Neurological manifestations of COVID-19: A comprehensive literature review and discussion of mechanisms

Unmasking the long-term effects: unravelling neuropsychiatric and neurological consequences of COVID-19

The COVID-19 pandemic has not only burdened healthcare systems but has also led to a new emerging medical enigma that is post-COVID-19 syndrome or "long COVID." Characterized by persistent symptoms that extend beyond the acute phase of the illness, long COVID has rapidly become a public health concern with ambiguous neurological and neuropsychiatric dimensions. This narrative review aims at synthesizing available research to decode the long-term impacts of COVID-19 on neurological and mental health. Drawing from a multitude of studies, this review synthesizes evidence on various neuropsychiatric and neurological symptoms, including cognitive deficits, mood disorders, and more. The narrative delves into potential pathogenic mechanisms, hoping to fill existing research gaps and offering directions for future inquiry. The objective is not just academic; it has immediate real-world implications. Understanding these long-term effects is crucial for developing effective treatments and interventions, thereby better serving the millions of individuals living with these lingering symptoms. As healthcare systems continue to grapple with the fallout from the pandemic, this review provides much-needed context and insights into an area that demands urgent research and action.

SARS‑CoV‑2 infection and associated risk factors for clinical cases of cerebral venous thrombosis: A case series

The present study focused on examining the association between the SARS-CoV-2 virus, responsible for the COVID-19 pandemic, and cerebral venous thrombosis (CVT), a specific form of stroke that affects the brain's vessels and sinuses. While COVID-19 is primarily recognized for its respiratory impact, it may also affect other organs, including the brain. One notable aspect of COVID-19 is its association with coagulopathy, an abnormal condition of blood clotting. Coagulopathy may result in various complications, including neurological ones such as stroke. The study analyzed data obtained from patients admitted to a neurology department who had confirmed neurological pathologies along with COVID-19. It specifically examined the cases of three patients with neurological conditions and COVID-19, discussing their risk factors and how their conditions progressed clinically. The study concluded that COVID-19 infection increases the likelihood of stroke, particularly within the initial 10 days after infection. CVT in particular is strongly linked to COVID-19 and its underlying mechanisms involve immune systemic processes, cytokine storms, increased blood thickness, thrombogenesis, hypercoagulability and inflammation. The presence of SARS-CoV-2 infection may worsen the procoagulant cascade, thereby affecting the clinical condition of patients with CVT. The study underscores the importance of recognizing this uncommon but treatable consequence of COVID-19 infection. Furthermore, it highlights the uniqueness of the study in evaluating COVID-19 infection in patients with CVT from Romania and South-East Europe. The findings support the existence of neurological disorders, including clotting complications in the brain's sinuses and vessels, in individuals infected with SARS-CoV-2. Several risk factors contribute to the development of CVT, such as infections, oral contraceptives, pregnancy, hematological disorders, trauma, autoimmune disorders and malignancies.

A Characterization of Neurology Consults for Inpatients with SARS-CoV-2 Infection Compared to Other Respiratory Viruses

Introduction: Neurological consultation for patients infected with SARS-CoV-2 is common; it is currently unknown whether the neurologist's approach to inpatient consultation of patients with SARS-CoV-2 should differ from the paradigm used to evaluate hospitalized patients with similar respiratory viruses. The goal of the present study is to determine if the preponderance of new neurologic diagnoses differs between inpatients with SARS-CoV-2 and similar non-SARS-CoV-2 respiratory viruses for whom neurology is consulted. Methods: We performed a retrospective chart analysis of inpatient neurologic consultations at three major Philadelphia-based hospitals. We compared the final neurologic diagnosis of 152 patients infected with SARS-CoV-2 to 54 patients with a similar ubiquitous non-SARS-CoV-2 respiratory virus (influenza A, influenza B, respiratory syncytial virus, rhinovirus, or adenovirus, the most commonly tested respiratory viruses at our institution). Secondary metrics included age, sex, level of care, prior neurologic diagnoses, and mortality. A multinomial logistic regression model was utilized to evaluate the relative difference between diagnostic category groups on all metrics. Results: The proportion of patients with seizure who were infected with SARS-CoV-2 admitted to an intensive care unit (ICU) was significantly higher than those who were admitted to a medical-surgical floor. SARS-CoV-2 was also associated with increased risk for ICU admission compared to other common respiratory viruses. SARS-CoV-2 inpatients requiring neurologic consultation were also more likely to be older and female as compared to the non-SARS-CoV-2 cohort. In other domains, the proportion of neurologic diagnoses between SAR-CoV-2 and non-SARS-CoV-2 respiratory viruses showed no significant difference. Conclusion: Patients requiring inpatient neurologic consultation with a diagnosis of SARS-CoV-2 infection or another respiratory virus were found to be remarkably similar in terms of their ultimate neurologic diagnosis, with the exception of a larger preponderance of seizure in critical-care-level patients with SARS-CoV-2 infection. Our study suggests that the neurological approach to patients hospitalized with SARS-CoV-2 should be similar to that for patients with similar common respiratory infections, noting that seizure was seen more frequently in critically ill patients infected with SARS-CoV-2.

Association of body mass index with COVID-19-related neurologic sequelae: a retrospective cohort study

We sought to explore the relationship between body mass index (BMI) and neurologic outcomes following acute COVID-19 infection. We conducted a retrospective electronic medical record-based cohort study enrolling adults with laboratory-confirmed acute COVID-19 infection who presented to 1 of 12 academic and community hospitals in Southwestern Ontario, Canada between April 1, 2020 and July 31, 2021. Primary subjective (anosmia, dysgeusia, and/or headache) and objective (aseptic meningitis, ataxia, delirium, encephalopathy, encephalitis, intracranial hemorrhage, ischemic stroke, and/or seizure) composite neurologic outcomes were assessed, comparing obese and overweight individuals to those with underweight/normal BMI indices, adjusting for baseline characteristics. Secondary outcomes (severity of illness, length of hospital stay, SARS-CoV-2 viral load, mortality) were similarly analyzed. A total of 1437 enrolled individuals, of whom 307 (21%), 456 (32%), and 674 (47%) were underweight/normal, overweight, and obese, respectively. On multivariable analysis, there was no association between BMI category and the composite outcome for subjective (odds ratio [OR] 1.17, 95% CI 0.84-1.64, Bonferroni p = 1.00 for obese; OR 1.02, 95% CI 0.70-1.48; Bonferroni p = 1.00 for overweight) and objective (OR 0.74, 95% CI 0.42-1.30, p = 0.29 for obese; OR = 0.80, 95% CI 0.45-1.43, p = 0.45 for overweight) neurologic manifestations. There was no association between BMI category and any secondary outcome measure and no evidence of effect modification by age or sex. This study demonstrates the absence of an association between BMI and neurologic manifestations following acute COVID-19 illness. Prospective studies using standardized data collection tools and direct measures of body fat are warranted to obtain more valid effect estimates.

