The thyroid is a small gland, shaped like a butterfly, that rests in the middle of the lower neck. Its primary function is to control the body's metabolism (rate at which cells perform duties essential to living). To control metabolism, the thyroid produces hormones, T4 and T3, which tell the body's cells how much energy to use.
A properly functioning thyroid will maintain the right amount of hormones needed to keep the body's metabolism functioning at a satisfactory rate. As the hormones are used, the thyroid creates replacements.
The quantity of thyroid hormones in the bloodstream is monitored and controlled by the pituitary gland. When the pituitary gland, which is located in the center of the skull below the brain, senses either a lack of thyroid hormones or a high level of thyroid hormones, it will adjust its own hormone (TSH) and send it to the thyroid to tell it what to do.
When the thyroid produces too much hormone, the body uses energy faster than it should. This condition is called hyperthyroidism. When the thyroid doesn't produce enough hormone, the body uses energy slower than it should. This condition is called hypothyroidism. There are many different reasons why either of these conditions might develop.
Currently, about 20 million Americans have some form of thyroid disease. People of all ages and races can get thyroid disease. However, women are 5 to 8 times more likely than men to have thyroid problems.
There are several different causes of thyroid disease. The following conditions cause hypothyroidism:
The following conditions cause hyperthyroidism:
The following are symptoms for hypothyroidism:
The following are symptoms for hyperthyroidism:
Thyroid disease can be difficult to diagnose because symptoms are easily confused with other conditions. Fortunately, there is a test, called the thyroid stimulating hormone (TSH) test, that can identify thyroid disorders even before the onset of symptoms. The Journal of the American Medical Association found that screening for mild thyroid failure in women and men over age 35 is as cost-effective as screening for more common problems such as high cholesterol or high blood pressure.
When thyroid disease is caught early, treatment can control the disorder even before the onset of symptoms.
The goal of treatment for any thyroid disorder is to restore normal blood levels of thyroid hormone.
Hypothyroidism is treated with a drug called levothyroxine. This is a synthetic hormone tablet that replaces missing thyroid hormone in the body. With careful monitoring, your doctor will adjust your dosage accordingly, and you'll soon be able to return to your normal lifestyle.
Hyperthyroidism, generally more difficult to treat, requires the normalization of thyroid hormone production. Treatment could involve drug therapy to block hormone production, radioactive iodine treatment that disables the thyroid, or even thyroid surgery to remove part or the entire gland.
The most popular treatment is radioactive iodine. This therapy often results in hypothyroidism, requiring the use of levothyroxine (synthetic replacement hormone) in order to restore normality.
Thyroid diseases are life-long conditions. With careful management, people with thyroid disease can live healthy, normal lives.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: 06/30/2016