SARS-CoV-2 and the brain: A review of the current knowledge on neuropathology in COVID-19

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the new coronavirus responsible for the pandemic disease in the last year, is able to affect the central nervous system (CNS). Compared with its well-known pulmonary tropism and respiratory complications, little has been studied about SARS-CoV-2 neurotropism and pathogenesis of its neurological manifestations, but also about postmortem histopathological findings in the CNS of patients who died from COVID-19 (coronavirus disease 2019). We present a systematic review, carried out according to the Preferred Reporting Items for Systematic Review standards, of the neuropathological features of COVID-19. We found 21 scientific papers, the majority of which refer to postmortem examinations; the total amount of cases is 197. Hypoxic changes are the most frequently reported alteration of brain tissue, followed by ischemic and hemorrhagic lesions and reactive astrogliosis and microgliosis. These findings do not seem to be specific to SARS-CoV-2 infection, they are more likely because of systemic inflammation and coagulopathy caused by COVID-19. More studies are needed to confirm this hypothesis and to detect other possible alterations of neural tissue. Brain examination of patients dead from COVID-19 should be included in a protocol of standardized criteria to perform autopsies on these subjects.