Serum neurofilament light chain in COVID-19 and the influence of renal function

COVID-19 is associated with various neurological symptoms. Serum neurofilament light chain (sNfL) is a robust marker for neuroaxonal injury. Recent studies have shown that elevated levels of sNfL are associated with unfavorable outcome in COVID-19 patients. However, neuroaxonal injury is rare in COVID-19, and renal dysfunction and hypoxia, both of which are known in severe COVID-19, can also increase sNfL levels. Thus, the meaning and mechanisms of sNfL elevation in COVID-19 patients remain unclear. We evaluated sNfL levels in 48 patients with COVID-19 (mean age = 63 years) and correlated them to clinical outcome, the form of oxygen therapy, and creatinine. Levels of sNfL were age adjusted and compared with normal values and z-scores. COVID-19 patients treated with nasal cannula had normal sNfL levels (mean sNfL = 19.6 pg/ml) as well as patients with high-flow treatment (mean sNfL = 40.8 pg/ml). Serum NfL levels were statistically significantly higher in COVID-19 patients treated with mechanical ventilation on intensive care unit (ICU) (mean sNfL = 195.7 pg/ml, p < 0.01). There was a strong correlation between sNfL elevation and unfavorable outcome in COVID-19 patients (p < 0.01). However, serum creatinine levels correlated directly and similarly with sNfL elevation and with unfavorable outcome in COVID-19 patients (p < 0.01). Additionally, multivariate analysis for serum creatinine and sNfL showed that both variables are jointly associated with clinical outcomes. Our results identify renal dysfunction as an important possible confounder for sNfL elevation in COVID-19. Thus, serum creatinine and renal dysfunction should be strongly considered in studies evaluating sNfL as a biomarker in COVID-19.

Reactive gliosis and neuroinflammation: prime suspects in the pathophysiology of post-acute neuroCOVID-19 syndrome

Introduction

As the repercussions from the COVID-19 pandemic continue to unfold, an ever-expanding body of evidence suggests that infection also elicits pathophysiological manifestations within the central nervous system (CNS), known as neurological symptoms of post-acute sequelae of COVID infection (NeuroPASC). Although the neurological impairments and repercussions associated with NeuroPASC have been well described in the literature, its etiology remains to be fully characterized.

Objectives

This mini-review explores the current literature that elucidates various mechanisms underlining NeuroPASC, its players, and regulators, leading to persistent neuroinflammation of affected individuals. Specifically, we provide some insights into the various roles played by microglial and astroglial cell reactivity in NeuroPASC and how these cell subsets potentially contribute to neurological impairment in response to the direct or indirect mechanisms of CNS injury.

Discussion

A better understanding of the mechanisms and biomarkers associated with this maladaptive neuroimmune response will thus provide better diagnostic strategies for NeuroPASC and reveal new potential mechanisms for therapeutic intervention. Altogether, the elucidation of NeuroPASC pathogenesis will improve patient outcomes and mitigate the socioeconomic burden of this syndrome.

Neurologic Complications of COVID-19

OBJECTIVE

This article describes the spectrum of neurologic complications occurring in acute or postacute infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as well as the neurologic risks and benefits of vaccination against SARS-CoV-2.

LATEST DEVELOPMENTS

Early in the COVID-19 pandemic, reports of neurologic complications of COVID-19 began to surface. A variety of neurologic conditions have since been reported in association with COVID-19. Understanding of the underlying mechanism of COVID-19 neurologic involvement continues to evolve; however, the evidence seems to suggest that aberrant inflammatory responses may play a role. In addition to neurologic symptoms in acute COVID-19, neurologic post-COVID-19 conditions are increasingly recognized. The development of COVID-19 vaccines has been essential in preventing the spread of COVID-19. With increasing numbers of vaccine doses administered, various neurologic adverse events have been reported.

ESSENTIAL POINTS

Neurologists must be aware of the potential acute, postacute, and vaccine-associated neurologic complications associated with COVID-19 and be poised to serve as integral members of multidisciplinary care teams for patients with COVID-19-related conditions.

Neurorecovery after Critical COVID-19 Illness

With the hundreds of millions of people worldwide who have been, and continue to be, affected by pandemic coronavirus disease (COVID-19) and its chronic sequelae, strategies to improve recovery and rehabilitation from COVID-19 are critical global public health priorities. Neurologic complications have been associated with acute COVID-19 infection, usually in the setting of critical COVID-19 illness. Neurologic complications are also a core feature of the symptom constellation of long COVID and portend poor outcomes. In this article, we review neurologic complications and their mechanisms in critical COVID-19 illness and long COVID. We focus on parallels with neurologic disease associated with non-COVID critical systemic illness. We conclude with a discussion of how recent findings can guide both neurologists working in post-acute neurologic rehabilitation facilities and policy makers who influence neurologic resource allocation.

Organokines in COVID-19: A Systematic Review

Coronavirus disease 2019 (COVID-19) is a viral infection caused by SARS-CoV-2 that induces a generalized inflammatory state. Organokines (adipokines, osteokines, myokines, hepatokines, and cardiokines) can produce beneficial or harmful effects in this condition. This study aimed to systematically review the role of organokines on COVID-19. PubMed, Embase, Google Scholar, and Cochrane databases were searched, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and 37 studies were selected, comprising more than 2700 individuals infected with the virus. Among COVID-19 patients, organokines have been associated with endothelial dysfunction and multiple organ failure due to augmented cytokines and increased SARS-CoV-2 viremia. Changes in the pattern of organokines secretion can directly or indirectly contribute to aggravating the infection, promoting immune response alterations, and predicting the disease progression. These molecules have the potential to be used as adjuvant biomarkers to predict the severity of the illness and severe outcomes.

Covid-19 a triggering factor of autoimmune and multi-inflammatory diseases

SARS-CoV-2 virus has attracted a lot of attention globally due to the autoimmune and inflammatory processes that were observed during the development of Covid-19 disease. Excessive activation of immune response and triggering of autoantibodies synthesis as well as an excessive synthesis of inflammatory cytokines and the onset of cytokine storm has a vital role in the disease outcome and the occurring autoimmune complications. This scenario is reminiscent of infiltration of lymphocytes and monocytes in specific organs and the increased production of autoantibodies and chemoattractants noted in other inflammatory and autoimmune diseases. The main goal of this study is to investigate the complex inflammatory processes that occur in Covid-19 disease and to find similarities with other inflammatory diseases such as multiple sclerosis (MS), acute respiratory distress syndrome (ARDS), rheumatoid arthritis (RA) and Kawasaki syndrome to advance existing diagnostic and therapeutic protocols. The therapy with Interferon-gamma (IFN-γ) and the use of S1P receptor modulators showed promising results. However, there are many unknowns about these mechanisms and possible novel therapies. Therefore, the inflammation and autoimmunity triggered by Covid-19 should be further investigated to improve existing diagnostic procedures and therapeutic protocols for Covid-19.

Aged brain and neuroimmune responses to COVID-19: post-acute sequelae and modulatory effects of behavioral and nutritional interventions

Advanced age is one of the significant risk determinants for coronavirus disease 2019 (COVID-19)-related mortality and for long COVID complications. The contributing factors may include the age-related dynamical remodeling of the immune system, known as immunosenescence and chronic low-grade systemic inflammation. Both of these factors may induce an inflammatory milieu in the aged brain and drive the changes in the microenvironment of neurons and microglia, which are characterized by a general condition of chronic inflammation, so-called neuroinflammation. Emerging evidence reveals that the immune privilege in the aging brain may be compromised. Resident brain cells, such as astrocytes, neurons, oligodendrocytes and microglia, but also infiltrating immune cells, such as monocytes, T cells and macrophages participate in the complex intercellular networks and multiple reciprocal interactions. Especially changes in microglia playing a regulatory role in inflammation, contribute to disturbing of the brain homeostasis and to impairments of the neuroimmune responses. Neuroinflammation may trigger structural damage, diminish regeneration, induce neuronal cell death, modulate synaptic remodeling and in this manner negatively interfere with the brain functions.In this review article, we give insights into neuroimmune interactions in the aged brain and highlight the impact of COVID-19 on the functional systems already modulated by immunosenescence and neuroinflammation. We discuss the potential ways of these interactions with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and review proposed neuroimmune mechanisms and biological factors that may contribute to the development of persisting long COVID conditions. We summarize the potential mechanisms responsible for long COVID, including inflammation, autoimmunity, direct virus-mediated cytotoxicity, hypercoagulation, mitochondrial failure, dysbiosis, and the reactivation of other persisting viruses, such as the Cytomegalovirus (CMV). Finally, we discuss the effects of various interventional options that can decrease the propagation of biological, physiological, and psychosocial stressors that are responsible for neuroimmune activation and which may inhibit the triggering of unbalanced inflammatory responses. We highlight the modulatory effects of bioactive nutritional compounds along with the multimodal benefits of behavioral interventions and moderate exercise, which can be applied as postinfectious interventions in order to improve brain health.

