Hypothyroidism

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VOL 107 / NO 1 / JANUARY 2000 / POSTGRADUATE MEDICINE

You feel sluggish and weary. Perhaps you nod off every now and then. Your skin is dry, your hair lifeless and thinning. You have no appetite but still gain weight. Your reactions are slow and your memory dull. Sounds dreadful, and yet this is a very common scenario that can be mistakenly considered part of "normal aging." All of these symptoms suggest an underactive thyroid gland, which can be treated to bring you back up to speed.

Hypothyroidism, a condition of low (hypo) thyroid function affects about 7 million people in the United States, mostly women over age 40. Early symptoms are so subtle that many cases are missed for years. Treatment, which is usually quite simple, sometimes leads to miraculous improvement.

What is happening here?
Your thyroid gland regulates a number of body processes. Thyroid hormones in the blood circulate to all your cells and help maintain the rate at which your body uses calories and how your body adjusts your heart rate, repairs muscles, and regulates temperature and many other functions. The thyroid has to release just the right amount of hormones to keep all these things in balance.

When production of thyroid hormone gets too low, the body seems to gear down to slow speed. Although the early symptoms are often vague, if your metabolism continues to slow down, you may have such signs as cold hands and feet, constipation, pale and dry skin, a puffy face, a hoarse voice, difficulty with balance, and confusion. Your blood cholesterol level might go up. Sometimes the thyroid gland becomes enlarged, forming what is called a goiter.

Some cases of hypothyroidism are caused by an autoimmune disorder. This occurs when the immune system produces antibodies (the body's protective disease-fighting proteins) that attack thyroid tissue and destroy the gland. Hypothyroidism can also occur after treatment for an overactive (hyper) thyroid gland. If you have been treated with radioactive iodine, have had radiation therapy to your head or neck, or have undergone thyroid surgery to remove all or most of your thyroid gland, you may be at increased risk for hypothyroidism. Congenital disorders, diseases of the pituitary gland (which normally stimulates the thyroid gland), and deficiency of iodine (an element necessary for the production of thyroid hormones) also can cause hypothyroidism.

What should you do if you suspect thyroid problems?
Talk with your doctor if you have concerns about fatigue, dry skin, forgetfulness, or any other symptoms. Thyroid hormone levels can be measured by a simple blood test. Low blood levels of a hormone called thyroxine (T₄) and high levels of a hormone called thyrotropin, or thyroid-stimulating hormone (TSH), often mean your thyroid is not working up to speed.

How is hypothyroidism treated?
A synthetic thyroid hormone called levothyroxine usually restores adequate thyroid hormone levels and gets your body back in gear. The medication may have to be slowly increased until the right dose is found. In some people, symptoms improve quickly; in others, it can take a while to reach the right dosage. Treatment usually is lifelong, but the drug has almost no side effects and is easy to take and quite inexpensive.

It is important to have your doctor check your progress every 2 to 3 months at first to make sure the drug dosage is correct. After that, an annual blood test provides good information about how the thyroid gland is working. Be sure you do not stop taking your medication once you begin to feel better. Symptoms almost always return if the medication is discontinued.

This information is not a substitute for medical treatment.

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