Hypothyroidism occurs when a patient’s thyroid gland does not produce enough thyroid hormone. This causes the person’s body processes (metabolism) to slow down, resulting in symptoms such as fatigue, intolerance to cold and dry skin.

Various disorders can cause the thyroid gland to release too little hormone, resulting in hypothyroidism. These include autoimmune diseases, certain medications, pregnancy, damage to the pituitary gland, and radiation and surgical treatments.  Treatments for excess thyroid hormone production, or hyperthyroidism, can lower the hormone levels enough to induce hypothyroidism. Potential complications of hypothyroidism include heart disease, muscle injury, cholesterol problems, infertility, birth defects or an enlarged thyroid (goiter).

Hypothyroidism can be difficult to diagnose because its symptoms vary considerably and may be found in other diseases. This illness is most common in women over the age of 50. As a result, physicians often screen for this disease during routine physical examinations of women in this age group. In other cases, a physician may check for hypothyroidism in patients who display symptoms.

Thyroid blood tests also are used to diagnose hypothyroidism. In most cases, levels of pituitary hormones that normally stimulate the thyroid can be high, while levels of hormones produced in the thyroid itself can be low. Patients may also have subclinical hypothyroidism, which does not cause symptoms but results in abnormal hormone levels.

Hormone medications can control hypothyroidism. These medications help return the body’s metabolism to a normal state. Patients may experience side effects when they take these medications in large amounts or during the initial phase of treatment while their dosages are being adjusted.