Encephalitis as a neurological complication of COVID-19: A systematic review and meta-analysis of incidence, outcomes, and predictors

Neurological complications caused by SARS-CoV-2

SUMMARYSARS-CoV-2 can not only cause respiratory symptoms but also lead to neurological complications. Research has shown that more than 30% of SARS-CoV-2 patients present neurologic symptoms during COVID-19 (A. Pezzini and A. Padovani, Nat Rev Neurol 16:636-644, 2020, https://doi.org/10.1038/s41582-020-0398-3). Increasing evidence suggests that SARS-CoV-2 can invade both the central nervous system (CNS) (M.S. Xydakis, M.W. Albers, E.H. Holbrook, et al. Lancet Neurol 20: 753-761, 2021 https://doi.org/10.1016/S1474-4422(21)00182-4 ) and the peripheral nervous system (PNS) (M.N. Soares, M. Eggelbusch, E. Naddaf, et al. J Cachexia Sarcopenia Muscle 13:11-22, 2022, https://doi.org/10.1002/jcsm.12896), resulting in a variety of neurological disorders. This review summarized the CNS complications caused by SARS-CoV-2 infection, including encephalopathy, neurodegenerative diseases, and delirium. Additionally, some PNS disorders such as skeletal muscle damage and inflammation, anosmia, smell or taste impairment, myasthenia gravis, Guillain-Barré syndrome, ICU-acquired weakness, and post-acute sequelae of COVID-19 were described. Furthermore, the mechanisms underlying SARS-CoV-2-induced neurological disorders were also discussed, including entering the brain through retrograde neuronal or hematogenous routes, disrupting the normal function of the CNS through cytokine storms, inducing cerebral ischemia or hypoxia, thus leading to neurological complications. Moreover, an overview of long-COVID-19 symptoms is provided, along with some recommendations for care and therapeutic approaches of COVID-19 patients experiencing neurological complications.

SARS-CoV-2 brainstem encephalitis in human inherited DBR1 deficiency

Inherited deficiency of the RNA lariat-debranching enzyme 1 (DBR1) is a rare etiology of brainstem viral encephalitis. The cellular basis of disease and the range of viral predisposition are unclear. We report inherited DBR1 deficiency in a 14-year-old boy who suffered from isolated SARS-CoV-2 brainstem encephalitis. The patient is homozygous for a previously reported hypomorphic and pathogenic DBR1 variant (I120T). Consistently, DBR1 I120T/I120T fibroblasts from affected individuals from this and another unrelated kindred have similarly low levels of DBR1 protein and high levels of RNA lariats. DBR1 I120T/I120T human pluripotent stem cell (hPSC)-derived hindbrain neurons are highly susceptible to SARS-CoV-2 infection. Exogenous WT DBR1 expression in DBR1 I120T/I120T fibroblasts and hindbrain neurons rescued the RNA lariat accumulation phenotype. Moreover, expression of exogenous RNA lariats, mimicking DBR1 deficiency, increased the susceptibility of WT hindbrain neurons to SARS-CoV-2 infection. Inborn errors of DBR1 impair hindbrain neuron-intrinsic antiviral immunity, predisposing to viral infections of the brainstem, including that by SARS-CoV-2.

The possible causal relationship between COVID-19 and imaging markers of cerebral small vessel disease: a Mendelian randomization study

OBJECTIVES

Observational studies have suggested that SARS-CoV-2 infection may increase the burden of cerebral small vessel disease (CSVD). This study aims to explore the causal correlation between COVID-19 and the imaging markers of CSVD using Mendelian randomization (MR) methods.

METHODS

Summary-level genome-wide association study (GWAS) statistics for COVID-19 susceptibility, hospitalization, and severity were utilized as proxies for exposure. Large-scale meta-analysis GWAS data on three neuroimaging markers of white matter hyperintensity, lacunar stroke, and brain microbleeds, were employed as outcomes. Our primary MR analysis employed the inverse variance weighted (IVW) approach, supplemented by MR-Egger, weighted median, and MR-PRESSO methods. We also conducted multivariable MR analysis to address confounding bias and validate the robustness of the established causal estimates. Comprehensive sensitivity analyses included Cochran's Q test, Egger-intercept analysis, MR-PRESSO, and leave-one-out analysis.

RESULTS

The MR analysis revealed a significant causal correlation between the severity of COVID-19 and an increased risk of lacunar stroke, as demonstrated by the IVW method (ORivw = 1.08, 95% CI: 1.03-1.16, pivw = 0.005, FDR = 0.047). Nevertheless, no causal correlations were observed between COVID-19 susceptibility or hospitalization and any CSVD imaging markers. The robustness and stability of these findings were further confirmed by multivariable MR analysis and comprehensive sensitivity analyses.

DISCUSSION

This study provides compelling evidence of a potential causal effect of severe COVID-19 on the incidence of lacunar stroke, which may bring fresh insights into the understanding of the comorbidity between COVID-19 and CSVD.

COVID-19 Neuroimaging Update: Pathophysiology, Acute Findings, and Post-Acute Developments

COVID-19 has prominent effects on the nervous system with important manifestations on neuroimaging. In this review, we discuss the neuroimaging appearance of acute COVID-19 that became evident during the early stages of the pandemic. We highlight the underlying pathophysiology mediating nervous system effects and neuroimaging appearances including systemic inflammatory response such as cytokine storm, coagulopathy, and para/post-infections immune mediated phenomena. We also discuss the nervous system manifestations of COVID-19 and the role of imaging as the pandemic has evolved over time, including related to the development of vaccines and the emergence of post-acute sequalae such as long COVID.

Clinical features of COVID-19-related encephalitis: comparison with the features of herpes virus encephalitis and autoimmune encephalitis

INTRODUCTION

Identifying coronavirus disease 2019 (COVID-19)-related encephalitis without clear etiological evidence is clinically challenging. The distinctions between this condition and other prevalent encephalitis types remain unknown. Therefore, we aimed to explore the similarities and differences in the clinical characteristics of COVID-19-related encephalitis and other encephalitis types.

METHODS

Adult patients with encephalitis admitted to the neurology department at Xuanwu Hospital were enrolled and categorized into the following six groups based on the results of metagenomic next-generation sequencing and autoimmune antibody detection in cerebrospinal fluid (CSF): COVID-19-related encephalitis (n = 36), herpes simplex virus type 1 encephalitis (HSV-1 encephalitis; n = 28), human herpesvirus 3 encephalitis (HHV-3 encephalitis; n = 10), NMDAR-antibody encephalitis (n = 18), LGI1-antibody encephalitis (n = 12), and GABAB-antibody encephalitis (n = 8).

RESULTS

The predominant characteristics of COVID-19-related encephalitis include a low incidence of seizures (38.9%), cognitive defects (30.6%), and meningeal irritation signs (8.3%). Compared with HSV-1 and HHV-3 encephalitis, COVID-19-related encephalitis exhibited lower white blood cell count (2.5 count/mm3), protein (32.2 mg/dL), and immunoglobulin M, G, and A levels (0.09, 3.2, and 0.46 mg/dL, respectively) in the CSF tests. Abnormal imaging findings were present in only 36.1% of COVID-19-related encephalitis cases, mostly showing diffuse inflammation scattered in various parts, which differed from HSV-1 encephalitis. Additionally, COVID-19-related encephalitis exhibited significant differences in clinical symptoms and CSF white blood cell counts compared with NMDAR-antibody encephalitis; however, it showed limited differences compared with LGI1-antibody and GABAB-antibody encephalitis.

DISCUSSION

COVID-19-related encephalitis and herpes virus or autoimmune encephalitis differ clinically. Symptoms and auxiliary examinations can be used as distinguishing tools.

