Evidence of Coronavirus (CoV) Pathogenesis and Emerging Pathogen SARS-CoV-2 in the Nervous System: A Review on Neurological Impairments and Manifestations.

The coronavirus disease 2019 (COVID-19) pandemic is an issue of global significance that has taken the lives of many across the world. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for its pathogenesis. The pulmonary manifestations of COVID-19 have been well described in the literature. Initially, it was thought to be limited to the respiratory system; however, we now recognize that COVID-19 also affects several other organs, including the nervous system. Two similar human coronaviruses (CoV) that cause severe acute respiratory syndrome (SARS-CoV-1) and Middle East respiratory syndrome (MERS-CoV) are also known to cause disease in the nervous system. The neurological manifestations of SARS-CoV-2 infection are growing rapidly, as evidenced by several reports. There are several mechanisms responsible for such manifestations in the nervous system. For instance, post-infectious immune-mediated processes, direct virus infection of the central nervous system (CNS), and virus-induced hyperinflammatory and hypercoagulable states are commonly involved. Guillain-Barré syndrome (GBS) and its variants, dysfunction of taste and smell, and muscle injury are numerous examples of COVID-19 PNS (peripheral nervous system) disease. Likewise, hemorrhagic and ischemic stroke, encephalitis, meningitis, encephalopathy acute disseminated encephalomyelitis, endothelialitis, and venous sinus thrombosis are some instances of COVID-19 CNS disease. Due to multifactorial and complicated pathogenic mechanisms, COVID-19 poses a large-scale threat to the whole nervous system. A complete understanding of SARS-CoV-2 neurological impairments is still lacking, but our knowledge base is rapidly expanding. Therefore, we anticipate that this comprehensive review will provide valuable insights and facilitate the work of neuroscientists in unfolding different neurological dimensions of COVID-19 and other CoV associated abnormalities.

Jha NK ，Ojha S ，Jha SK ，Dureja H ，Singh SK ，Shukla SD ，Chellappan DK ，Gupta G ，Bhardwaj S ，Kumar N ，Jeyaraman M ，Jain R ，Muthu S ，Kar R ，Kumar D ，Goswami VK ，Ruokolainen J ，Kesari KK ，Singh SK ，Dua K ... -  《-》

The neurology of COVID-19 revisited: A proposal from the Environmental Neurology Specialty Group of the World Federation of Neurology to implement international neurological registries.

A comprehensive review of the neurological disorders reported during the current COVID-19 pandemic demonstrates that infection with SARS-CoV-2 affects the central nervous system (CNS), the peripheral nervous system (PNS) and the muscle. CNS manifestations include: headache and decreased responsiveness considered initial indicators of potential neurological involvement; anosmia, hyposmia, hypogeusia, and dysgeusia are frequent early symptoms of coronavirus infection. Respiratory failure, the lethal manifestation of COVID-19, responsible for 264,679 deaths worldwide, is probably neurogenic in origin and may result from the viral invasion of cranial nerve I, progressing into rhinencephalon and brainstem respiratory centers. Cerebrovascular disease, in particular large-vessel ischemic strokes, and less frequently cerebral venous thrombosis, intracerebral hemorrhage and subarachnoid hemorrhage, usually occur as part of a thrombotic state induced by viral attachment to ACE2 receptors in endothelium causing widespread endotheliitis, coagulopathy, arterial and venous thromboses. Acute hemorrhagic necrotizing encephalopathy is associated to the cytokine storm. A frontal hypoperfusion syndrome has been identified. There are isolated reports of seizures, encephalopathy, meningitis, encephalitis, and myelitis. The neurological diseases affecting the PNS and muscle in COVID-19 are less frequent and include Guillain-Barré syndrome; Miller Fisher syndrome; polyneuritis cranialis; and rare instances of viral myopathy with rhabdomyolysis. The main conclusion of this review is the pressing need to define the neurology of COVID-19, its frequency, manifestations, neuropathology and pathogenesis. On behalf of the World Federation of Neurology we invite national and regional neurological associations to create local databases to report cases with neurological manifestations observed during the on-going pandemic. International neuroepidemiological collaboration may help define the natural history of this worldwide problem.

Román GC ，Spencer PS ，Reis J ，Buguet A ，Faris MEA ，Katrak SM ，Láinez M ，Medina MT ，Meshram C ，Mizusawa H ，Öztürk S ，Wasay M ，WFN Environmental Neurology Specialty Group ... -  《-》

Neurological manifestations associated with SARS-CoV-2 and other coronaviruses: A narrative review for clinicians.

