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We measured brain injury markers, inflammatory mediators, and autoantibodies in 203 participants with COVID-19; 111 provided acute sera (1-11 days post admission) and 56 with COVID-19-associated neurological diagnoses provided subacute/convalescent sera (6-76 weeks post-admission). Compared to 60 controls, brain injury biomarkers (Tau, GFAP, NfL, UCH-L1) were increased in acute sera, significantly more so for NfL and UCH-L1, in patients with altered consciousness. Tau and NfL remained elevated in convalescent sera, particularly following cerebrovascular and neuroinflammatory disorders. Acutely, inflammatory mediators (including IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) were higher in participants with altered consciousness, and correlated with brain injury biomarker levels. Inflammatory mediators were lower than acute levels in convalescent sera, but levels of CCL2, CCL7, IL-1RA, IL-2Rα, M-CSF, SCF, IL-16 and IL-18 in individual participants correlated with Tau levels even at this late time point. When compared to acute COVID-19 patients with a normal GCS, network analysis showed significantly altered immune responses in patients with acute alteration of consciousness, and in convalescent patients who had suffered an acute neurological complication. The frequency and range of autoantibodies did not associate with neurological disorders. However, autoantibodies against specific antigens were more frequent in patients with altered consciousness in the acute phase (including MYL7, UCH-L1, GRIN3B, and DDR2), and in patients with neurological complications in the convalescent phase (including MYL7, GNRHR, and HLA antigens). In a novel low-inoculum mouse model of SARS-CoV-2, while viral replication was only consistently seen in mouse lungs, inflammatory responses were seen in both brain and lungs, with significant increases in CCL4, IFNγ, IL-17A, and microglial reactivity in the brain. Neurological injury is common in the acute phase and persists late after COVID-19, and may be driven by a para-infectious process involving a dysregulated host response.Graphical abstract(a) The acute cohort (days 1-11 post-hospitilisation) showed elevated pro-inflammatory cytokines, brain injury markers, and autoantibodies. The sub-acute/convalescent cohort (weeks to months post-COVID+ve test) retained elevated brain injury markers but lower proinflammatory cytokines and autoantibodies.(b) The mouse model of para-infectious brain with no active viral replication, had increased cytokines (IFNγ and IL-17A) and microglia reactivity (increased Iba1 expression).Created using Biorender.

Many patients with meningitis have no aetiology identified leading to unnecessary antimicrobials and prolonged hospitalisation. We used viral capture sequencing to identify possible pathogenic viruses in adults with community-acquired meningitis.Cerebrospinal fluid (CSF) from 73 patients was tested by VirCapSeq-VERT, a probe set designed to capture viral targets using high throughput sequencing. Patients were categorised as suspected viral meningitis - CSF pleocytosis, no pathogen identified (n = 38), proven viral meningitis - CSF pleocytosis with a pathogen identified (n = 15) or not meningitis - no CSF pleocytosis (n = 20).VirCapSeq-VERT detected virus in the CSF of 16/38 (42%) of those with suspected viral meningitis, including twelve individual viruses. A potentially clinically relevant virus was detected in 9/16 (56%). Unexpectedly Toscana virus, rotavirus and Saffold virus were detected and assessed to be potential causative agents.VirCapSeq-VERT increases the probability of detecting a virus. Using this agnostic approach we identified Toscana virus and, for the first time in adults, rotavirus and Saffold virus, as potential causative agents in adult meningitis. Further work is needed to determine the prevalence of atypical viral candidates as well as the clinical impact of using sequencing methods in real time. This knowledge can help to reduce antimicrobial use and hospitalisations leading to both patient and health system benefits.

