(See also Overview of the Thyroid Gland Overview of the Thyroid Gland The thyroid is a small gland, measuring about 2 inches (5 centimeters) across, that lies just under the skin below the Adam’s apple in the neck. The two halves (lobes) of the gland are connected... read more .)
Subacute thyroiditis usually begins suddenly. In this disorder, inflammation causes the thyroid gland to release excessive amounts of thyroid hormones, resulting in hyperthyroidism Hyperthyroidism Hyperthyroidism is overactivity of the thyroid gland that leads to high levels of thyroid hormones and speeding up of vital body functions. Graves disease is the most common cause of hyperthyroidism... read more , almost always followed by transient hypothyroidism Hypothyroidism Hypothyroidism is underactivity of the thyroid gland that leads to inadequate production of thyroid hormones and a slowing of vital body functions. Facial expressions become dull, the voice... read more and finally normal thyroid function.
Subacute thyroiditis often follows a viral illness and begins with what many people call a sore throat but actually proves to be neck pain localized to the thyroid. Many people with subacute thyroiditis feel extremely tired. The thyroid gland becomes increasingly tender, and the person usually develops a low-grade fever (99 to 101° F [37 to 38º C]). The pain may shift from one side of the neck to the other, spread to the jaw and ears, and hurt more when the head is turned or when the person swallows. Subacute thyroiditis is often mistaken at first for a dental problem or a throat or ear infection.
The diagnosis of subacute thyroiditis is made based on a person's symptoms and the results of the examination and thyroid function tests Thyroid function tests The thyroid is a small gland, measuring about 2 inches (5 centimeters) across, that lies just under the skin below the Adam’s apple in the neck. The two halves (lobes) of the gland are connected... read more . Sometimes, it may difficult to differentiate subacute thyroiditis from Graves disease Graves disease Hyperthyroidism is overactivity of the thyroid gland that leads to high levels of thyroid hormones and speeding up of vital body functions. Graves disease is the most common cause of hyperthyroidism... read more , in which case doctors do a thyroid scan and uptake test. Because of the inflammation, little or no radioactivity is taken up by the thyroid gland in subacute thyroiditis while uptake is increased in Graves disease. Thyroid ultrasonography can also help diagnose subacute thyroiditis.
Most people recover completely from this type of thyroiditis. Generally the thyroiditis resolves by itself within a few months, but sometimes it comes back or, more rarely, damages enough of the thyroid gland to cause permanent hypothyroidism.
Aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) can relieve the pain and inflammation. In severe cases, doctors may recommend corticosteroids, such as prednisone, which are gradually decreased over 6 to 8 weeks. When corticosteroids are discontinued abruptly or too early, symptoms often return in full force. When symptoms of hyperthyroidism are severe, a beta-blocker may be recommended.
If symptoms of hypothyroidism are severe or if hypothyroidism becomes permanent, synthetic thyroid hormone (levothyroxine) may be needed.