Posterior reversible encephalopathy syndrome and reversible cerebral vasoconstriction syndrome in patients with COVID-19 infection: is there a link? A systematic review and case report analysis

During the SARS-CoV2 pandemic, several cases of Posterior Reversible Encephalopathy Syndrome (PRES) and of Reversible Cerebral Vasoconstriction Syndrome (RCVS) in COVID-19 patients have been reported, but the link between these syndromes and COVID-19 is unclear. We performed a systematic review, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to evaluate whether SARS-CoV2 infection or the drugs used to treat it could be deemed potential risk factors for PRES or RCVS. We performed a literature search. We found 70 articles (60 on PRES and 10 on RCVS) concerning n = 105 patients (n = 85 with PRES, n = 20 with RCVS). We analyzed the clinical characteristics of the two populations separately, then performed an inferential analysis to search for other independent risk factors. We found fewer than usual PRES-related (43.9%) and RCVS-related (45%) risk factors in patients with COVID-19. Such a low incidence of risk factors for PRES and RCVS might suggest the involvement of COVID-19 as an additional risk factor for both diseases due to its capability to cause endothelial dysfunction. We discuss the putative mechanisms of endothelial damage by SARS-CoV2 and antiviral drugs which may underlie the development of PRES and RCVS.

Incidence of Epilepsy and Seizures Over the First 6 Months After a COVID-19 Diagnosis: A Retrospective Cohort Study

BACKGROUND AND OBJECTIVES

The relationship between COVID-19 and epilepsy is uncertain. We studied the potential association between COVID-19 and seizures or epilepsy in the 6 months after infection.

METHODS

We applied validated methods to an electronic health records network (TriNetX Analytics) of 81 million people. We closely matched people with COVID-19 infections to those with influenza. In each cohort, we measured the incidence and hazard ratios (HRs) of seizures and epilepsy. We stratified data by age and by whether the person was hospitalized during the acute infection. We then explored time-varying HRs to assess temporal patterns of seizure or epilepsy diagnoses.

RESULTS

We analyzed 860,934 electronic health records. After matching, this yielded 2 cohorts each of 152,754 patients. COVID-19 was associated with an increased risk of seizures and epilepsy compared with influenza. The incidence of seizures within 6 months of COVID-19 was 0.81% (95% CI 0.75-0.88; HR compared with influenza 1.55 [1.39-1.74]). The incidence of epilepsy was 0.30% (0.26-0.34; HR compared with influenza 1.87 [1.54-2.28]). The HR of epilepsy after COVID-19 compared with influenza was greater in people who had not been hospitalized and in individuals younger than 16 years. The time of peak HR after infection differed by age and hospitalization status.

DISCUSSION

The incidence of new seizures or epilepsy diagnoses in the 6 months after COVID-19 was low overall, but higher than in matched patients with influenza. This difference was more marked in people who were not hospitalized, highlighting the risk of epilepsy and seizures even in those with less severe infection. Children appear at particular risk of seizures and epilepsy after COVID-19 providing another motivation to prevent COVID-19 infection in pediatric populations. That the varying time of peak risk related to hospitalization and age may provide clues as to the underlying mechanisms of COVID-associated seizures and epilepsy.

Neurological Manifestations of Non-Severe COVID-19-A Multidirectional Approach

COVID-19 remains a significant clinical issue worldwide, with frequent neurological manifestations. In this study, the authors combine data obtained from the patient's medical history, physical examinations, and additional test results in the pursuit of any clinically relevant connections. Fifty-eight adult patients hospitalized in the Department of Neurology and Infectiology over a five-months period were retrospectively enrolled in this study. On admission, all patients included in this study were classified as mild or moderate COVID-19 cases, according to the World Health Organization (WHO) guidelines. Laboratory tests, Electroencephalography (EEG), and Magnetic Resonance Imaging (MRI) were performed. There was no statistically significant difference in the Neutrophil-Lymphocyte Ratio (NLR), C-reactive protein (CRP), and Interleukin 6 (IL-6) in patients who reported to the hospital within a week from the symptoms' onset and in those who reported later. In total, 49.06% of patients with eligible EEG recordings presented abnormal brain activity, while 27.59% of the study population had COVID-19-associated MRI findings. EEG and MRI abnormality occurrence did not correlate with the incidence of mild neurological symptoms (headache, olfactory, and gustatory disorders) of the SARS-CoV-2 infection. In three patients in this study population, unprovoked generalized epileptic seizures occurred for the first time in their life. Non-severe SARS-CoV-2 infection causes functional and structural abnormalities within the central nervous system. Brain microhemorrhages are frequently present in non-severe COVID-19 patients. There is no significant association between mild neurological symptoms of COVID-19 and additional test abnormalities. The time from SARS-CoV-2 infection's onset to hospital admission does not seem to influence the prognostic value of CRP, IL-6, and NLR in non-severe COVID-19. Mild-to-moderate SARS-CoV-2 infection can be a trigger factor for epilepsy and epileptic seizures.

Mechanisms, Effects, and Management of Neurological Complications of Post-Acute Sequelae of COVID-19 (NC-PASC)

With a growing number of patients entering the recovery phase following infection with SARS-CoV-2, understanding the long-term neurological consequences of the disease is important to their care. The neurological complications of post-acute sequelae of SARS-CoV-2 infection (NC-PASC) represent a myriad of symptoms including headaches, brain fog, numbness/tingling, and other neurological symptoms that many people report long after their acute infection has resolved. Emerging reports are being published concerning COVID-19 and its chronic effects, yet limited knowledge of disease mechanisms has challenged therapeutic efforts. To address these issues, we review broadly the literature spanning 2020-2022 concerning the proposed mechanisms underlying NC-PASC, outline the long-term neurological sequelae associated with COVID-19, and discuss potential clinical interventions.

The GABA and GABA-Receptor System in Inflammation, Anti-Tumor Immune Responses, and COVID-19

GABA and GABA_A-receptors (GABA_A-Rs) play major roles in neurodevelopment and neurotransmission in the central nervous system (CNS). There has been a growing appreciation that GABA_A-Rs are also present on most immune cells. Studies in the fields of autoimmune disease, cancer, parasitology, and virology have observed that GABA-R ligands have anti-inflammatory actions on T cells and antigen-presenting cells (APCs), while also enhancing regulatory T cell (Treg) responses and shifting APCs toward anti-inflammatory phenotypes. These actions have enabled GABA_A-R ligands to ameliorate autoimmune diseases, such as type 1 diabetes (T1D), multiple sclerosis (MS), and rheumatoid arthritis, as well as type 2 diabetes (T2D)-associated inflammation in preclinical models. Conversely, antagonism of GABA_A-R activity promotes the pro-inflammatory responses of T cells and APCs, enhancing anti-tumor responses and reducing tumor burden in models of solid tumors. Lung epithelial cells also express GABA-Rs, whose activation helps maintain fluid homeostasis and promote recovery from injury. The ability of GABA_A-R agonists to limit both excessive immune responses and lung epithelial cell injury may underlie recent findings that GABA_A-R agonists reduce the severity of disease in mice infected with highly lethal coronaviruses (SARS-CoV-2 and MHV-1). These observations suggest that GABA_A-R agonists may provide off-the-shelf therapies for COVID-19 caused by new SARS-CoV-2 variants, as well as novel beta-coronaviruses, which evade vaccine-induced immune responses and antiviral medications. We review these findings and further advance the notions that (1) immune cells possess GABA_A-Rs to limit inflammation in the CNS, and (2) this natural "braking system" on inflammatory responses may be pharmacologically engaged to slow the progression of autoimmune diseases, reduce the severity of COVID-19, and perhaps limit neuroinflammation associated with long COVID.