The past two decades have been marked by three epidemics linked to emerging coronaviruses. The COVID-19 pandemic highlighted the existence of neurological manifestations associated with SARS-CoV-2 infection and raised the question of the neuropathogenicity of coronaviruses. The aim of this review was to summarize the current data about neurological manifestations and diseases linked to human coronaviruses. Articles have been identified by searches of PubMed and Google scholar up to September 25, 2020, using a combination of coronavirus and neurology search terms and adding relevant references in the articles. We found five cohorts providing prevalence data of neurological symptoms among a total of 2533 hospitalized COVID-19 patients, and articles focusing on COVID-19 patients with neurological manifestations including a total of 580 patients. Neurological symptoms involved up to 73% of COVID-19 hospitalized patients, and were mostly headache, myalgias and impaired consciousness. Central nervous system (CNS) manifestations reported in COVID-19 were mostly non-specific encephalopathies that represented between 13% and 40% of all neurological manifestations; post-infectious syndromes including acute demyelinating encephalomyelitis (ADEM, n=13), acute necrotizing encephalopathy (ANE, n=4), Bickerstaff's encephalitis (n=5), generalized myoclonus (n=3) and acute transverse myelitis (n=7); other encephalitis including limbic encephalitis (n=9) and miscellaneous encephalitis with variable radiologic findings (n=26); acute cerebrovascular diseases including ischemic strokes (between 1.3% and 4.7% of COVID-19 patients), hemorrhagic strokes (n=17), cerebral venous thrombosis (n=8) and posterior reversible encephalopathy (n=5). Peripheral nervous system (PNS) manifestations reported in COVID-19 were the following: Guillain-Barré syndrome (n=31) and variants including Miller Fisher syndrome (n=3), polyneuritis cranialis (n=2) and facial diplegia (n=2); isolated oculomotor neuropathy (n=6); critical illness myopathy (n=6). Neuropathological studies in COVID-19 patients demonstrated different patterns of CNS damage, mostly ischemic and hemorrhagic changes with few cases of inflammatory injuries. Only one case suggested SARS-CoV-2 infiltration in endothelial and neural cells. We found 10 case reports or case series describing 22 patients with neurological manifestations associated with other human coronaviruses. Among them we found four MERS patients with ADEM or Bickerstaff's encephalitis, two SARS patients with encephalitis who had a positive SARS-CoV PCR in cerebrospinal fluid, five patients with ischemic strokes associated with SARS, eight MERS patients with critical illness neuromyopathy and one MERS patient with Guillain-Barré Syndrome. An autopsy study on SARS-CoV patients demonstrated the presence of the virus in the brain of eight patients. The wide range of neurological manifestations and diseases associated with SARS-CoV-2 is consistent with multiple pathogenic pathways including post-infectious mechanisms, septic-associated encephalopathies, coagulopathy or endothelitis. There was no definite evidence to support direct neuropathogenicity of SARS-CoV-2.

Maury A ，Lyoubi A ，Peiffer-Smadja N ，de Broucker T ，Meppiel E ... -  《REVUE NEUROLOGIQUE》

COVID-19: A Global Threat to the Nervous System.

In less than 6 months, the severe acute respiratory syndrome-coronavirus type 2 (SARS-CoV-2) has spread worldwide infecting nearly 6 million people and killing over 350,000. Initially thought to be restricted to the respiratory system, we now understand that coronavirus disease 2019 (COVID-19) also involves multiple other organs, including the central and peripheral nervous system. The number of recognized neurologic manifestations of SARS-CoV-2 infection is rapidly accumulating. These may result from a variety of mechanisms, including virus-induced hyperinflammatory and hypercoagulable states, direct virus infection of the central nervous system (CNS), and postinfectious immune mediated processes. Example of COVID-19 CNS disease include encephalopathy, encephalitis, acute disseminated encephalomyelitis, meningitis, ischemic and hemorrhagic stroke, venous sinus thrombosis, and endothelialitis. In the peripheral nervous system, COVID-19 is associated with dysfunction of smell and taste, muscle injury, the Guillain-Barre syndrome, and its variants. Due to its worldwide distribution and multifactorial pathogenic mechanisms, COVID-19 poses a global threat to the entire nervous system. Although our understanding of SARS-CoV-2 neuropathogenesis is still incomplete and our knowledge is evolving rapidly, we hope that this review will provide a useful framework and help neurologists in understanding the many neurologic facets of COVID-19. ANN NEUROL 2020;88:1-11 ANN NEUROL 2020;88:1-11.

Koralnik IJ ，Tyler KL 《-》

Effects of the severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus (MERS-CoV) on the nervous system. What can we expect from SARS -CoV-2?

Monroy-Gómez J ，Torres-Fernández O 《-》