The scintigraphic diagnosis of subacute thyroiditis in hospitalized patients with acute COVID-19 infection

 Extrapulmonary manifestations of COVID-19 must not be neglected during the pandemic. Subacute thyroiditis is one of the possible complications people encounter during post-COVID-19 days. Thyroid scintigraphy and radioiodine uptake test help discriminate hyperthyroidism from destructive thyrotoxicosis. Finding a more precise way to diagnose subacute thyroiditis can help in the early detection and treatment of thyroid-related disorders.

 In this cross-sectional study, we evaluated 69 cases of COVID-19. Patients were divided into moderate and severe groups based on their clinical conditions. A thyroid scintigraphy scan was performed on the discharge day. Imaging was done 15-20 minutes after intravenous administration of 3-5 mCi of [99mTc]TcO4-. Scan findings were compared between moderate and severe groups and other participants' demographic and clinical features.

 In 69 patients, according to thyroid scintigraphy, 25 (36%) cases were reported as thyroiditis, and the rest were normal. There was no significant difference between the normal and subacute thyroiditis groups based on age, gender, past medical history, the severity of COVID-19, laboratory values and clinical signs and symptoms. Patients with subacute thyroiditis experienced palpitation and sore throat significantly higher than the normal group (P=0.002 and P=0.009, respectively).

 We conclude that patients admitted due to acute COVID-19 infection experiencing palpitation and sore throat can develop subacute thyroiditis more than others. Whereas the severity of the disease and laboratory testing were not diagnostic in subacute thyroiditis, thyroid scintigraphy may help in early detection.