Neurological Complications of COVID-19: Unraveling the Pathophysiological Underpinnings and Therapeutic Implications

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease (COVID-19), induced a global pandemic with a diverse array of clinical manifestations. While the acute phase of the pandemic may be waning, the intricacies of COVID-19's impact on neurological health remain a crucial area of investigation. Early recognition of the spectrum of COVID-19 symptoms, ranging from mild fever and cough to life-threatening respiratory distress and multi-organ failure, underscored the significance of neurological complications, including anosmia, seizures, stroke, disorientation, encephalopathy, and paralysis. Notably, patients requiring intensive care unit (ICU) admission due to neurological challenges or due to them exhibiting neurological abnormalities in the ICU have shown increased mortality rates. COVID-19 can lead to a range of neurological complications such as anosmia, stroke, paralysis, cranial nerve deficits, encephalopathy, delirium, meningitis, seizures, etc., in affected patients. This review elucidates the burgeoning landscape of neurological sequelae associated with SARS-CoV-2 infection and explores the underlying neurobiological mechanisms driving these diverse manifestations. A meticulous examination of potential neuroinvasion routes by SARS-CoV-2 underscores the intricate interplay between the virus and the nervous system. Moreover, we dissect the diverse neurological manifestations emphasizing the necessity of a multifaceted approach to understanding the disease's neurological footprint. In addition to elucidating the pathophysiological underpinnings, this review surveys current therapeutic modalities and delineates prospective avenues for neuro-COVID research. By integrating epidemiological, clinical, and diagnostic parameters, we endeavor to foster a comprehensive analysis of the nexus between COVID-19 and neurological health, thereby laying the groundwork for targeted therapeutic interventions and long-term management strategies.

COVID-19 Presenting as Encephalitis and Myopericarditis: A Report of a Rare Case

COVID-19 might present with a wide range of clinical manifestations, from mild respiratory distress to severe multi-organ dysfunction. We present a unique case of complex COVID-19 presentation in a 45-year-old female who initially developed general symptoms such as fever, cough, headache, and weakness, which escalated to coma, requiring intubation and ICU admission. A brain MRI revealed lesions compatible with encephalitis, the cause of which remained unexplained after an in-depth clinical, laboratory, and imaging investigation. While in the ICU, the patient also developed cardiac tamponade, requiring pericardiocentesis, and atypical electrocardiographic changes. After treatment with steroids, her condition improved, and the patient was extubated and transferred to the ward. Upon checkup, cardiac MRI revealed fibrous tissue in the inferior cardiac wall and the adjacent intraventricular septum. In the absence of an alternative diagnosis, it might be important to consider the central nervous system and cardiac involvement in patients with COVID-19.

COVID-19: Unveiling the Neuropsychiatric Maze-From Acute to Long-Term Manifestations

The SARS-CoV-2 virus has spread rapidly despite implementing strategies to reduce its transmission. The disease caused by this virus has been associated with a diverse range of symptoms, including common neurological manifestations such as dysgeusia, anosmia, and myalgias. Additionally, numerous cases of severe neurological complications associated with this disease have been reported, including encephalitis, stroke, seizures, and Guillain-Barré syndrome, among others. Given the high prevalence of neurological manifestations in this disease, the objective of this review is to analyze the mechanisms by which this virus can affect the nervous system, from its direct invasion to aberrant activation of the immune system and other mechanisms involved in the symptoms, including neuropsychiatric manifestations, to gain a better understanding of the disease and thus facilitate the search for effective therapeutic strategies.

Management, risk factors and treatment outcomes of rhegmatogenous retinal detachment associated with giant retinal tears: scoping review

BACKGROUND

Rhegmatogenous retinal detachment (RRD) is a serious condition that occurs when the retina detaches from its underlying retinal pigment epithelium. RRDs associated with giant retinal tears (GRTs) are caused by retinal tears at least 90° or one-quarter of the circumferential extent. This scoping review systematically identifies and summarizes clinical studies evaluating surgical techniques for the management of GRT-related RRDs, discusses functional and visual outcomes and the risk factors affecting treatment outcomes.

METHODS

This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Scopus, Google Scholar, and Springer Link databases were searched for relevant papers (from January 2001 to March 2023). Studies that were published in the English language and reported the risk factors, management, and treatment outcomes of GRT-related RRDs were included in the review. The outcome measures included anatomic success rates, changes in BCVA (logMAR) from baseline to the final follow-up, and adverse events.

RESULTS

A total of 11,982 articles were identified. After the title and abstract review, 71 studies were deemed eligible for full-text review. Thirty-six studies that met the eligibility criteria were included in the final review. Four surgical techniques were identified: pars plana vitrectomy (PPV), combined PPV and scleral buckling, scleral buckling alone, and pneumatic retinopexy. Various types of tamponades, including gas, silicone oil, and air, have been used. PPV was the most commonly used surgical technique in 33.1-100% of patients. Among the 20 studies that used PPV alone, 17 were associated with preoperative PVR. In addition, scleral buckling alone or in combination with PPV was reported as a treatment option in 10 studies, with 2-100% of patients experiencing scleral buckling alone and 13.6-100% experiencing combined PPV and complementary scleral buckling. Primary anatomic success (PAS) was achieved with retinal reattachment via a single operation with no residual tamponade, whereas final anatomic success (FAS) was achieved via more than one operation with no residual tamponade. Reported single surgery anatomic success (SSAS) rates range from 65.51 to 100%. The preoperative best-corrected visual acuity (BCVA) ranged from 0.067 to 2.47 logMAR, whereas the postoperative BCVA ranged from 0.08 to 2.3 logMAR. An improvement in visual acuity was observed in 29 studies. Cataracts (3.9-28.3%) were the most common postoperative complication, followed by high IOP (0.01-51.2%) and PVR (0.8-31.57%).

CONCLUSION

PPV is the most common surgical technique, and currently microincision vitrectomy surgery (MIVS) systems are commonly employed. Silicone oil is the most frequently used tamponade in RRD repair. Risk factors for GRT-related RRD include age, sex, lens status, high myopia status, proliferative vitreoretinopathy (PVR), presenting visual acuity, the extent of the GRT and retinal detachment, and macular involvement. Future research areas include guidelines to reduce variability in the reporting of surgical methodology, choice of tamponades, and reporting of functional and visual outcomes to inform the best therapeutic interventions in GRT-related RRD.

COVID-19 and Clostridioides difficile Coinfection Analysis in the Intensive Care Unit

Since the emergence of SARS-CoV-2 in late 2019, the global mortality attributable to COVID-19 has reached 6,972,152 deaths according to the World Health Organization (WHO). The association between coinfection with Clostridioides difficile (CDI) and SARS-CoV-2 has limited data in the literature. This retrospective study, conducted at Mureș County Clinical Hospital in Romania, involved 3002 ICU patients. Following stringent inclusion and exclusion criteria, 63 patients were enrolled, with a division into two subgroups-SARS-CoV-2 + CDI patients and CDI patients. Throughout their hospitalization, the patients were closely monitored. Analysis revealed no significant correlation between comorbidities and invasive mechanical ventilation (IMV) or non-invasive mechanical ventilation (NIMV). However, statistically significant associations were noted between renal and hepatic comorbidties (p = 0.009), death and CDI-SARS-CoV-2 coinfection (p = 0.09), flourochinolone treatment and CDI-SARS-CoV-2 infection (p = 0.03), and an association between diabetes mellitus and SARS-CoV-2-CDI infection (p = 0.04), as well as the need for invasive mechanical ventilation (p = 0.04). The patients with CDI treatment were significantly younger and received immuno-modulator or corticotherapy treatment, which was a risk factor for opportunistic agents. Antibiotic and PPI (proton pump inhibitor) treatment were significant risk factors for CDI coinfection, as well as for death, with PPI treatment in combination with antibiotic treatment being a more significant risk factor.

