More on the thyroid

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OVERVIEW OF THE THYROID GLAND AND ITS DISORDERS

The thyroid is a butterfly shaped gland which wraps around the front part of the windpipe just below the Adam's apple. It produces hormones that regulate the body's metabolism and organ function. Indeed, the thyroid gland can be considered "Gland Central," because its hormone influences essentially every organ, every tissue and every cell in the body. The most common thyroid disorder is an underactive thyroid, or hypothyroidism. This results when the thyroid fails to produce enough hormone. Less frequently, an overactive thyroid condition, or hyperthyroidism, occurs when the thyroid produces more thyroid hormone than is needed. If properly treated, patients with thyroid disorders lead normal, active lives. When left untreated, however, thyroid disorders can affect a patient's cardiovascular system, reproductive system and major organs.

HYPOTHYROIDISM

Hypothyroidism (underactive thyroid) affects approximately 11 million Americans, primarily women and the elderly. In the U.S., the most common cause of hypothyroidism is Hashimoto's disease, a condition caused when the immune system produces antibodies that destroy the thyroid. As the damaged thyroid gland produces less thyroid hormones, the pituitary gland secretes more thyroid-stimulating hormone (TSH) to encourage the thyroid to work harder. This increased demand on the thyroid may cause it to enlarge, resulting in what is commonly known as a goiter. Signs and Symptoms

In the case of mild thyroid failure, patients often do not show obvious symptoms and thus may not even be aware of their condition. Left untreated, however, mild thyroid failure can progress to where symptoms begin to surface. Some of the signs and symptoms of overt hypothyroidism include:

Fatigue Dry, coarse skin and hair Mood swings Hoarse voice Forgetfulness Difficulty swallowing Weight gain

Intolerance to cold

Detection and Diagnosis

Hypothyroidism may be difficult to detect because its often vague signs and symptoms are frequently confused with other conditions, such as the natural aging process, menopause or stress. Many patients remain undiagnosed and untreated for years due to their lack of awareness of hypothyroidism and its signs and symptoms.

Fortunately, even mild hypothyroidism can be detected by a sensitive TSH (thyroid stimulating hormone) test, which enables physicians to identify thyroid disorders much earlier than with previous tests. By detecting hypothyroidism in its early stages, physicians may administer treatment and prevent the onset of symptoms. In addition to having a high degree of sensitivity, the TSH test is also cost-effective. According to a recent study published in the Journal of the American Medical Association, using a TSH test to periodically screen for mild thyroid failure in men and women 35 and older is as cost-effective as screening for more common medical conditions such as high cholesterol or high blood pressure.

Treatment

The goal for treating hypothyroidism is to restore normal blood levels of thyroid hormone by replacing missing hormone. The treatment of choice for hypothyroidism involves supplementing the body's naturally produced hormone with a synthetic hormone tablet, levothyroxine sodium, which is generally taken for life.

After levothyroxine sodium therapy has been prescribed, periodic TSH tests are needed to monitor thyroid hormone levels. Because patient dosage requirements may change over time according to age, body weight, cardiovascular status and other diseases or medications, it is essential to monitor patients' medication needs on a regular basis. Monitoring precise dosages effectively prevents recurrence of symptoms of hypothyroidism and prevents over-replacement, which can in turn lead to hyperthyroidism.

Hypothyroid patients should not switch to different brands of levothyroxine sodium without consulting a physician. Both the American Association of Clinical Endocrinologists (AACE) and the American Thyroid Association have recently released clinical guidelines recommending that patients be retested and their dosages adjusted accordingly if they switch levothyroxine sodium products. AACE further advocates that physicians treat patients with the same brand of levothyroxine throughout their lifetime.

HYPERTHYROIDISM

Hyperthyroidism, a less common thyroid disorder, occurs when the thyroid gland becomes overactive and produces too much thyroid hormone. It affects approximately one million Americans, and is more prevalent among women, particularly those in their 30s and 40s. The most common form of this disorder is Graves' disease, the illness that affected Olympic athlete Gail Devers and former First Lady Barbara Bush. The cause of Graves' disease is unknown. Signs and Symptoms

The spectrum of possible signs and symptoms resulting from an overactive thyroid includes:

Irritability/nervousness Sleep disturbances Muscle weakness/tremors Enlarged thyroid (goiter) Irregular menstrual periods Heat intolerance Weight loss

Vision problems or eye irritation

Treatment

Treatment of an overactive thyroid may be complex and requires a long-term care plan. Once diagnosis is confirmed, treatment involves reducing the amount of thyroid hormone produced by the gland. Treatment methods for hyperthyroidism include antithyroid drug therapy, which blocks thyroid hormone production; radioactive iodine treatment, in which the overactive thyroid is disabled and reduced in size; and thyroid surgery to remove part or all of the gland, which is usually used to treat very young patients with Graves' disease and older patients with diseased thyroid glands.

Radioactive iodine therapy is currently the treatment of choice in most cases in the United States. Patients are given a dose of radioactive iodine that essentially "shuts down" thyroid hormone production. Normal hormone levels must often be restored through levothyroxine sodium tablets. These patients require careful lifetime management to ensure they are receiving the proper dosage of thyroid medication.