Severe neurologic syndrome associated with Middle East respiratory syndrome corona virus (MERS-CoV)

Neurological manifestations of COVID-19: a systematic review and meta-analysis of proportions

BACKGROUND

Coronaviruses mainly affect the respiratory system; however, there are reports of SARS-CoV and MERS-CoV causing neurological manifestations. We aimed at discussing the various neurological manifestations of SARS-CoV-2 infection and to estimate the prevalence of each of them.

METHODS

We searched the following electronic databases; PubMed, MEDLINE, Scopus, EMBASE, Google Scholar, EBSCO, Web of Science, Cochrane Library, WHO database, and ClinicalTrials.gov . Relevant MeSH terms for COVID-19 and neurological manifestations were used. Randomized controlled trials, non-randomized controlled trials, case-control studies, cohort studies, cross-sectional studies, case series, and case reports were included in the study. To estimate the overall proportion of each neurological manifestations, the study employed meta-analysis of proportions using a random-effects model.

RESULTS

Pooled prevalence of each neurological manifestations are, smell disturbances (35.8%; 95% CI 21.4-50.2), taste disturbances (38.5%; 95%CI 24.0-53.0), myalgia (19.3%; 95% CI 15.1-23.6), headache (14.7%; 95% CI 10.4-18.9), dizziness (6.1%; 95% CI 3.1-9.2), and syncope (1.8%; 95% CI 0.9-4.6). Pooled prevalence of acute cerebrovascular disease was (2.3%; 95%CI 1.0-3.6), of which majority were ischaemic stroke (2.1%; 95% CI 0.9-3.3), followed by haemorrhagic stroke (0.4%; 95% CI 0.2-0.6), and cerebral venous thrombosis (0.3%; 95% CI 0.1-0.6).

CONCLUSIONS

Neurological symptoms are common in SARS-CoV-2 infection, and from the large number of cases reported from all over the world daily, the prevalence of neurological features might increase again. Identifying some neurological manifestations like smell and taste disturbances can be used to screen patients with COVID-19 so that early identification and isolation is possible.

Cross-Talk Between Key Players in Patients with COVID-19 and Ischemic Stroke: A Review on Neurobiological Insight of the Pandemic

The global pandemic of novel coronavirus disease 2019 (COVID-19) has taken the entire human race by surprise and led to an unprecedented number of mortalities worldwide so far. Current clinical studies have interpreted that angiotensin-converting enzyme 2 (ACE2) is the host receptor for severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). In addition, ACE2 is the major component of the renin-angiotensin system. ACE2 deteriorates angiotensin II, a peptide that is responsible for the promotion of stroke. The downregulation of ACE2 further activates an immunological cascade. Thus, researchers need to explore and examine the possible links between COVID-19 and ischemic stroke (IS). Human ACE2 expression level and pattern in various tissues might be decisive for the vulnerability, symptoms, and treatment outcomes of the SARS-CoV-2 infection. The swift increase in the knowledge of SARS-CoV-2 has given creditable evidence that SARS-CoV-2 infected patients also encounter neurological deficits. As the SARS-CoV-2 binds to ACE2, it will hamper the activity of ACE2 in providing neuroprotection, especially in the case of stroke patients. Due to the downregulation of ACE2, the inflammatory response is activated in the ischemic penumbra. The COVID-19 pandemic has affected people with various pre-existing diseases, including IS, in such a way that these patients need special care and attention for their survival. Several clinical trials are currently ongoing worldwide as well as many other projects are in different stages of conceptualization and planning to facilitate the effective management of stroke patients with COVID-19 infection.

Understanding the Immunologic Characteristics of Neurologic Manifestations of SARS-CoV-2 and Potential Immunological Mechanisms

Similar to its predecessors, coronavirus disease 2019 (COVID-19) exhibits neurotrophic properties, which lead to progression of neurologic sequelae. Besides direct viral invasion to the central nervous system (CNS), indirect CNS involvement through viral-mediated immune response is plausible. Aberrant immune pathways such as extreme release of cytokines (cytokine storm), autoimmunity mediated by cross-reactivity between CNS components and viral particles, and microglial activation propagate CNS damage in these patients. Here, we review the currently available evidence to discuss the plausible immunologic pathways that may contribute to the development of COVID-19 neurological complications, namely Alzheimer's disease, Parkinson's disease, stroke, multiple sclerosis, Guillain-Barre syndrome, seizure, and brainstem involvement.

Encephalopathy in COVID-19 patients; viral, parainfectious, or both?

We describe the clinical, laboratory and radiological features of 3 critically ill patients with COVID-19 who developed severe encephalopathy. The first patient did not regain consciousness when sedation was removed at the end of 2 weeks of intensive care. He had received treatment with convalescent plasma. His clinical examination was remarkable for intact brainstem reflexes, roving eye movements, later transient ocular flutter; and then what appeared to be slow ocular dipping. He had no coherent volitional response to the environment. The second patient recovered with measurable cognitive deficits after a prolonged period of encephalopathy. He had received combination treatment with interferon beta 1b and lopinavir/ritonavir. The third patient remained in persistent, severe agitated delirium and died 3 months into his illness. The MRI of the 3 patients showed multifocal abnormalities predominantly in the cerebral white matter, with varying involvement of the grey matter, brainstem and spinal cord. Case 1's MRI changes were consistent with acute disseminated encephalomyelitis. The patients also displayed blood markers, to varying degree, of autoimmunity and hypercoagulability. We were not able to convincingly show, from microbiological as well as immunological evaluation, if the effects of COVID-19 on these patients' nervous system were a direct consequence of the virus, proinflammatory-thrombotic state or a combination. Patient 1 responded partially to empirical, albeit delayed, therapy with intravenous immunoglobulins. Patient 2 recovered with no specific treatment. These cases illustrate the need to understand the full spectrum of encephalopathy associated with COVID-19 so as to better guide its management.

Neurotropism of SARS-CoV-2 and its neuropathological alterations: Similarities with other coronaviruses

A novel coronavirus (SARS-CoV-2) emerged from Wuhan, China, and spread quickly around the world. In addition to fever, cough and shortness of breath, it was confirmed that the patients also have manifestations towards the central nervous system (CNS), especially those critically ill ones. In this review, we will discuss how SARS-CoV-2 gain access to the CNS and the possible consequences. Both SARS-CoV-2 and SARS-CoV-1 in 2002 share the same receptor angiotensin-converting enzyme 2 (ACE2), which can be found in the brain and mediate the disease process. Both direct attack of SARS-CoV-2 and the abnormal immune response in the CNS would contribute to the disease. Also, there is a relationship between SARS-CoV-2 and the occurrence of acute cerebrovascular diseases.

Applications of Non-invasive Neuromodulation for the Management of Disorders Related to COVID-19

Background: Novel coronavirus disease (COVID-19) morbidity is not restricted to the respiratory system, but also affects the nervous system. Non-invasive neuromodulation may be useful in the treatment of the disorders associated with COVID-19. Objective: To describe the rationale and empirical basis of the use of non-invasive neuromodulation in the management of patients with COVID-10 and related disorders. Methods: We summarize COVID-19 pathophysiology with emphasis of direct neuroinvasiveness, neuroimmune response and inflammation, autonomic balance and neurological, musculoskeletal and neuropsychiatric sequela. This supports the development of a framework for advancing applications of non-invasive neuromodulation in the management COVID-19 and related disorders. Results: Non-invasive neuromodulation may manage disorders associated with COVID-19 through four pathways: (1) Direct infection mitigation through the stimulation of regions involved in the regulation of systemic anti-inflammatory responses and/or autonomic responses and prevention of neuroinflammation and recovery of respiration; (2) Amelioration of COVID-19 symptoms of musculoskeletal pain and systemic fatigue; (3) Augmenting cognitive and physical rehabilitation following critical illness; and (4) Treating outbreak-related mental distress including neurological and psychiatric disorders exacerbated by surrounding psychosocial stressors related to COVID-19. The selection of the appropriate techniques will depend on the identified target treatment pathway. Conclusion: COVID-19 infection results in a myriad of acute and chronic symptoms, both directly associated with respiratory distress (e.g., rehabilitation) or of yet-to-be-determined etiology (e.g., fatigue). Non-invasive neuromodulation is a toolbox of techniques that based on targeted pathways and empirical evidence (largely in non-COVID-19 patients) can be investigated in the management of patients with COVID-19.

