Is Subacute Thyroiditis an Underestimated Manifestation of SARS-CoV-2 Infection? Insights From a Case Series

Context: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected more than 18 million people worldwide and the pandemic is still spreading. After the first case we reported, we observed 4 additional cases of subacute thyroiditis (SAT) related to SARS-CoV-2 infection. Objectives: The objective of this work is to describe additional cases of SAT associated with SARS-CoV-2 infection to alert physicians that SAT may be a manifestation of SARS-CoV-2 infection. Methods: We describe clinical, biochemical, and imaging features of 4 patients with SAT related to SARS-CoV-2 infection. Results: All patients were female (age, 29-46 years). SAT developed 16 to 36 days after the resolution of coronavirus disease 2019 (COVID-19). Neck pain radiated to the jaw and palpitations were the main presenting symptoms and were associated with fever and asthenia. One patient was hospitalized because of atrial fibrillation. Thyroid function tests (available for 3 individuals) were suggestive of destructive thyroiditis, and inflammatory markers were high. At neck ultrasound the thyroid was enlarged, with diffuse and bilateral hypoechoic areas and (in 3 patients) absent vascularization at color Doppler. Symptoms disappeared a few days after commencement of treatment (prednisone in 3 patients and ibuprofen in 1). Six weeks after the onset of SAT, all patients were asymptomatic and inflammatory markers had returned to normal range. Two patients were euthyroid, whereas 2 were diagnosed with subclinical hypothyroidism. Conclusions: SAT may be an underestimated manifestation of COVID-19. Clinicians should keep in mind the possible occurrence of SAT during and after SARS-CoV-2 infection.