Possible post-COVID epilepsy: A review of epilepsy monitoring unit admissions during the two years of COVID-19 pandemic

Large scale healthcare data shows that new-onset epilepsy is noted in 0.3 % patients within 6 months of COVID-19 infection. We analyzed diagnostic epilepsy monitoring unit (EMU) evaluations to identify and report such cases. We thoroughly reviewed our EMU database and identified patients having "COVID" or "Corona" virus mention in their medical record from 03/15/2020 to 02/28/2022. Patients with epilepsy prior to COVID infection were excluded. Among 62 patients without prior epilepsy evaluated in the EMU for new-onset spells after confirmed COVID-19 infection, three patients were diagnosed with focal epilepsy. These three women without epilepsy risk factors had seizure onset at the time of, or within one to three months of, COVID-19 diagnosis. Their 3 T MRI imaging was non-lesional but revealed bilateral enlarged perivascular spaces. The video EEG monitoring was consistent with temporal or fronto-temporal lobe epilepsy in all three patients. Two of them developed drug-resistant epilepsy within six months of seizure onset. Our thorough analysis of diagnostic EMU evaluations during the two years of pandemic reveals three cases of post-COVID-19 epilepsy after non-symptomatic to mild disease. Although coincidental epilepsy onset cannot be ruled out, larger multicenter or national database investigations are needed to further analyze the possibility of post-COVID epilepsy.

Inventory study of an early pandemic COVID-19 cohort in South-Eastern Sweden, focusing on neurological manifestations

BACKGROUND

Neurological manifestations in patients with COVID-19 have been reported previously as outcomes of the infection. The purpose of current study was to investigate the occurrence of neurological signs and symptoms in COVID-19 patients, in the county of Östergötland in southeastern Sweden.

METHODS

This is a retrospective, observational cohort study. Data were collected between March 2020 and June 2020. Information was extracted from medical records by a trained research assistant and physician and all data were validated by a senior neurologist.

RESULTS

Seventy-four percent of patients developed at least one neurological symptom during the acute phase of the infection. Headache (43%) was the most common neurological symptom, followed by anosmia and/or ageusia (33%), confusion (28%), hallucinations (17%), dizziness (16%), sleep disorders in terms of insomnia and OSAS (Obstructive Sleep Apnea) (9%), myopathy and neuropathy (8%) and numbness and tingling (5%). Patients treated in the ICU had a higher male presentation (73%). Several risk factors in terms of co-morbidities, were identified. Hypertension (54.5%), depression and anxiety (51%), sleep disorders in terms of insomnia and OSAS (30%), cardiovascular morbidity (28%), autoimmune diseases (25%), chronic lung diseases (24%) and diabetes mellitus type 2 (23%) founded as possible risk factors.

CONCLUSION

Neurological symptoms were found in the vast majority (74%) of the patients. Accordingly, attention to neurological, mental and sleep disturbances is warranted with involvement of neurological expertise, in order to avoid further complications and long-term neurological effect of COVID-19. Furthermore, risk factors for more severe COVID-19, in terms of possible co-morbidities that identified in this study should get appropriate attention to optimizing treatment strategies in COVID-19 patients.

Frequency and burden of neurological manifestations upon hospital presentation in COVID-19 patients: Findings from a large Brazilian cohort

BACKGROUND

Scientific data regarding the prevalence of COVID-19 neurological manifestations and prognosis in Latin America countries is still lacking. Therefore, the study aims to understand neurological manifestations of SARS-CoV 2 infection and outcomes in the Brazilian population.

METHODS

This study is part of the Brazilian COVID-19 Registry, a multicentric cohort, including data from 37 hospitals. For the present analysis, patients were grouped according to the presence of reported symptoms (i.e., headache; anosmia and ageusia; syncope and dizziness) vs. clinically-diagnosed neurological manifestations (clinically-defined neurological syndrome: neurological signs or diagnoses captured by clinical evaluation) and matched with patients without neurological manifestations by age, sex, number of comorbidities, hospital of admission, and whether or not patients had underlying neurological disease.

RESULTS

From 6,635 hospitalized patients with COVID-19, 30.8% presented reported neurological manifestations, 10.3% were diagnosed with a neurological syndrome and 60.1% did not show any neurological manifestations. In patients with reported symptoms, the most common ones were headache (20.7%), ageusia (11.1%) and anosmia (8.0%). In patients with neurological syndromes, acute encephalopathy was the most common diagnosis (9.7%). In the matched analysis, patients with neurological syndromes presented more cases of septic shock (17.0 vs. 13.0%, p = 0.045), intensive care unit admission (45.3 vs. 38.9%, p = 0.023), and mortality (38.7 vs. 32.6%, p = 0.026; and 39.2 vs. 30.3%, p < 0.001) when compared to controls.

CONCLUSION

COVID-19 in-hospital patients with clinically defined neurological syndromes presented a higher incidence of septic shock, ICU admission and death when compared to controls.

First-episode psychotic disorders in the wake of the COVID-19 pandemic: a descriptive review of casereports

OBJECTIVE

Since the onset of COVID-19 pandemic, many case reports and case series dealt with new-onset psychotic disorders in patients either infected with SARS-CoV-2 or thematically linked to the pandemic, but without an infection. Our aim was to provide a comprehensive collection of these reports to illustrate the nature of these psychoses.

METHODS

We conducted a literature search in MEDLINE, Embase, PsycINFO, using search terms regarding first-episode psychotic disorders in the context of corona.

RESULTS

96 case reports or case series covering 146 patients (62 without and 84 with SARS-CoV-2 infection) were found. Compared to patients without infection, patients with infection showed significantly more often visual hallucinations (28.6% vs 8.1%), confusion (36.9% vs 11.3%), an acute onset of illness (88.5% vs 59.6%) and less often depression (13.1% vs 35.5%) and a delusional content related to the pandemic (29.5% vs 78.3%). Both groups had an equally favourable outcome with a duration of psychosis ≤2 weeks in half and full remission in two-thirds of patients. In patients with infection, signs of inflammation were reported in 78.3% and increased CRP in 58.6%. While reports on patients with infection are continuously published, no report about patients without infection was found after July 2020.

CONCLUSION

Cases without infection were considered reactive and originated all from the first wave of the corona pandemic. In cases with infection, inflammation was considered as the main pathogenetic factor but was not found in all patients. Diagnosis was impeded by the overlap of psychosis with delirium.

COVID-19: Brain Effects

Severe acute respiratory syndrome coronavirus 2, the novel coronavirus responsible for the coronavirus disease (COVID-19), affects the brain. Neurologic and neuropsychiatric symptoms may manifest in the acute and post-acute phases of illness. The vulnerability of the brain with aging further increases the burden of disease in the elderly, who are at the highest risk of complications and death from COVID-19. The mechanisms underlying the effects of COVID-19 on the brain are not fully known. Emerging evidence vis-à-vis pathogenesis and etiologies of COVID-19 brain effects is promising and may pave the way for future research and development of interventions.