Encephalitis is associated with psychiatric symptoms in the acute and post-acute stages, and many survivors experience long-term sequelae. Despite this, the breadth and severity of mental health symptoms in survivors of encephalitis has not been systematically reported. We recruited adults who had been diagnosed with encephalitis of any aetiology to complete a web-based questionnaire assessing a wide range of mental health symptoms and disorders. In total, 445 respondents from 31 countries (55.1% UK, 23.1% USA, 2.2% low-and middle-income countries) completed the survey, with a median seven years since encephalitis diagnosis; 84.7% were diagnosed by a neurologist or infectious diseases doctor. Infectious encephalitis constituted 65.4% of cases, autoimmune 29.7%. Mean age was 50.1 years (SD 15.6); 65.8% were female. The most common self-reported psychiatric symptoms were anxiety (75.2%), sleep problems (64.4%), mood problems (62.2%), unexpected crying (35.2%), and aggression (29.9%). Rates of self-reported psychiatric diagnoses following encephalitis were high: anxiety (44.0%), depression (38.6%), panic disorder (15.7%), and post-traumatic stress disorder (PTSD, 21.3%); these rates were broadly consistent with the results of a validated self-report measure, the Psychiatric Diagnostic Screening Questionnaire (PDSQ). Severe mental illnesses such as psychosis (3.3%) and bipolar affective disorder (3.1%) were also reported. Many respondents also felt they had symptoms of disorders including anxiety (37.5%), depression (28.1%), PTSD (26.8%), or panic disorder (20.9%) which had not been diagnosed by a professional. Overall, rates of major self-reported psychiatric diagnoses and symptoms did not significantly differ between autoimmune and infectious encephalitis. In total, 37.5% of respondents had thought about suicide, and 4.4% had attempted suicide since their encephalitis diagnosis. Over half (53.5%) reported that they either had no, or substandard, access to appropriate care for their mental health. High rates of sensory hypersensitivities (>75%) suggest a previously unreported association between encephalitis and this distressing symptom cluster. This large international survey indicates that psychiatric symptoms following encephalitis are common, and that mental healthcare provision to this population may be inadequate, highlighting a need for increased provision of proactive psychiatric care for these patients.

Background and objectivesOne year after the onset of the coronavirus disease 2019 (COVID-19) pandemic, we aimed to summarize the frequency of neurologic manifestations reported in patients with COVID-19 and to investigate the association of these manifestations with disease severity and mortality.MethodsWe searched PubMed, Medline, Cochrane library, ClinicalTrials.gov, and EMBASE for studies from December 31, 2019, to December 15, 2020, enrolling consecutive patients with COVID-19 presenting with neurologic manifestations. Risk of bias was examined with the Joanna Briggs Institute scale. A random-effects meta-analysis was performed, and pooled prevalence and 95% confidence intervals (CIs) were calculated for neurologic manifestations. Odds ratio (ORs) and 95% CIs were calculated to determine the association of neurologic manifestations with disease severity and mortality. Presence of heterogeneity was assessed with I2, meta-regression, and subgroup analyses. Statistical analyses were conducted in R version 3.6.2.ResultsOf 2,455 citations, 350 studies were included in this review, providing data on 145,721 patients with COVID-19, 89% of whom were hospitalized. Forty-one neurologic manifestations (24 symptoms and 17 diagnoses) were identified. Pooled prevalence of the most common neurologic symptoms included fatigue (32%), myalgia (20%), taste impairment (21%), smell impairment (19%), and headache (13%). A low risk of bias was observed in 85% of studies; studies with higher risk of bias yielded higher prevalence estimates. Stroke was the most common neurologic diagnosis (pooled prevalence 2%). In patients with COVID-19 ≥60 years of age, the pooled prevalence of acute confusion/delirium was 34%, and the presence of any neurologic manifestations in this age group was associated with mortality (OR 1.80, 95% CI 1.11–2.91).DiscussionUp to one-third of patients with COVID-19 analyzed in this review experienced at least 1 neurologic manifestation. One in 50 patients experienced stroke. In those >60 years of age, more than one-third had acute confusion/delirium; the presence of neurologic manifestations in this group was associated with nearly a doubling of mortality. Results must be interpreted with the limitations of observational studies and associated bias in mind.Systematic Review RegistrationPROSPERO CRD42020181867.

Background Seizures can occur unpredictably in patients with acute encephalitis syndrome (AES), and many suffer from poor long-term neurological sequelae. Establishing factors associated with acute seizures risk and poor outcomes could support clinical care. We aimed to conduct regional and volumetric analysis of cerebral oedema on magnetic resonance imaging (MRI) in patients with AES. We assessed the relationship of brain oedema with acute seizure activity and long-term neurological outcome. Methods In a multi-centre cohort study, adults and children presenting with an AES were recruited in the UK. The clinical and brain MRI data were retrospectively reviewed. The outcomes variables were inpatient acute seizure activity and neurological disability at six-months post-discharge. A poor outcome was defined as a Glasgow outcome score (GOS) of 1–3. We quantified regional brain oedema on MRI through stereological examination of T2-weighted images using established methodology by independent and blinded assessors. Clinical and neuroimaging variables were analysed by multivariate logistic regression to assess for correlation with acute seizure activity and outcome. Results The study cohort comprised 69 patients (mean age 31.8 years; 53.6% female), of whom 41 (59.4%) had acute seizures as inpatients. A higher Glasgow coma scale (GCS) score on admission was a negative predictor of seizures (OR 0.61 [0.46–0.83], p = 0.001). Even correcting for GCS on admission, the presence of cortical oedema was a significant risk factor for acute seizure activity (OR 5.48 [1.62–18.51], p = 0.006) and greater volume of cerebral oedema in these cortical structures increased the risk of acute seizures (OR 1.90 [1.12–3.21], p = 0.017). At six-month post-discharge, 21 (30.4%) had a poor neurological outcome. Herpes simplex virus encephalitis was associated with higher risk of poor outcomes in univariate analysis (OR 3.92 [1.08–14.20], p = 0.038). When controlling for aetiology, increased volume of cerebral oedema was an independent risk factor for adverse neurological outcome at 6 months (OR 1.73 [1.06–2.83], p = 0.027). Conclusions Both the presence and degree of cerebral oedema on MRIs of patients with AES may help identify patients at risk of acute seizure activity and subsequent long-term morbidity.

