Hashimoto's thyroiditis-related myopathy in a patient with SARS-CoV-2 infection: A case report and systematic literature review.

RATIONALE: Hashimoto's thyroiditis (HT) is a common autoimmune disease. However, its presentation and management in the context of COVID-19 are unclear, and COVID-19-triggered HT, along with myopathy and persistent creatine kinase (CK) levels, have not been previously reported. Moreover, no literature review is currently available on HT in the context of COVID-19. This study is a case report and systematic review of the literature. PATIENT CONCERNS: A 33-year-old man was admitted with acute-onset myalgia, anosmia, loss of taste, fever, and upper respiratory tract symptoms. DIAGNOSES: He was diagnosed with coronavirus disease (COVID-19) during hospitalization and had abnormal CK levels. The elevated CK level persisted even after the resolution of COVID-19. After excluding myopathies and cardiac factors, HT was diagnosed. INTERVENTIONS: CK levels did not decrease appreciably until 14 d after levothyroxine administration. OUTCOMES: The patient was discharged from the hospital in good health. In the systematic literature review, 7 case reports on COVID-19-associated HT were observed, although no incidence of associated myopathy or persistent elevation of CK was noted. LESSONS: This case report highlights the potential link between COVID-19 and autoimmune thyroid diseases. In particular, this study underscores the significance of recognizing new-onset autoimmune thyroid disease in COVID-19-positive patients with elevated CK levels that cannot be attributed to other factors. This systematic review offers additional perspectives for diagnosing and managing HT in COVID-19 settings. Overall, the findings of this study could have important clinical implications for the care of COVID-19 patients, as early identification and treatment of autoimmune thyroid disease could help prevent long-term complications. Additional research is essential to elucidate the fundamental correlations between COVID-19 and HT and assess the effectiveness of therapeutic approaches for autoimmune thyroid conditions related to COVID-19.