Neurological manifestations of COVID-19: a review of what we know so far

Neurogenesis is disrupted in human hippocampal progenitor cells upon exposure to serum samples from hospitalized COVID-19 patients with neurological symptoms

Coronavirus disease 2019 (COVID-19), represents an enormous new threat to our healthcare system and particularly to the health of older adults. Although the respiratory symptoms of COVID-19 are well recognized, the neurological manifestations, and their underlying cellular and molecular mechanisms, have not been extensively studied yet. Our study is the first one to test the direct effect of serum from hospitalised COVID-19 patients on human hippocampal neurogenesis using a unique in vitro experimental assay with human hippocampal progenitor cells (HPC0A07/03 C). We identify the different molecular pathways activated by serum from COVID-19 patients with and without neurological symptoms (i.e., delirium), and their effects on neuronal proliferation, neurogenesis, and apoptosis. We collected serum sample twice, at time of hospital admission and approximately 5 days after hospitalization. We found that treatment with serum samples from COVID-19 patients with delirium (n = 18) decreased cell proliferation and neurogenesis, and increases apoptosis, when compared with serum samples of sex- and age-matched COVID-19 patients without delirium (n = 18). This effect was due to a higher concentration of interleukin 6 (IL6) in serum samples of patients with delirium (mean ± SD: 229.9 ± 79.1 pg/ml, vs. 32.5 ± 9.5 pg/ml in patients without delirium). Indeed, treatment of cells with an antibody against IL6 prevented the decreased cell proliferation and neurogenesis and the increased apoptosis. Moreover, increased concentration of IL6 in serum samples from delirium patients stimulated the hippocampal cells to produce IL12 and IL13, and treatment with an antibody against IL12 or IL13 also prevented the decreased cell proliferation and neurogenesis, and the increased apoptosis. Interestingly, treatment with the compounds commonly administered to acute COVID-19 patients (the Janus kinase inhibitors, baricitinib, ruxolitinib and tofacitinib) were able to restore normal cell viability, proliferation and neurogenesis by targeting the effects of IL12 and IL13. Overall, our results show that serum from COVID-19 patients with delirium can negatively affect hippocampal-dependent neurogenic processes, and that this effect is mediated by IL6-induced production of the downstream inflammatory cytokines IL12 and IL13, which are ultimately responsible for the detrimental cellular outcomes.

Autonomic dysfunction in patients with COVID‑19

Purpose

Autonomic dysfunction in patients with viral infections has been described before. In this study, we aimed to evaluate autonomic functions in patients with the coronavirus infectious disease 2019 (COVİD-19).

Methods

In this cross-sectional study, we compared 112 patients who had recovered from COVID-19 and 106 healthy controls. Symptoms of autonomic dysfunction were assessed with the SCOPA-AUT scale.

Results

Pupillomotor, urinary and sudomotor subscores of SCOPA-AUT scale were significantly higher in the COVID-19 patient group (p = 0.03, p = 0,006, p = 0.0001, respectively). There were no significant difference in terms of gastrointestinal, cardiovascular, sexual subscores and total SCOPA-AUT scores between the patient and control groups. The presence of fatigue symptom in the acute phase of COVID-19 increased the total SCOPA-AUT score by 2.2 points (p = 0.04) whereas the presence of smell loss (OR = 5.82, p = 0.01) and dyspnea (OR = 5.8, p = 0.03) were significant risk factors for pupillomotor dysfunction. The urinary, cardiovascular, sexual subscores and the total score of SCOPA-AUT scale were positively correlated with the age of the patient group.

Conclusion

Our study suggests that many patients might have prolonged symptoms of autonomic dysfunction after the acute phase of COVID-19 that might worsen the clinical recovery.

Neurological Manifestations in a Cohort of Egyptian Patients with COVID-19: A Prospective, Multicenter, Observational Study

