Hyperthyroidism

What is hyperthyroidism?

Hyperthyroidism, also called overactive thyroid, is a condition where your thyroid makes and releases high levels of thyroid hormone. It has multiple possible causes. The main thyroid hormones are triiodothyronine (T3), thyroxine (T4) and thyroid stimulating hormone (TSH).

Hyperthyroidism speeds up your metabolism, which can affect several aspects of your health. The condition can throw your whole well-being off balance. You may not feel like yourself or even feel out of control of your body. It’s important to get medical treatment if you develop signs of hyperthyroidism so you can get back to feeling like yourself.

How common is hyperthyroidism?

Hyperthyroidism is relatively rare. Approximately 1.3% of people in the United States have it.

What are the symptoms of hyperthyroidism?

Hyperthyroidism can impact your entire body, so there are many symptoms. You may experience some of these symptoms and not others, or many of them at the same time. Symptoms of hyperthyroidism can include:

• Rapid heart rate (tachycardia) and/or heart palpitations.
• Increased blood pressure.
• Shakiness, like hand tremors.
• Feeling anxious, nervous and/or irritable.
• Weight loss despite a regular or increased appetite.
• Diarrhea or more frequent pooping.
• Increased sweating and sensitivity to warm temperatures.
• Hair loss or brittle hair.
• Difficulty sleeping (insomnia).
• Menstrual period changes, like lighter or missed periods.
• Swelling and enlargement of your neck (goiter).
• Swelling or bulging of your eyes (thyroid eye disease).

These symptoms can start suddenly or develop slowly over time. It’s important to see your healthcare provider if you develop hyperthyroidism symptoms.

What causes hyperthyroidism?

Medical conditions and situations that can cause hyperthyroidism include:

• Graves’ disease: This is an autoimmune condition that makes your thyroid overactive. Graves’ disease is the most common cause of hyperthyroidism. Your chances of developing it increase if you have a biological family history of thyroid disease and/or another autoimmune condition.
• Thyroid nodules: These are lumps or growths of cells in your thyroid gland. They can sometimes produce excess thyroid hormone. Healthcare providers may call this toxic multinodular goiter (TMNG). Thyroid nodules are rarely cancerous.
• Thyroiditis: Thyroiditis is inflammation of your thyroid gland. It can cause hyperthyroidism temporarily. After this phase — the thyrotoxic phase — it may cause hypothyroidism (underactive thyroid). When the inflammation goes away, your hormone levels may stabilize.
• Consuming excess iodine: Consuming too much iodine (through foods or medications) can cause your thyroid to produce more thyroid hormone. Iodine is a mineral that your thyroid uses to create thyroid hormone. Receiving IV iodinated contrast (iodine “dye”) or taking amiodarone (a medication) may cause hyperthyroidism.
• TSH-releasing pituitary adenoma (thyrotropinoma): This is a growth in your pituitary gland that releases excess thyroid-stimulating hormone (TSH). Your pituitary gland normally releases TSH to trigger your thyroid to release thyroid hormone. Excess TSH can lead to excess thyroid hormone. This is a very rare cause of hyperthyroidism.

What are the risk factors for hyperthyroidism?

Factors that increase your risk of developing hyperthyroidism include:

• Biological family history of thyroid disease and/or autoimmune conditions.
• Smoking.
• Pregnancy (for postpartum thyroiditis).

How is hyperthyroidism diagnosed?

The diagnostic process for hyperthyroidism may involve multiple steps, including:

• A physical exam: To start, your healthcare provider will do a physical exam to check for signs of hyperthyroidism, like an enlarged thyroid, rapid heart rate and warm, moist skin.
• Thyroid blood tests: Blood tests can check your thyroid hormone levels. When you have hyperthyroidism, levels of the thyroid hormones T3 and T4 are above normal and thyroid-stimulating hormone (TSH) is often (but not always) lower than normal.
• Thyroid antibody blood test: This test can check if Graves’ disease is the cause.
• Imaging tests: Various imaging tests of your thyroid can help diagnose hyperthyroidism and its cause. They include a radioactive iodine uptake (RAIU) test and scan and a thyroid ultrasound. Your provider will go over the options and processes with you and recommend the test they think is best.

What is the treatment for hyperthyroidism?