Fatal Acute Hemorrhagic Encephalomyelitis and Antiphospholipid Antibodies following SARS-CoV-2 Vaccination: A Case Report

Acute hemorrhagic encephalomyelitis (AHEM) is a rare hyperacute form of acute disseminated encephalomyelitis (ADEM). The disease is characterized by fulminant inflammation and demyelination in the brain and spinal cord and is often preceded by an infection or vaccination. This case report presents a 53-year-old male with rheumatoid arthritis and ongoing treatment with methotrexate and etanercept who developed fatal AHEM following the second dose of the COVID-19 vaccine. The disease course was complicated by multiorgan thromboembolic disease and the presence of high/moderate levels of cardiolipin IgG antibodies and anti-beta-2 glycoprotein 1 IgG antibodies suggesting a possible antiphospholipid syndrome. Treatment with immunosuppressive therapies failed to improve the course. The report comprises comprehensive clinical, neuroimaging, and neuropathological findings. The case highlights diagnostic challenges in a patient with several preceding risk factors, including autoimmune disease, immunotherapy, and vaccination, with possible pathophysiological implications. The temporal association with the COVID-19 vaccination may suggest possible causality although evidence cannot be ascertained. Reporting possible adverse events following COVID-19 vaccination is important to identify at-risk populations and to accomplish control of the current pandemic.

Prevalence, Patterns, Prognosis, and Psychosocial Impact of Olfactory and Gustative Dysfunctions Among Saudi COVID-19 Patients

Objective The objective of this study is to estimate the prevalence of olfactory and gustative dysfunctions (OGD) and analyze their pattern and psychosocial impact among COVID-19 patients. Method A cross-sectional study was conducted among 194 confirmed COVID-19 cases at Al-Noor Specialist Hospital between 1 September 2020 and 30 September 2021. A questionnaire was translated and modified from another study to collect the baseline demographic data and medical history; characterization of smell and taste loss separately, including timing, level, practices or treatment used to restore, recovery, and symptom duration; and the psychological impact of OGD using six items to explore the multidimensional impact, such as daily activity, job performance, and social life. A four-point Likert-type agreement scale was used, and an impact score was calculated. Result As high as 97.4% and 94.8% of the participants declared having experienced a certain level of olfactory and gustative dysfunction, respectively. In the majority of these cases, the dysfunction occurred after the acute phase of the disease and persisted less than one month after onset. Social life (78.4%), job performance (64.4%), and daily life activities (42.8%) were the most frequently impacted dimensions, and 32% of the participants were deemed to have experienced a high psychosocial impact. Younger participants, females, and certain job categories were significantly more impacted than their counterparts. Conclusion OGDs are highly frequent in COVID-19 patients. They are described to be relatively severe and have frequent psychosocial impacts, notably in females and the younger age category. Further research is warranted to determine efficacious preventive and management strategies in order to prevent their long-term impact on wellbeing.

A GABA-receptor agonist reduces pneumonitis severity, viral load, and death rate in SARS-CoV-2-infected mice

Gamma-aminobutyric acid (GABA) and GABA-receptors (GABA-Rs) form a major neurotransmitter system in the brain. GABA-Rs are also expressed by 1) cells of the innate and adaptive immune system and act to inhibit their inflammatory activities, and 2) lung epithelial cells and GABA-R agonists/potentiators have been observed to limit acute lung injuries. These biological properties suggest that GABA-R agonists may have potential for treating COVID-19. We previously reported that GABA-R agonist treatments protected mice from severe disease induced by infection with a lethal mouse coronavirus (MHV-1). Because MHV-1 targets different cellular receptors and is biologically distinct from SARS-CoV-2, we sought to test GABA therapy in K18-hACE2 mice which develop severe pneumonitis with high lethality following SARS-CoV-2 infection. We observed that GABA treatment initiated immediately after SARS-CoV-2 infection, or 2 days later near the peak of lung viral load, reduced pneumonitis severity and death rates in K18-hACE2 mice. GABA-treated mice had reduced lung viral loads and displayed shifts in their serum cytokine/chemokine levels that are associated with better outcomes in COVID-19 patients. Thus, GABA-R activation had multiple effects that are also desirable for the treatment of COVID-19. The protective effects of GABA against two very different beta coronaviruses (SARS-CoV-2 and MHV-1) suggest that it may provide a generalizable off-the-shelf therapy to help treat diseases induced by new SARS-CoV-2 variants and novel coronaviruses that evade immune responses and antiviral medications. GABA is inexpensive, safe for human use, and stable at room temperature, making it an attractive candidate for testing in clinical trials. We also discuss the potential of GABA-R agonists for limiting COVID-19-associated neuroinflammation.

Atypical Guillain-Barré syndrome presenting with fluctuating weakness

Guillain-Barré Syndrome (GBS) is an immune-mediated polyneuropathy, most often occurring within weeks of an infection. Cases of COVID-19-related GBS have been reported, and the typical presentation is a progressive ascending paralysis. We describe a case of a 40-year-old with recent symptomatic COVID-19 who presented with atypical GBS findings, hand weakness that progressed to tetraplegia within 24 hours. He had hyperreflexia on his initial exam and did not meet diagnostic criteria for GBS. Inconsistent neurological findings with spontaneous improvement of symptoms, unremarkable initial evaluation including lumbar puncture, and anxiety further complicated the diagnosis. On day 6, he was intubated for diaphragmatic paralysis, and repeat lumbar puncture showed albumin-cytologic dissociation. Intravenous immunoglobulin followed by plasmapheresis improved strength and allowed for extubation. This case highlights the difficulty of recognizing heterogenic GBS presentations.

Cognitive dysfunction associated with COVID-19: Prognostic role of circulating biomarkers and microRNAs

COVID-19 is renowned as a multi-organ disease having subacute and long-term effects with a broad spectrum of clinical manifestations. The evolving scientific and clinical evidence demonstrates that the frequency of cognitive impairment after COVID-19 is high and it is crucial to explore more clinical research and implement proper diagnostic and treatment strategies. Several central nervous system complications have been reported as comorbidities of COVID-19. The changes in cognitive function associated with neurodegenerative diseases develop slowly over time and are only diagnosed at an already advanced stage of molecular pathology. Hence, understanding the common links between COVID-19 and neurodegenerative diseases will broaden our knowledge and help in strategizing prognostic and therapeutic approaches. The present review focuses on the diverse neurodegenerative changes associated with COVID-19 and will highlight the importance of major circulating biomarkers and microRNAs (miRNAs) associated with the disease progression and severity. The literature analysis showed that major proteins associated with central nervous system function, such as Glial fibrillary acidic protein, neurofilament light chain, p-tau 181, Ubiquitin C-terminal hydrolase L1, S100 calcium-binding protein B, Neuron-specific enolase and various inflammatory cytokines, were significantly altered in COVID-19 patients. Furthermore, among various miRNAs that are having pivotal roles in various neurodegenerative diseases, miR-146a, miR-155, Let-7b, miR-31, miR-16 and miR-21 have shown significant dysregulation in COVID-19 patients. Thus the review consolidates the important findings from the numerous studies to unravel the underlying mechanism of neurological sequelae in COVID-19 and the possible association of circulatory biomarkers, which may serve as prognostic predictors and therapeutic targets in future research.