Background: The COVID-19 pandemic has reached over 276 million people globally with 5.3 million deaths as of 22nd December 2021. COVID-19-associated acute and long-term neurological manifestations are well recognized. The exact profile and the timing of neurological events in relation to the onset of infection are worth exploring. The aim of the current body of work was to determine the frequency, pattern, and temporal profile of neurological manifestations in a cohort of Egyptian patients with confirmed COVID-19 infection. Methods: This was a prospective study conducted on 582 hospitalized COVID-19 patients within the first two weeks of the diagnosis of COVID-19 to detect any specific or non-specific neurological events. Results: The patients’ mean (SD) age was 46.74 (17.26) years, and 340 (58.42%) patients were females. The most commonly encountered COVID-19 symptoms were fever (90.72%), cough (82.99%), and fatigue (76.98%). Neurological events (NE) detected in 283 patients (48.63%) and were significantly associated with a severe COVID-19 at the onset (OR: 3.13; 95% CI: 2.18–4.51; p < 0.0001) and with a higher mortality (OR: 2.56; 95% CI: 1.48–5.46; p = 0.019). The most frequently reported NEs were headaches (n = 167) and myalgias (n = 126). Neurological syndromes included stroke (n = 14), encephalitis (n = 12), encephalopathy (n = 11), transverse myelitis (n = 6) and Guillain-Barré syndrome (n = 4). Conclusions: Neurological involvement is common (48.63%) in COVID-19 patients within the first two weeks of the illness. This includes neurological symptoms such as anosmia, headaches, as well as a constellation of neurological syndromes such as stroke, encephalitis, transverse myelitis, and Guillain-Barré syndrome. Severity of acute COVID-19 illness and older age are the main risk factors.

Update on neurological symptoms in patients infected with severe acute respiratory syndrome coronavirus-2

Novel coronavirus 19 (COVID-19) is the latest and most intense epidemic, which is caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). In addition to causing respiratory symptoms, SARS-CoV-2 can have severe effects on the nervous system. Clinically, COVID-19 patients have been reported ranging from mild hypogeusia and hyposmia to severe neurological disorders, such as encephalopathy, encephalitis, strokes, and seizures syndrome. However, the pathological mechanisms of this SARS-CoV-2 neuro aggressiveness remain unclear, so it is of great significance to explore the neurological effects of SARS-CoV-2 infection. To facilitate clinicians to timely recognize the manifestations of COVID-19 patients with neurological injury and timely treatment, the author hereby reviews the latest research progress in the possible pathways, clinical manifestations, and pathogenesis of COVID-19 patients with nerve injury.

Neurological symptoms of COVID-19 infection; a cross-sectional study on hospitalized COVID-19 patients in Iran

BACKGROUND

Coronavirus disease 2019 (COVID-19), a global issue now, can have a variety of clinical manifestations. Hundreds of articles have discussed different aspects of this infectious disease, such as physiopathology, epidemiology, clinical manifestations and treatment protocols. Recently, neurological manifestations of the disease have been found to be pretty common among COVID-19 patients. Here, neurological symptoms of COVID-19 infection with a focus on non-cerebrovascular complications are discussed in a large study population.

METHODS

Neurological symptoms of 891hospitalized COVID-19 patients from March to June 2020 in a major Hospital, Tehran, Iran, were reviewed. Demographic characteristics and neurological manifestations were analyzed.

RESULTS

Among 891 hospitalized COVID-19 patients, the following symptoms were observed: headache (63.9%), sleeping problems (51.3%), hyposmia/anosmia (46%), dizziness (45.4%), hypogeusia (42.1%), memory issues (31.5%), auditory disturbances (17.5%), paralysis (3.7%) and seizures (1.7%). In 29.7% of the patients, a neurological symptom was the initiating symptoms of the infection. Females were more likely to show headache and dizziness compared to males (p value<0.05). Headache intensity was also higher in females compared to males (p value<0.05). Headache prevalence was lower in older patients (p value<0.05), while memory loss and impaired consciousness were higher by increasing age (p values=0.002 and 0.001, respectively).

CONCLUSION

Neurological manifestations were common among COVID-19 patients under study. Headache, as the most common neurological symptom among COVID-19 patients, was the most prevalent and intense among the female population. Headache, dizziness, sleeping problems, hyposmia/anosmia and hypogeusia were common COVID-19 neurological manifestations, while memory issues, auditory disturbances, paralysis, and seizures were less common.

Anisocoria in an intubated patient with COVID-19

The effects of COVID-19 on the eye are still widely unknown. We describe a case of a patient who was intubated and proned in the intensive care unit (ICU) for COVID-19 and developed unilateral anisocoria. CT venogram excluded a cavernous sinus thrombosis. MRI of the head showed microhaemorrhages in the midbrain where the pupil reflex nuclei are located. After the patient was stepped down from ICU, intraocular pressure (IOP) was found to be raised in that eye. A diagnosis of subacute closed angle glaucoma was made. It is important for clinicians to rule out thrombotic causes in patients who develop acute anisocoria. It is also crucial to measure IOP in patients who develop ophthalmic pathology and have been proned for extended periods.

