Thyroid Disorders

Hypothyroidism

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

Hypothyroidism occurs when the thyroid gland fails to produce enough thyroid hormone. Without enough thyroid hormone, the body becomes tired and run down. Every organ system slows, including the brain, which affects concentration; the gut, causing constipation; and metabolism -- the rate at which the body burns energy -- resulting in weight gain. Although there are many different causes of hypothyroidism, the resulting effect on the body is the same.

The most common cause of hypothyroidism is Hashimoto's thyroiditis, a disease in which the body's immune system attacks the thyroid gland. Failure of the pituitary gland to secrete a hormone to stimulate the thyroid gland, called secondary hypothyroidism, is a less common cause of hypothyroidism. Other causes include congenital defects, surgical removal of the thyroid gland, irradiation of the gland and inflammatory conditions.

The condition is more common in women and people over the age of 50. Other risk factors include thyroid surgery and exposure of the neck to X-ray or radiation treatments. With proper treatment, patients with hypothyroidism can regain full control of their lives and completely eliminate symptoms.

The symptoms of hypothyroidism depend on the amount of decrease in thyroid hormone and the duration of time in which the decrease has been present. Most patients experience mild symptoms, which are often confused with other problems. Symptoms may include:

• Fatigue
• Joint or muscle stiffness
• Decreased hearing
• Weight gain
• Dry skin
• Sensitivity to cold
• Coarseness or loss of hair
• Goiter, or an enlarged thyroid causing a lump in the neck
• Constipation
• Memory and mental impairment
• Depression
• Irritability
• Irregular or heavy menstruation
• Slowed heart rate
• Decreased libido

Reviewed by health care specialists at UCSF Medical Center.
Last updated May 8, 2007