Background Scrub typhus has become a leading cause of central nervous system (CNS) infection in endemic regions. As a treatable condition, prompt recognition is vital. However, few studies have focused on describing the symptomology and outcomes of neurological scrub typhus infection. We conducted a systematic review and meta-analysis to report the clinical features and case fatality ratio (CFR) in patients with CNS scrub typhus infection. Methods A search and analysis plan was published in PROSPERO [ID 328732]. A systematic search of PubMed and Scopus was performed and studies describing patients with CNS manifestations of proven scrub typhus infection were included. The outcomes studied were weighted pooled prevalence (WPP) of clinical features during illness and weighted CFR. Results Nineteen studies with 1,221 (656 adults and 565 paediatric) patients were included. The most common clinical features in CNS scrub typhus were those consistent with non-specific acute encephalitis syndromes (AES), such as fever (WPP 100.0% [99.5%-100.0%, I2 = 47.8%]), altered sensorium (67.4% [54.9–78.8%, I2 = 93.3%]), headache (65.0% [51.5–77.6%, I2 = 95.1%]) and neck stiffness 56.6% (29.4–80.4%, I2 = 96.3%). Classical features of scrub typhus were infrequently identified; an eschar was found in only 20.8% (9.8%-34.3%, I2 = 95.4%) and lymphadenopathy in 24.1% (95% CI 11.8% - 38.9%, I2 = 87.8%). The pooled CFR (95% CI) was 3.6% (1.5%– 6.4%, I2 = 67.3%). Paediatric cohorts had a CFR of 6.1% (1.9–12.1%, I2 = 77%) whilst adult cohorts reported 2.6% (0.7–5.3%, I2 = 43%). Conclusion Our meta-analyses illustrate that 3.6% of patients with CNS manifestations of scrub typhus die. Clinicians should have a high index of suspicion for scrub typhus in patients presenting with AES in endemic regions and consider starting empiric treatment whilst awaiting results of investigations, even in the absence of classical signs such as an eschar or lymphadenopathy.

BACKGROUND: Neuropsychiatric presentations of monkeypox (MPX) infection have not been well characterised, despite evidence of nervous system involvement associated with the related smallpox infection. METHODS: In this pre-registered (PROSPERO ID 336649) systematic review and meta-analysis, we searched MEDLINE, EMBASE, PsycINFO, AMED and the preprint server MedRxiv up to 31/05/2022. Any study design of humans infected with MPX that reported a neurological or psychiatric presentation was included. For eligible symptoms, we calculated a pooled prevalence using an inverse variance approach and corresponding 95% confidence intervals. The degree of variability that could be explained by between-study heterogeneity was assessed using the I 2 statistic. Risk of bias was assessed with the Newcastle Ottawa Scale and the Joanna Briggs Institute quality assessment tool. FINDINGS: From 1705 unique studies, we extracted data on 19 eligible studies (1512 participants, 1031 with confirmed infection using CDC criteria or PCR testing) most of which were cohort studies and case series with no control groups. Study quality was generally moderate. Three clinical features were eligible for meta-analysis: seizure 2.7% (95% CI 0.7-10.2%, I2 0%), confusion 2.4% (95% CI 1.1-5.2%, I2 0%) and encephalitis 2.0% (95% 0.5-8.2%, I2 55.8%). Other frequently reported symptoms included myalgia, headache and fatigue, where heterogeneity was too high for estimation of pooled prevalences, possibly as a result of differences in viral clades and study methodology. INTERPRETATION: There is preliminary evidence for a range of neuropsychiatric presentations including severe neurological complications (encephalitis and seizure) and nonspecific neurological features (confusion, headache and myalgia). There is less evidence regarding the psychiatric presentations or sequelae of MPX. This may warrant surveillance within the current MPX outbreak, with prospective longitudinal studies evaluating the mid- to long-term sequelae of the virus. Robust methods to evaluate the potential causality of MPX with these clinical features are required. More evidence is necessary to explain heterogeneity in prevalence estimates. FUNDING: UKRI/MRC (MR/V03605X/1), MRC-CSF (MR/V007181/1), MRC/AMED (MR/T028750/1) and the Wellcome Trust (102186/B/13/Z) and (102186/B/13/Z) and UCLH BRC.