Computational Investigation of Structural Dynamics of SARS-CoV-2 Methyltransferase-Stimulatory Factor Heterodimer nsp16/nsp10 Bound to the Cofactor SAM

Recently, a highly contagious novel coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, has emerged, posing a global threat to public health. Identifying a potential target and developing vaccines or antiviral drugs is an urgent demand in the absence of approved therapeutic agents. The 5'-capping mechanism of eukaryotic mRNA and some viruses such as coronaviruses (CoVs) are essential for maintaining the RNA stability and protein translation in the virus. SARS-CoV-2 encodes S-adenosyl-L-methionine (SAM) dependent methyltransferase (MTase) enzyme characterized by nsp16 (2'-O-MTase) for generating the capped structure. The present study highlights the binding mechanism of nsp16 and nsp10 to identify the role of nsp10 in MTase activity. Furthermore, we investigated the conformational dynamics and energetics behind the binding of SAM to nsp16 and nsp16/nsp10 heterodimer by employing molecular dynamics simulations in conjunction with the Molecular Mechanics Poisson-Boltzmann Surface Area (MM/PBSA) method. We observed from our simulations that the presence of nsp10 increases the favorable van der Waals and electrostatic interactions between SAM and nsp16. Thus, nsp10 acts as a stimulator for the strong binding of SAM to nsp16. The hydrophobic interactions were predominately identified for the nsp16-nsp10 interactions. Also, the stable hydrogen bonds between Ala83 (nsp16) and Tyr96 (nsp10), and between Gln87 (nsp16) and Leu45 (nsp10) play a vital role in the dimerization of nsp16 and nsp10. Besides, Computational Alanine Scanning (CAS) mutagenesis was performed, which revealed hotspot mutants, namely I40A, V104A, and R86A for the dimer association. Hence, the dimer interface of nsp16/nsp10 could also be a potential target in retarding the 2'-O-MTase activity in SARS-CoV-2. Overall, our study provides a comprehensive understanding of the dynamic and thermodynamic process of binding nsp16 and nsp10 that will contribute to the novel design of peptide inhibitors based on nsp16.

Neuroinvasive potential of SARS-CoV2 with neuroradiological and neuropathological findings: is the brain a target or a victim?

Coronaviridae family includes pathogen viruses for humans, that lead to clinical conditions with main respiratory involvement; many of these viruses have notoriously a neuroinvasive potential, as demonstrated by published data on SARS-CoV and MERS-CoV epidemics, as well by results obtained in experimental models. During pandemic of coronavirus disease 2019 (COVID-19), it is noticed that the central nervous system involvement represented a truly significant moment in the history of some COVID-19 patients; indeed, clinical and radiological features published in literature regarding COVID-19 disease are consistent with a neurological involvement. It is also known that histopathological data related to SARS-CoV2 infection have been published with considerable delay, which was even greater for neuropathological information. Moreover, many published data are incomplete, and often the lesions described are not directly related to the action of the virus. In this review, we collected the available radiological and neuropathological information, in order to delineate a more complete picture of the relationship between SARS-Cov2 and brain, focusing our attention on the two most important neuroinvasion routes for the virus. We also highlighted what we consider methodological mistakes both in the autopsy procedures and brain study in COVID-19 deaths. We emphasize the need for a complete study of all the organs in case of autopsy. It is important that through this experience, we no longer do the mistake of neglecting the brain.

How Does SARS-CoV-2 Affect the Central Nervous System? A Working Hypothesis

Interstitial pneumonia was the first manifestation to be recognized as caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); however, in just a few weeks, it became clear that the coronavirus disease-2019 (COVID-19) overrun tissues and more body organs than just the lungs, so much so that it could be considered a systemic pathology. Several studies reported the involvement of the conjunctiva, the gut, the heart and its pace, and vascular injuries such as thromboembolic complications and Kawasaki disease in children and toddlers were also described. More recently, it was reported that in a sample of 214 SARS-CoV-2 positive patients, 36.4% complained of neurological symptoms ranging from non-specific manifestations (dizziness, headache, and seizures), to more specific symptoms such hyposmia or hypogeusia, and stroke. Older individuals, especially males with comorbidities, appear to be at the highest risk of developing such severe complications related to the Central Nervous System (CNS) involvement. Neuropsychiatric manifestations in COVID-19 appear to develop in patients with and without pre-existing neurological disorders. Growing evidence suggests that SARS-CoV-2 binds to the human Angiotensin-Converting Enzyme 2 (ACE2) for the attachment and entrance inside host cells. By describing ACE2 and the whole Renin Angiotensin Aldosterone System (RAAS) we may better understand whether specific cell types may be affected by SARS-CoV-2 and whether their functioning can be disrupted in case of an infection. Since clear evidences of neurological interest have already been shown, by clarifying the topographical distribution and density of ACE2, we will be able to speculate how SARS-CoV-2 may affect the CNS and what is the pathogenetic mechanism by which it contributes to the specific clinical manifestations of the disease. Based on such evidences, we finally hypothesize the process of SARS-CoV-2 invasion of the CNS and provide a possible explanation for the onset or the exacerbation of some common neuropsychiatric disorders in the elderly including cognitive impairment and Alzheimer disease.

Impact of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the Nervous System: Implications of COVID-19 in Neurodegeneration

Coronavirus Disease 2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome coronavirus-2 (SARS-CoV-2), began in December 2019, in Wuhan, China and was promptly declared as a pandemic by the World Health Organization (WHO). As an acute respiratory disease, COVID-19 uses the angiotensin-converting enzyme 2 (ACE2) receptor, which is the same receptor used by its predecessor, SARS-CoV, to enter and spread through the respiratory tract. Common symptoms of COVID-19 include fever, cough, fatigue and in a small population of patients, SARS-CoV-2 can cause several neurological symptoms. Neurological malaise may include severe manifestations, such as acute cerebrovascular disease and meningitis/encephalitis. Although there is evidence showing that coronaviruses can invade the central nervous system (CNS), studies are needed to address the invasion of SARS-CoV-2 in the CNS and to decipher the underlying neurotropic mechanisms used by SARS-CoV-2. This review summarizes current reports on the neurological manifestations of COVID-19 and addresses potential routes used by SARS-CoV-2 to invade the CNS.