The unfolding palette of COVID-19 multisystemic syndrome and its neurological manifestations

Although our current knowledge of the pathophysiology of COVID-19 is still fragmentary, the information so far accrued on the tropism and life cycle of its etiological agent SARS-CoV-2, together with the emerging clinical data, suffice to indicate that the severe acute pulmonary syndrome is the main, but not the only manifestation of COVID-19. Necropsy studies are increasingly revealing underlying endothelial vasculopathies in the form of micro-haemorrhages and micro-thrombi. Intertwined with defective antiviral responses, dysregulated coagulation mechanisms, abnormal hyper-inflammatory reactions and responses, COVID-19 is disclosing a wide pathophysiological palette. An additional property in categorising the disease is the combination of tissue (e.g. neuro- and vasculo-tropism) with organ tropism, whereby the virus preferentially attacks certain organs with highly developed capillary beds, such as the lungs, gastrointestinal tract, kidney and brain. These multiple clinical presentations confirm that the acute respiratory syndrome as described initially is increasingly unfolding as a more complex nosological entity, a multiorgan syndrome of systemic breadth. The neurological manifestations of COVID-19, the focus of this review, reflect this manifold nature of the disease.

Divulging the Intricacies of Crosstalk Between NF-Kb and Nrf2-Keap1 Pathway in Neurological Complications of COVID-19

The severity of COVID-19 infection is surging day by day. With the cases increasing daily, it is becoming more and more essential to understand the pathogenic mechanisms underlying the severity of the disease. It is now well known that the infection manifests itself primarily as respiratory, but the involvement of the other organ systems has now been documented in many studies. SARS-CoV-2 can invade the nervous system by a multitude of proposed mechanisms that have been discussed in this review. NF-κB and Nrf2 are transcription factors that regulate genes responsible for inflammatory and anti-oxidant response respectively. Specific focus in this review has been given to NF-κB and Nrf2 pathways that are involved in the cytokine storm and oxidative stress that are the hallmarks of COVID-19. As the immune injury is an important mechanism of neuro-invasion and neuroinflammation, there is the possible involvement of these two pathways in the neurological complications. The crosstalk mechanisms of these signaling pathways have also been discussed. Immuno-modulators both synthetic and natural are promising candidates in catering to the pathologies targeted in the aforementioned pathways.

Encephalopathy at admission predicts adverse outcomes in patients with SARS-CoV-2 infection

Aims

To determine if neurologic symptoms at admission can predict adverse outcomes in patients with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2).

Methods

Electronic medical records of 1053 consecutively hospitalized patients with laboratory‐confirmed infection of SARS‐CoV‐2 from one large medical center in the USA were retrospectively analyzed. Univariable and multivariable Cox regression analyses were performed with the calculation of areas under the curve (AUC) and concordance index (C‐index). Patients were stratified into subgroups based on the presence of encephalopathy and its severity using survival statistics. In sensitivity analyses, patients with mild/moderate and severe encephalopathy (defined as coma) were separately considered.

Results

Of 1053 patients (mean age 52.4 years, 48.0% men [n = 505]), 35.1% (n = 370) had neurologic manifestations at admission, including 10.3% (n = 108) with encephalopathy. Encephalopathy was an independent predictor for death (hazard ratio [HR] 2.617, 95% confidence interval [CI] 1.481–4.625) in multivariable Cox regression. The addition of encephalopathy to multivariable models comprising other predictors for adverse outcomes increased AUCs (mortality: 0.84–0.86, ventilation/ intensive care unit [ICU]: 0.76–0.78) and C‐index (mortality: 0.78 to 0.81, ventilation/ICU: 0.85–0.86). In sensitivity analyses, risk stratification survival curves for mortality and ventilation/ICU based on severe encephalopathy (n = 15) versus mild/moderate encephalopathy (n = 93) versus no encephalopathy (n = 945) at admission were discriminative (p < 0.001).

Conclusions

Encephalopathy at admission predicts later progression to death in SARS‐CoV‐2 infection, which may have important implications for risk stratification in clinical practice.

Acute necrotic hemorrhagic leukoencephalitis related to COVID-19: a report of 2 cases

Acute necrotic hemorrhagic leukoencephalitis (ANHLE) is a subform of acute disseminating leukoencephalitis which is a post viral or vaccination uncommon disease with poor prognosis. Radiological findings include multiple or diffuse lesions involving the white matter and sparing the cortex with or without rim enhancement. In addition to areas of hemorrhages with possible involvement of basal ganglia and thalami. We describe the imaging findings for 2 cases of ANHLE; a 59-years-old male and a 47-years-old female. Both of them were tested positive of SARS-COVID2 with presentation of consciousness loss and respiratory failure. CT and MRI brain show global white matter changes associated with acute hemorrhagic necrosis, although uncommon, are compatible with postviral acute necrotic hemorrhagic leukoencephalitis with end point of death for the first patient and coma for the second patient.

