June 16, 2000 -- The next time you go to the doctor, don't be surprised if he or she gives you a thyroid test. Even if you don't have any symptoms, you may be one of millions of Americans who have either an underactive or an overactive thyroid gland.
Many people with thyroid abnormalities have obvious symptoms that cause them to seek help, but many others do not. Because the symptoms tend to develop slowly and can mimic other things, thyroid disease is often difficult to diagnose without lab tests.
Symptoms of underactive thyroid, known as hypothyroidism, can include fatigue, weight gain, intolerance to cold, dry skin, high cholesterol, depression, and an enlarged thyroid gland. But some people have thyroid problems with no obvious symptoms at all.
An estimated 11 million Americans, many of them women over age 50, have underactive thyroid, and a smaller number -- about 2 million -- have overactive thyroid. Symptoms of overactive thyroid can include fatigue, weight loss, profuse sweating, intolerance to heat, nervousness, difficulty sleeping, and an enlarged thyroid gland.
In a recent issue of the journal Archives of Internal Medicine, a group of thyroid experts recommends that doctors start screening all adults for thyroid disease beginning at around age 35, regardless of whether they have symptoms or risk factors. They also suggest that screening be done every five years after that.
"Not everyone agrees with starting at age 35," says Gilbert H. Daniels, MD, one of the experts who helped draft the guidelines. "We think it's a reasonable thing to do." Daniels is an associate professor of medicine at Harvard Medical School in Boston.
The guidelines recommend that doctors give everyone age 35 and older a thyroid test called a serum TSH assay. If the test result is not normal, treatment varies according to the cause of the abnormal result and whether there are other related problems.
Treatment for underactive thyroid typically involves giving thyroid hormone to compensate for the lack of hormone in the body. Treatment for overactive thyroid is more complex and may involve giving a radioactive substance that slows down production of thyroid hormone. A last resort is surgical removal of the gland itself.
One thing that is important to remember is that an abnormal test doesn't necessarily mean you have thyroid disease. Other illnesses -- and even some medications -- can temporarily affect thyroid hormone levels.
That is one reason, says endocrinologist Linda Lester, MD, that doctors should always retest patients with no symptoms who have an abnormal result on a thyroid test. If the second test still shows evidence of a thyroid problem, treatment should be started, because even minor thyroid dysfunction can cause other health problems.
"This is easy to treat and we can treat with really minimal side effects," says Lester, who is an assistant professor of medicine in the division of endocrinology at Oregon Health Sciences University. She reviewed the guidelines for WebMD.
In addition to adults age 35 and older, Lester says there is now new evidence that women of child-bearing age, who are in their 20s and early 30s, also should be tested because, left undetected, thyroid disease can affect the health of their babies.
- New guidelines from a group of thyroid experts recommend that everyone be screened for thyroid disease every five years, beginning at age 35.
- The symptoms of thyroid disease can be easily missed, but it is important to treat, because it can lead to other health problems.
- An underactive thyroid can be treated with thyroid hormone; treatment for overactive thyroid is more complex and varies according to the cause of the problem.