Clinical Characteristics, Diagnosis, and Treatment of Major Coronavirus Outbreaks

Human coronavirus infections have been known to cause mild respiratory illness. It changed in the last two decades as three global outbreaks by coronaviruses led to significant mortality and morbidity. SARS CoV-1 led to the first epidemic of the twenty first century due to coronavirus. SARS COV-1 infection had a broad array of symptoms with respiratory and gastrointestinal as most frequent. The last known case was reported in 2004. Middle East respiratory syndrome coronavirus (MERS-CoV) led to the second outbreak in 2012, and case fatality was much higher than SARS. MERS-CoV has a wide array of clinical presentations from mild, moderate to severe, and some patients end up with acute respiratory distress syndrome (ARDS). The third and recent outbreak by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) started in December 2019, which lead to a global pandemic. Patients with SARS-CoV2 infection can be asymptomatic or have a range of symptoms with fever, cough, and shortness of breath being most common. Reverse transcriptase-Polymerase chain reaction (RT-PCR) is a diagnostic test of choice for SARS CoV-1, MERS-CoV, and SARS CoV-2 infections. This review aims to discuss epidemiological, clinical features, diagnosis, and management of human coronaviruses with a focus on SARS CoV-1, MERS-CoV, and SARS CoV-2.

Potential for Cognitive Communication Impairment in COVID-19 Survivors: A Call to Action for Speech-Language Pathologists

Purpose Severe acute respiratory syndrome coronavirus 2 is the virus resulting in COVID-19 infections in nearly 4.3 million Americans with COVID-19 in the United States as of July 29, 2020, with nearly 150,000 deaths and hundreds of thousands of survivors (https://www.coronavirus.jhu.edu/map.html). This tutorial reviews (a) what has been reported about neurological insults in cases of COVID-19 infection, (b) what is known from similar conditions in other disorders, and (c) how that combined information can inform clinical decision making. Method PubMed and the Cochrane Central Register of Controlled Trials were searched for COVID-19 or other coronavirus infections, cognitive impairment observed following critical care, and disorders for which intermittent or chronic hypoxia is characteristic. These were combined with searches relating to cognition, brain, and communication. All searches were conducted between April 8 and May 23, 2020. Meta-analyses and randomized clinical trials addressing other critical illnesses were also included to extend findings to potential cognitive communication outcomes following COVID-19. Results COVID-19 infection results in a combination of (a) respiratory infection with mechanical ventilation secondary to inadequate oxygenation, (b) inflammatory system reactivity, and (c) increased blood clotting factors. These affect central nervous system function incurring long-term cognitive communication impairment in a proportion of survivors. Diagnostic and intervention approaches for such impairments are discussed. Conclusions The existing literature on cognitive sequela of COVID-19 infection is small to date, but much can be learned from similar viral infections and disorders. Although COVID-19 is novel, the speech-language pathology approaches to evaluation and intervention of other populations of critical care patients are applicable. However, speech-language pathologists have not routinely been involved in these patients' acute care. As such, this is a call to action to speech-language pathologists to address the unprecedented numbers of patients who will need their services early in the disease process and throughout recovery.

Neurocovid: Pharmacological Recommendations for Delirium Associated With COVID-19

BACKGROUND

The pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as one of the biggest health threats of our generation. A significant portion of patients are presenting with delirium and neuropsychiatric sequelae of the disease. Unique examination findings and responses to treatment have been identified.

OBJECTIVE

In this article, we seek to provide pharmacologic and treatment recommendations specific to delirium in patients with COVID-19.

METHODS

We performed a literature search reviewing the neuropsychiatric complications and treatments in prior coronavirus epidemics including Middle Eastern respiratory syndrome and severe acute respiratory syndrome coronaviruses, as well as the emerging literature regarding COVID-19. We also convened a work group of consultation-liaison psychiatrists actively managing patients with COVID-19 in our hospital. Finally, we synthesized these findings to provide preliminary pharmacologic recommendations for treating delirium in these patients.

RESULTS

Delirium is frequently found in patients who test positive for COVID-19, even in the absence of respiratory symptoms. There appears to be a higher rate of agitation, myoclonus, abulia, and alogia. No data are currently available on the treatment of delirium in patients with COVID-19. Extrapolating from general delirium treatment, Middle Eastern respiratory syndrome/severe acute respiratory syndrome case reports, and our experience, preliminary recommendations for pharmacologic management have been assembled.

CONCLUSIONS

COVID-19 is associated with neuropsychiatric symptoms. Low-potency neuroleptics and alpha-2 adrenergic agents may be especially useful in this setting. Further research into the pathophysiology of COVID-19 will be key in developing more targeted treatment guidelines.

Ruptured cerebral pseudoaneurysm in an adolescent as an early onset of COVID-19 infection: case report

The clinical manifestations of coronavirus disease 2019 (COVID-19) are non-specific and multi-inflammatory. They vary from mild to severe manifestations that can be life-threatening. The association of SARS-CoV-2 infection and pseudoaneurysm formation or rupture of an already existing aneurysm is still unexplored. Several mechanisms may be involved, including the direct destruction to the artery by the viral infection or through the release of the inflammatory cytokines. We are presenting a case of a 13-year-old girl with a ruptured cerebral pseudoaneurysm of the left middle cerebral artery (M2 segment) with severe intracerebral hemorrhage as the earliest manifestation of COVID-19 infection.

COVID-19-associated encephalitis successfully treated with combination therapy

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A case of COVID-19 with clinical features of acute demyelinating encephalomyelitis.

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The patient was successfully treated with immunoglobulins and cytokine blockade.

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Acute encephalitis amenable to immunomodulation could be a feature of COVID-19.

Background

Acute encephalitis can occur in different viral diseases due to infection of the brain or by an immune mechanism. Severe novel coronavirus disease 2019 (COVID-19) is associated with a major immune inflammatory response with cytokine upregulation including interleukin 6 (IL-6). We report a case presenting with acute encephalitis that was diagnosed as having severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection with hyperinflammatory systemic response and recovered after therapy with immunoglobulins and cytokine blockade.

Case report

A 39-year-old-man was brought to the Emergency Department with drowsiness, mental disorientation, intermittent fever and headache. A brain magnetic resonance imaging showed extensive involvement of the brain including cortical and subcortical right frontal regions, right thalamus, bilateral temporal lobes and cerebral peduncles, with no leptomeningeal enhancement. Cerebrospinal fluid (CSF) showed a leukocyte count of 20/µL (90% lymphocytes), protein level of 198 mg/dL, and glucose of 48 mg/dL. SARS-CoV-2 was detected in nasopharyngeal swabs by reverse-transcriptase-PCR (RT-PCR) but it was negative in the CSF. Remarkable laboratory findings in blood tests included low lymphocyte count and elevated ferritin, IL-6 and D-dimer. He had a complicated clinical course requiring mechanical ventilation. Intravenous immunoglobulins and cytokine blockade with tocilizumab, an IL-6 receptor antagonist, were added considering acute demyelinating encephalomyelitis. The patient made a full recovery, suggesting that it could have been related to host inflammatory response.

Conclusion

This case report indicates that COVID-19 may present as an encephalitis syndrome mimicking acute demyelinating encephalomyelitis that could be amenable to therapeutic modulation.

