HYPOTHYROIDISM

General Information

DEFINITION--Underactive thyroid gland which causes an underproduction of thyroid hormone. The thyroid is a small butterfly-shaped gland in the neck. Virtually all metabolic processes are affected by the thyroid hormone.

BODY PARTS INVOLVED--Thyroid gland (located in the neck below the Adam's apple); endocrine system.

SEX OR AGE MOST AFFECTED--Both sexes of adults, but more common in women.

SIGNS & SYMPTOMS--

It is unlikely one person will have all the following symptoms, but most will have several:

• Decreased tolerance for cold.
• Decreased sweating.
• Decreased appetite.
• Constipation.
• Chest pain.
• Coarse or slow-growing hair.
• Slow, rapid or irregular heartbeat.
• Weight gain or extreme thinness.
• Placidity or nervousness.
• Sleepiness or insomnia.
• Mental impairment, including depression, psychosis or poor memory.
• Fluid retention, especially around the eyes.
• Dull facial expression and droopy eyelids.
• Coarse skin.
• Decreased tolerance for medication.
• Decreased sex drive and infertility.
• Menstrual disorders.
• Anemia.
• Numbness and tingling of the hands and feet.
• Deepened or hoarse voice.

CAUSES--

Sometimes unknown. Following are the most common causes:

• Autoimmune disease, in which the body's immune system functions abnormally and attacks the thyroid gland.
• Radioactive iodine treatment.
• Surgery for hyperthyroidism.
• Iodine deficiency in the diet.
• Decreased activity of the pituitary gland, which secretes a thyroid-stimulating hormone.
• Use of drugs, such as lithium, that may depress thyroid function.

RISK INCREASES WITH

• Adults over 60.
• Obesity.
• Surgery for hyperthyroidism.
• X-ray treatments.

HOW TO PREVENT

• No known measures to prevent primary hypothyroidism.
• Take replacement thyroid for life after thyroid surgery or destruction of the thyroid gland by radiation treatment.

What To Expect

DIAGNOSTIC MEASURES--

• Your own observation of symptoms.
• Medical history and physical exam by a doctor.
• Laboratory blood studies of thyroid hormones. Lab studies can confirm the diagnosis of hypothyroidism, but they cannot indicate how much replacement therapy is needed.

APPROPRIATE HEALTH CARE

• Self-care after diagnosis.
• Doctor's treatment.
• You may require hospitalization if complicating emergencies occur, such as myxedema coma (extremely rare in warm climates, more common in cold climates).

POSSIBLE COMPLICATIONS

• Myxedema coma, a life-threatening complication of hypothyroidism.
• Increased susceptibility to infection.
• Adrenal crisis with vigorous treatment of hypothyroidism.
• Infertility.
• Overtreatment over long periods can lead to bone demineralization.

PROBABLE OUTCOME--Usually curable with careful thyroid-replacement therapy.

How To Treat

GENERAL MEASURES---- The goal of treatment is to provide the body with enough thyroid substance for efficient body function. Medical evaluation may be necessary for several months to establish the correct dose of thyroid replacement.

MEDICATION--Your doctor will prescribe thyroid-replacement hormones. Dosage requirements will depend on age, weight, sex, capacity of thyroid function, other drugs you take and intestinal function.

ACTIVITY--No restrictions. Stay as active as possible.

DIET--No special diet for hypothyroidism. Avoid constipation by eating a high-fiber diet. Weight loss diet recommended if you are overweight (see both diets in Appendix).

Call Your Doctor If

• You have symptoms of hypothyroidism.
• Symptoms don't improve within 3 weeks after treatment begins.
• New, unexplained symptoms develop. Drugs used in treatment may produce side effects.
• Coma or seizures occur. Get emergency help immediately!