Clinical characteristics and outcomes of COVID-19-associated encephalopathy in children

Apart from the typical respiratory symptoms, coronavirus disease 2019 (COVID-19) also affects the central nervous system, leading to central disorders such as encephalopathy and encephalitis. However, knowledge of pediatric COVID-19-associated encephalopathy is limited, particularly regarding specific subtypes of encephalopathy. This study aimed to assess the features of COVID-19-associated encephalopathy/encephalitis in children. We retrospectively analyzed a single cohort of 13 hospitalized children with COVID-19-associated encephalopathy. The primary outcome was the descriptive analysis of the clinical characteristics, magnetic resonance imaging and electroencephalography findings, treatment progression, and outcomes. Thirteen children among a total of 275 (5%) children with confirmed COVID-19 developed associated encephalopathy/encephalitis (median age, 35 months; range, 3-138 months). Autoimmune encephalitis was present in six patients, acute necrotizing encephalopathy in three, epilepsy in three, and central nervous system small-vessel vasculitis in one patient. Eight (62%) children presented with seizures. Six (46%) children exhibited elevated blood inflammatory indicators, cerebrospinal fluid inflammatory indicators, or both. Two (15%) critically ill children presented with multi-organ damage. The magnetic resonance imaging findings varied according to the type of encephalopathy/encephalitis. Electroencephalography revealed a slow background rhythm in all 13 children, often accompanied by epileptic discharges. Three (23%) children with acute necrotizing encephalopathy had poor prognoses despite immunotherapy and other treatments. Ten (77%) children demonstrated good functional recovery without relapse. This study highlights COVID-19 as a new trigger of encephalopathy/encephalitis in children. Autoimmune encephalitis is common, while acute necrotizing encephalopathy can induce poor outcomes. These findings provide valuable insights into the impact of COVID-19 on children's brains.

Early-onset herpes simplex encephalitis type 1 triggered by COVID-19 disease: A case report

Coronavirus disease 2019 (COVID-19) causes a systemic inflammatory response and a temporary immunosuppression of hosts. Several reports have showed that reactivation of herpes simplex virus type 1 (HSV-1) is strongly associated with COVID-19. We present a case of a 66-year-old female, who developed HSV-1 encephalitis, showing impaired consciousness and typical MRI findings such as hyperintense lesions in the temporal lobe, insular cortices, bilateral medial frontal lobe on diffusion-weighted imaging, 7 days after the onset of COVID-19 symptoms. The number of cases of encephalitis in patients with COVID-19 is increasing. However, there has been limited reports of HSV-1 encephalitis following COVID-19, especially for cases with an interval of 7 days or less from the onset of COVID-19 symptoms to the onset of HSV-1 encephalitis. Our case highlights the importance of considering HSV-1 encephalitis in the differential when managing a patient with COVID-19-associated neurologic complications, even if it is in the early stages of COVID-19.

Clinical features and virologic lineages of COVID-19-associated encephalitis in Taiwanese children during early epidemic wave of omicron in 2022: Report from a medical center

BACKGROUND

A surge of encephalitis was reported in children during the early wave of the omicron epidemic in Taiwan. Information on the COVID-19-associated encephalitis, including epidemiologic features and factors of unfavorable outcomes, remained unclear.

METHODS

A total of 128 hospitalized Taiwanese children with laboratory-confirmed COVID-19 were enrolled between April 01, 2022, and May 31, 2022. The information on demographics and clinical features was abstracted from the medical records. Virologic lineages were determined by sequences of the spike protein. Factors associated with encephalitis and unfavorable outcomes were identified by comparisons to children without encephalitis and with favorable outcomes, respectively.

RESULTS

The leading syndromes associated with COVID-19 in hospitalized children were febrile seizure (20, 15.7%), fever as the solitary symptom (18, 14.1%), and croup syndrome (14, 10.9%). Encephalitis was diagnosed in nine (7.03%) children. When compared to the three leading syndromes, children with encephalitis were at older ages, had greater rates of hypotension, PICU admissions, use of inotropic agents (P < .001 for all above comparisons), mortality (P = .008), and longer hospital stays (P = .016), but not the underlying comorbidities (P = .376). Unfavorable outcomes were identified in 3 (33.3%) of 9 encephalitis cases and associated with a lower Glasgow coma scale, hypotension, and higher C-reactive protein (P < .05 for all). BA.2.3.7 was the dominant sublineage in children with or without encephalitis.

CONCLUSIONS

Omicron BA.2.3.7 can cause fulminant and lethal encephalitis in healthy children. Depressed consciousness and hypotension at presentation were significant risks of unfavorable outcomes for pediatric COVID-19-associated encephalitis.

New Onset Seizures in Hospitalized COVID-19 Patients; A Systematic Review and Meta-Analysis

Objective

Seizures in COVID-19 patients continue to be a common reason for consulting the neurology service in the inpatient setting. This paper assesses the frequency of new onset seizures in adult hospitalized COVID-19 patients.

Method

PubMed and EMBASE were searched, with fifteen cohort studies identified to calculate the primary outcome, which was the frequency of new onset seizures in hospitalized COVID-19 patients. An inverse variance meta-analysis of single proportions with a random effects model was applied to these cohort studies to calculate the primary outcome. Risk of bias in individual studies was assessed using the 10-item risk of bias tool for prevalence studies.

Results

The meta-analysis revealed a frequency of .71% (95% confidential interval: .32-1.25, I2 = 89%, 147/28242 patients) for acute symptomatic seizures in patients with COVID-19. For secondary outcomes, the risk of seizures in patients who had EEG completed was 8.49% (95% confidential interval: .62-24.07, I2 = 14%, 44/535 patients). Slightly less than half of patients with COVID-19 and seizures were reported to have acute imaging abnormalities (45.7%) with acute vascular insults being commonly reported. Only a small percentage of COVID-19 patients with seizures (2.8%) met the criteria for COVID-19 encephalitis as determined by the international encephalitis consortium.

Conclusion

The frequency of seizures in COVID-19 was .71% (95% confidential interval: .32-1.25). Slightly less than half of COVID-19 patients had head imaging abnormalities as a complication of COVID-19 infection. Only a small percentage of patients with seizures and COVID-19 met the criteria for COVID-19 encephalitis.

Neurological complications during the Omicron COVID-19 wave in China: A cohort study

BACKGROUND AND PURPOSE

The aim was to investigate the neurological complications associated with coronavirus disease 19 (COVID-19) during the 2022 Omicron wave.

METHODS AND ANALYSIS

The medical records of a cohort of people admitted to neurological wards of three participating tertiary centres in Sichuan from 12 December 2022 to 12 January 2023 were reviewed. Demographics and clinical data were obtained and analysed with an interest in COVID-19-related new-onset or worse neurological symptoms. The current data were also compared in two centres with similar data from the same period 12 months earlier.

RESULTS

In all, 790 people were enrolled, of whom 436 were positive for COVID-19. Ninety-nine had new onset COVID-related neurological problems, or their known neurological condition deteriorated during the wave. There was a significant difference in demographics from the findings amongst admissions 12 months earlier as there was an increase in the average age, the incidence of encephalitis and encephalopathy, and mortality rates. One hundred and one received COVID-specific antivirals, intravenous glucocorticoids and intravenous immunoglobulin therapy. No differences were seen between these and those who did not use them.

CONCLUSION

New-onset neurological conditions, particularly encephalitis and encephalopathy, increased significantly during this period. Deterioration of existing neurological conditions, such as seizure exacerbation, was also observed. A large-scale treatment trial of people with COVID-19 infection presenting with neurological disorders is still needed.

An Adolescent Presenting With Mania and Catatonia Associated With Coronavirus Disease-2019 Encephalitis

There is growing evidence that coronavirus disease-2019 (COVID-19) infection may have various neuropsychiatric manifestations and long-term outcomes. In this article, the authors report a rare case of a 16-year-old male with no previous history of psychiatric illness who presented with an acute manic episode, including laughing for no evident reason, talking to himself, isolation, irritability, sleeplessness, decreased appetite, prolonged staring episodes, having delusions about being harmed or controlled, and aggression. Despite initiating outpatient treatment with a mood stabilizer and antipsychotic for presumed bipolar disorder with psychotic features, his symptoms worsened, and he became catatonic with a decreased level of consciousness, leading to his hospitalization on day 10. Although he had not shown typical evidence of infection with COVID-19 in the days leading up to or during his hospitalization and his initial COVID-19 test was negative, his COVID-19 test was positive on day 14, and his chest X-ray showed infiltrations. His acute manic symptoms and catatonia were identified to be associated with COVID-19 encephalitis after excluding other causes. He responded well to treatment with lorazepam for catatonia and a course of intravenous immunoglobulin, methylprednisolone, and remdesivir for COVID-19 encephalitis. This case demonstrates the workup and treatment of a rare neuropsychiatric manifestation of COVID-19 encephalitis in an adolescent, which started with no past psychiatric history and no typical symptoms of COVID-19 infection.