Neurologic Manifestations of COVID-19

Neurological manifestations of novel coronavirus disease (COVID-19) are reported to occur in as much as 37% of the affected patients. These manifestations range from headache and dizziness to altered mental status and consciousness, anosmia, ageusia, sensory disturbances, and stroke. The mechanisms by which the neurological symptoms arise are not yet determined but may either proceed as an indirect consequence of systemic hyperinflammation or result from the direct invasion of the virus to neural and glial cells. The neural invasion can explain both the retrograde pathway of encephalitis and the early manifestation of anosmia by invading the olfactory bulb. Moreover, in the case of attacking the brain stem, it may take part in the early apnea manifestation reported by patients. Additionally, neurotropism of the virus could be the cause of acute hemorrhagic encephalitis. Hyperinflammation can have acute and prolonged effects in the nervous system, such as acute demyelination and predisposition to multiple sclerosis. Moreover, the pro-inflammatory state contributes to hypercoagulation, which in turn could result in cerebrovascular injuries in COVID-19 patients. This chapter would discuss that the neurologic manifestations of the COVID-19 are to be looked at as a multifactorial entangled phenomenon.

Neuro-imaging manifestations of COVID-19: Predilection for PICA infarcts

COVID-19 has been an ever-evolving viral pandemic which can cause systemic disturbance especially in some of the critically ill patients. Neurologic or Neuro-imaging manifestations of COVID-19 are being increasingly reported in these patients and mainly consist of ischemic strokes, hypoxic ischemic injury and non-specific encephalopathy. Ischemic strokes as expected more commonly afflict major vascular territories, likely due to accentuated hypercoagulability in these patients. Certain vascular territories may be more susceptible to ischemic infarcts. We observed higher predilection for infarcts in posterior inferior cerebellar artery (PICA). This may represent another peculiarity of this pandemic.

Changes in EEG Recordings in COVID-19 Patients as a Basis for More Accurate QEEG Diagnostics and EEG Neurofeedback Therapy: A Systematic Review

INTRODUCTION AND PURPOSE

The SARS-CoV-2 virus is able to cause abnormalities in the functioning of the nervous system and induce neurological symptoms with the features of encephalopathy, disturbances of consciousness and concentration and a reduced ability to sense taste and smell as well as headaches. One of the methods of detecting these types of changes in COVID-19 patients is an electroencephalogram (EEG) test, which allows information to be obtained about the functioning of the brain as well as diagnosing diseases and predicting their consequences. The aim of the study was to review the latest research on changes in EEG in patients with COVID-19 as a basis for further quantitative electroencephalogram (QEEG) diagnostics and EEG neurofeedback training. Description of the state of knowledge: Based on the available scientific literature using the PubMed database from 2020 and early 2021 regarding changes in the EEG records in patients with COVID-19, 17 publications were included in the analysis. In patients who underwent an EEG test, changes in the frontal area were observed. A few patients were not found to be responsive to external stimuli. Additionally, a previously non-emerging, uncommon pattern in the form of continuous, slightly asymmetric, monomorphic, biphasic and slow delta waves occurred.

CONCLUSION

The results of this analysis clearly indicate that the SARS-CoV-2 virus causes changes in the nervous system that can be manifested and detected in the EEG record. The small number of available articles, the small number of research groups and the lack of control groups suggest the need for further research regarding the short and long term neurological effects of the SARS-CoV-2 virus and the need for unquestionable confirmation that observed changes were caused by the virus per se and did not occur before. The presented studies described non-specific patterns appearing in encephalograms in patients with COVID-19. These observations are the basis for more accurate QEEG diagnostics and EEG neurofeedback training.

A sydenham chorea attack associated with COVID-19 infection

The coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 appeared in Wuhan, China in December 2019 and quickly spread around the world and is considered a global pandemic. This disease, which is pre-infected with respiratory and cardiovascular system symptoms, can also occur in many organ systems. Since the beginning of the pandemic, cases related to neurological involvement have been reported in the literature and studies coercing neurological findings and complications have been published. COVID-19 can cause wide spectrum of neurological phenotypes from severe to milder. To the best of our knowledge, our case is the first report describing the chorea in a patient associated with COVİD-19. In this article, we aim to present a patient who was admitted with chorea on the 3rd day of the COVID-19 followed by Sydenham chorea, which had already improved. This report expands the phenotypic spectrum of COVID-19 and suggests that COVID-19 can be associated with or trigger chorea.

