Thyroiditis

Definition

Thyroiditis is inflammation of the thyroid gland, a butterfly-shaped organ next to the windpipe.

Description

The thyroid is the largest gland in the neck. It produces, secretes, and stores thyroxine (T₄), a hormone that influences the metabolism of just about every body process.

When the thyroid gland is functioning properly, hormone release is carefully regulated. When bacteria or viruses invade and inflame the gland, T₄ surges into the bloodstream and raises hormone levels that then discourage the gland from creating more T₄. Eventually the hormone stores are exhausted, the thyroid loses its ability to manufacture T₄, and an underactive thyroid (hypothyroidism) results.

The major cause of hypothyroidism, thyroiditis affects about 12 million people in the United States. This condition is more common in women than in men and usually develops between ages 30–50.

Hashimoto's disease

Some cases of Hashimoto's disease remain stable for years. Others slowly progress to hypothyroidism, which is treated with thyroid hormone replacement therapy.

Subacute thyroiditis

Most patients with subacute thyroiditis recover fully after no more than a few months. This condition occasionally recurs, but severe or long-term complications are rare.

Silent thyroiditis

Four of every five patients with silent thyroiditis recover completely within three months. The thyroid status of these patients should be evaluated within 12 months. Because silent thyroiditis recurs in 10% of patients within three years and may progress to hypothyroidism, medical monitoring should continue for three years after recovery appears complete.

Acute thyroiditis

Acute thyroiditis requires emergency treatment with antibiotics and surgery.

Diagnosis

Family physicians and endocrinologists usually base a diagnosis of thyroiditis on:

• blood levels of thyroid hormones, thyroid-stimulating hormone, and anti-thyroid antibodies
• personal and family medical history
• the appearance of a patient's thyroid gland

Thyroid antibodies present in 95% of patients with Hashimoto's thyroiditis make it possible to diagnose this disease without surgery or biopsy. A blood test that measures sedimentation rate, an indication of the extent of inflammation, is a useful tool for diagnosing subacute thyroiditis.

Treatment

Medical therapy for thyroiditis includes:

• antibiotics to fight infection
• high doses of aspirin to relieve inflammation
• hormones to suppress or replace thyroid function
• pain medications

Cortisone drugs are sometimes prescribed to reduce persistent inflammation. In rare instances, surgery can be used to drain infection or relieve pressure near the thyroid gland.

Prognosis

Thyroiditis usually responds to treatment, and some patients recover normal thyroid function without treatment. Because permanent loss of thyroid function is a possibility and life-long thyroid replacement therapy may be necessary, regular medical monitoring should continue even after the patient has apparently recovered.

Prevention

Flu shots or immunizations for measles, mumps, and rubella may help prevent conditions associated with subacute thyroiditis. There is no known way to prevent other forms of thyroiditis.

ORGANIZATIONS

The Thyroid Foundation of America. 350 Ruth Sleeper Hall, Parkman St., Boston, MA 02114. (800) 232-8321. <http://www.clark.net/pub/tfa>.

The Thyroid Society for Education and Research. 7515 South Main St., Suite 545, Houston, TX 77030. (800) 849-7643. <http:the-thyroid-society.org/thyroid.html>.

OTHER

"Chronic Thyroiditis (Hashimoto's disease)." Health Answers.com 30 Apr. 1998 <http://www.healthanswers.com>.

"How do Doctors Test for Thyroiditis?" The Thyroid Society Page. 20 Apr. 1998 <http://the-thyroid-society.org>.

"Silent Thyroiditis." The Merck Page. 22 Apr. 1998 <http://www.merck.com>.

"Subacute Thyroiditis." The Merck Page. 22 Apr. 1998 <http://www.merck.com>.

"Subacute Thyroiditis." HealthAnswers.com 30 Apr. 1998 <http://healthanswers.com>.

"Thyroiditis." ThriveOnline. 21 Apr. 1998 <http://thriveonline.oxygen.com>.

"What are the Main Types of Thyroiditis?" The Thyroid Society Page. 20 Apr. 1998 <http://the-thyroid-society.org>.

"What is Thyroiditis?" The Thyroid Society Page. 20 Apr. 1998 <http://the-thyroid-society.org>.

"Your Thyroid." Endocrine Web Page. 22 Apr. 1998 <http://www.endocrineweb.com>.

Maureen Haggerty

KEY TERMS

Addison's disease—A disease that results from a deficiency in adrenocortical hormones.

Diabetes mellitus—A disorder of the pancreas. This chronic disorder of carbohydrate metabolism results in hyperglycemia and glycosuria.

Goiter—An abnormal enlargement of the thryroid gland.

Graves' disease—Also called hyperthyroidism, this disease results from overactivity of the thyroid gland.

Subacute—An abnormal condition present in a person who appears to be clinically well.

Vitiligo—A benign skin disease that results in irregular patches of skin that are totally lacking in color.