[Autoimmune encephalitis: psychiatric aspects]

Autoimmune encephalitis is a group of diseases researched by both neurologists and psychiatrists. Despite a large number of studies and practical recommendations, the differential diagnosis and early diagnostics still remains an important issue. The most difficult to diagnose are cases that debut as mental disorders and/or occur without neurological symptoms. The literature review presents the current state of the problem with an emphasis on the practice of a psychiatrist.

Associations between COVID-19 and putative markers of neuroinflammation: A diffusion basis spectrum imaging study

COVID-19 remains a significant international public health concern. Yet, the mechanisms through which symptomatology emerges remain poorly understood. While SARS-CoV-2 infection may induce prolonged inflammation within the central nervous system, the evidence primarily stems from limited small-scale case investigations. To address this gap, our study capitalized on longitudinal UK Biobank neuroimaging data acquired prior to and following COVID-19 testing (N=416 including n=224 COVID-19 cases; Mage=58.6). Putative neuroinflammation was assessed in gray matter structures and white matter tracts using non-invasive Diffusion Basis Spectrum Imaging (DBSI), which estimates inflammation-related cellularity (DBSI-restricted fraction; DBSI-RF) and vasogenic edema (DBSI-hindered fraction; DBSI-HF).We hypothesized that COVID-19 case status would be associated with increases in DBSI markers after accounting for potential confound (age, sex, race, body mass index, smoking frequency, and data acquisition interval) and multiple testing. COVID-19 case status was not significantly associated with DBSI-RF (|β|'s<0.28, pFDR >0.05), but with greater DBSI-HF in left pre- and post-central gyri and right middle frontal gyrus (β's>0.3, all pFDR=0.03). Intriguingly, the brain areas exhibiting increased putative vasogenic edema had previously been linked to COVID-19-related functional and structural alterations, whereas brain regions displaying subtle differences in cellularity between COVID-19 cases and controls included regions within or functionally connected to the olfactory network, which has been implicated in COVID-19 psychopathology. Nevertheless, our study might not have captured acute and transitory neuroinflammatory effects linked to SARS-CoV-2 infection, possibly due to symptom resolution before the imaging scan. Future research is warranted to explore the potential time- and symptom-dependent neuroinflammatory relationship with COVID-19.

The clinical epidemiology, management, and outcomes of patients diagnosed with encephalitis in North Carolina, 2015-2020

IMPORTANCE

Despite the relatively high mortality and the difficulty in diagnosis, nearly one-third of patients hospitalized with a documented diagnosis of encephalitis did not undergo a lumbar puncture (LP). When an LP was performed, pathogen-specific testing was greatly underutilized. Infectious etiologies were most common, but over 40% of cases were idiopathic at discharge. These findings suggest that there is a substantial opportunity to improve the quality of care through more accurate and timely diagnosis.

Risk factors of Omicron variant associated acute encephalitis/encephalopathy in children

BACKGROUND

Outbreak of Omicron BA.2 in Taiwan led to an increased number of acute encephalitis/encephalopathy cases in children and several fatal cases drew public attention. In pre-Omicron period, pediatric cases of COVID-19-associated acute encephalitis have been reported and during Omicron epidemic, febrile convulsions, encephalitis were mentioned more frequently. The outcome of patients with neurological complications was worse. However, few studies investigated the risk factors, pathophysiology and prognosis of COVID-19-associated encephalitis/encephalopathy. Here, we describe the presentation of pediatric cases of COVID-19-associated acute encephalitis/encephalopathy and explore the associated risk factors.

METHODS

Pediatric patients with confirmed SARS-CoV-2 infections were prospectively enrolled at admission at Chang Gung Memorial Hospital between April and August 2022. Patients were categorized into groups of acute encephalitis/encephalopathy, febrile convulsions or mild disease. Demographic descriptions, clinical manifestations and laboratory data were collected.

RESULTS

Of 288 acute COVID-19 patients, there were 38 (13.2%) acute encephalitis/encephalopathy, 40 (13.9%) febrile convulsions, and 210 (72.9%) mild disease. Among acute encephalitis/encephalopathy group, the mean age was 68.3 ± 45.0 months. The common neurological symptoms were lethargy (65.8%), seizures (52.6%), and impaired consciousness (34.2%). Over 3 years old (adjusted odds ratio [aOR]: 7.57, p < 0.001), absolute neutrophil count ≥3150/μL (aOR: 5.46, p = 0.008), and procalcitonin ≥0.5 ng/mL (aOR: 4.32, p = 0.021) were independent factors for acute encephalitis/encephalopathy.

CONCLUSIONS

Most cases of COVID-19-associated acute encephalitis/encephalopathy showed no evidence of direct viral invasion but associations with older age, increased peripheral neutrophil, and serum procalcitonin. These findings may imply the neutrophil-mediated systemic inflammatory response plays an important role on central nerve system, leading to cerebral dysfunction.

Treatment of Cognitive Deficits and Behavioral Symptoms Following COVID-19-Associated Autoimmune Encephalitis With Intravenous Immunoglobulin: A Case Report and Review of the Literature

Coronavirus disease 2019 (COVID-19) is associated with long-term neuropsychiatric sequelae. We describe a 60-year-old male patient's history and symptom trajectory encompassing the development of behavioral symptoms and cognitive deficits following pneumonia and subsequent autoimmune encephalitis associated with COVID-19. We also describe changes in these facets with correlative changes in his immunological parameters after both acute intravenous immunoglobulin (IVIG) therapy and chronic periodic IVIG therapy every two weeks over the course of two years. ​​​​​​We review the literature on the treatment of long COVID-19 symptoms spanning cognitive and behavioral domains. In addition, we also elucidate current literature on the role of IVIG infusions for these symptoms using our patient's presentation and improvement in symptoms as an illustrative example.

Brain MRI findings in neurologically symptomatic COVID-19 patients: a systematic review and meta-analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) has been associated with nervous system involvement, with more than one-third of COVID-19 patients experiencing neurological manifestations. Utilizing a systematic review, this study aims to summarize brain MRI findings in COVID-19 patients presenting with neurological symptoms.

METHODS

Systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist. The electronic databases of PubMed/MEDLINE, Embase, Scopus, and Web of Science were systematically searched for literature addressing brain MRI findings in COVID-19 patients with neurological symptoms.

RESULTS

25 publications containing a total number of 3118 COVID-19 patients with neurological symptoms who underwent MRI were included. The most common MRI findings and the respective pooled incidences in decreasing order were acute/subacute infarct (22%), olfactory bulb abnormalities (22%), white matter abnormalities (20%), cerebral microbleeds (17%), grey matter abnormalities (12%), leptomeningeal enhancement (10%), ADEM (Acute Disseminated Encephalomyelitis) or ADEM-like lesions (10%), non-traumatic ICH (10%), cranial neuropathy (8%), cortical gray matter signal changes compatible with encephalitis (8%), basal ganglia abnormalities (5%), PRES (Posterior Reversible Encephalopathy Syndrome) (3%), hypoxic-ischemic lesions (4%), venous thrombosis (2%), and cytotoxic lesions of the corpus callosum (2%).

CONCLUSION

The present study revealed that a considerable proportion of patients with COVID-19 might harbor neurological abnormalities detectable by MRI. Among various findings, the most common MRI alterations are acute/subacute infarction, olfactory bulb abnormalities, white matter abnormalities, and cerebral microbleeds.

