Eur J Neurol. 2021 May 13. doi: 10.1111/ene.14913. Online ahead of print.
INTRODUCTION: Although COVID-19 predominantly affects the respiratory system, recent studies have reported the occurrence of neurological disorders such as stroke, in relation to COVID-19 infection. Encephalitis is an inflammatory condition of the brain that has been described as a severe neurological complication of COVID-19. Despite a growing number of reported cases, encephalitis related to COVID-19 infection has not been adequately characterized. To address this gap, this systematic review and meta-analysis aims to describe the incidence, clinical course and outcomes of patients who suffer from encephalitis as a complication of COVID-19.
METHODS: All studies published between November 1, 2019 and October 24, 2020 that reported on patients who developed encephalitis as a complication of COVID-19 were included. Only cases with radiological and/or biochemical evidence of encephalitis were included.
RESULTS: In this study, 610 studies were screened and 23 studies reporting findings from 129,008 patients, including 138 with encephalitis, were included. The average time from diagnosis of COVID-19 to onset of encephalitis is 14.5 days (Range: 10.8-18.2 days). The average incidence of encephalitis as a complication of COVID-19 was 0.215% (95% CI: 0.056% to 0.441%). The average mortality rate of encephalitis in COVID-19 patients was 13.4% (95% CI: 3.8% to 25.9%). These patients also had deranged clinical parameters including raised serum inflammatory markers and CSF pleocytosis.
CONCLUSION: Although encephalitis is an uncommon complication of COVID-19, when present, it results in significant morbidity and mortality. Severely-ill COVID-19 patients are at higher risk of suffering from encephalitis as a complication of the infection.