What Is Hyperthyroidism?

The thyroid is an endocrine gland located in your neck that regulates energy levels, creates proteins, and determines how the body should respond to all of the hormones in the system.

Hyperthyroidism (or an over-active thyroid) occurs when an individual’s thyroid produces too much of the thyroid hormone that controls these systems. People with hyperthyroidism may need to take medication to help stop the over-production of thyroid hormone.

Causes of Hyperthyroidism:

Thyroid problems are often genetic. There are several conditions that can cause hyperthyroidism.

The most common cause for hyperthyroidism is an autoimmune disorder called Graves' Disease, which causes the body to attack the thyroid gland.  The body’s immune system creates antibodies called thyroid-stimulating immunoglobin (TSI) which bonds with the cells of the thyroid gland, acting much like the normally present thyroid-stimulating hormone (TSH) which tells the thyroid to produce thyroid hormone.  This results in the thyroid producing too much thyroid hormone. Patients with Graves' Disease usually have an enlarged thyroid (called a goiter), although goiters may also become enlarged due to a lack of thyroid hormone.

In addition to the symptoms of hyperthyroidism outlined below, patients with Graves’ Disease may also have Graves’ opthalmopathy, a condition in which the patient’s eyes appear enlarged because the eyelids are retracted and the eyes bulge out of the eye sockets.  The patient’s immune system attacks the muscles and tissues around the eyes; the resulting inflammation and increase in tissue mass behind the eye socket causes the eyeballs to bulge.  In some cases, the pressure can be severe enough to impact the optic nerve, leading to a loss of vision.  Patients may also have thickened or red skin on their shins; this condition is usually painless and is known as Graves’ dermopathy. 

Hyperthyroidism can also be caused by a small growths inside the gland called nodules. Most nodules are harmless, but in more serious cases called toxic nodular goiter, excess thyroid hormone will be produced.

If the gland is inflamed, the patient may have thyroiditis, which also causes excess thyroid hormone production and release. Most of the time thyroiditis is caused by a virus that will pass through the system within weeks.

Some women may develop postpartum thyroiditis a few months after the birth of their child.

Who Gets Hyperthyroidism?

Anyone can get hyperthyroidism, but the condition is most often genetic and rates are highest in women between the ages of 30 and 40 years. Those of Japanese descent are more likely to develop the condition, as well as individuals with a family history of Graves' Disease or other thyroid problems.

If you have an autoimmune disease (such as Addison's Disease or Type 1 Diabetes) or you are a smoker, you are at higher risk for hyperthyroidism.

Those who have received radiation treatments to the upper chest or neck and those who have had thyroid surgery are also more prone to developing hyperthyroidism.

Symptoms of Hyperthyroidism:

  • Feeling nervous, moody, weak, or tired
  • Shaky hands
  • Increased or irregular heart beat
  • Trouble breathing
  • Excessive sweating or heat intolerance due to heightened metabolism
  • Warm, red, itchy skin
  • More bowel movements than usual
  • Fine, soft hair that falls out easily
  • Losing weight despite eating the same or more than usual
  • Difficulty sleeping, resulting in fatigue during the day
  • Disruptions in menstruation


This list is by no means all-inclusive or meant to diagnose hyperthyroidism. In addition, symptoms can gradually occur over time, which makes them more difficult to detect.

If you suspect you may have hyperthyroidism, call your doctor. In rare cases where hyperthyroidism is left untreated, heart and bone problems or a potentially fatal condition called "thyroid storm" may result.

Diagnosis of Hyperthyroidism:

Physicians will administer a simple blood test to diagnose hyperthyroidism. The test will check the levels of different hormones in your blood; these are called TSH, T3 and T4.

When abnormalities are found in the levels of these hormones, individuals may be referred to an endocrinologist for further testing to determine if the pituitary gland and/or hypothalamus are contributing to the problem.

Mild cases of hyperthyroidism may be left undiagnosed because the hormone levels are still within the normal realm, such as in early cases of the disease.

In addition, sometimes the normal range of thyroid hormones for an individual may differ from the clinical standards; this is why it is important to seek the advice of an endocrinologist if hyperthyroidism is suspected.

Treatment for Hyperthyroidism:

Many patients with hyperthyroidism are given pills called beta-blockers to address symptoms while their doctor is formulating a treatment plan. Beta-blockers slow the heart rate and assist with the shaking hands that may accompany hyperthyroidism.

Even if your symptoms don't bother you, it is essential that your doctor gives you a treatment plan. Radioactive iodine and antithyroid medications are frequently used to assist the thyroid in producing a more manageable amount of the thyroid hormone.

Radioactive iodine is the most common form of treatment; many are cured after one dose, as the medication destroys part of your thyroid gland, leaving the rest of your body unharmed. In some cases, individuals who undergo radioactive iodine therapy may develop hypothyroidism.

Antithyroid medication is a treatment used when symptoms are mild.  These medications can be problematic, as they may stop working.  In these cases, radioactive iodine treatment is usually recommended.

Related Resource Pages on Band Back Together:

Addison's Disease

Hypothyroidism

Additional Resources:

The American Thyroid Association provides medical news and information for thyroid-related issues. They also operate a hotline: 1-800-THYROID.

The Hormone Foundation has resources for patients and professionals looking for additional information on hormone-related issues, and runs the hotline 1-800-HORMONE.

The Endocrine Society provides news and advocacy information for all endocrine disorders.

The American Association of Clinical Endocrinologists’ website can help you find an endocrinologist in your area.

EndocrineWeb has a Hyperthyroidism Center, as well as a page detailing thyroid problems experienced by some pregnant women.

Thyroid Patients' Advocacy Group UK has articles and information on living with hyperthyroidism and advocacy efforts for the condition.