Neurological consequences of COVID-19

Abstract

In December 2019, cases of pneumonia caused by infection with the previously unknown severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), leading to coronavirus disease 2019 (COVID-19), were identified. Typical manifestations of COVID-19 are fever, cough, fatigue and dyspnoea. Initially, it was thought that the mechanism of action of SARS-CoV-2 was only associated with respiratory tract invasion, but it was later revealed that the infection might involve many other organs and systems, including the central and peripheral nervous systems. Neurological complications associated with SARS-CoV-2 infection include encephalopathy, encephalitis, meningitis, acute disseminated encephalomyelitis (ADEM), ischaemic and haemorrhagic stroke and cerebral venous sinus thrombosis. In cases of peripheral nervous system involvement, smell and taste disorders, myopathy or the signs and symptoms of Guillain‒Barré syndrome are observed. The most common early neurological complications, particularly during the first year of the epidemic, were anosmia and taste disorders, which, according to some studies, occurred in over 80 percent of patients with COVID-19. The proportion of patients with serious neurological manifestations was small compared to the global number of patients, but the numbers of SARS-CoV-2 infections and critical patients increased substantially. The experience from 2 years of the pandemic has shown that approximately 13% of infected patients suffer from severe neurological complications. The relationship between SARS-CoV-2 and the nervous system is not only a cause of neurological complications in previously healthy individuals but also directly and indirectly affects the courses of many nervous system diseases.

Host Genetic Variants Linked to COVID-19 Neurological Complications and Susceptibility in Young Adults—A Preliminary Analysis

“…As previously reported, neurological impairments are more frequently associated with a severe COVID-19 course, including critical illness and hospitalization [ 2 , 21 , 22 ]. Therefore, we hypothesized that young adults with long-term neurological symptoms could be the carriers of risky SNP alleles, which have previously been associated with mental problems and severe disease courses in adults.…”

“…The effect of the SARS-CoV-2 virus on the respiratory system, cardiovascular system, and gastrointestinal tract has been repeatedly demonstrated [ 1 , 2 ]. Together with epidemiological data on disease severity related to anthropometric parameters and concomitant chronic pathology [ 1 ], the role of genetic factors in COVID-19 illness and disease severity has been reported (for review, see [ 2 , 3 , 4 ]). Twin studies have elucidated a substantial genetic influence for predicted COVID-19, with a concordance rate of 80% in MZ twins [ 4 ].…”

“…Together with the well-established negative effects of SARS-CoV-2 on the pulmonary system, gastrointestinal tract, and cardiovascular system, the virus can also penetrate the blood–brain barrier, affect both neurons and glial cells, and cause neurological complications [ 3 ]. Different pathomechanisms underlie the development of neurological impairments, including post-COVID-19 syndrome, such as chronic fatigue, cognitive dysfunction, mood and sleep disorders, pain syndromes, and smell and taste impairments [ 2 ]. Previous research has indicated a causal relationship between genetically mediated hospitalized and critical COVID-19 and later memory problems, such as Alzheimer’s disease (AD) and other types of dementia [ 11 ].…”

“…Nonetheless, data on the genetic-related effects of SARS-CoV-2 infection on the presence of accompanying neurological symptoms and long-term neurological consequences in younger individuals are lacking. Although several specific findings of gene variants implicated in disease susceptibility [ 19 ] and severe COVID-19 [ 20 ] in children have been reported, it was also suggested that coronaviral infection may result in an enhanced rate of mental health problems later in life [ 2 ]. Therefore, the identification of plausible host genetic variants associated with an elevated risk of developing neurological repercussions during SARS-CoV-2 infection and over a long-term period in younger individuals is of relevance.…”

Human iPS cell-derived sensory neurons can be infected by SARS-CoV-2 strain WA1/2020 as well as variants delta and omicron

“…Peripheral neuropathies have been reported in many COVID-19 cases throughout the world 13,14,23 . The most common form of peripheral neuropathy associated with SARS-CoV-2 infection is anosmia, with cases reported from the first wave of the pandemic when the variant alpha was predominant 13,14,23 . While the delta variant seemed to equally affect the peripheral nervous system, the more transmissible and less severe omicron variant showed a decrease in reported anosmia and peripheral neuropathies 24 .…”