A rapid heart rate (100 or more beats per minute)… an increased appetite that’s accompanied by unexplained weight loss (perhaps five to 15 pounds over several weeks’ time)… sweating… anxiety… a mild hand or finger tremor… difficulty sleeping… and fatigue can point to a number of different health problems.
So it’s not surprising that many doctors fail to identify these symptoms as red flags for hyperthyroidism (overactive thyroid). Because the symptoms also can be subtle — especially in older adults — hyperthyroidism is often difficult to diagnose.
Screening to detect hyperthyroidism, which affects about 2.5 million Americans, requires a blood test that measures thyroid-stimulating hormone (TSH). The thyroid hormones T3 (triiodothyronine) and T4 (thyroxine) sometimes are also measured. The TSH test, which should be part of the annual physical for men and women beginning at age 40, is also used to screen for hypothyroidism (underactive thyroid).
Recent development: New treatment guidelines for hyperthyroidism, based on the latest scientific evidence, are expected to be released later this year by the American Thyroid Association and American Association of Clinical Endocrinologists. Highlights of the new guidelines…
GRAVES’ DISEASE
Hyperthyroidism is most commonly caused by Graves’ disease, an auto-immune disorder in which the antibodies that normally protect against bacteria and other invaders attack the thyroid gland, stimulating excess production of thyroid hormones. Left untreated, Graves’ disease can lead to heart rhythm disorders, congestive heart failure and osteoporosis.
There are three main treatments to control symptoms of Graves’ disease — antithyroid medication (to lower levels of thyroid hormones)… radioactive iodine (to shrink the thyroid gland)… and surgery (to remove the thyroid gland).
What’s new: The new guidelines say that all three of these options should be considered by the patient and physician. This contrasts with doctors’ earlier belief that radioactive iodine was the best treatment for most people with hyperthyroidism because it is easy to administer (it’s taken by mouth) and effective.
- Antithyroid medication reduces the thyroid’s hormone production. Treatment for 12 to 18 months produces lasting remission in 20% to 30% of people with hyperthyroidism. Side effects may include rash, hives, occasional fever, joint or muscle pain and, rarely, a reduction in white blood cells that can lead to life-threatening infection.
With antithyroid medication, the thyroid gland remains functional. However, it takes more than a year to determine whether the medication will work. If it doesn’t, radioactive iodine or surgery will likely be required. Latest drug therapy approach: The two antithyroid medications, methimazole (Tapazole) and propylthiouracil(PTU), used to be considered interchangeable, but the new guidelines say that PTU should be used only in special circumstances (for example, early in a pregnancy) — the drug can cause serious liver damage, sometimes resulting in death.
- Radioactive iodine. With this treatment, you swallow a small capsule containing a radioactive chemical, which is absorbed by the thyroid. Over several weeks or months, radioactivity destroys the overactive thyroid hormone-producing cells and shrinks the thyroid gland.
Risks are lowest with radioactive iodine, but it takes six weeks to two months for the treatment to reach its full effect.
Be sure to discuss with your doctor any precautions you should take to protect those around you from the radiation.
- Surgery (thyroidectomy) removes the thyroid gland and is immediately effective. Serious complications, such as damage to nearby calcium-regulating (parathyroid) glands or vocal cords, can result but are rare when the procedure is performed by an experienced surgeon.
Almost everyone who has radioactive iodine therapy or surgery must take thyroid hormone supplements for life to maintain adequate thyroid hormone levels.
WHEN EYE DAMAGE OCCURS
In about one of every four people with Graves’ disease, the condition also affects the eyes. Sometimes it’s too mild to be noticed without an exam, but in about 20% of those with Graves’ eye disease, the eyelids swell… the eyes become dry, irritated and sensitive to light… and they may develop a bulging appearance. Some people feel pressure behind the eyes. The disorder usually lasts one to two years and often improves on its own. In 3% to 5% of cases, the condition is severe enough to threaten sight.
Only recently have doctors begun to understand why Graves’ eye disease occurs. In part, it’s because the same antibodies that cause hyperthyroidism attack cells in the back of the eye, turning them into fat cells. These fat cells secrete chemicals that attract water and lead to inflammation, resulting in swelling and tissue damage.
Treatment for Graves’ eye disease attempts to minimize damage — using steroids to decrease inflammation… or surgery (for example, to remove excess tissue behind the eye to reduce a bulging appearance).
What’s new: Since Graves’ eye disease may worsen in some 15% of patients when hyperthyroidism is treated with radioactive iodine, the new guidelines recommend that a patient who has a mild, active case of the eye disorder discuss with his/her doctor whether to take a corticosteroid, such as prednisone (Sterapred), to reduce irritation and swelling behind the eyeball and to prevent bulging eyes from worsening. If you have moderate or severe eye disease that is active, you should probably avoid radioactive iodine until your eye symptoms improve.
Recent breakthrough: Researchers are hopeful that drugs such as rituximab, originally approved for the treatment of lymphoma and now being used experimentally for Graves’ eye disease, will block the inflammatory reaction that causes eye damage.
THYROID NODULES
Another main cause of hyperthyroidism is the existence of one or more hyperfunctioning nodules (growths) within the thyroid. Nodules, which are usually noncancerous, are more common past age 60.
What’s new: According to the guidelines, surgery and radioactive iodine are the only treatment options for most people with thyroid nodules — antithyroid medication only temporarily reverses the hyperthyroidism. Surgery is best if cancer is suspected (based on a fine-needle aspiration biopsy of the nodule)… or if the thyroid is enlarged enough to interfere with breathing.
What Is HYPERTHYROIDISM?
When the thyroid (a butterfly-shaped gland located at the base of the neck) produces too much thyroid hormone, the condition is known as hyperthyroidism. With hyperthyroidism, metabolism speeds up, causing such symptoms as rapid heartbeat and sudden, unexplained weight loss.
