What is Hashimoto's thyroiditis?
Thyroiditis, or inflammation of the thyroid gland, has many causes. The most common cause is Hashimoto's thyroiditis. This is a chronic inflammatory disorder of the thyroid gland caused by abnormal blood antibodies and white blood cells attacking
and damaging thyroid cells. The end result of this so-called "autoimmune" destruction is hypothyroidism caused by the complete absence of thyroid cells. However, in many patients, sufficient thyroid reserve remains to prevent hypothyroidism.
Hashimoto's thyroiditis is most common among women, particularly older women, and tends to run in families. The condition occurs more frequently among people with certain chromosomal abnormalities, including Down, Turner's, and Klinefelter's syndromes. Hashimoto's thyroiditis often begins with a painless, firm enlargement of the thyroid gland or a feeling of fullness in the neck. The gland usually has a rubbery texture and sometimes feels lumpy. In about 50% of people with Hashimoto's thyroiditis, the thyroid becomes underactive. In most of the rest, the thyroid remains normal. In a small number of people, the gland initially becomes overactive, after which it usually becomes underactive.
Doctors perform thyroid function tests on blood samples to determine whether the gland is functioning normally; however, the diagnosis is based on a physical examination and the results of a blood test to determine whether the person has antithyroid antibodies, which attack the thyroid gland. The level of thyroid-stimulating hormone (TSH) is measured to be sure that hypothyroidism is not present. Most people eventually develop hypothyroidism and then must take thyroid hormone replacement therapy for the rest of their lives. Thyroid hormone may also be useful in reducing the size of the enlarged thyroid gland. People with Hashimoto's thyroiditis should avoid excess iodine (which can cause hypothyroidism) from natural sources, such as kelp tablets and seaweed.
Hashimoto's disease slowly destroys thyroid tissue and robs the gland of its ability to change iodine into T4. The condition progresses so gradually that many people who have it do not realize anything is wrong until the enlarged gland forms a goiter, a swelling seen and felt in the front of the neck. This may not happen until weeks or even years after an individual develops Hashimoto's. |