Brain MRI Findings in Severe COVID-19: A Retrospective Observational Study

Background Brain MRI parenchymal signal abnormalities have been associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Purpose To describe the neuroimaging findings (excluding ischemic infarcts) in patients with severe coronavirus disease 2019 (COVID-19) infection. Materials and Methods This was a retrospective study of patients evaluated from March 23, 2020, to April 27, 2020, at 16 hospitals. Inclusion criteria were (a) positive nasopharyngeal or lower respiratory tract reverse transcriptase polymerase chain reaction assays, (b) severe COVID-19 infection defined as a requirement for hospitalization and oxygen therapy, (c) neurologic manifestations, and (d) abnormal brain MRI findings. Exclusion criteria were patients with missing or noncontributory data regarding brain MRI or brain MRI showing ischemic infarcts, cerebral venous thrombosis, or chronic lesions unrelated to the current event. Categorical data were compared using the Fisher exact test. Quantitative data were compared using the Student t test or Wilcoxon test. P < .05 represented a significant difference. Results Thirty men (81%) and seven women (19%) met the inclusion criteria, with a mean age of 61 years ± 12 (standard deviation) (age range, 8-78 years). The most common neurologic manifestations were alteration of consciousness (27 of 37, 73%), abnormal wakefulness when sedation was stopped (15 of 37, 41%), confusion (12 of 37, 32%), and agitation (seven of 37, 19%). The most frequent MRI findings were signal abnormalities located in the medial temporal lobe in 16 of 37 patients (43%; 95% confidence interval [CI]: 27%, 59%), nonconfluent multifocal white matter hyperintense lesions seen with fluid-attenuated inversion recovery and diffusion-weighted sequences with variable enhancement, with associated hemorrhagic lesions in 11 of 37 patients (30%; 95% CI: 15%, 45%), and extensive and isolated white matter microhemorrhages in nine of 37 patients (24%; 95% CI: 10%, 38%). A majority of patients (20 of 37, 54%) had intracerebral hemorrhagic lesions with a more severe clinical presentation and a higher admission rate in intensive care units (20 of 20 patients [100%] vs 12 of 17 patients without hemorrhage [71%], P = .01) and development of the acute respiratory distress syndrome (20 of 20 patients [100%] vs 11 of 17 patients [65%], P = .005). Only one patient had SARS-CoV-2 RNA in the cerebrospinal fluid. Conclusion Patients with severe coronavirus disease 2019 and without ischemic infarcts had a wide range of neurologic manifestations that were associated with abnormal brain MRI scans. Eight distinctive neuroradiologic patterns were described. © RSNA, 2020.

COVID-19 in clinical practice: A narrative synthesis

The coronavirus disease 2019 (COVID-19) was first reported in the city of Wuhan, China. The disease rapidly spread to the rest of China, to Southern-East Asia, then to Europe, America, and on to the rest of the world. COVID-19 is associated with a betacoronavirus named SARS-CoV-2. The virus penetrates the organism through the respiratory tract, conveyed by contaminated droplets. The main cell receptor targeted is the surface-bound ACE-2. As of the 26th July 2020, 15,200,000 COVID-19 cases and 650,000 deaths were reported worldwide. The mortality rate is estimated between 1.3 and 18.3%. The reproductive rate without any public health intervention is estimated around 4-5.1 in France. Most hospitalized patients for COVID-19 present respiratory symptoms, which in some cases is associated with fever. Up to 86% of admissions to ICU are related to acute respiratory failure. To date, no anti-viral therapy has proven its efficacy considering randomized trials. Only immunomodulatory treatments such as corticosteroids have shown to cause significant improvement in patient outcome.

Guillain-Barre syndrome during COVID-19 pandemic: an overview of the reports

Similar to severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), the coronavirus disease 2019 (COVID-19) has neurological symptoms. COVID-19 patients have such clinical symptoms as headache, vomiting, nausea, dizziness, myalgia, anosmia, ageusia, and disorder of consciousness. These symptoms confirm that the nervous system is involved in the COVID-19 infection. Guillain-Barré syndrome (GBS) is a heterogeneous disorder which often follows a viral infection. According to the assessment case reports from the beginning of the COVID-19 infection so far, it is possible that GBS is linked to the COVID-19 infection. It seems that paying attention to the neurological effects of COVID-19 is necessary.

COVID-19: Can the symptomatic SARS-CoV-2 infection affect the homeostasis of the gut-brain-microbiota axis?

COVID-19 is associated with acute and lethal pneumonia, causing the severe acute respiratory syndrome (SARS), which is not confined to the respiratory tract, as demonstrated by clinical evidence of the involvement of multiple organs, including the central nervous system (CNS). In this context, we hypothesized that both oligosymptomatic and symptomatic patients present an imbalance in the microbiota-gut (immune system) and nervous system axis, worsening the clinical picture. The brain constantly receives a direct and indirect influence from the intestine, more specifically from the immune system and intestinal microbiota. The presence of SARS-CoV-2 in the intestine and CNS, can contribute to both neurological disorders and gut immune system imbalance, events potentialized by an intestinal microbiota dysbiosis, aggravating the patient's condition and causing more prolonged harmful effects.

Neuropilin‑1 as a new potential SARS‑CoV‑2 infection mediator implicated in the neurologic features and central nervous system involvement of COVID‑19

Infection by the severe acute respiratory syndrome (SARS) coronavirus‑2 (SARS‑CoV‑2) is the cause of the new viral infectious disease (coronavirus disease 2019; COVID‑19). Emerging evidence indicates that COVID‑19 may be associated with a wide spectrum of neurological symptoms and complications with central nervous system (CNS) involvement. It is now well‑established that entry of SARS‑CoV‑2 into host cells is facilitated by its spike proteins mainly through binding to the angiotensin‑converting enzyme 2 (ACE‑2). Preclinical studies have suggested that neuropilin‑1 (NRP1), which is a transmembrane receptor that lacks a cytosolic protein kinase domain and exhibits high expression in the respiratory and olfactory epithelium, may also be implicated in COVID‑19 by enhancing the entry of SARS‑CoV‑2 into the brain through the olfactory epithelium. In the present study, we expand on these findings and demonstrate that the NRP1 is also expressed in the CNS, including olfactory‑related regions such as the olfactory tubercles and paraolfactory gyri. This furthers supports the potential role of NRP1 as an additional SARS‑CoV‑2 infection mediator implicated in the neurologic manifestations of COVID‑19. Accordingly, the neurotropism of SARS‑CoV‑2 via NRP1‑expressing cells in the CNS merits further investigation.

SARS-CoV-2-mediated encephalitis: Role of AT2R receptors in the blood-brain barrier

At the end of 2019, there was an outbreak of a new Coronavirus 2019 (COVID-19 disease). Studies suggest that SARS-CoV-2 can cause infection in the central nervous system (CNS) and trigger neurological symptoms that include headache, nausea and vomiting, mental confusion and loss of smell or taste. These findings reveal that Coronaviruses have neurological tropism and neuroinvasive capacity. The spread of SARS-CoV-2 in the brain tissue possibly occurs through the systemic circulation as reported in patients affected by SARS-CoV. Evidence highlights similarity between the SARS-CoV genome and SARS-CoV-2 and that both interact with the angiotensin-converting enzyme type 2 (ACE2) located in the brain tissue of infected patients. Hence, the presence of ACE2 is likely in the CNS to mediate the entry of the SARS-CoV-2 virus into neural tissue. Our hypothesis suggests that SARS-CoV-2 can cause encephalitis through the production of inflammatory mediators and activation of immune system cells resulting from the interaction of the ACE2 receptor with the viral Spike protein that causes an increase in angiotensin II. This mechanism has the ability to activate immune system cells by exacerbating stimuli at the angiotensin 2 receptor (AT2R). Thus, it leads to a status of brain injury preceded by vascular damage and destruction of the blood-brain barrier, making it responsible for the installation of acute inflammation.

Central Nervous System Manifestations Associated with COVID-19

Purpose of Review

Coronavirus disease 2019 (COVID-19) has become a global health crisis of our time. The disease arises from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that binds to angiotensin-converting enzyme 2 (ACE2) receptors on host cells for its internalization. COVID-19 has a wide range of respiratory symptoms from mild to severe and affects several other organs, increasing the complexity of the treatment. There is accumulating evidence to suggest that SARS-CoV-2 can target the nervous system. In this review, we provide an account of the COVID-19 central nervous system (CNS) manifestations.