Serum neurofilament light chain levels in Covid-19 patients without major neurological manifestations

Background

Increased serum levels of neurofilament light chain (sNFL), a biomarker of neuroaxonal damage, have been reported in patients with Covid-19. We aimed at investigating whether sNFL is increased in Covid-19 patients without major neurological manifestations, is associated with disease severity, respiratory and routine blood parameters, and changes longitudinally in the short term.

Methods

sNFL levels were measured with single molecule array (Simoa) technology in 57 hospitalized Covid-19 patients without major neurological manifestations and in 30 neurologically healthy controls. Patients were evaluated for PaO2/FiO2 ratio on arterial blood gas, Brescia Respiratory Covid Severity Scale (BRCSS), white blood cell counts, serum C-reactive protein (CRP), plasma D-dimer, plasma fibrinogen, and serum creatinine at admission. In 20 patients, NFL was also measured on serum samples obtained at a later timepoint during the hospital stay.

Results

Covid-19 patients had higher baseline sNFL levels compared to controls, regardless of disease severity. Baseline sNFL correlated with serum CRP and plasma D-dimer in patients with mild disease, but was not associated with measures of respiratory impairment. Longitudinal sNFL levels tended to be higher than baseline ones, albeit not significantly, and correlated with serum CRP and plasma D-dimer. The PaO2/FiO2 ratio was not associated with longitudinal sNFL, whereas BRCSS only correlated with longitudinal sNFL variation.

Conclusions

We provide neurochemical evidence of subclinical axonal damage in Covid-19 also in the absence of major neurological manifestations. This is apparently not fully explained by hypoxic injury; rather, systemic inflammation might promote this damage. However, a direct neurotoxic effect of SARS-CoV-2 cannot be excluded.

Neurological manifestations by sex and age group in COVID-19 inhospital patients

Introduction

Neurological manifestations have been associated with a poorer prognosis in COVID-19. However, data regarding their incidence according to sex and age groups is still lacking.

Methods

This retrospective multicentric cohort collected data from 39 Brazilian hospitals from 17 cities, from adult COVID-19 admitted from March 2020 to January 2022. Neurological manifestations presented at hospital admission were assessed according to incidence by sex and age group.

Results

From 13,603 COVID-19 patients, median age was 60 years old and 53.0% were men. Women were more likely to present with headaches (22.4% vs. 17.7%, p < 0.001; OR 1.36, 95% confidence interval [CI] 1.22–1.52) than men and also presented a lower risk of having seizures (OR 0.43, 95% CI 0.20–0.94). Although delirium was more frequent in women (6.6% vs. 5.7%, p = 0.020), sex was not associated with delirium in the multivariable logistc regresssion analysis. Delirium, syncope and coma increased with age (1.5% [18–39 years] vs. 22.4% [80 years or over], p < 0.001, OR 1.07, 95% CI 1.06–1.07; 0.7% vs. 1.7%, p = 0.002, OR 1.01, 95% CI 1.00–1.02; 0.2% vs. 1.3% p < 0.001, OR 1.04, 95% CI 1.02–1.06), while, headache (26.5% vs. 7.1%, OR 0.98, 95% CI 0.98–0.99), anosmia (11.4% vs. 3.3%, OR 0.99, 95% CI] 0.98–0.99 and ageusia (13.1% vs. 3.5%, OR 0.99, CI 0.98–0.99) decreased (p < 0.001 for all).

Conclusion

Older COVID-19 patients were more likely to present delirium, syncope and coma, while the incidence of anosmia, ageusia and headaches decreased with age. Women were more likely to present headache, and less likely to present seizures.

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Older COVID-19 patients were more likely to present delirium and coma.

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Younger COVID-19 patients were more likely to report anosmia, ageusia and headache.

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Women with COVID-19 are more likely to present headache.

Acute to Chronic Electro-Clinical Manifestations of Neuro-COVID and the Long-Haul Consequences in People With Epilepsy: A Review

Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) infection can involve the central nervous system (CNS). Acute symptomatic seizures or epileptiform discharges have not been commonly reported in patients with altered mental status related to coronavirus disease 2019 (COVID-19) infection. However, long-term neurological symptoms have been reported after COVID-19 infection (i.e., brain fog, cognitive complaints, and confusion), suggesting chronic encephalopathy. People with epilepsy (PWE) have been specifically affected by the COVID-19 pandemic, with changes in their seizure frequency, quality of life, health care accessibility, and medication interactions. This narrative review highlights possible pathophysiological mechanisms of COVID-19 on the brain, related to short- and long-term epileptiform activity and the impact of this infection on PWE.

Inflammatory reflex disruption in COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in Wuhan, China, in late 2019 and caused coronavirus disease 2019 (COVID-19), which is still a global pandemic. In most infected people, SARS-CoV-2 can only cause moderate symptoms, while in other patients, it leads to severe illness and eventually death. Although the main clinical manifestation of COVID-19 is often seen in the lungs, this disease affects almost all body organs. The excessive and prolonged release of inflammatory cytokines that may occur in COVID-19 patients, known as cytokine storms, stimulates undesired immune responses and can cause various tissues damage. In the current review article, we focus on the potential advantages of the intrinsic cholinergic anti-inflammatory pathway (CAP) as the efferent arm of inflammatory reflex in COVID-19 management. Considering this endogenous protective mechanism against chronic inflammation, we focused on the effects of SARS-CoV-2 in the destruction of this anti-inflammatory system. Several studies indicated the interaction of SARS-CoV-2 with the alpha7 subtype of the nicotinic acetylcholine receptor as the effector molecule of the inflammatory reflex. On the other hand, neurological manifestations have increasingly been identified as significant extrapulmonary manifestations of COVID-19. The rational connection between these findings and COVID-19 pathogenesis may be an important issue in both our understanding and dealing with this disease. COVID-19 is deeply rooted in our daily life and requires an urgent need for the establishment of effective therapeutic options, and all the possible treatments must be considered for the control of such inflammatory conditions.

Dissecting the Molecular Mechanisms Surrounding Post-COVID-19 Syndrome and Neurological Features

Many of the survivors of the novel coronavirus disease (COVID-19) are suffering from persistent symptoms, causing significant morbidity and decreasing their quality of life, termed “post-COVID-19 syndrome” or “long COVID”. Understanding the mechanisms surrounding PCS is vital to developing the diagnosis, biomarkers, and possible treatments. Here, we describe the prevalence and manifestations of PCS, and similarities with previous SARS epidemics. Furthermore, we look at the molecular mechanisms behind the neurological features of PCS, where we highlight important neural mechanisms that may potentially be involved and pharmacologically targeted, such as glutamate reuptake in astrocytes, the role of NMDA receptors and transporters (EAAT2), ROS signaling, astrogliosis triggered by NF-κB signaling, KNDy neurons, and hypothalamic networks involving Kiss1 (a ligand for the G-protein-coupled receptor 54 (GPR54)), among others. We highlight the possible role of reactive gliosis following SARS-CoV-2 CNS injury, as well as the potential role of the hypothalamus network in PCS manifestations.

SARS-CoV-2 Morbidity in the CNS and the Aged Brain Specific Vulnerability

The infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be the cause of a fatal disease known as coronavirus disease 2019 (COVID-19) affecting the lungs and other organs. Particular attention has been given to the effects of the infection on the brain due to recurring neurological symptoms associated with COVID-19, such as ischemic or hemorrhagic stroke, encephalitis and myelitis, which are far more severe in the elderly compared to younger patients. The specific vulnerability of the aged brain could derive from the impaired immune defenses, from any of the altered homeostatic mechanisms that contribute to the aging phenotype, and from particular changes in the aged brain involving neurons and glia. While neuronal modifications could contribute indirectly to the damage induced by SARS-CoV-2, glia alterations could play a more direct role, as they are involved in the immune response to viral infections. In aged patients, changes regarding glia include the accumulation of dystrophic forms, reduction of waste removal, activation of microglia and astrocytes, and immunosenescence. It is plausible to hypothesize that SARS-CoV-2 infection in the elderly may determine severe brain damage because of the frail phenotype concerning glial cells.

