Pathophysiological Mechanisms and Neurological Manifestations in COVID-19

With increasing knowledge of the coronavirus disease 2019 (COVID-19), we now understand that COVID-19 presents with various extrapulmonary manifestations with multiorgan involvement. Involvement of the central nervous system (CNS) occurs probably via transsynaptic spread or transfer across the blood-brain barrier. Hypoxia, immune-mediated injury, and vascular damage are the potential mechanisms for the CNS manifestations. Headache, dizziness, chemosensory disturbances, such as loss of smell, taste, encephalopathy, stroke, etc., are among the commonly encountered neurological presentations. Headache is identified as one of the red flag symptoms for COVID-19. Sudden onset of loss of smell and/or taste in the absence of nasal congestion can help in COVID-19 case identification and testing prioritization. Both hemorrhagic and ischemic brain injury is common in patients developing stroke. Besides these, COVID-19-associated CNS involvement demands more careful attention toward patients with existing neurological disorders especially that are managed with immunosuppressant agents. In all, neurological involvement in COVID-19 is not uncommon and may precede, occur concomitantly or after the respiratory involvement. It may also be the sole presentation in some of the patients necessitating high vigilance for COVID-19. In this review, we briefly discussed the pathogenesis of CNS involvement and some important neurological manifestations in COVID-19.