Neuroprotective Agents with Therapeutic Potential for COVID-19

COVID-19 patients can exhibit a wide range of clinical manifestations affecting various organs and systems. Neurological symptoms have been reported in COVID-19 patients, both during the acute phase of the illness and in cases of long-term COVID. Moderate symptoms include ageusia, anosmia, altered mental status, and cognitive impairment, and in more severe cases can manifest as ischemic cerebrovascular disease and encephalitis. In this narrative review, we delve into the reported neurological symptoms associated with COVID-19, as well as the underlying mechanisms contributing to them. These mechanisms include direct damage to neurons, inflammation, oxidative stress, and protein misfolding. We further investigate the potential of small molecules from natural products to offer neuroprotection in models of neurodegenerative diseases. Through our analysis, we discovered that flavonoids, alkaloids, terpenoids, and other natural compounds exhibit neuroprotective effects by modulating signaling pathways known to be impacted by COVID-19. Some of these compounds also directly target SARS-CoV-2 viral replication. Therefore, molecules of natural origin show promise as potential agents to prevent or mitigate nervous system damage in COVID-19 patients. Further research and the evaluation of different stages of the disease are warranted to explore their potential benefits.

Gut-brain pathogenesis of post-acute COVID-19 neurocognitive symptoms

Approximately one third of non-hospitalized coronavirus disease of 2019 (COVID-19) patients report chronic symptoms after recovering from the acute stage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Some of the most persistent and common complaints of this post-acute COVID-19 syndrome (PACS) are cognitive in nature, described subjectively as "brain fog" and also objectively measured as deficits in executive function, working memory, attention, and processing speed. The mechanisms of these chronic cognitive sequelae are currently not understood. SARS-CoV-2 inflicts damage to cerebral blood vessels and the intestinal wall by binding to angiotensin-converting enzyme 2 (ACE2) receptors and also by evoking production of high levels of systemic cytokines, compromising the brain's neurovascular unit, degrading the intestinal barrier, and potentially increasing the permeability of both to harmful substances. Such substances are hypothesized to be produced in the gut by pathogenic microbiota that, given the profound effects COVID-19 has on the gastrointestinal system, may fourish as a result of intestinal post-COVID-19 dysbiosis. COVID-19 may therefore create a scenario in which neurotoxic and neuroinflammatory substances readily proliferate from the gut lumen and encounter a weakened neurovascular unit, gaining access to the brain and subsequently producing cognitive deficits. Here, we review this proposed PACS pathogenesis along the gut-brain axis, while also identifying specific methodologies that are currently available to experimentally measure each individual component of the model.

Case Report: High-dose steroid and IVIG successful treatment in a case of COVID-19-associated autoimmune encephalitis: a literature review

Autoimmune encephalitis is a rare but critical complication of COVID-19. The management of COVID-19-associated autoimmune encephalitis includes the use of steroids, intravenous immunoglobulin (IVIG), plasmapheresis, and monoclonal antibody therapy. This study presented a patient with critical COVID-19 autoimmune encephalitis who rapidly recovered after the initiation of corticosteroids and IVIG therapy. This study reviewed the current literature on the pathophysiological mechanisms, diagnosis, and management of COVID-19-associated autoimmune encephalitis.

Autoimmune encephalitis in COVID-19 patients: a systematic review of case reports and case series

Background

There is mounting evidence suggesting that autoimmune encephalitis (AE) can be observed as a neurological complication in patients with COVID-19. This review aimed to summarize the clinical manifestations, types, and outcomes of COVID-19-associated AE.

Methods

A systematic search was conducted in the PubMed, Embase, and Web of Science databases to identify case reports and case series related to COVID-19-associated AE from 1 January 2020 to 31 March 2023. After a thorough screening and evaluation, irrelevant articles were excluded. Relevant information concerning types, clinical manifestations, and outcomes was extracted and synthesized.

Results

A total of 37 studies, comprising 34 case reports and 3 case series, were included in this review. Among the 42 COVID-19-associated AE patients, 21 (50%) cases were classified as an unknown antibodies (Ab) type of COVID-19-associated AE, 10 (23.80%) cases as anti-N-methyl-D-aspartate (NMDA) encephalitis, 4 (9.5%) cases as limbic encephalitis, and 3 (7.1%) cases as anti-myelin-oligodendrocyte-glycoprotein encephalitis, along with other rare types of AE. Disturbance of consciousness, seizures, and psychiatric symptoms were identified as the main clinical manifestations of COVID-19-associated AE. While the symptoms of AE displayed variation, most patients achieved full recovery although a few experienced residual symptoms of neurological damage.

Conclusion

This systematic review comprehensively describes the characteristics of COVID-19-associated AE. The main type of COVID-19-associated AE identified in this study is an unknown Ab type of COVID-19-associated AE. Despite the potentially life-threatening risks of COVID-19-associated AE, the majority of patients survived, with some patients reporting residual neurological symptoms.

Prevalence, pathogenesis and spectrum of neurological symptoms in COVID-19 and post-COVID-19 syndrome: a narrative review

Neurological symptoms are not uncommon during severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and reflect a broad spectrum of neurological disorders of which clinicians should be aware. The underlying pathogenesis of neurological disease in coronavirus disease 2019 (COVID-19) may be due to four mechanisms of nervous system dysfunction and injury: i) direct viral neurological invasion; ii) immune dysregulation; iii) endothelial dysfunction and coagulopathy; and iv) severe systemic COVID-19 disease. Neurological manifestations of acute COVID-19 include headache, peripheral neuropathies, seizures, encephalitis, Guillain-Barré syndrome, and cerebrovascular disease. Commonly reported long term neurological sequelae of COVID-19 are cognitive dysfunction and dysautonomia, which despite being associated with severe acute disease are also seen in people with mild disease. Assessment of cognitive dysfunction after COVID-19 is confounded by a high prevalence of comorbid fatigue, anxiety, and mood disorders. However, other markers of neuroaxonal breakdown suggest no significant neuronal injury apart from during severe acute COVID-19. The long term impact of COVID-19 on neurological diseases remains uncertain and requires ongoing vigilance.

Pathophysiology, diagnosis, and management of neuroinflammation in covid-19

Although neurological complications of SARS-CoV-2 infection are relatively rare, their potential long term morbidity and mortality have a significant impact, given the large numbers of infected patients. Covid-19 is now in the differential diagnosis of a number of common neurological syndromes including encephalopathy, encephalitis, acute demyelinating encephalomyelitis, stroke, and Guillain-Barré syndrome. Physicians should be aware of the pathophysiology underlying these presentations to diagnose and treat patients rapidly and appropriately. Although good evidence has been found for neurovirulence, the neuroinvasive and neurotropic potential of SARS-CoV-2 is limited. The pathophysiology of most complications is immune mediated and vascular, or both. A significant proportion of patients have developed long covid, which can include neuropsychiatric presentations. The mechanisms of long covid remain unclear. The longer term consequences of infection with covid-19 on the brain, particularly in terms of neurodegeneration, will only become apparent with time and long term follow-up.

Mitigating neurological, cognitive, and psychiatric sequelae of COVID-19-related critical illness

Despite advances in the treatment and mitigation of critical illness caused by infection with SARS-CoV-2, millions of survivors have a devastating, post-acute infection syndrome known as long COVID. A large proportion of patients with long COVID have nervous system dysfunction, which is also seen in the distinct but overlapping condition of post-intensive care syndrome (PICS), putting survivors of COVID-19-related critical illness at high risk of long-lasting morbidity affecting multiple organ systems and, as a result, engendering measurable deficits in quality of life and productivity. In this Series paper, we discuss neurological, cognitive, and psychiatric sequelae in patients who have survived critical illness due to COVID-19. We review current knowledge of the epidemiology and pathophysiology of persistent neuropsychological impairments, and outline potential preventive strategies based on safe, evidence-based approaches to the management of pain, agitation, delirium, anticoagulation, and ventilator weaning during critical illness. We highlight priorities for current and future research, including possible therapeutic approaches, and offer considerations for health services to address the escalating health burden of long COVID.