Recent Findings

A broad spectrum of the CNS manifestations including headache, impaired consciousness, delirium, loss of smell and taste, encephalitis, seizures, strokes, myelitis, acute disseminated encephalomyelitis, neurogenic respiratory failure, encephalopathy, silent hypoxemia, generalized myoclonus, neuroleptic malignant syndrome and Kawasaki syndrome has been reported in patients with COVID-19.

Summary

CNS manifestations associated with COVID-19 should be considered in clinical practice. There is a need for modification of current protocols and standing orders to provide better care for COVID-19 patients presenting with neurological symptoms.

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?

Coronaviruses cause respiratory and gastrointestinal disorders in animals and humans. The current SARS-CoV-2, the COVID-19 infectious agent, belongs to a subgroup called betacoronavirus including the SARS-CoV and MERS-CoV responsible for epidemics in 2002 and 2012, respectively. These viruses can also infect the nervous system due to their affinity for the human angiotensin-converting enzyme 2 (ACE2) expressed in neurons and glial cells. Infections with SARS-CoV, MERS-CoV, and now SARS-CoV-2 also produce neurological signs such as acute cerebrovascular disease, impaired consciousness, and muscle injury, as well as dizziness, hypogeusia, hyposmia, hypoxia, neuralgia, and hypoxic encephalopathy. For this reason, close attention should be paid to the neurological manifestations of COVID-19 patients.

Coronavirus Infection of the Central Nervous System: Animal Models in the Time of COVID-19

Naturally occurring coronaviral infections have been studied for several decades in the context of companion and production animals, and central nervous system involvement is a common finding, particularly in cats with feline infectious peritonitis (FIP). These companion and production animal coronaviruses have many similarities to recent human pandemic-associated coronaviruses such as SARS-CoV, MERS-CoV, and SARS-CoV2 (COVID-19). Neurological involvement is being increasingly recognized as an important clinical presentation in human COVID-19 patients, often associated with para-infectious processes, and potentially with direct infection within the CNS. Recent breakthroughs in the treatment of coronaviral infections in cats, including neurological FIP, have utilized antiviral drugs similar to those currently in human COVID-19 clinical trials. Differences in specific coronavirus and host factors are reflected in major variations in incidence and mechanisms of CNS coronaviral infection and pathology between species; however, broad lessons relating to treatment of coronavirus infection present within the CNS may be informative across species.

[Clinical and pathogenetic aspects of nervous system impairments in COVID-19]

Neurological manifestations are reported in 6-36% of patients with COVID-19. They could be divided into direct (viral), secondary (somatogenic) and post(para)infectious (autoimmune) variants according to the pathogenetic mechanisms of their development. The most common type is a secondary impairment of the nervous system presented with encephalopathy of hypoxic, infectious/toxic or dysmetabolic origin. Its major mechanism is related to the brain edema while clinical presentations include non-specific symptoms such as headaches, dizziness and consciousness impairments. Only single reports exist on coronavirus meningoencephalitides. Postinfectious complications of COVID-19 mostly presented with different forms of Gulliane-Barre syndrome. Stroke is registered in 2.5-5% of COVID-19 cases. Their development is associated with hypercoagulation and endothelial dysfunction. Strokes more often develop in elderly with established vascular risk factors and severe COVID-1 but they might also be observed in people younger than 50 years of age and in those with relatively mild forms of the disease. More research is needed in this area.

Neuroethical and Societal Challenges of 21st Century Epidemics

Neurologic and neuropsychiatric manifestations of COVID-19 are affecting a growing number of people worldwide. We provide a brief overview of these manifestations, contrasting them with those of other 21st century viral epidemics, as well as mitigation strategies, and societal and moral considerations related to the pandemic. We highlight unique concerns relating to COVID-19 given the scale of infection, mental health challenges faced by health care providers and the general public, and the unprecedented social consequences, including benefits and possible harms associated with continuous connectedness using modern digital communication.

A range of new ethical concerns accompanies the neurological and neuropsychiatric manifestations of COVID-19 compared with neuro-related symptoms and sequelae of past 21st century viral epidemics and pandemics.

The unique concerns of COVID-19 can be attributed to the scale of infection, mental health impacts, and access to digital communication technology.

Anxiety associated with the ethical and moral complexities of caring for patients, triaging them during a pandemic, and anticipating surges in cases may be as detrimental to the mental well-being of frontline health care workers as post-traumatic stress.

Previous recommendations for use of digital technology, especially among children, are being reconsidered in light of the demands for remote school, work, and socialization during the pandemic.

Neurological manifestations in COVID-19: a systematic review and meta-analysis

OBJECTIVE

Following the outbreak of coronavirus 2019 (COVID-19), there is strong evidence of neurological involvement in these patients. We aimed to determine the clinical characteristics of neurological manifestations in COVID-19.

METHOD

A systematic review of studies reporting neurological manifestations published between 1 December, 2019 and 11 May, 2020 was performed. Studies were grouped based on neurological manifestation. Pooled analyses of individual patient's clinical characteristics and olfactory and gustatory dysfunction prevalence were performed.

RESULTS

Of 486 studies identified, 48 were included. 70 patients with 73 neurological manifestations were reported. 39 (53.4%) patients had stroke, 18 (24.7%) had Guillain-Barré syndrome and variants, 11 (15.1%) had meningitis, encephalitis, encephalopathy, or myelitis, and five (6.8%) had seizures. They had a mean age of 61.9 ± 17.7 years (60.6% male). Neurological disease occurred 8.1 ± 6.8 days from initial symptoms. Average mortality rate was 17.8%. Stroke has a mortality rate of 25.6%. Olfactory and gustatory dysfunction occurred in 59.9% and 57.5%, respectively.

CONCLUSIONS

Stroke is the most frequently reported neurological manifestation in COVID-19 and has the highest mortality rate. Neurological manifestations tend to develop one to two weeks after the onset of respiratory disease. There is significant morbidity and mortality associated with COVID-19 neurological manifestations.

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

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.

Neurological complications of coronavirus infection; a comparative review and lessons learned during the COVID-19 pandemic

INTRODUCTION

Coronavirus disease-19 (COVID-19) pandemic continues to grow all over the world. Several studies have been performed, focusing on understanding the acute respiratory syndrome and treatment strategies. However, there is growing evidence indicating neurological manifestations occur in patients with COVID-19. Similarly, the other coronaviruses (CoV) epidemics; severe acute respiratory syndrome (SARS-CoV-1) and Middle East respiratory syndrome (MERS-CoV) have been associated with neurological complications.

METHODS

This systematic review serves to summarize available information regarding the potential effects of different types of CoV on the nervous system and describes the range of clinical neurological complications that have been reported thus far in COVID-19.

RESULTS

Two hundred and twenty-five studies on CoV infections associated neurological manifestations in human were reviewed. Of those, 208 articles were pertinent to COVID-19. The most common neurological complaints in COVID-19 were anosmia, ageusia, and headache, but more serious complications, such as stroke, impairment of consciousness, seizures, and encephalopathy, have also been reported.

CONCLUSION

There are several similarities between neurological complications after SARS-CoV-1, MERS-CoV and COVID-19, however, the scope of the epidemics and number of patients are very different. Reports on the neurological complications after and during COVID-19 are growing on a daily basis. Accordingly, comprehensive knowledge of these complications will help health care providers to be attentive to these complications and diagnose and treat them timely.

