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Thyroid Diseases

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What is the thyroid and why should I worry about it?

The thyroid is a small gland in the neck, just under the Adam's apple. Shaped like a butterfly, the thyroid plays an important role in a person's health and affects every organ, tissue, and cell in the body. It makes hormones that help to regulate the body's metabolism (how the body uses and stores energy from foods eaten) and organ functions. When the thyroid is not working properly (called thyroid disorder), it can affect your body weight, energy level, muscle strength, skin health, menstrual cycle (periods), memory, heart rate, and cholesterol level. Thyroid disorders happen: when the thyroid gland is not as active as it should be (called underactive thyroid); when the thyroid is more active than it should be (called overactive thyroid); or when the thyroid is enlarged (called goiter or nodule). People with thyroid enlargement can have underactive, overactive or normal thyroid function. Thyroid disorders are much more common in women than in men. About 1 out of every 8 American women will develop a thyroid disorder. Underactive or overactive thyroid can be found with a simple blood test (called a thyroid stimulating hormone or TSH test), and is most often treated with medication and sometimes surgery or radioactive iodine.

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What are the different types of thyroid disorders?

Thyroid disorders include:

  • Hypothyroidism (underactive thyroid). This is the most common type of thyroid disorder, where the thyroid makes too little of the thyroid hormone that your body needs to function properly. It is most often caused by Hashimoto's disease. With this disease, the body's immune system (which normally protects you from disease) thinks the thyroid is a foreign invader and tries to destroy the thyroid. When damage is done to the thyroid, it can become larger (called goiter). Not getting enough iodine in a person's diet can also cause hypothyroidism, but this is more common outside of the United States (in the U.S., many products such as salt and bread are supplemented with iodine, making iodine deficiency rare).

    Being female, over 40 years of age, having a close family member with thyroid disease, and recently having had a baby are things that can increase the chance of getting hypothyroidism.

  • Hyperthyroidism (overactive thyroid). When the thyroid gland is overactive, it makes too much of the thyroid hormone that your body needs to be healthy. This condition affects women more than men. In young women, hyperthyroidism is most often caused by Graves' disease. With this disease, the body's immune system tricks the thyroid into making too much thyroid hormone. The entire thyroid becomes enlarged and overactive. Older women may get another form of hyperthyroidism (toxic nodular goiter), where overactive thyroid cells group together and form a lump in the neck (called a thyroid nodule) that makes more of the thyroid hormone than the body needs. Some thyroid disorders initially cause overactive thyroid, but at a later point in time cause underactive thyroid, due to damage done to the thyroid gland.

  • Postpartum thyroiditis. After giving birth, a woman's thyroid can swell and become larger or inflamed. This can cause changing levels of thyroid hormone in the body. Sometimes high levels can be followed by low levels of thyroid hormone. After 6 months or less, this condition usually goes away with no permanent damage to the thyroid. While common, thyroid disorders after pregnancy are often hard to detect since some of the symptoms, such as having trouble sleeping, fatigue, depression, or weight change are viewed as normal when a woman has a new baby. The symptoms can also be mild. Usually only short-term treatment is required until the thyroid recovers normal function. Sometimes after pregnancy, a woman can get hypothyroidism (underactive thyroid), which persists and needs long-term treatment with medication.

  • Thyroid cancer. This type of cancer is most often found as a lump (or nodule) in the thyroid gland. It is not a common type of cancer and most thyroid nodules are benign (not cancer). Other signs of thyroid cancer include swelling in the lymph nodes of the neck and trouble swallowing or breathing. Although anyone can get thyroid cancer, people who as children had head or neck x-ray treatments for tonsillitis or other conditions (from about the 1920s to the 1960s) are more likely to get this cancer. It is treated with surgery, which removes the cancer, sometimes followed by radioactive iodine therapy, which kills the cancer.

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What are the signs of a thyroid disorder?

It can be hard to tell if you have a thyroid disorder because these disorders can have signs that are common and often confused with other conditions. If you think you have a thyroid disorder, talk with your health care provider and ask if a blood test for a thyroid disorder is indicated. A simple blood test measures thyroid stimulating hormone, or TSH, to find overactive and underactive thyroid disorders.

Signs of hypothyroidism, or underactive thyroid, include:

  • Fatigue
  • Weight gain
  • Mood swings
  • Forgetfulness
  • Hoarse voice
  • Dry, coarse skin and hair
  • Trouble swallowing
  • Not being able to stand the cold
  • Increased cholesterol
  • Heavy or irregular periods or trouble getting pregnant
  • An enlarged thyroid (goiter)

Signs of hyperthyroidism, or overactive thyroid, include:

  • Weight loss
  • Feeling irritable and nervous
  • Weakness in muscles and tremors
  • Having menstrual periods that are not regular
  • Troubled, or disturbed sleep
  • Problems seeing or eye irritations
  • Having an enlarged thyroid (goiter)
  • Not being able to stand the heat
  • Palpitations or rapid heart beats
  • Frequent bowel movements

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How are thyroid disorders treated?

Thyroid disease can be treated with medication alone or with surgery, radioactive iodine or a combination of these treatments. Hypothyroidism (underactive thyroid) is treated with thyroid replacement therapy. A synthetic hormone is taken daily to increase the amount of thyroid hormone in a person's body. The drug most health care providers prescribe is levothyroxine sodium. This is the same hormone the thyroid normally makes. Treatment for hyperthyroidism (overactive thyroid) aims to decrease the amount of thyroid hormone in a person's body. This is done through medications that block the formation and release of thyroid hormone into the body or with radioactive iodine treatment, which destroys the overactive thyroid tissue. Surgery can also be done to remove part or all of the thyroid gland, but this is usually done to remove a nodule rather than to treat overactive thyroid. If you have ever had a thyroid disorder, it is important to check your thyroid levels with your health care provider on a regular basis.

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For more information...

Office of Scientific and Health Information

Thyroid Foundation of America, Inc.

The American Thyroid Association

American Foundation of Thyroid Patients

Endocrine Society

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Thyroid Diseases