Information on an Underactive Thyroid

An underactive thyroid, also known as hypothyroidism, occurs when the thyroid gland does not produce an adequate amount of thyroid hormone. Thyroid hormone is required by nearly every tissue in the body and a lack of it can interfere with the body's normal chemical reactions. It can also cause health problems if not properly treated.

Symptoms

• The severity of symptoms can vary based on the degree of hormone deficiency, but can include weight gain, constipation, fatigue, high cholesterol, depression and muscle weakness.

Causes

• There are a number of causes of underactive thyroid, including autoimmune diseases, radiation therapy, thyroid surgery and certain medications, such as lithium.

Risk Factors

• The risk of developing an underactive thyroid increases with age, and women older than 50 are most at risk. Also, if you have a relative with an autoimmune disorder, you are more likely to develop an underactive thyroid.

Tests and Diagnosis

• A blood test is done to measure the amount of thyroid-stimulating hormone (TSH) and thyroid hormone thyroxine (THT) levels. A high TSH and low THT level is an indication of an underactive thyroid.

Treatment

• The only treatment, which will be required for the rest of your life, involves taking levothyroxine, a synthetic hormone that's sold under the names Unithroid, Levoxyl, Synthroid and Levothroid. It returns your body's hormones to a normal level.