Cerebral venous sinus thrombosis associated with COVID-19: a case series and literature review

BACKGROUND

Since the emergence of COVID-19 pandemic, several cases of cerebral venous sinus thrombosis (CVST) have been reported in SARS-CoV-2 infected individuals.

METHODS

Consecutive patients with documented SARS-CoV-2 infection, as well as clinical and radiological characteristics of CVST, were reported from three teaching hospitals in the South West, North West, and the center of Iran between June and July 2020. We also searched the abstract archives until the end of August 2020 and gathered 28 reported cases. The diagnostic criteria for SARS-CoV-2 infection were determined according to SARS-CoV-2 detection in oropharyngeal or nasopharyngeal samples in clinically suspected patients. Demographics, prominent COVID-19 symptoms, confirmatory tests for SARS-CoV-2 infection diagnosis, the interval between the diagnosis of SARS-CoV-2 infection and CVST, clinical and radiological features of CVST, therapeutic strategies, CVST outcomes, rate of hemorrhagic transformation, and mortality rate were investigated.

RESULTS

Six patients (31-62 years-old) with confirmed CVST and SARS-CoV-2 infection were admitted to our centers. Four patients had no respiratory symptoms of SARS-CoV-2 infection. Five patients developed the clinical manifestations of CVST and SARS-CoV-2 infection simultaneously. Three patients had known predisposing factors for CVST. Despite receiving CVST and SARS-CoV-2 infection treatments, four patients died. SARS-COV-2 associated CVST patients were older (49.26 vs. 37.77 years-old), had lower female/male ratio (1.42 vs. 2.19), and higher mortality rate (35.29% vs. 6.07%) than CVST not associated with COVID-19.

CONCLUSIONS

The role of SARS-CoV-2 as a "cause" versus an "additive contributor" remains to be elucidated. Practitioners should be aware of the possibility of CVST in SARS-CoV-2 infection.

Optic Nerve Head Parameters and Peripapillary Retinal Nerve Fiber Layer Thickness in Patients with Coronavirus Disease 2019

Purpose: To quantify the optic nerve head (ONH) and peripapillary retinal nerve fiber layer (pRNFL) thickness in patients with Coronavirus Disease-2019 (COVID-19) and compare the measurements with a healthy control group.Methods: In a comparative cross-sectional observational study, ONH and pRNFL thickness were evaluated in patients with a history of COVID-19, at least 2 weeks after recovery from the systemic disease, and compared with an age-matched, normal control group.Results: Thirty COVID-19 patients along with 60 age- and gender-matched healthy controls were studied. Mean average pRNFL thickness was 105.0 ± 16.3 µm in the COVID-19 patients, compared to 99.0 ± 9.0 µm in the controls (p = .31). The pRNFL thicknesses in all sectors was higher in patients with a history of COVID-19; however, this did not reach statistical significance. Similarly, ONH parameters were not significantly different between the groups.Conclusion: Patients recovered from COVID-19 had unremarkable alterations in the peripapillary RNFL thickness.Abbreviations: ONH: Optic Nerve HeadRNFL: Retinal Nerve Fiber LayerSD-OCT: Spectral-Domain Optical Coherence TomographyCOVID-19: Coronavirus Disease 2019SARS-CoV-2: Severe Acute Respiratory Syndrome Coronavirus 2CNS: Central Nervous SystemACE: Angiotensin-Converting EnzymeRT-PCR: Reverse Transcription-Polymerase Chain Reaction.

Sudomotor dysfunction in patients recovered from COVID-19

Dysautonomia has been reported in COVID-19. Sweat function testing has been proposed to assess autonomic neuropathy. Fifty Indian patients consulting for neurological symptoms participated in this observational study. The NHS questionnaire for neurological symptoms was completed and electrochemical skin conductance was measured using Sudoscan. The 26% of patients with sweat dysfunction i) were older (p = 0.001), ii) were more frequently treated at home (p = 0.008), iii) were more likely to have received antiviral treatment (p = 0.0006), and iv) more frequently reported at least one motor, sensory or autonomic symptom (p = 0.04). This preliminary study suggests that patients with COVID-19 should be screened for dysautonomia.

Para-infectious anti-GD2/GD3 IgM myelitis during the Covid-19 pandemic: Case report and literature review

BACKGROUND

Even though SARS-CoV-2 is a predominantly respiratory virus, several reports have described various neurological disorders, from the beginning of the pandemic. The first para-infectious myelitis case was described in Wuhan in February 2020. Nevertheless, data from registries and reviews are scarce.