COVID-19 smart diagnosis in the Emergency Department: all-in in practice

Introduction

Coronavirus Disease 19 (COVID-19) diagnosis has been a major problem in most Emergency Departments (EDs) and other senior care facilities. Various clinical manifestations, and the several radiologic and laboratory data combined with the misleading test results to identify the virus, are responsible for certain misdiagnoses, especially in suspected cases needing urgent management and treatment. Although emergency and other front-line physicians struggle to manage COVID-19 patients, still existent cases with ambiguous diagnosis trammel the ED safety and responsibility.

Areas Covered

This review article summarizes on a large scale the common information for the medical history, clinical examinations, radiology and laboratory data for SARS-CoV-2. We summarize the available literature using the PubMed, Science Direct and EMBASE databases published until December 2021 on the general information for COVID-19 diagnosis, and, finally, we propose algorithms for a precise and on-the-spot diagnosis the disease.

Expert Opinion

COVID-19 diagnosis has appeared to be such ambiguous, and physicians need to correlate medical history, medical examination, potential extrapulmonary manifestations, along with laboratory and radiologic data, for a prompt COVID-19 diagnosis.

AT1 Receptors: Their Actions from Hypertension to Cognitive Impairment

Hypertension is one of the most prevalent cardiovascular disorders worldwide, affecting 1.13 billion people, or 14% of the global population. Hypertension is the single biggest risk factor for cerebrovascular dysfunction. According to the American Heart Association, high blood pressure (BP), especially in middle-aged individuals (~ 40 to 60 years old), is associated with an increased risk of dementia, later in life. Alzheimer’s disease and cerebrovascular disease are the two leading causes of dementia, accounting for around 80% of the total cases and usually combining mixed pathologies from both. Little is known regarding how hypertension affects cognitive function, so the impact of its treatment on cognitive impairment has been difficult to assess. The brain renin-angiotensin system (RAS) is essential for BP regulation and overactivity of this system has been established to precede the development and maintenance of hypertension. Angiotensin II (Ang-II), the main peptide within this system, induces vasoconstriction and impairs neuro-vascular coupling by acting on brain Ang-II type 1 receptors (AT₁R). In this review, we systemically analyzed the association between RAS and biological mechanisms of cognitive impairment, from the perspective of AT₁R located in the central nervous system. Additionally, the possible contribution of brain AT₁R to global cognition decline in COVID-19 cases will be discussed as well.

Microglia Do Not Restrict SARS-CoV-2 Replication following Infection of the Central Nervous System of K18-Human ACE2 Transgenic Mice

Unlike SARS-CoV-1 and MERS-CoV, infection with SARS-CoV-2, the viral pathogen responsible for COVID-19, is often associated with neurologic symptoms that range from mild to severe, yet increasing evidence argues the virus does not exhibit extensive neuroinvasive properties. We demonstrate SARS-CoV-2 can infect and replicate in human iPSC-derived neurons and that infection shows limited antiviral and inflammatory responses but increased activation of EIF2 signaling following infection as determined by RNA sequencing. Intranasal infection of K18 human ACE2 transgenic mice (K18-hACE2) with SARS-CoV-2 resulted in lung pathology associated with viral replication and immune cell infiltration. In addition, ∼50% of infected mice exhibited CNS infection characterized by wide-spread viral replication in neurons accompanied by increased expression of chemokine (Cxcl9, Cxcl10, Ccl2, Ccl5 and Ccl19) and cytokine (Ifn-λ and Tnf-α) transcripts associated with microgliosis and a neuroinflammatory response consisting primarily of monocytes/macrophages. Microglia depletion via administration of colony-stimulating factor 1 receptor inhibitor, PLX5622, in SARS-CoV-2 infected mice did not affect survival or viral replication but did result in dampened expression of proinflammatory cytokine/chemokine transcripts and a reduction in monocyte/macrophage infiltration. These results argue that microglia are dispensable in terms of controlling SARS-CoV-2 replication in in the K18-hACE2 model but do contribute to an inflammatory response through expression of pro-inflammatory genes. Collectively, these findings contribute to previous work demonstrating the ability of SARS-CoV-2 to infect neurons as well as emphasizing the potential use of the K18-hACE2 model to study immunological and neuropathological aspects related to SARS-CoV-2-induced neurologic disease. IMPORTANCE Understanding the immunological mechanisms contributing to both host defense and disease following viral infection of the CNS is of critical importance given the increasing number of viruses that are capable of infecting and replicating within the nervous system. With this in mind, the present study was undertaken to evaluate the role of microglia in aiding in host defense following experimental infection of the central nervous system (CNS) of K18-hACE2 with SARS-CoV-2, the causative agent of COVID-19. Neurologic symptoms that range in severity are common in COVID-19 patients and understanding immune responses that contribute to restricting neurologic disease can provide important insight into better understanding consequences associated with SARS-CoV-2 infection of the CNS.

COVID-19-Associated Encephalopathy—Case Series and Clinical Considerations

Neurological manifestations of the SARS-CoV-2 infection are present in up to 80% of the affected patients. While the majority of them is benign, in certain patients, viral replication in the central nervous system results in a severe disruption in cognitive function as well as basic life functions. In this case series, the authors present a detailed description of the three SARS-CoV-2 infection cases, which were all complicated by severe encephalopathy. Consecutive neurological status changes were described for each patient with detailed imaging and clinical sequelae. In the discussion, the authors highlight similarities in the course of the disease in presented patients, as well as common features in test results. An effective causal treatment could not be introduced in any of the patients, nor could the progression of the central nervous system (CNS) damage be stopped. The authors hope that the experiences they gathered will help to accelerate the diagnostic and therapeutic process in other patients with COVID-19-associated encephalopathy and can result in introducing an effective treatment.

Microglia do not restrict SARS-CoV-2 replication following infection of the central nervous system of K18-hACE2 transgenic mice.. [PMID: 34816260 PMCID: PMC8609895 DOI: 10.1101/2021.11.15.468761]

Unlike SARS-CoV-1 and MERS-CoV, infection with SARS-CoV-2, the viral pathogen responsible for COVID-19, is often associated with neurologic symptoms that range from mild to severe, yet increasing evidence argues the virus does not exhibit extensive neuroinvasive properties. We demonstrate SARS-CoV-2 can infect and replicate in human iPSC-derived neurons and that infection shows limited anti-viral and inflammatory responses but increased activation of EIF2 signaling following infection as determined by RNA sequencing. Intranasal infection of K18 human ACE2 transgenic mice (K18-hACE2) with SARS-CoV-2 resulted in lung pathology associated with viral replication and immune cell infiltration. In addition, ∼50% of infected mice exhibited CNS infection characterized by wide-spread viral replication in neurons accompanied by increased expression of chemokine (Cxcl9, Cxcl10, Ccl2, Ccl5 and Ccl19) and cytokine (Ifn-λ and Tnf-α) transcripts associated with microgliosis and a neuroinflammatory response consisting primarily of monocytes/macrophages. Microglia depletion via administration of colony-stimulating factor 1 receptor inhibitor, PLX5622, in SARS-CoV-2 infected mice did not affect survival or viral replication but did result in dampened expression of proinflammatory cytokine/chemokine transcripts and a reduction in monocyte/macrophage infiltration. These results argue that microglia are dispensable in terms of controlling SARS-CoV-2 replication in in the K18-hACE2 model but do contribute to an inflammatory response through expression of pro-inflammatory genes. Collectively, these findings contribute to previous work demonstrating the ability of SARS-CoV-2 to infect neurons as well as emphasizing the potential use of the K18-hACE2 model to study immunological and neuropathological aspects related to SARS-CoV-2-induced neurologic disease.

