ABSTRACT
Various factors can lead to thyroiditis, including any acute inflammatory process, especially viral illness. While coronavirus disease 2019 (COVID-19) has been linked to disorders of various systems, there is a lack of literature showing an association of coronavirus with the cause of Hashimoto's thyroiditis. Several possible mechanisms for this outcome have been proposed;chief among them is molecular mimicry. Here, we are reporting a case of Hashimoto's thyroiditis incited by COVID-19 in a 34-year-old obese female who presented with anxiety, behavioral changes, and repeated head movements. The patient had an elevated thyroid stimulating hormone (TSH) level, a low thyroxine (T4) level, and a positive anti-microsomal antibody screen. The patient also tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA. Ultrasound of the patient's neck showed an enlarged heterogeneous thyroid gland. Thyroid replacement therapy with intravenous levothyroxine was started with the subsequent oral transition. Concurrently, she received antibiotics, steroids, and low-molecular-weight heparin for COVID-19. The patient exhibited significant improvement in her mental status, with an eventual return to baseline. The results of the thyroid panel obtained at the outpatient follow-up were normal. Although there is a paucity of data to show COVID-19 as a cause of this painless thyroiditis, this case demonstrates such causality between these two.