Anosmia: a missing link in the neuroimmunology of coronavirus disease 2019 (COVID-19)

Just before 2020 began, a novel coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), brought for humans a potentially fatal disease known as coronavirus disease 2019 (COVID-19). The world has thoroughly been affected by COVID-19, while there has been little progress towards understanding the pathogenesis of COVID-19. Patients with a severe phenotype of disease and those who died from the disease have shown hyperinflammation and were more likely to develop neurological manifestations, linking the clinical disease with neuroimmunological features. Anosmia frequently occurs early in the course of COVID-19. The prevalence of anosmia would be influenced by self-diagnosis as well as self-misdiagnosis in patients with COVID-19. Despite this, the association between anosmia and COVID-19 has been a hope for research, aiming to understand the pathogenesis of COVID-19. Studies have suggested differently probable mechanisms for the development of anosmia in COVID-19, including olfactory cleft syndrome, postviral anosmia syndrome, cytokine storm, direct damage of olfactory sensory neurons, and impairment of the olfactory perception center in the brain. Thus, the observation of anosmia would direct us to find the pathogenesis of COVID-19 in the central nervous system, and this is consistent with numerous neurological manifestations related to COVID-19. Like other neurotropic viruses, SARS-CoV-2 might be able to enter the central nervous system via the olfactory epithelium and induce innate immune responses at the site of entry. Viral replication in the nonneural olfactory cells indirectly causes damage to the olfactory receptor nerves, and as a consequence, anosmia occurs. Further studies are required to investigate the neuroimmunology of COVID-19 in relation to anosmia.

Coronaviruses and gastrointestinal diseases

The effects of coronaviruses on the respiratory system are of great concern, but their effects on the digestive system receive much less attention. Coronaviruses that infect mammals have shown gastrointestinal pathogenicity and caused symptoms such as diarrhea and vomiting. Available data have shown that human coronaviruses, including the newly emerged SARS-CoV-2, mainly infect the respiratory system and cause symptoms such as cough and fever, while they may generate gastrointestinal symptoms. However, there is little about the relation between coronavirus and digestive system. This review specifically addresses the effects of mammalian and human coronaviruses, including SARS-CoV-2, on the digestive tract, helping to cope with the new virus infection-induced disease, COVID-19.

A Canadian perspective on severe acute respiratory syndrome coronavirus 2 infection and treatment: how prevalent underlying inflammatory disease contributes to pathogenesis

The coronavirus disease 2019 (COVID-19), a serious respiratory illness caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has emerged as a global pandemic. Canada reported its first case of COVID-19 on the 25th January 2020. By March 2020, the virus had spread within Canadian communities reaching the most frail and vulnerable elderly population in long-term care facilities. The majority of cases were reported in the provinces of Quebec, Ontario, Alberta, and British Columbia, and the highest mortality was seen among individuals aged 65 years or older. Canada has the highest prevalence and incidence rates of several chronic inflammatory diseases, such as multiple sclerosis, inflammatory bowel disease, and Parkinson's disease. Many elderly Canadians also live with comorbid medical illnesses, such as hypertension, diabetes, cardiovascular disease, and chronic lung disease, and are more likely to suffer from severe COVID-19 with a poor prognosis. It is becoming increasingly evident that underlying inflammatory disease contributes to the pathogenesis of SARS-CoV-2. Here, we review the mechanisms behind SARS-CoV-2 infection, and the host inflammatory responses that lead to resolution or progression to severe COVID-19 disease. Furthermore, we discuss the landscape of COVID-19 therapeutics that are currently in development in Canada.

Neurologic manifestations in 1760 COVID-19 patients admitted to Papa Giovanni XXIII Hospital, Bergamo, Italy

OBJECTIVES

Evidences from either small series or spontaneous reporting are accumulating that SARS-CoV-2 involves the Nervous Systems. The aim of this study is to provide an extensive overview on the major neurological complications in a large cohort of COVID-19 patients.

METHODS

Retrospective, observational analysis on all COVID-19 patients admitted from February 23rd to April 30th, 2020 to ASST Papa Giovanni XXIII, Bergamo, Italy for whom a neurological consultation/neurophysiological assessment/neuroradiologic investigation was requested. Each identified neurologic complication was then classified into main neurologic categories.

RESULTS

Of 1760 COVID-19 patients, 137 presented neurologic manifestations that manifested after COVID-19 symptoms in 98 pts and was the presenting symptom in 39. Neurological manifestations were classified as: (a) cerebrovascular disease [53 pts (38.7%)] including 37 ischemic and 11 haemorrhagic strokes, 4 transient ischemic attacks, 1 cerebral venous thrombosis; (b) peripheral nervous system diseases [31 (22.6%)] including 17 Guillain-Barrè syndromes; (c) altered mental status [49 (35.8%)] including one necrotizing encephalitis and 2 cases with RT-PCR detection of SARS-Cov-2 RNA in CSF; (d) miscellaneous disorders, among whom 2 patients with myelopathy associated with Ab anti-SARS-CoV-2 in CSF. Patients with peripheral nervous system involvement had more frequently severe ARDS compared to patients with cerebrovascular disease (87.1% vs 42%; difference = 45.1% 95% CI 42.0-48.2; χ²= 14.306; p < 0.0002) and with altered mental status (87.1% vs 55.6%; difference = 31.5% 95% CI 27.5-37.5%; χ²= 7.055; p < 0.01).

CONCLUSION

This study confirms that involvement of nervous system is common in SARS-CoV-2 infection and offers clinicians useful information for prevention and prompt identification in order to set the adequate therapeutic strategies.

Stroke and Novel Coronavirus Infection in Humans: A Systematic Review and Meta-Analysis

Background: As the world witnessed the devastation caused by the coronavirus disease 2019 (COVID-19) outbreak, a growing body of literature on COVID-19 is also becoming increasingly available. Stroke has increasingly been reported as a complication of COVID-19 infection. However, a systematic synthesis of the available data has not been conducted. Therefore, we performed a systematic review and meta-analysis of currently available epidemiological, clinical, and laboratory data related to both stroke and COVID-19 infection. Methods: We systematically searched Medline, Cinahl, and PubMed for studies related to stroke and COVID-19 from inception up to June 4, 2020. We selected cohort studies, case series, and case reports that reported the occurrence of stroke in COVID-19 patients. A fixed-effects model was used to estimate the pooled frequency of stroke in COVID-19 patients with a 95% confidence interval (CI). Results: Twenty-eight studies were included in the systematic review and seven studies for the meta-analysis. The pooled frequency of stroke in COVID-19 patients was 1.1% (95% CI: 0.8, 1.3). The heterogeneity was low (I 2 = 0.0%). Even though the frequency of stroke among patients having COVID-19 infection was low, those with concomitant COVID-19 infection and stroke suffered from a more severe infection and eventually had a poorer prognosis with a higher mortality rate (46.7%) than COVID-19 alone. Many COVID-19 patients shared the common traditional risk factors for stroke. We noted that ischemic stroke involving the anterior circulation with large vessels occlusion is the most common type of stroke with more strokes seen in multi-territorial regions, suggesting systemic thromboembolism. An elevated level of D-dimers, C-reactive protein, ferritin, lactic acid dehydrogenase, troponin, ESR, fibrinogen, and a positive antiphospholipid antibody were also noted in this review. Conclusions: The occurrence of stroke in patients with COVID-19 infection is uncommon, but it may pose as an important prognostic marker and indicator of severity of infection, by causing large vessels occlusion and exhibiting a thrombo-inflammatory vascular picture. Physicians should be made aware and remain vigilant on the possible two-way relationship between stroke and COVID-19 infection. The rate of stroke among patients with COVID-19 infection may increase in the future as they share the common risk factors.