Encephalitis: diagnosis, management and recent advances in the field of encephalitides

Encephalitis describes inflammation of the brain parenchyma, typically caused by either an infectious agent or through an autoimmune process which may be postinfectious, paraneoplastic or idiopathic. Patients can present with a combination of fever, alterations in behaviour, personality, cognition and consciousness. They may also exhibit focal neurological deficits, seizures, movement disorders and/or autonomic instability. However, it can sometimes present non-specifically, and this combined with its many causes make it a difficult to manage neurological syndrome. Despite improved treatments in some forms of encephalitides, encephalitis remains a global concern due to its high mortality and morbidity. Prompt diagnosis and administration of specific and supportive management options can lead to better outcomes. Over the last decade, research in encephalitis has led to marked developments in the understanding, diagnosis and management of encephalitis. In parallel, the number of autoimmune encephalitis syndromes has rapidly expanded and clinically characteristic syndromes in association with pathogenic autoantibodies have been defined. By focusing on findings presented at the Encephalitis Society's conference in December 2021, this article reviews the causes, clinical manifestations and management of encephalitis and integrate recent advances and challenges of research into encephalitis.

Long-term central nervous system (CNS) consequences of COVID-19 in children

INTRODUCTION

Neurological/neuropsychiatric symptoms are commonly reported by children/young people with long COVID, especially headache, fatigue, cognitive deficits, anosmia and ageusia, dizziness, mood symptoms, and sleep problems. However, reported prevalence estimates are highly variable due to study heterogeneity and often small sample size; most studies only considered short-term follow-ups; and, apart from mood and sleep problems, neuropsychiatric conditions have received less attention. Considering the potential debilitating effects of neurological/neuropsychiatric conditions, a comprehensive review of the topic is timely, and needed to support clinical recognition as well as to set the direction for future research.

AREAS COVERED

The authors discuss neurological/neuropsychiatric manifestations of long COVID in pediatric populations, with a focus on prevalence, associated demographic characteristics, and potential pathogenetic mechanisms.

EXPERT OPINION

Children/young people may develop persistent neurological/neuropsychiatric symptoms following acute SARS-CoV-2 infection, which may affect daily functioning and well-being. Studies in larger samples with longer follow-ups are needed to clarify prevalence and symptom duration; as well as less investigated risk factors, including genetic predisposition, ethnicity, and comorbidities. Controlled studies may help separate infection-related direct effects from pandemic-related psychosocial stressors. Clarifying pathogenetic mechanisms is paramount to develop more targeted and effective treatments; whilst screening programs and psychoeducation may enhance early recognition.

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.

Viral meningitis and encephalitis: an update

PURPOSE OF REVIEW

The most common infectious etiologies of meningitis and encephalitis are viruses. In this review, we will discuss current epidemiology, prevention, diagnosis, and treatment of the most common causes of viral meningitis and encephalitis worldwide.

RECENT FINDINGS

Viral meningitis and encephalitis are increasingly diagnosed as molecular diagnostic techniques and serologies have become more readily available worldwide but recent progress in novel antiviral therapies remains limited. Emerging and re-emerging viruses that have caused endemic or worldwide outbreaks or epidemics are arboviruses (e.g., West Nile virus, Japanese encephalitis, Tick borne encephalitis, Dengue, Zika, Toscana), enteroviruses (e.g., Enterovirus 71, Enterovirus D68), Parechoviruses, respiratory viruses [e.g., severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza, metapneumoviruses, measles, mumps], and herpes viruses [e.g., herpes simplex virus (HSV) type 1 (HSV-1), HSV-2, human herpes (HV) 6, varicella zoster virus (VZV)]. Future efforts should concentrate in increasing availability for those viruses with effective vaccination [e.g., Japanese encephalitis, Tick borne encephalitis, varicella zoster viruses, SARS-CoV-2, influenza], prompt initiation of those with encephalitis with treatable viruses (e.g., HSV-1, VZV), increasing the diagnostic yield by using novel techniques such as metagenomic sequencing and avoiding unnecessary antibiotics in those with viral meningitis or encephalitis.

SUMMARY

We review the current epidemiology, clinical presentation, diagnosis, and treatment of the common causative agents of viral meningitis and encephalitis worldwide.

Addressing vaccine-preventable encephalitis in vulnerable populations

PURPOSE OF REVIEW

Vaccinations have been pivotal in lowering the global disease burden of vaccine-preventable encephalitides, including Japanese encephalitis, tick-borne encephalitis, measles encephalitis, and rabies encephalitis, among others.

RECENT FINDINGS

Populations vulnerable to vaccine-preventable infections that may lead to encephalitis include those living in endemic and rural areas, military members, migrants, refugees, international travelers, younger and older persons, pregnant women, the immunocompromised, outdoor, healthcare and laboratory workers, and the homeless. There is scope for improving the availability and distribution of vaccinations, vaccine equity, surveillance of vaccine-preventable encephalitides, and public education and information.

SUMMARY

Addressing these gaps in vaccination strategies will allow for improved vaccination coverage and lead to better health outcomes for those most at risk for vaccine-preventable encephalitis.

SARS-CoV-2 and the nervous system: current perspectives

SARS-CoV-2 infection frequently causes neurological impairment in both adults and children. Recent publications have described significant aspects of the viral pathophysiology associated with neurological dysfunction. In theory, neurological manifestations following SARS-CoV-2 infection may be caused directly by the effects of the virus infecting the brain or indirectly by the local and systemic immune responses against the virus. Neurological manifestations can occur during the acute phase as well as in the post-acute phase of the infection. In this review, we discuss recent literature describing the association of nervous system disorders with COVID-19.

A Hybrid Deep Neural Approach for Segmenting the COVID Affection Area from the Lungs X-Ray Images

Nowadays, COVID severity prediction has attracted widely in medical research because of the disease severity. Hence, the image processing application is also utilized to analyze COVID severity identification using lungs X-ray images. Thus, several intelligent schemes were employed to detect the COVID-affected part of the lungs X-ray images. However, the traditional neural approaches reported less severity classification accuracy due to the image complexity score. So, the present study has presented a novel chimp-based Adaboost Severity Analysis (CbASA) implemented in the MATLAB environment. Hence, the lung's X-ray images are utilized to test the working performance of the designed model. All public imaging data sources contain more noisy features, so the noise features are removed in the initial hidden layer of the novel CbASA then the noise-free data is imported into the classification phase. Feature extraction, segmentation, and severity specification have been performed in the classification layer. Finally, the performance of the classification score has been measured and compared with other models. Subsequently, the presented novel CbASA has earned the finest classification outcome.

Relapsing Encephalomyelitis After COVID-19 Infection and Vaccination: From the National MS Society Case Conference Proceedings

Prior case studies suggest that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its vaccines may unmask CNS neuroinflammatory conditions. We present a case of relapsing steroid-responsive encephalomyelitis after SARS-CoV-2 infection and subsequent COVID-19 vaccination. We also characterize the frequency of CNS neuroinflammatory events reported in the literature after both SARS-CoV-2 infection and COVID-19 vaccination.

Prevalence and Mortality Risk of Neurological Disorders during the COVID-19 Pandemic: An Umbrella Review of the Current Evidence

INTRODUCTION

Coronavirus disease 2019 (COVID-19), a global pandemic, has infected approximately 10% of the world's population. This comprehensive review aimed to determine the prevalence of various neurological disorders in COVID-19 without overlapping meta-analysis errors.

METHODS

We searched for meta-analyses on neurological disorders following COVID-19 published up to March 14, 2023. We obtained 1,184 studies, of which 44 meta-analyses involving 9,228,588 COVID-19 patients were finally included. After confirming the forest plot of each study and removing overlapping individual studies, a re-meta-analysis was performed using the random-effects model.

RESULTS

The summarized combined prevalence of each neurological disorder is as follows: stroke 3.39% (95% confidence interval, 1.50-5.27), dementia 6.41% (1.36-11.46), multiple sclerosis 4.00% (2.50-5.00), epilepsy 5.36% (-0.60-11.32), Parkinson's disease 0.67% (-1.11-2.45), encephalitis 0.66% (-0.44-1.77), and Guillain-Barré syndrome 3.83% (-0.13-7.80). In addition, the mortality risk of patients with comorbidities of COVID-19 is as follows: stroke OR 1.63 (1.23-2.03), epilepsy OR 1.71 (1.00-2.42), dementia OR 1.90 (1.31-2.48), Parkinson's disease OR 3.94 (-2.12-10.01).