METHODS

A 40-year-old female with T5-T6 SARS-CoV-2 para-infectious myelitis is reported. A literature review of the published literature on the SARS-CoV-2 and para-infectious myelitis was done. Epidemiological, clinical, laboratory, image, treatment, and outcome data are described.

RESULTS

Particular findings of our case are that Covid-19 was asymptomatic and anti-GD2/GD3 IgM was found. 18 para-infectious myelitis occurred over a wide age range (Beh et al., 2013-67), mean age 50.7±18.6 years, with 10/18 (55.6%) women. Covid-19 involvement was variable from asymptomatic cases to severe Covid-19 resulting in death. The mean time to establish myelitis from the onset of Covid-19 symptoms was 10.3 ±7.8 days (0-24). The most common clinical form was transverse myelitis (14/18 patients, 77.7%) and the most frequent radiological form was longitudinally extensive myelitis (11/17 patients, 64.7%). In CSF mild lymphocytosis (14/16, 87.5%) with low cellularity (40.9±49.7/μL) and elevated proteins (11/16, 77.8%, mean 145.0 mg±159.0/dL) were frequent. Oligoclonal bands were usually negative (7/9, 77.7%) and mirror pattern was found in 2/7 patients (33.3%). SARS-CoV-2 PCR in CSF was negative in 10/10 cases.

CONCLUSION

SARS-CoV-2 can cause myelitis by immune-mediated mechanisms. Clinical-radiological characteristics of Covid-19 para-infectious myelitis were variable and non-specific.

Neurological features and outcome in COVID-19: dementia can predict severe disease

The COVID-19 pandemic has infected more than 22 million people worldwide. Although much has been learned about COVID-19, we do not know much about its neurological features and their outcome. This observational study was conducted on the patients of Imam Hossein Hospital, and 361 adult patients (214 males) with confirmed diagnosis of COVID-19 from March 5, 2020 to April 3, 2020, were enrolled. Data was gathered on age, sex, comorbidities, initial symptoms, symptoms during the disease course, neurological symptoms, and outcome. The mean age of the patients was 61.90 ± 16.76 years. The most common initial symptoms were cough, fever, and dyspnea. In 21 patients (5.8%), the initial symptom was neurological. History of dementia was associated with severe COVID-19 disease (odds ratio = 1.28). During the course of the disease, 186 patients (51.52%) had at least one neurological symptom, the most common being headache (109 [30.2%]), followed by anosmia/ageusia (69, [19.1%]), and dizziness (54, [15%]). Also, 31 patients had neurological complications (8.58%). Anosmia, ageusia, dizziness, and headache were associated with favorable outcome (P < 0.001), while altered mental status and hemiparesis were associated with poor outcome. The mortality rate of patients who had neurological complications was more than twice than that of patients without neurological complication (P = 0.008). Almost half of the patients experienced at least one neurological symptom, which may be the initial presentation of COVID-19. Dementia appears to be associated with severe COVID-19. Mortality was higher in patients with neurological complications, and these patients needed more intensive care.

Crosstalk Between Covid-19 and Associated Neurological Disorders: A Review

COVID-19 is a global pandemic, primarily affecting the pulmonary system but its effects on other systems are not certain. Coronavirus, the causative organism, binds with angiotensinconverting enzyme 2 (ACE2) receptors in the lungs and produces pneumonia-like symptoms. Other than lungs, ACE2 receptors are also seen in the endothelium of blood vessels. Therefore, viruses can bind to the ACE2 that is present in the endothelium of brain blood vessels and thus can invade BBB, leading to neuronal damage. It is also believed that olfactory cells rich in ACE2 receptors may act as the main route of viral spread into various parts of the brain. The reported neurological effects of SARS-CoV-2 include cerebrovascular diseases, ageusia and anosmia, Guillain Barre Syndrome, and viral encephalitis. The extent of neurological involvement in SARS-CoV-2 infection warrants the necessity of further research to systematically classify neurological complications associated with SARS-CoV-2 infection, its diagnosis, and treatment. As ACE2 receptors are present in various other organs, it is obligatory to study the effect of coronavirus on other organs also. Since the long-lasting effects of the COVID-19 are unclear, more studies should be conducted to confirm the effect of the virus on the central nervous system. This review highlights the reported neurological manifestations of SARS-CoV-2 and its mechanism.

