Subacute Thyroiditis

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2). It usually presents with mild common cold-like symptoms. However, it can lead to series of complications with some of them being fatal. One of the rare and potentially neglected manifestations of COVID-19 is subacute thyroiditis (SAT). Viral causes of SAT documented so far include several viruses, but according to the newest reports, SARS-CoV-2 should also be added to the list. The median time between COVID-19 diagnosis and the onset of SAT symptoms is reported to be 29 days. Patients mostly present with triphasic course of symptoms - thyrotoxicosis, followed by hypothyroidism and euthyroidism. Although limited number of SAT cases after SARS-CoV-2 infection are reported, physicians should consider SAT as a differential diagnosis in COVID-19 patients. The routine assessment of thyroid function in patients with clinical suspicion of SAT or with the suspicion of any other thyroid dysfunction is advised.