Neurological manifestations of COVID-19, SARS and MERS

Since December 2019, the world is affected by an outbreak of a new disease named COVID-19, which is an acronym of 'coronavirus disease 2019'. Coronaviruses (CoV) were assumed to be associated with mild upper respiratory tract infections, such as common cold. This perception changed in time due to occurrence of the Severe Acute Respiratory Syndrome (SARS) caused by SARS-CoV in 2002 and the Middle East Respiratory Syndrome (MERS) caused by MERS-CoV in 2012, both inducing an epidemic severe viral pneumonia with potentially respiratory failure and numerous extra-pulmonary manifestations. The novel coronavirus, SARS-CoV-2, is likewise a causative pathogen for severe viral pneumonia with the risk of progression to respiratory failure and systemic manifestations. In this review, we will give a summary of the neurological manifestations due to SARS and MERS, as those might predict the neurological outcome in the novel COVID-19. Additionally, we provide an overview of the current knowledge concerning neurological manifestations associated with COVID-19, to the extent that literature is already available as the pandemic is still ongoing.

COVID-19: Are we dealing with a multisystem vasculopathy in disguise of a viral infection?

After the emergence of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in the last two decades, the world is facing its new challenge in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic with unprecedented global response. With the expanding domain of presentations in COVID-19 patients, the full range of manifestations is yet to unfold. The classical clinical symptoms for SARS-CoV-2 affected patients are dry cough, high fever, dyspnoea, lethal pneumonia whereas many patients have also been found to be associated with a few additional signs and clinical manifestations of isolated vasculopathy. Albeit a deep and profound knowledge has been gained on the clinical features and management of COVID-19, less clear association has been provided on SARS-CoV-2 mediated direct or indirect vasculopathy and its possible correlation with disease prognosis. The accumulative evidences suggest that novel coronavirus, apart from its primary respiratory confinement, may also invade vascular endothelial cells of several systems including cerebral, cardio-pulmonary as well as renal microvasculature, modulating multiple visceral perfusion indices. Here we analyse the phylogenetic perspective of SARS-CoV-2 along with other strains of β-coronaviridae from a standpoint of vasculopathic derangements. Based on the existing case reports, literature and open data bases, we also analyse the differential pattern of vasculopathy related changes in COVID-19 positive patients. Besides, we debate the need of modulation in clinical approach from a hemodynamical point of view, as a measure towards reducing disease transmission, morbidity and mortality in SARS-CoV-2 affected patients.

Facing acute neuromuscular diseases during COVID-19 pandemic: focus on Guillain-Barré syndrome

In December 2019, a cluster of cases with 2019 Novel Coronavirus pneumonia from Wuhan, China, aroused worldwide concern due to an escalating outbreak in all the countries in the world. Coronavirus belongs to a family of single-stranded RNA viruses, which includes severe acute respiratory syndrome (SARS-CoV) and Middle East respiratory syndrome (MERS-CoV), that have caused human epidemics with high fatality. The spectrum of the novel coronavirus disease (SARS-Co-2 or COVID-19) ranges from asymptomatic infections to fatal pneumonia, and differs from other viral pulmonary infections. MERS-CoV is known to be potentially neuroinvasive. Extensive reports from China documented central and peripheral nervous system involvement in patients with COVID-19, and identified in angiotensin converting enzyme2 (ACE2), which is present in multiple human organs, the functional receptor for this virus. Guillain-Barré syndrome (GBS) has recently been associated to COVID-19 rising concern among physicians. This review summarizes the current state of knowledge on GBS during or after COVID-19 infection, attempting to clarify the pathophysiology of the associated respiratory dysfunction and failure.

COVID-19 and neurological symptoms: is the SARS-CoV-2 virus neurotropic?

IMPORTANCE

The most notable symptoms of the Coronavirus Disease 2019 (COVID-19) pandemic are fever, cough, dyspnea, and in severe cases, adult respiratory distress syndrome (ARDS.) But neurological symptoms including confusion, stroke, and encephalopathy are reported, and anosmia and hypogeusia are also common indicating that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be neurotropic.

OBSERVATIONS

The SARS-Co-1 and 2 viruses bind to angiotensin converting enzyme 2 (ACE2), which is present on human brain endothelium and non-neuronal cells in the nasopharynx and lingual epithelium. However, SARS-CoV-1 and 2 do not bind rodent ACE2 avidly, which has required the generation of humanized ACE2 transgenic animal models of disease. Transgenic mouse models suggest that the SARS- CoV-1 and Middle East respiratory syndrome (MERS)-CoV are neurotropic and infect and damage the brain, including the cardiorespiratory centers in the medulla. The symptoms of anosmia and hypogeusia indicate a portal to the brain. The relationship between encephalitis lethargica and post encephalitis parkinsonism to the Spanish Flu (H1N1 influenza virus) is unclear but raises the question of long term neurological complications of pandemics.

CONCLUSIONS AND RELEVANCE

There is a concern that there may be long term neurological sequelae of infection with SARS-CoV-2. Registries and long term neurological follow up with longitudinal cohort studies of COVID19 positive patients are needed.

SARS-CoV-2, an Underestimated Pathogen of the Nervous System

Numerous clinical studies have reported neurological symptoms in COVID-19 patients since the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), apart from the atypical signs of pneumonia. Angiotensin-converting enzyme-2 (ACE-2), a potential receptor for SARS-CoV-2 entry, is expressed on various brain cells and cerebral parts, i.e., subfornical organ, paraventricular nucleus, nucleus of the tractus solitarius, and rostral ventrolateral medulla, as well as in non-cardiovascular areas such as the motor cortex and raphe. The resident CNS cells like astrocytes and microglia also express ACE-2, thus highlighting the vulnerability of the nervous system to SARS-CoV-2 infection. Additionally, transmembrane serine protease 2 (TMPRSS2) and furin facilitate virus entry into the host. Besides, the probable routes of virus entry into the nervous system include the hematogenic pathway, through the vagus, the olfactory nerve, or the enteric nervous system. However, the trajectory of SARS-CoV-2 to the brain needs investigation. Furthermore, a Th17-mediated cytokine storm is seen in COVID-19 cases with higher levels of IL-1β/2/7/8/9/10/17, GM-CSF, IFN-γ, TNF-α, CXCL-10, MCP1, and MIP1α/β. Some cytokines can cross the blood-brain barrier and activate the brain's immune cells to produce neural cytokines, leading to neuronal dysfunctions. Nonetheless, most of the neurological conditions developed due to viral infections may not have effective and registered treatments. Although, some antivirals may inhibit the virus-mediated pathogenesis and prove to be suitable in COVID-19 treatment. Therefore, clinicians' and researchers' collective expertise may unravel the potential of SARS-CoV-2 infection to prevent short-term and long-term CNS damage.

Neurological manifestations in COVID-19 and its possible mechanism

In December 2019, the first cases of the acute respiratory illness now known as Corona Virus Disease 2019 (COVID-19) occurred in Wuhan, Hubei Province, China. The main clinical manifestations of COVID-19 are a fever, dry cough and general weakness, although in some patients, a headache, tight chest, diarrhea, etc. are the first clinical manifestations. Neurological practice is involved in all aspects of medicine, from primary care for patients with migraines to consultations with patients in the intensive care unit. Few disorders spare the nervous system, and newly emerging infections are no exception. As neurologists, we are concerned about the effects of SARS-CoV-2 infections on the nervous system. Multiple neuropathy, rhabdomyolysis, cerebrovascular disease, central nervous system infections and other common neurological diseases require attention during this outbreak.

The prognosis and prevention measures for mental health in COVID-19 patients: through the experience of SARS

Due to the high pathogenicity and mortality, the COVID-19 disaster caused global panic and anxiety. At present, diagnosis and treatment are of great concern. As time progresses, however, the sequelae caused by many other organ system complications and treatments will become increasingly obvious, and psychosomatic symptoms are one of these changes with great potential impact. Studies have shown that symptoms like poor sleep quality, anxiety and even delirium are not uncommon in patients during isolation. By summarizing the follow-up study on mental and psychological health of SARS in the past 10 years, and combining the characteristics of the existing cases of COVID-19, we will provide suggestions for the prevention and treatment of psychological diseases in clinical practice.