Multiple potential targets of opioids in the treatment of acute respiratory distress syndrome from COVID-19

COVID-19 can present with a variety of clinical features, ranging from asymptomatic or mild respiratory symptoms to fulminant acute respiratory distress syndrome (ARDS) depending on the host's immune responses and the extent of the associated pathologies. This implies that several measures need to be taken to limit severely impairing symptoms caused by viral-induced pathology in vital organs. Opioids are most exploited for their analgesic effects but their usage in the palliation of dyspnoea, immunomodulation and lysosomotropism may represent potential usages of opioids in COVID-19. Here, we describe the mechanisms involved in each of these potential usages, highlighting the benefits of using opioids in the treatment of ARDS from SARS-CoV-2 infection.

SARS-CoV-2/COVID-19 in multiple sclerosis patients receiving disease-modifying therapy

•

MS-related disability is an independent risk factor for COVID-19 severity.

•

Most likely, disease-modifying therapy does not affect the severity of COVID-19.

•

Special caution should be applied when administering DMT causing lymphopenia in patients with MS and COVID-19.

At the end of 2019, the COVID-19 pandemic began, which at the time of writing continues to be a serious problem for many areas of medicine, including neurology. Since patients with multiple sclerosis (MS) often exhibit motor disability and receive disease-modifying therapy (DMT), which has an immunosuppressive effect, it is plausible that this will affect the susceptibility of MS patients to COVID-19, as well as the course of this disease. However, current data indicate that the use of DMT does not cause negative prognosis in COVID-19 sufferers, but the motor disability progression associated with MS does. In this study, we present the case reports of 4 patients with relapsing-remitting MS, who developed COVID-19, and despite the use of DMT the course of the disease was mild. Two patients were treated with dimethyl fumarate, one with Interferon β1b and one with glatiramer acetate. One of the patients using dimethyl fumarate had lymphopenia. All patients had symptoms of COVID-19 from the nervous system, the most frequent being headache, which occurred in all patients. The aim of this article is to present a case series of four patients with MS and COVID-19, and to discuss the available literature on COVID-19 in patients with MS, with particular consideration of the impact of DMT.

Retinal changes in COVID-19 hospitalized cases

The main objective of this study was to evaluate the retinas of severely or critically ill COVID-19 patients during their hospital stay, at varying time points after symptoms onset. This was a case series observed during May 2020 in two referral centers for COVID-19 treatment in Rio de Janeiro, Brazil. 47 eyes from 25 hospitalized patients with severe or critical confirmed illness were evaluated. A handheld retinal camera was used to acquire bilateral fundus images at several time points after symptoms onset. Electronic health records were retrospectively analyzed and clinical data collected. Severe and critical diseases were noticed in 52% (13/25) and 48% (12/25) of enrolled patients, respectively. Retinal changes were present in 12% (3/25) of patients: a 35 year-old male demonstrated bilateral nerve fiber layer infarcts and microhemorrhages in the papillomacular bundle, but required mechanical ventilation and developed severe anemia and systemic hypotension, acute kidney injury and neurologic symptoms during the course of the disease (critical illness); a 56 year-old male, who required full enoxaparin anticoagulation due to particularly elevated D-dimer (>5.0 mcg/mL), demonstrated unilateral and isolated flame-shaped hemorrhages; and a 49 year-old hypertensive male showed bilateral and discrete retinal dot and blot microhemorrhages. The other 22 patients evaluated did not demonstrate convincing retinal changes upon examination. There was no correlation between disease severity and admission serum levels of CRP, D-dimer and ferritin. This was the first study to show that vascular retinal changes may be present in not insignificant numbers of severe or critical COVID-19 inpatients. These retinal changes, only seen after morbid developments, were likely secondary to clinical intercurrences or comorbidities instead of a direct damage by SARS-CoV-2, and may be important and easily accessible outcome measures of therapeutic interventions and sentinels of neurologic and systemic diseases during COVID-19 pandemic.

Retinal involvement and ocular findings in COVID-19 pneumonia patients

Changes in immune and coagulation systems and possible viral spread through the blood–brain barrier have been described in SARS-CoV-2 infection. In this study, we evaluated the possible retinal involvement and ocular findings in severe COVID-19 pneumonia patients. A cross-sectional study was conducted on 46 patients affected by severe COVID-19 who were hospitalized in one intensive care unit (ICU) and in two infectious disease wards, including bedside eye screening, corneal sensitivity assessment and retinography. A total of 43 SARS-CoV-2-positive pneumonia patients affected with COVID-19 pneumonia were included, including 25 males and 18 females, with a median age of 70 years [IQR 59–78]. Except for one patient with unilateral posterior chorioretinitis of opportunistic origin, of whom aqueous tap was negative for SARS-CoV-2, no further retinal manifestation related to COVID-19 infection was found in our cohort. We found 3 patients (7%) with bilateral conjunctivitis in whom PCR analysis on conjunctival swabs provided negative results for SARS-CoV-2. No alterations in corneal sensitivity were found. We demonstrated the absence of retinal involvement in SARS-CoV-2 pneumonia patients. Ophthalmologic evaluation in COVID-19, particularly in patients hospitalized in an ICU setting, may be useful to reveal systemic co-infections by opportunistic pathogens.

