Thyroid Disease

Hypothyroidism occurs when the thyroid gland does not make enough of the thyroid hormones to maintain your normal body metabolism.

The most common cause of hypothyroidism is a disorder known as thyroiditis—an inflammation of the thyroid gland. The most common type of thyroiditis is called Hashimoto disease. In this disease, the immune system—your body’s natural defense against disease—mistakes cells in the thyroid gland for harmful invaders. Your body sends out white blood cells to destroy the thyroid gland. The pituitary gland then releases TSH to tell the thyroid gland to make more thyroid hormone. This demand on the thyroid gland can cause it to enlarge. This enlargement is called a goiter. Hypothyroidism also can result from a diet that does not have enough iodine, although this type of hypothyroidism is rare in the United States.

The symptoms of hypothyroidism are slow to develop. Common symptoms of hypothyroidism include the following:

• Fatigue or weakness
• Weight gain
• Decreased appetite
• Change in menstrual periods
• Loss of sex drive
• Feeling cold when others do not
• Constipation
• Muscle aches
• Puffiness around the eyes
• Brittle nails
• Hair loss

In most cases, hypothyroidism is treated with medication that contains thyroid hormone. The dosage of the medication is increased slowly until a normal level of thyroid hormone has been reached in the blood.

Hyperthyroidism results when the thyroid gland makes too much thyroid hormone. This causes your metabolism to speed up.

The most common cause of hyperthyroidism is a disorder known as Graves disease. It most often affects women between the ages of 20 years and 40 years. A late sign of Graves disease is often a wide-eyed stare or bulging eyes.

Hyperthyroidism also may result from medication. Taking too much thyroid hormone when being treated for hypo-thyroidism can lead to symptoms of an overactive thyroid. Lumps in the thyroid called hot nodules are another cause. These lumps produce excess thyroid hormone.

Common symptoms of hyperthyroidism include the following:

• Fatigue
• Weight loss
• Nervousness
• Rapid heart beat
• Increased sweating
• Feeling hot when others do not
• Changes in menstrual periods
• More frequent bowel movements
• Tremors

Anti-thyroid medication can be used to reduce the amount of thyroid hormone your body is making. Medications known as beta-blockers control rapid heart beat.

If these medications do not help, your health care provider may suggest treatment with high-dose radioactive iodine to destroy parts of the thyroid gland. In some cases, surgery may be needed to remove the thyroid gland.

A nodule is a lump in the thyroid gland. When a thyroid nodule is found, it will be checked to see if it is benign (not cancer) or malignant (cancer).

Your health care provider may use ultrasound to examine the nodule. Nodules may be further examined by a procedure known as fine needle aspiration or biopsy.

If no cancer cells are found, your health care provider may either prescribe medication to decrease the size of your nodule or suggest surgery to remove it. If cancer cells are found, further treatment will be needed. Thyroid cancer usually can be treated with success.

Many medications used to treat thyroid disease in pregnancy are safe for your unborn child. However, your health care provider may monitor you closely while you are being treated. Radioactive iodine, which is sometimes used to treat hyperthyroidism, cannot be taken during pregnancy. It may injure the thyroid gland of the fetus and may cause the baby to have hypothyroidism.

Some women may not have thyroid problems during pregnancy, but develop problems after childbirth. This condition is called postpartum thyroiditis. It often is a short-term problem and hormone levels quickly return to normal.

Regular screening for thyroid disease should be done every 5 years beginning at age 50 years. Women at risk may need to be screened earlier or more often.