Autoimmune encephalitis associated with COVID-19: A systematic review

INTRODUCTION: There are increasing reports of COVID-19 related neurological complications which may be due to direct viral invasion, or immune mediated inflammatory diseases such as autoimmune encephalitis and ADEM (acute demyelinating encephalomyelitis). In this study, a systematic review is presented of the reported cases infected by the COVID-19 who were diagnosed with various forms of autoimmune encephalitis (AE). METHODS: The authors searched three databases including PubMed, Scopus, and Web of science for extracting original articles on coronavirus/ COVID-19 and AE. RESULTS: Eighteen articles were considered in this study, including 15 case reports, and three case series with a total of 81 patients. Among the studies, 19 cases were reported with AE including 7 (37%) cases of limbic encephalitis, 5 (26%) patients with anti-N-methyl-d-aspartate (NMDA) receptor encephalitis, 2 (11%) with AE presenting as new-onset refractory status epilepticus (NORSE), 1 (5%) case of steroid-responsive encephalitis, and 4 (21%) cases with an unknown type of AE. CONCLUSION: Our systematic review revealed evidence on AE development in patients infected with the COVID-19. Clinicians should be aware of the possible diagnosis of AE when considering other neurological differential diagnosis in SARS-CoV-2 infected patients.