Neurological Involvements of SARS-CoV2 Infection

Abstract

COVID-19 is a pandemic viral infection caused by a novel coronavirus, SARS-CoV2, which is a global concern of the twenty-first century for its rapid spreading in a short period. Apart from its known acute respiratory involvements, the CNS manifestations of COVID-19 are common. These neurological symptoms are diverse and could range from mild nonspecific or specific symptoms such as the loss of various sensory perceptions, the worrying autoimmune Guillain-Barré syndrome, to the life-threatening acute disseminated encephalomyelitis, and the CNS-mediated respiratory distress. An autopsy report documented the presence of SARS-CoV2 in brain tissues of a COVID-19 patient. However, there is no definite conclusion on the mechanisms of SARS-CoV2 neuroinvasion. These proposed mechanisms include the direct viral invasion, the systemic blood circulation, or the distribution of infected immune cells. Concerning these different neuropathophysiologies, COVID-19 patients who are presenting with either the early-onset, multiple, and severe CNS symptoms or rapid respiratory deterioration should be suspected for the direct viral neuroinvasion, and appropriate management options should be considered. This article reviews the neurological manifestations, the proposed neuroinvasive mechanisms, and the potential neurological sequelae of SARS-CoV2.

Keywords: Angiotensin-converting enzyme 2 receptor; COVID-19; Neuroinvasion; SARS-CoV2; Severe acute respiratory syndrome.

Fig. 1

Proposed mechanism for SARS-CoV2 neuroinvasion. (i) SARS-CoV2 can directly infect the olfactory nerve and retrogradely disseminate across the cribriform plate of the ethmoid bone into the central nervous system (CNS). (ii) The systemic circulation could distribute and enable the virus to enter the cerebral blood flow. (iii) The infected leukocytes can also infiltrate into brain tissues through the glial-lymphatic system and serve as the reservoir for the viral delivery in the CNS