Neurological Components in Coronavirus Induced Disease: A Review of the Literature Related to SARS, MERS, and COVID-19

Background. COVID-19 has been declared the pandemic of the 21st century, causing more than 45,000 deaths worldwide. The abrupt release of SARS-CoV-2 demonstrated the potential infection, morbidity, and lethality of zoonotic viruses and human-to-human transmission. Fever, cough, and fatigue are reported as the most common symptoms of the disease, including acute respiratory distress syndrome, and also signs of severe illness, such as shock, acute cardiac injury, and renal lesions, are described. Considering the previous works related to human coronavirus and other zoonotic infections, it has been demonstrated that the neuroinvasive propensity is a common characteristic of coronaviruses, especially in SARS-CoV and MERS-CoV. Objective. In the present review, we analyzed the potential neurological components involved in coronavirus infections and detailed the neurological syndromes related to COVID-19. We also examined the mechanism of transmission and CNS pathology related to other viruses with similar structures such as SARS-CoV and MERS-CoV. Methods. A comprehensive search of different original articles and clinical, experimental, and review studies was conducted in MEDLINE/PubMed, Scopus, and Web of Science. We selected 92 articles that have been published in journals or preprints according to the search words and the inclusion and exclusion criteria. Results. COVID-19 patients may experience neurological symptoms such as headache, impaired mental status, confusion, dizziness, nausea and vomiting, anosmia/hyposmia, and dysgeusia/hypogeusia as initial symptoms, with more severe manifestations such as seizures or coma later on. The neurological signs shown are clinical symptoms similar to those reported for SARS-CoV and MERS-CoV. Given that both SARS-CoV and MERS-CoV have similar structures, these viruses may share comparable neurological symptoms and similar progression. Coronaviruses are linked to central nervous system dysfunction, and they are also reported as the probable cause of multiple sclerosis, encephalitis, and meningitis.

Severe Acute Respiratory Syndrome Coronavirus 2 Impact on the Central Nervous System: Are Astrocytes and Microglia Main Players or Merely Bystanders?

With confirmed coronavirus disease 2019 (COVID-19) cases surpassing the 18 million mark around the globe, there is an imperative need to gain comprehensive understanding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although the main clinical manifestations of COVID-19 are associated with respiratory or intestinal symptoms, reports of neurological signs and symptoms are increasing. The etiology of these neurological manifestations remains obscure, and probably involves several direct pathways, not excluding the direct entry of the virus to the central nervous system (CNS) through the olfactory epithelium, circumventricular organs, or disrupted blood–brain barrier. Furthermore, neuroinflammation might occur in response to the strong systemic cytokine storm described for COVID-19, or due to dysregulation of the CNS rennin-angiotensin system. Descriptions of neurological manifestations in patients in the previous coronavirus (CoV) outbreaks have been numerous for the SARS-CoV and lesser for Middle East respiratory syndrome coronavirus (MERS-CoV). Strong evidence from patients and experimental models suggests that some human variants of CoV have the ability to reach the CNS and that neurons, astrocytes, and/or microglia can be target cells for CoV. A growing body of evidence shows that astrocytes and microglia have a major role in neuroinflammation, responding to local CNS inflammation and/or to disbalanced peripheral inflammation. This is another potential mechanism for SARS-CoV-2 damage to the CNS. In this comprehensive review, we will summarize the known neurological manifestations of SARS-CoV-2, SARS-CoV and MERS-CoV; explore the potential role for astrocytes and microglia in the infection and neuroinflammation; and compare them with the previously described human and animal CoV that showed neurotropism to propose possible underlying mechanisms.

The potential role of microvascular pathology in the neurological manifestations of coronavirus infection

Human coronaviruses are highly pathogenic viruses that pose a serious threat to human health. Examples include the severe acute respiratory syndrome outbreak of 2003 (SARS-CoV-1), the Middle East Respiratory Syndrome (MERS-CoV) outbreak of 2012, and the current SARS-CoV-2 (COVID-19) pandemic. Herein, we review the neurological manifestations of coronaviruses and discuss the potential pathogenic role of blood-brain barrier dysfunction. We present the hypothesis that pre-existing vascular damage (due to aging, cardiovascular disease, diabetes, hypertension or other conditions) facilitates infiltration of the virus into the central nervous system (CNS), increasing neuro-inflammation and the likelihood of neurological symptoms. We also discuss the role of a neuroinflammatory cytokine profile in both blood-brain barrier dysfunction and macrovascular disease (e.g. ischemic stroke and thromboembolism). Future studies are needed to better understand the involvement of the microvasculature in coronavirus neuropathology, and to test the diagnostic potential of minimally-invasive screening tools (e.g. serum biomarkers, fluorescein retinal angiography and dynamic-contrast MRI).

Neuropsychological functioning in severe acute respiratory disorders caused by the coronavirus: Implications for the current COVID-19 pandemic

Objective: The coronavirus class of respiratory viruses - including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19) - has been associated with central nervous system (CNS) disease. In fact, multiple mechanisms of CNS involvement have been proposed, making it difficult to identify a unitary syndrome that can be the focus of clinical work and research. Neuropsychologists need to understand the potential cognitive and psychological sequelae of COVID-19 and the impact of the interventions (e.g., ICU, ventilation) that have been used in treating patients with severe forms of the illness.Method: We briefly review the literature regarding the neurological and neuropsychological effects of similar coronaviruses, the limited information that has been published to date on COVID-19, and the literature regarding the long-term cognitive and psychological effects of undergoing treatment in the intensive care unit (ICU).Results: We discuss the roles that neuropsychologists can play in assessing and treating the cognitive difficulties and psychiatric symptoms described.Conclusions: At this time, the mechanisms, correlates, and effects of COVID-19 are poorly understood, but information gleaned from the literature on similar viruses and utilized interventions should help inform neuropsychologists as they begin to work with this population.

Neurological Aspects of SARS-CoV-2 Infection: Mechanisms and Manifestations

The human infection of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a public health emergency of international concern that has caused more than 16.8 million new cases and 662,000 deaths as of July 30, 2020. Although coronavirus disease 2019 (COVID-19), which is associated with this virus, mainly affects the lungs, recent evidence from clinical and pathological studies indicates that this pathogen has a broad infective ability to spread to extrapulmonary tissues, causing multiorgan failure in severely ill patients. In this regard, there is increasing preoccupation with the neuroinvasive potential of SARS-CoV-2 due to the observation of neurological manifestations in COVID-19 patients. This concern is also supported by the neurotropism previously documented in other human coronaviruses, including the 2002-2003 SARS-CoV-1 outbreak. Hence, in the current review article, we aimed to summarize the spectrum of neurological findings associated with COVID-19, which include signs of peripheral neuropathy, myopathy, olfactory dysfunction, meningoencephalitis, Guillain-Barré syndrome, and neuropsychiatric disorders. Furthermore, we analyze the mechanisms underlying such neurological sequela and discuss possible therapeutics for patients with neurological findings associated with COVID-19. Finally, we describe the host- and pathogen-specific factors that determine the tissue tropism of SARS-CoV-2 and possible routes employed by the virus to invade the nervous system from a pathophysiological and molecular perspective. In this manner, the current manuscript contributes to increasing the current understanding of the neurological aspects of COVID-19 and the impact of the current pandemic on the neurology field.