There are many treatment options for hyperthyroidism. Depending on the cause, some options may be better for you than others. Your healthcare provider will discuss each option with you and help you determine the best treatment plan.

Antithyroid medications

Methimazole (Tapazole®) and propylthiouracil (PTU) block the ability of your thyroid to make hormones. These medications are the most common treatment for hyperthyroidism. They can usually control thyroid function within two to three months. Your symptoms may get better within days to weeks.

Radioactive iodine (RAI) therapy

RAI therapy involves taking radioactive iodine by mouth in a single capsule or liquid dose. The radioactive iodine targets your thyroid cells specifically and destroys them. RAI usually leads to permanent destruction of your thyroid, which will cure hyperthyroidism. Most people who receive this treatment must take thyroid hormone medication (levothyroxine) for the rest of their lives to maintain normal thyroid hormone levels.

Surgery

A surgeon may remove all or part of your thyroid gland through surgery (thyroidectomy). This will correct hyperthyroidism but will usually cause hypothyroidism, requiring lifelong thyroid hormone medication.

Beta-blockers

Beta-blockers are medications that can help manage hyperthyroidism symptoms like rapid heartbeat, nervousness and shakiness. But they don’t change the level of hormones in your blood. Your provider may recommend beta-blockers alongside another treatment.

Each of these treatments has specific side effects and risks. Your provider will go over them with you. Don’t hesitate to ask questions.

What is the prognosis for someone with hyperthyroidism?

Hyperthyroidism is a treatable condition. Most people do well with treatment. While some forms of treatment require you to take medication for the rest of your life, this will help keep your thyroid hormone levels in a healthy range.

Untreated hyperthyroidism caused by Graves’ disease may get worse over time and cause complications, like Graves’ eye disease (Graves’ ophthalmopathy). If you have Graves’ disease, ask your healthcare provider how you can best manage the condition.

What happens if hyperthyroidism is left untreated?

Complications from untreated or undertreated hyperthyroidism include:

• Atrial fibrillation (Afib).
• Congestive heart failure.
• Infertility.
• Ischemic stroke.
• Osteoporosis.

A rare and life-threatening complication of hyperthyroidism is thyroid storm (thyroid crisis or thyrotoxic crisis). It happens when your thyroid makes and releases a large amount of thyroid hormone in a short amount of time. It’s an emergency that requires immediate medical attention.

Untreated or inadequately treated hyperthyroidism can cause thyroid storm. Stressors like infection, injury or surgery may trigger it.

When should I see my healthcare provider?

If you’re experiencing signs and symptoms of hyperthyroidism, it’s important to see your healthcare provider so they can assess your condition and recommend treatment.

If you already have a diagnosis, you’ll likely need to see your provider regularly to make sure your treatment is working.

If you’re experiencing signs of thyroid storm, like a high fever and very fast heart rate, get to the nearest hospital as soon as possible.

Does hyperthyroidism cause weight gain?

Hyperthyroidism doesn’t typically cause weight gain. In fact, some people experience weight loss — even with an increased appetite. This is because hyperthyroidism speeds up your metabolic rate, causing your body to use more calories for energy than usual.

Hypothyroidism (underactive thyroid) slows down your metabolism, which may lead to weight gain.

Can I develop hyperthyroidism during pregnancy?

During early pregnancy, your body needs to produce more thyroid hormones than normal to help the developing fetus. Having thyroid hormone levels that are a little higher than normal is OK, but if your levels increase dramatically, your healthcare provider may need to form a treatment plan. High levels of thyroid hormones can impact not only you but also the fetus.

It can be difficult to diagnose hyperthyroidism during pregnancy because your thyroid hormone levels naturally increase and the other symptoms of pregnancy can mask signs of the condition.

What foods should I avoid with hyperthyroidism?

Eating too many iodine-rich or iodine-fortified foods may cause hyperthyroidism or make it worse in some cases.

If you have hyperthyroidism, your healthcare provider may recommend certain changes to your diet. Always consult your provider or a registered dietitian before making drastic changes to your diet. Know that diet changes alone often can’t fix hyperthyroidism. You’ll likely need medical treatment.

If your provider recommends a low-iodine diet, try to avoid the following foods:

• Fish.
• Seaweed and kelp.
• Crab and lobster.
• Sushi.
• Prawns.
• Algae and alginate
• Milk and dairy products, like cheese.
• Egg yolks.
• Iodized salt.