The incidence and pathophysiology of neurological symptoms in COVID-19

Abstract

The central nervous system seems to be quite vulnerable to SARS-CoV-2, leading to a variety of alteration pathways, high incidence and variability of the neurological symptoms of COVID-19. The COVID-19 symptoms, possibly associated with alteration to the central nervous system, include hyperthermia, shortness of breath, fatigue, headache, dizziness, dysphonia, dysphagia, hyposmia and anosmia, hypogeusia and ageusia, impairment of consciousness. The impairment of olfaction and gustation are the most common symptoms of the nervous system alteration (98% and 70%, respectively), which is most likely a consequence of the alteration of the receptors. Presumably the pathogenesis of dysphonia and dysphagia may involve neurodegenerative mechanisms or may be associated with a predominantly demyelinating alteration of the caudal cranial nerves. Pathomorphological findings in the brain of the COVID-19 patients include diffuse hypoxic and focal ischemic injuries of various sizes up to ischemic infarctions (in thrombosis of large arteries); microangiopathy; vasculitis; diapedetic and confluent hemorrhages with possible progression to hemorrhagic infarctions and rarely intracerebral hematomas. Acute cerebrovascular accident worsens the course of COVID-19 and can worsen the clinical outcome, taking into account the mechanisms of the central nervous system alteration in highly contagious coronavirus infections (SARS-CoV, MERS, SARS-CoV-2), including embolism, hypoxia, neurodegeneration, systemic inflammatory response and immune-mediated alteartion to the nervous tissue. A fairly rare complication of coronavirus infection, however, acute myelitis requires attention due to the severity of neurological disorders. The literature data show high incidence and polymorphism of the symptoms of the central nervous system alteration, as well as the important role of the cerebrovascular and neurodegenerative pathogenesis of brain alteration in COVID-19, which is taken into account in examining and treating the patients with new coronavirus infection. (1 figure, bibliography: 61 refs)