CONCLUSION

Our results show that the prevalence and mortality risk may increase in some neurological diseases during the COVID-19 pandemic. Future studies should elucidate the precise mechanisms for the link between COVID-19 and neurological diseases, determine which patient characteristics predispose them to neurological diseases, and consider potential global patient management.

Translocator protein (TSPO)-PET as diagnostic and monitoring tool in COVID-19 related MRI-negative brainstem encephalitis: a case report

BACKGROUND

Encephalitis and myelitis have been linked to both COVID-19 vaccination and infection, causing symptoms such as reduced consciousness, mental state alterations and seizures. Remarkably, most cases do not show significant structural alterations on MRI scans, which poses a diagnostic challenge.

METHODS

We present the diagnostic workup and clinical course of a patient who developed a progressive brainstem syndrome two weeks after COVID-19 vaccination and subsequent infection. We used translocator protein (TSPO)-PET scans for the first time to investigate COVID-related neuroinflammation.

RESULTS

The patient developed oculomotor disorder, dysarthria, paresthesia in all distal limbs and spastic-atactic gait. CSF analysis revealed mild lymphocytic pleocytosis with normal protein levels. Brain and spinal cord MRI scans were negative, but TSPO/PET scans showed increased microglia activity in the brainstem, which correlated with the clinical course. Steroid treatment led to clinical improvement, but relapse occurred during prednisone taper after four weeks. Plasmapheresis had no significant effect; however, complete remission was achieved with cyclophosphamide and methotrexate, with normal TSPO signal ten months after onset.

CONCLUSIONS

TSPO-PET can be a valuable tool in the diagnostic and therapeutic monitoring of COVID-19-related encephalitis, particularly in cases where MRI scans are negative. Aggressive immunosuppressive therapy can lead to sustained remission.

Review of Neurological Manifestations of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can affect any part of the neuraxis. Many neurological conditions have been attributed to be caused by SARS-CoV-2, namely encephalopathy (acute necrotizing encephalopathy and encephalopathy with reversible splenial lesions), seizures, stroke, cranial nerve palsies, meningoencephalitis, acute disseminated encephalomyelitis (ADEM), transverse myelitis (long and short segment), Guillain-Barré syndrome (GBS) and its variants, polyneuritis cranialis, optic neuritis (ON), plexopathy, myasthenia gravis (MG), and myositis. The pathophysiology differs depending on the time frame of presentation. In patients with concomitant pulmonary disease, for instance, acute neurological illness appears to be caused by endotheliopathy and cytokine storm. Autoimmunity and molecular mimicry are causative for post-coronavirus disease 2019 (COVID-19)-sequelae. It has not yet been shown that the virus can penetrate the central nervous system (CNS) directly. This review aims to describe the disease and root pathogenic cause of the various neurological manifestations of COVID-19. We searched Pubmed/Medline and Google Scholar using the keywords "SARS-CoV-2" and "neurological illness" for articles published between January 2020 and November 2022. Then, we used the SWIFT-Review (Sciome LLC, North Carolina, United States), a text-mining workbench for systematic review, to classify the 1383 articles into MeSH hierarchical tree codes for articles on various parts of the nervous system, such as the CNS, peripheral nervous system, autonomic nervous system, neuromuscular junction, sensory system, and musculoskeletal system. Finally, we reviewed 152 articles in full text. SARS-CoV-2 RNA has been found in multiple brain areas without any histopathological changes. Despite the absence of in vivo virions or virus-infected cells, CNS inflammation has been reported, especially in the olfactory bulb and brain stem. SARS-CoV-2 genomes and proteins have been found in affected individuals' brain tissues, but corresponding neuropathologic changes are seldom found in these cases. Additionally, viral RNA can rarely be identified in neurological patients' CSF post hoc SARS-CoV-2 infection. Most patients with neurological symptoms do not have active viral replication in the nervous system and infrequently have typical clinical and laboratory characteristics of viral CNS infections. Endotheliopathy and the systemic inflammatory response to SARS-CoV-2 infection play a crucial role in developing neuro-COVID-19, with proinflammatory cytokine release mediating both pathological pathways. The systemic inflammatory mediators likely activate astrocytes and microglia across the blood-brain barrier, indirectly affecting CNS-specific immune activation and tissue injury. The management differs according to co-morbidities and the neurological disorder.

Cerebrospinal Fluid Protein Markers Indicate Neuro-Damage in SARS-CoV-2-Infected Nonhuman Primates

Neurologic manifestations are among the most frequently reported complications of COVID-19. However, given the paucity of tissue samples and the highly infectious nature of the etiologic agent of COVID-19, we have limited information to understand the neuropathogenesis of COVID-19. Therefore, to better understand the impact of COVID-19 on the brain, we used mass-spectrometry-based proteomics with a data-independent acquisition mode to investigate cerebrospinal fluid (CSF) proteins collected from two different nonhuman primates, Rhesus Macaque and African Green Monkeys, for the neurologic effects of the infection. These monkeys exhibited minimal to mild pulmonary pathology but moderate to severe central nervous system (CNS) pathology. Our results indicated that CSF proteome changes after infection resolution corresponded with bronchial virus abundance during early infection and revealed substantial differences between the infected nonhuman primates and their age-matched uninfected controls, suggesting these differences could reflect altered secretion of CNS factors in response to SARS-CoV-2-induced neuropathology. We also observed the infected animals exhibited highly scattered data distributions compared to their corresponding controls indicating the heterogeneity of the CSF proteome change and the host response to the viral infection. Dysregulated CSF proteins were preferentially enriched in functional pathways associated with progressive neurodegenerative disorders, hemostasis, and innate immune responses that could influence neuroinflammatory responses following COVID-19. Mapping these dysregulated proteins to the Human Brain Protein Atlas found that they tended to be enriched in brain regions that exhibit more frequent injury following COVID-19. It, therefore, appears reasonable to speculate that such CSF protein changes could serve as signatures for neurologic injury, identify important regulatory pathways in this process, and potentially reveal therapeutic targets to prevent or attenuate the development of neurologic injuries following COVID-19.

Encephalopathy in a Young Female With COVID-19: A Case Report

Cases of severe central nervous system (CNS) complications have been reported in relation to coronavirus-19 (COVID-19). Cases of encephalitis have been reported primarily in older patients with multiple comorbidities. We present a case of encephalitis in a young female patient with a history of chronic marijuana use that presented with nausea, vomiting, and acute altered mental status. Extensive testing for infectious and autoimmune causes of encephalitis were negative, except for a positive COVID-19 test. She was treated with steroids and intravenous immune globulin (IVIG) and improved with residual mutism.

Human brain organoids to explore SARS-CoV-2-induced effects on the central nervous system

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). In less than three years, an estimated 600 million infections with SARS-CoV-2 occurred worldwide, resulting in a pandemic with tremendous impact especially on economic and health sectors. Initially considered a respiratory disease, COVID-19, along with its long-term sequelae (long-COVID) rather is a systemic disease. Neurological symptoms like dementia or encephalopathy were reported early during the pandemic as concomitants of the acute phase and as characteristics of long-COVID. An excessive inflammatory immune response is hypothesized to play a major role in this context. However, direct infection of neural cells may also contribute to the neurological aspects of (long)-COVID-19. To mainly explore such direct effects of SARS-CoV-2 on the central nervous system, human brain organoids provide a useful platform. Infecting these three-dimensional tissue cultures allows the study of viral neurotropism as well as of virus-induced effects on single cells or even the complex cellular network within the organoid. In this review, we summarize the experimental studies that used SARS-CoV-2-infected human brain organoids to unravel the complex nature of (long)-COVID-19-related neurological manifestations.

Encephalitis Associated With SARS-CoV-2 Infection in a Child With Chiari Malformation Type I

BACKGROUND/AIM

There is increasing evidence that patients infected with SARS-CoV-2 develop neurological manifestations such as encephalitis. The purpose of this article was to present a case of viral encephalitis associated with SARS-CoV-2 in a 14-year-old child with Chiari malformation type I.

