speed up the process that causes weak bones (osteoporosis) and increase your risk for broken bones.

Sometimes hyperthyroidism gets better without treatment. However, a serious problem called thyroid storm can happen if you have too much thyroid hormone. It happens most often when you are under stress, such as with an injury, infection, or surgery. In thyroid storm, your blood pressure, heart rate, and temperature can all get very high. Thyroid storm can be a life-threatening emergency. The best way to prevent it is to control hyperthyroidism.

What is the cause?

High thyroid levels may be caused by:

• Grave's disease, which is an autoimmune disorder. This means that your body's defenses against infection attack your body's own tissue by mistake. In the case of Graves' disease, the autoimmune response changes the thyroid gland and causes it to make too much hormone.
• Thyroid nodules, which are lumps on your thyroid gland that can make extra thyroid hormone. Most thyroid nodules are not cancer.
• Thyroiditis, which is swelling and irritation of the thyroid gland. Thyroiditis may be caused by a virus or bacteria. It also happens to some women after giving birth. Sometimes the cause of thyroiditis is not known.
• Taking in too much iodine from medicine or supplements.
• Taking too much thyroid hormone to treat low thyroid levels. If you take thyroid hormones, you should have your thyroid levels checked as often as recommended by your provider. Also make sure your healthcare provider knows about any other medicines, herbs, or supplements that you are taking. Some medicines and supplements can change how thyroid medicine works.
• In rare cases, a tumor in your thyroid gland or your pituitary gland can cause your thyroid gland to make too much hormone. The pituitary gland is located at the base of your brain. Your pituitary gland controls how much thyroid hormone is made by your thyroid gland. A tumor in your pituitary gland may cause your thyroid gland to make too much thyroid hormone.

Some thyroid problems may be inherited, which means that the problem may be passed from parents to children through their genes. Genes are inside each cell of your body. They contain the information that tells your body how to develop and work.

What are the symptoms?

Symptoms may include:

• Feeling nervous and anxious
• Trouble sleeping
• Feeling tired, weak, or shaky
• Feeling hot, sweaty, even when it is cold
• Fast or irregular heartbeat
• Enlarged thyroid gland (goiter) that makes your neck look swollen
• Having bowel movements more often
• Weight loss

Some people with hyperthyroidism also have an eye problem that keeps the eyelids from completely closing over one or both eyes. The eyes may bulge from their sockets and feel dry and irritated. The muscles that move the eyes may be affected, which may limit movement of the eyes. One eye may be affected more than the other.

A thyroid storm causes severe restlessness, confusion, sweating, and diarrhea. Your heart will beat very fast, your blood pressure will get very high, and you will have a high fever. Thyroid storm is an emergency. If you are having symptoms of thyroid storm, call 911 or have someone take you to the emergency room right away.

How is it diagnosed?

Your healthcare provider will ask about your medical history and symptoms and will examine you. Tests may include:

• Blood tests
• A thyroid scan that uses radioactive iodine to see how well your thyroid gland is working

How is it treated?

Treatment for hyperthyroidism depends on the cause. Treatment for hyperthyroidism lowers the amount of thyroid hormone in your body. Hyperthyroidism may be treated with medicine, radiation, or surgery:

• Anti-thyroid medicines lower the amount of thyroid hormone made by the thyroid gland. The medicine usually starts to control hyperthyroidism within a few months. You will likely need to keep taking the medicine for at least a year or two. Your healthcare provider may adjust your dosage often during that time. Your thyroid levels could go up again, even while you are taking medicine, so you will need to have regular checkups with your healthcare provider.
• A pill containing radioactive iodine may be used to kill thyroid cells that are making too much hormone. After this treatment, you may need to take thyroid hormone medicine for the rest of your life.
• If medicine and radiation do not successfully treat the problem, you may need surgery to remove part or all of your thyroid gland. Surgery usually cures the disease, but you will need to take thyroid hormone medicine for the rest of your life.

Medicine called beta-blockers may be prescribed to help control your symptoms. Beta-blockers do not cure hyperthyroidism, but they can make you feel better within a few hours.

You may be referred to an eye specialist for an eye exam. Eye problems related to thyroid disease need to be treated to prevent loss of vision. Problems with the eye muscles and eyelids, as well as crowding in the eye socket from swelling, may be treated with steroid medicine or surgery. Eye problems related to hyperthyroidism may continue even after the thyroid problem is treated. Sometimes treatment makes the eye problems worse.

If you are pregnant or breast-feeding, high thyroid hormone levels can cause problems for both you and your baby. Medicines used to treat high thyroid levels can affect your baby’s thyroid gland. If you are pregnant or breastfeeding, or become pregnant during your treatment, tell your healthcare provider.

How can I take care of myself?

Follow the full course of treatment prescribed by your healthcare provider. Don’t stop taking your medicine or change the way you take it unless your provider tells you to change or stop taking the medicine.

You will need to have blood tests to check your thyroid hormone level every few months for the rest of your life. The tests can help make sure you are getting the right amount of medicine.

Do not smoke. Nonsmokers respond better to treatment of thyroid disease than smokers. Smoking can worsen the eye problems that can happen with thyroid disease.

Ask your healthcare provider:

• How and when you will get your test results
• How long it will take to recover
• If there are activities you should avoid and when you can return to your normal activities
• How to take care of yourself at home
• What symptoms or problems you should watch for and what to do if you have them

Make sure you know when you should come back for a checkup. Keep all appointments for provider visits or tests.

Most healthcare providers recommend waiting at least a year after treatment to get pregnant. If you have a problem with your thyroid gland and are planning a pregnancy:

• Visit your healthcare provider before you try to get pregnant to make sure that your thyroid problem is controlled. Good control of a thyroid problem may make it easier to get pregnant.
• Be sure to follow your provider’s instructions carefully for taking medicine to control your thyroid hormone levels before and during pregnancy.