Neurological Complications of SARS-CoV, MERS-CoV, and COVID-19

Abstract

This review provides an overview of studies and case reports of neurological and neuromuscular complications associated with severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and coronavirus disease 2019 (COVID-19) and describes the possible mechanisms of viral transmission to the central nervous system (CNS). Coronavirus family has shown central and peripheral nervous system tropism in multiple retrospective studies and case reports from different parts of the world. To date, the reported cases of neurological and neuromuscular complications associated with coronaviruses, especially COVID-19, are increasing. Neurological and neuromuscular symptoms and complications ranging from headache and anosmia to more severe encephalitis and stroke have been reported in many studies. However, the neurotropism mechanism of coronaviruses is still not clear and the evidence of central nervous system (CNS) involvement is limited despite the number of studies that attempted to illustrate the possible CNS invasion mechanisms. The reported neurological complications of coronaviruses are summarized in this article.

Keywords: COVID-19; Encephalopathy; MERS; Neurological complications; SARS; Stroke.

Fig. 1

The possible mechanisms of coronavirus transmission to the central nervous system. (1) Primary olfactory epithelium neurons and the olfactory bulb. (2) Infected monocytes/macrophages can cross the BBB and infect the neural cells. (3) Coronavirus interaction with ACE2 receptors on the endothelial cells of the BBB. Lastly, trans-synaptic transmission between PNS and CNS neurons. ACE2 angiotensin-converting enzyme 2, BBB blood‑brain barrier, CNS central nervous system, PNS peripheral nervous system. This figure was created using the website https://app.biorender.com