Central Nervous System Targets and Routes for SARS-CoV-2: Current Views and New Hypotheses

As the coronavirus disease 2019 (COVID-19) pandemic unfolds, neurological signs and symptoms reflect the involvement of targets beyond the primary lung effects. The etiological agent of COVID-19, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exhibits neurotropism for central and peripheral nervous systems. Various infective mechanisms and paths can be exploited by the virus to reach the central nervous system, some of which bypass the blood-brain barrier; others alter its integrity. Numerous studies have established beyond doubt that the membrane-bound metalloprotease angiotensin-converting enzyme 2 (ACE2) performs the role of SARS-CoV-2 host-cell receptor. Histochemical studies and more recently transcriptomics of mRNA have dissected the cellular localization of the ACE2 enzyme in various tissues, including the central nervous system. Epithelial cells lining the nasal mucosae, the upper respiratory tract, and the oral cavity, bronchoalveolar cells type II in the pulmonary parenchyma, and intestinal enterocytes display ACE2 binding sites at their cell surfaces, making these epithelial mucosae the most likely viral entry points. Neuronal and glial cells and endothelial cells in the central nervous system also express ACE2. This short review analyzes the known entry points and routes followed by the SARS-CoV-2 to reach the central nervous system and postulates new hypothetical pathways stemming from the enterocytes lining the intestinal lumen.

Neurological manifestations of COVID-19: available evidences and a new paradigm

The recent pandemic outbreak of coronavirus is pathogenic and a highly transmittable viral infection caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2). In this time of ongoing pandemic, many emerging reports suggested that the SARS-CoV-2 has inimical effects on neurological functions, and even causes serious neurological damage. The neurological symptoms associated with COVID-19 include headache, dizziness, depression, anosmia, encephalitis, stroke, epileptic seizures, and Guillain-Barre syndrome along with many others. The involvement of the CNS may be related with poor prognosis and disease worsening. Here, we review the evidence of nervous system involvement and currently known neurological manifestations in COVID-19 infections caused by SARS-CoV-2. We prioritize the 332 human targets of SARS-CoV-2 according to their association with brain-related disease and identified 73 candidate genes. We prioritize these 73 genes according to their spatio-temporal expression in the different regions of brain and also through evolutionary intolerance analysis. The prioritized genes could be considered potential indicators of COVID-19-associated neurological symptoms and thus act as a possible therapeutic target for the prevention and treatment of CNS manifestations associated with COVID-19 patients.

Review of Burden, Clinical Definitions, and Management of COVID-19 Cases

Our understanding of SARS-CoV-2, the virus responsible for coronavirus disease 2019 (COVID-19), its clinical manifestations, and treatment options continues to evolve at an unparalleled pace. This review sought to summarize the key literature regarding transmission, case definitions, clinical management, and the burden of COVID-19. Our review of the literature showed that SARS-CoV-2 was mainly transmitted via inhalation of respiratory droplets containing the virus and had a mean incubation period of 4-6 days. The commonly reported symptoms were fever (75.3% ± 18.7%) and cough (62.6% ± 17.7%) across the spectrum of clinical disease-mild, moderate, severe, and critical, but with the disease phenotype varying with severity. Categorization of these cases for home care or hospital management needs to be defined, with risk stratification accounting for the age of the patient and the presence of underlying comorbidities. The case definitions varied among countries, which could have contributed to the differences in the case fatality rates among affected countries. The severity and risk of death due to COVID-19 was associated with age and underlying comorbidities. Asymptomatic cases, which constitute 40-80% of COVID-19 cases are a considerable threat to control efforts. The presence of fever and cough may be sufficient to warrant COVID-19 testing, but using these symptoms in isolation will miss a proportion of cases. A clear definition of a COVID-19 case is essential for the management, treatment, and tracking of clinical illness, and to inform the quarantine measures and social distancing that can help control the spread of SARS-CoV-2.