CASE REPORT

The patient manifested frontal headache, nausea, vomiting, skin pallor, right side Babinski sign and was diagnosed with Chiari malformation type I. He was admitted with generalized seizures and suspected encephalitis. Brain inflammation and viral RNA in the cerebrospinal fluid suggested SARS-CoV-2 encephalitis. These findings indicate that the SARS-CoV-2 test in CSF of patients with neurological manifestations, confusion, and fever during the COVID-19 pandemic should be carried out even when there is no evidence of respiratory infection. To our knowledge, this presentation of encephalitis associated with COVID-19 has not yet been reported in a patient with a congenital syndrome such as Chiari malformation type I.

CONCLUSION

Further clinical data are needed to determine the complications of encephalitis due to SARS-CoV-2 in patients with Chiari malformation type I to standardize diagnosis and treatment.

[The alleged mechanisms of olfactory disorders in the new coronavirus infection]

In March 2020, the World Health Organization (WHO) announced the beginning of the COVID-19 pandemic, which continues to the present. A change in the sense of smell, up to the complete disappearance of odors, is regarded as one of the early symptoms of the disease. Sometimes anosmia was the only sign of infection of the patient. As is known, a disturbance of the sense of smell indicates a serious pathology of the brain, such as the consequences of traumatic brain injuries, strokes, Alzheimer's disease, Parkinson's disease, autoimmune diseases, a side-effect of drug therapy. The review is dedicated to the pathogenesis of anosmia in COVID-19. For a better understanding of the pathogenesis, the article presents a brief anatomy and physiology of the olfactory organ as well as the probable mechanisms of anosmia: encephalitis, inflammatory edema of the olfactory cleft, olfactory epithelium damage, apoptosis of bipolar neurons, damage of olfactory cell cilia and damage of olfactory bulbs. Because of the rapid accumulation of information on this topic, there is a need to structure, periodic systematization and presentation to a wide range of specialists.

Investigation of Neurological Complications after COVID-19 Vaccination: Report of the Clinical Scenarios and Review of the Literature

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), broke out in 2019 and became a pandemic in 2020. Since then, vaccines have been approved to prevent severe illness. However, vaccines are associated with the risk of neurological complications ranging from mild to severe. Severe complications such as vaccine-induced immune thrombotic thrombocytopenia (VITT) associated with acute ischaemic stroke have been reported as rare complications post-COVID-19 vaccination. During the pandemic era, VITT evaluation is needed in cases with a history of vaccination within the last month prior to the event. Cerebral venous sinus thrombosis (CVST) should be suspected in patients following immunization with persistent headaches who are unresponsive to analgesics. In this article, we investigated neurological complications after COVID-19 vaccination and provided more subsequent related clinical studies of accurate diagnosis, pathophysiological mechanisms, incidence, outcome, and management.

Late neurological consequences of SARS-CoV-2 infection: New challenges for the neurologist

Objective

In this study, a systematic review of the literature was performed to study the frequency of neurological symptoms and diseases in adult patients with COVID-19 that may be late consequences of SARS-CoV-2 infection.

Methods

Relevant studies were identified through electronic explorations of Scopus, PubMed, and Google Scholar. We followed PRISMA guidelines. Data were collected from studies where the diagnosis of COVID-19 was confirmed and its late neurological consequences occurred at least 4 weeks after initial SARS-CoV-2 infection. Review articles were excluded from the study. Neurological manifestations were stratified based on frequency (above 5, 10, and 20%), where the number of studies and sample size were significant.

Results

A total of 497 articles were identified for eligible content. This article provides relevant information from 45 studies involving 9,746 patients. Fatigue, cognitive problems, and smell and taste dysfunctions were the most frequently reported long-term neurological symptoms in patients with COVID-19. Other common neurological issues were paresthesia, headache, and dizziness.

Conclusion

On a global scale of patients affected with COVID-19, prolonged neurological problems have become increasingly recognized and concerning. Our review might be an additional source of knowledge about potential long-term neurological impacts.

A decrease in the incidence of encephalitis in South Korea during the COVID-19 pandemic: A nationwide study between 2010 and 2021

Limited data are available on the impact of the coronavirus disease (COVID-19) pandemic on encephalitis. Therefore, we evaluated trends in encephalitis in South Korea between 2010 and 2021 using data from the National Health Insurance Service. During the pandemic (February 2020 to 2021), the monthly incidence of encephalitis declined by 0.027 per 100 000 population (95% confidence interval [CI]: -0.055 to 0.001, p = 0.062) compared to that before the pandemic. In subgroup analysis, the estimated coefficient for level change during the pandemic in the 0-4 and 5-9 years age groups were -2.050 (95% CI: -2.972 to -1.128, p < 0.001) and -0.813 (95% CI: -1.399 to -0.227, p = 0.008), respectively. The annual incidence of encephalitis during the pandemic period significantly decreased in the 0-4 and 5-9 years age groups (incidence rate ratio: 0.34 [p = 0.007] and 0.28 [p = 0.024], respectively). The intensive care unit admission rate (39.1% vs. 58.9%, p  < 0.001) and cases of death (8.9% vs. 11.1%, p < 0.001) decreased significantly during the pandemic compared to the prepandemic. During the pandemic, the incidence of encephalitis decreased markedly in South Korea, particularly in children aged ≤9 years. In addition, there were changes in the clinical outcome of encephalitis during the COVID-19 pandemic.

Can COVID-19 Vaccines Induce Premature Non-Communicable Diseases: Where Are We Heading to?

According to the WHO, as of January 2023, more than 850 million cases and over 6.6 million deaths from COVID-19 have been reported worldwide. Currently, the death rate has been reduced due to the decreased pathogenicity of new SARS-CoV-2 variants, but the major factor in the reduced death rates is the administration of more than 12.8 billion vaccine doses globally. While the COVID-19 vaccines are saving lives, serious side effects have been reported after vaccinations for several premature non-communicable diseases (NCDs). However, the reported adverse events are low in number. The scientific community must investigate the entire spectrum of COVID-19-vaccine-induced complications so that necessary safety measures can be taken, and current vaccines can be re-engineered to avoid or minimize their side effects. We describe in depth severe adverse events for premature metabolic, mental, and neurological disorders; cardiovascular, renal, and autoimmune diseases, and reproductive health issues detected after COVID-19 vaccinations and whether these are causal or incidental. In any case, it has become clear that the benefits of vaccinations outweigh the risks by a large margin. However, pre-existing conditions in vaccinated individuals need to be taken into account in the prevention and treatment of adverse events.

Magnetic Resonance Imaging (MRI) Findings in COVID-19 Associated Encephalitis

We conducted this study to investigate the scope of the MRI neuroimaging manifestations in COVID-19-associated encephalitis. From January 2020 to September 2021, patients with clinical diagnosis of COVID-19-associated encephalitis, as well as concomitant abnormal imaging findings on brain MRI, were included. Two board-certified neuro-radiologists reviewed these selected brain MR images, and further discerned the abnormal imaging findings. 39 patients with the clinical diagnosis of encephalitis as well as abnormal MRI findings were included. Most (87%) of these patients were managed in ICU, and 79% had to be intubated-ventilated. 15 (38%) patients died from the disease, while the rest were discharged from the hospital. On MRI, FLAIR hyperintensities in the insular cortex were the most common finding, seen in 38% of the patients. Micro-hemorrhages on the SWI images were equally common, also seen in 38% patients. FLAIR hyperintensities in the medial temporal lobes were seen in 30%, while FLAIR hyperintensities in the posterior fossa were evident in 20%. FLAIR hyperintensities in basal ganglia and thalami were seen in 15%. Confluent FLAIR hyperintensities in deep and periventricular white matter, not explained by microvascular angiopathy, were detected in 7% of cases. Cortical-based FLAIR hyperintensities in 7%, and FLAIR hyperintensity in the splenium of the corpus callosum in 7% of patients. Finally, isolated FLAIR hyperintensity around the third ventricle was noted in 2% of patients.