Subacute lymphocytic thyroiditis is a form of thyroiditis. Subacute lymphocytic thyroiditis may occur at any age and is more common in females. A variant of subacute lymphocytic thyroiditis occurs postpartum: postpartum thyroiditis. Both of these entities can be considered subtypes of Hashimoto's thyroiditis and have an autoimmune basis. Anti-thyroid antibodies are common in all three and the underlying histology is similar. ^{[1] [2]} This disorder should not be confused with de Quervain's thyroiditis which is another form of subacute thyroiditis.

Symptoms and signs

Subacute lymphocytic thyroiditis features a small goiter without tenderness. This condition tends to have a phase of hyperthyroidism followed by a return to a euthyroid state, and then a phase of hypothyroidism, followed again by a return to the euthyroid state. The time span of each phase can vary; however, each phase usually lasts 2–3 months. ^[1]

Diagnosis

Subacute lymphocytic thyroiditis can only be diagnosed correctly by taking a radioactive iodine uptake test (RAIU) test. ^{[1] [3]} During both the hyperthyroid and hypothyroid phases, radioiodine uptake is decreased. ^[4] This situation contrasts greatly with the elevated iodine uptake found in patients with Graves' disease. ^[1]

Treatment

Treatment is based on symptoms. Beta-blockers relieve rapid heart rate and excessive sweating during the hyperthyroid phase. ^[4]

References