Importance

Understanding the immunological mechanisms contributing to both host defense and disease following viral infection of the CNS is of critical importance given the increasing number of viruses that are capable of infecting and replicating within the nervous system. With this in mind, the present study was undertaken to evaluate the role of microglia in aiding in host defense following experimental infection of the central nervous system (CNS) of K18-hACE2 with SARS-CoV-2, the causative agent of COVID-19. Neurologic symptoms that range in severity are common in COVID-19 patients and understanding immune responses that contribute to restricting neurologic disease can provide important insight into better understanding consequences associated with SARS-CoV-2 infection of the CNS.

Neurological Manifestations and Outcomes in a Retrospective Cohort of Mexican Inpatients with SARS-CoV-2 Pneumonia: Design of a Risk Profile

We analyzed the neurological manifestations in Mexican patients hospitalized with pneumonia due to COVID-19 and investigated the association between demographic, clinical, and biochemical variables and outcomes, including death. A retrospective, analytical study was conducted using the electronic records of patients hospitalized between 1 April 2020 and 30 September 2020. Records of 1040 patients were analyzed: 31.25% died and 79.42% had neurological symptoms, including headache (80.62%), anosmia (32.20%), ageusia (31.96%), myopathy (28.08%), disorientation (14.89%), encephalopathy (12.22%), neuropathy (5.4%), stroke (1.3%), seizures (1.3%), cerebral hemorrhage (1.08%), encephalitis (0.84%), central venous thrombosis (0.36%), and subarachnoid hemorrhage (0.24%). Patients also had comorbidities, such as hypertension (42.30%), diabetes mellitus (38.74%), obesity (61.34%), chronic obstructive pulmonary disease (3.17%), and asthma (2.01%). Factors associated with neurological symptoms were dyspnea, chronic obstructive pulmonary disease, advanced respiratory support, prolonged hospitalization, and worsening fibrinogen levels. Factors associated with death were older age, advanced respiratory support, amine management, chronic obstructive pulmonary disease, intensive care unit management, dyspnea, disorientation, encephalopathy, hypertension, neuropathy, diabetes, male sex, three or more neurological symptoms, and obesity grade 3. In this study we designed a profile to help predict patients at higher risk of developing neurological complications and death following COVID-19 infection.

Occurrence of Guillain-Barre Syndrome During the Initial Symptomatic Phase of COVID-19 Disease: Coincidence or Consequence?

Viral infections are frequently present before the clinical manifestation of Guillain-Barre syndrome (GBS). Multiple studies on coronaviruses have shown that these viruses have neurotropic characteristics, and their molecular mimicry can induce inflammatory demyelinating neuropathy. Herein, we describe a case of a GBS in an 85-year-old patient infected with SARS-CoV-2, manifested with acute progressive symmetric ascending quadriparesis, urinary dysautonomia, and dysphagia, who responded well to treatment with intravenous human immunoglobulin.

Case report of restless anal syndrome as restless legs syndrome variant after COVID-19

Background

Coronavirus disease 2019 (COVID-19) has a broad spectrum from respiratory and nasopharyngeal symptoms, cerebrovascular diseases, impaired consciousness, and skeletal muscle injury. Emerging evidence has indicated the neural spread of this novel coronavirus. Restless legs syndrome (RLS) is a common neurological, sensorimotor disorder, but highly under diagnosis disorder. Restless anal syndrome as restless legs syndrome variant associated with COVID-19 has been previously not published. We report a case presenting with restless anal syndrome following COVID-19.

Case presentation

Although a 77-year-old male with COVID-19 improved to normal respiratory function 21 days after admission and treatment of favipiravir 200 mg per day for 14 days and dexamethasone 6.6 mg per day for 5 days, the insomnia and anxiety symptoms remained. Several weeks after discharge, he gradually began to experience restless, deep anal discomfort, approximately 10 cm from the perineal region. The following features were observed in the anal region; urge to move is essential, with worsening with rest, improvement with exercise, and worsening at evening. Colonoscopy revealed internal haemorrhoids without other rectal lesions. Neurological findings including deep tendon reflex, perineum loss of sensory and spinal cord injury, revealed no abnormalities. Diabetes militias, kidney dysfunction and iron deficiency status were not confirmed. Family history of RLS and periodic limb movements were not observed. Clonazepam at 1.5 mg per day resulted in the alleviation restless anal discomfort.

Conclusions

We reported a case presenting with restless anal syndrome following affection of COVID-19 as restless legs syndrome variant. This case fulfilled 4 essential features of RLS, urge to move, worsening with rest, improvement with exercise, and worsening at evening. To date, no case of restless anal syndrome associated with COVID-19 has been previously published. This case report may reflect the associative impacts of COVID-19 on the neuropsychiatric state. The long-term outcomes of neuropsychiatric conditions should continue to be monitored.

Immunopathology of SARS-COV-2 and Neurological Manifestations Caused by the Virus: A Review of the Literature

SARS-CoV-2 (Severe Acute Respiratory Syndrome), or the disease caused by the new coronavirus, the source of COVID-19, has rapidly turned into a pandemic, a danger with an impact on human health.

Various neurological manifestations associated with SARS-CoV-2 infection have been reported in the literature and are currently classified into central nervous system-related (headache, dizziness, cerebrovascular disease, epilepsy) and peripheral nervous system-related (anosmia, ageusia, muscle pain, Guillain-Barré syndrome). However, it remains difficult to establish a link between these neurological manifestations and the underlying mechanisms.

In the current context, physicians need to be aware of the broad spectrum of neurological symptoms associated with infection with this virus for early diagnosis and appropriate treatment.

In this review, we aim to highlight the pathways of SARS-CoV-2 virus invasion, the neurotropism of the virus and the immunopathological mechanisms underlying the neurological manifestations associated with COVID-19 disease.

SARS-CoV-2, Trait Anxiety, and the Microbiome

During the COVID-19 pandemic, research on the relationships between the virus and its human host has become fundamental to understand this pathology and its effects. Attaining this profound understanding is critical for the effective containment and treatment of infections caused by the virus. In this review, we present some possible mechanisms by which psychopathological symptoms emerge following viral infections of the central nervous system (CNS). These proposed mechanisms are based on microbial communication and the induced priming of microglial antibody activation within the CNS through Toll-like receptor signaling. In this process, chronic microglial activation causes increased glutamate release in virally-altered, high-density neuronal structures, thereby modulating cognitive networks and information integration processes. This modulation, in turn, we suggest, affects the accuracy of sensory integration and connectivity of major control networks, such as the default mode network. The chronic activation of immunological responses and neurochemical shifts toward an elevated glutamate/gamma-aminobutyric acid ratio lead to negative reinforcement learning and suboptimal organismic functioning, for example, maintaining the body in an anxious state, which can later become internalized as trait anxiety. Therefore, we hypothesize that the homeostatic relationship between host, microbiome, and virome, would be decisive in determining the efficiency of subsequent immunological responses, disease susceptibility, and long-term psychopathological effects of diseases that impact the CNS, such as the COVID-19.