Subacute Thyroiditis

Subacute thyroiditis (SAT), also known as giant cell thyroiditis, subacute granulomatous thyroiditis, de Quervain’s thyroiditis, or pseudogranulomatous thyroiditis, was described for the first time in 1895 by Mygind. It is the most common cause of thyroid pain, although it is a rare cause of thyrotoxicosis. It is a self-limiting inflammatory disorder and can be triggered by many viral infections being recently associated with COVID-19. It presents with an elevation of acute phase reactants as well as an elevation of triiodothyronine (T3) and thyroxine (T4) and a decrease of thyroid-stimulating hormone (TSH). Usually, the autoantibodies are negative. The classical course of the disease includes a stage of hyperthyroidism followed by a stage of hypothyroidism, usually transitory. SAT has a symptomatic treatment and consists of non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids when is more symptomatic. Beta-blockers improve symptoms of hyperthyroidism.