Neurological manifestations in coronavirus disease 2019 (COVID-19) patients: a systematic review of literature

BACKGROUND: The exact incidence of neurological complications from coronavirus disease 2019 (COVID-19) infection remains unknown. Neurological symptoms are more common with severe form of the disease. Through neuro-invasion, the virus can affect both neurons and glial cells and induce wide range of neurological pathologies. OBJECTIVES: To systematically assess the neurological manifestations in patients diagnosed with COVID-19. METHODS: A systematic literature search of the PubMed, Scopus, and Cochrane databases was performed. Randomized controlled trials, nonrandomized controlled trials, observational studies of neurological manifestations in patients diagnosed with COVID-19. RESULTS: All three-database search identified 89 publications. A total of 22 full-text articles assessed for eligibility with 12 articles excluded. Altogether, the included studies reported 290 patients with neurological manifestations. Neurological manifestations were subdivided into central causes (CNS) and peripheral causes (PNS). CNS symptoms is commoner representing 91% of all neurological patients with 9% only with PNS. Headache represented the commonest neurological symptoms in regard to number of patients, meanwhile dizziness has the highest incidence with 11.9%. Neurological manifestations were divided according to COVID-19 severity into: (1) nonsevere and (2) severe; with all CNS manifestations were more in severe patients except headache were more in nonsevere patients. All included studies were on adult patients except one study in pediatric patients with limited number of participants. CONCLUSIONS: From the descriptive analyses and available data of relatively small sample-sized studies, it can be concluded that in spite of the aforementioned limitations, that a wide spectrum of neurological manifestations including CNS and PNS can occur in COVID-19 patients.