Neuropathology of COVID-19

The COVID-19 pandemic has placed global health care systems under unprecedented strain but has, at the same time, provided a unique opportunity for pathologists to turn autopsy findings into directly actionable insights into patient care. The current data on the neuropathology of COVID-19 remains preliminary and is limited by the lack of suitable controls, but certain tentative conclusions can be drawn. SARS-CoV-2 can infect multiple cell types in the central nervous system and does so in a subset of patients, although the clinical significance of direct infections remains in the central nervous system (CNS) and the peripheral nervous system (PNS) infections remains unclear. The best-described neuropathological manifestations of COVID-19 in the brain are variable patterns of neuroinflammation and vascular injury, although again, it remains unclear to what degree these findings are specifically due to COVID-19. There is also intriguing preliminary data to suggest a complex relationship between COVID-19 and neurodegeneration, with certain alleles that increase AD risk also increasing the risk of severe COVID-19, and conversely, the possibility that COVID-19 may increase the risk of neurodegenerative disease. The neuropathology of so-called "long-COVID" and the potential effects of COVID-19, or critical illness in general, on neurodegenerative disease remains unclear. There is thus an urgent need for long-term cohort studies of COVID-19 survivors, including brain donation, particularly in elderly patients, with careful recruitment of controls with similar non-COVID inflammatory illnesses.