ObjectiveIn patients with encephalitis, the development of acute symptomatic seizures is highly variable, but when present is associated with a worse outcome. We aimed to determine the factors associated with seizures in encephalitis and develop a clinical prediction model.MethodsWe analysed 203 patients from 24 English hospitals (2005–2008) (Cohort 1). Outcome measures were seizures prior to and during admission, inpatient seizures and status epilepticus. A binary logistic regression risk model was converted to a clinical score and independently validated on an additional 233 patients from 31 UK hospitals (2013–2016) (Cohort 2).ResultsIn Cohort 1, 121 (60%) patients had a seizure including 103 (51%) with inpatient seizures. Admission Glasgow Coma Scale (GCS) ≤8/15 was predictive of subsequent inpatient seizures (OR (95% CI) 5.55 (2.10 to 14.64), pA clinical model of overall seizure risk identified admission GCS along with aetiology (autoantibody-associated OR 11.99 (95% CI 2.09 to 68.86) and Herpes simplex virus 3.58 (95% CI 1.06 to 12.12)) (area under receiver operating characteristics curve (AUROC) =0.75 (95% CI 0.701 to 0.848), pConclusionAge, GCS, fever and aetiology can effectively stratify acute seizure risk in patients with encephalitis. These findings can support the development of targeted interventions and aid clinical trial design for antiseizure medication prophylaxis.

Seizures can occur unpredictably in patients with acute encephalitis syndrome (AES), and many suffer from poor long-term neurological sequelae. Establishing factors associated with acute seizures risk and poor outcomes could support clinical care. We aimed to conduct regional and volumetric analysis of cerebral oedema on magnetic resonance imaging (MRI) in patients with AES. We assessed the relationship of brain oedema with acute seizure activity and long-term neurological outcome.In a multi-centre cohort study, adults and children presenting with an AES were recruited in the UK. The clinical and brain MRI data were retrospectively reviewed. The outcomes variables were inpatient acute seizure activity and neurological disability at six-months post-discharge. A poor outcome was defined as a Glasgow outcome score (GOS) of 1-3. We quantified regional brain oedema on MRI through stereological examination of T2-weighted images using established methodology by independent and blinded assessors. Clinical and neuroimaging variables were analysed by multivariate logistic regression to assess for correlation with acute seizure activity and outcome.The study cohort comprised 69 patients (mean age 31.8 years; 53.6% female), of whom 41 (59.4%) had acute seizures as inpatients. A higher Glasgow coma scale (GCS) score on admission was a negative predictor of seizures (OR 0.61 [0.46-0.83], p = 0.001). Even correcting for GCS on admission, the presence of cortical oedema was a significant risk factor for acute seizure activity (OR 5.48 [1.62-18.51], p = 0.006) and greater volume of cerebral oedema in these cortical structures increased the risk of acute seizures (OR 1.90 [1.12-3.21], p = 0.017). At six-month post-discharge, 21 (30.4%) had a poor neurological outcome. Herpes simplex virus encephalitis was associated with higher risk of poor outcomes in univariate analysis (OR 3.92 [1.08-14.20], p = 0.038). When controlling for aetiology, increased volume of cerebral oedema was an independent risk factor for adverse neurological outcome at 6 months (OR 1.73 [1.06-2.83], p = 0.027).Both the presence and degree of cerebral oedema on MRIs of patients with AES may help identify patients at risk of acute seizure activity and subsequent long-term morbidity.

ObjectiveTo investigate features of Guillain-Barré syndrome (GBS) following SARS-CoV-2 vaccines and evaluate for a causal link between the two.MethodsWe captured cases of GBS after SARS-CoV-2 vaccination through a national, open-access, online surveillance system. For each case, the certainty of GBS was graded using the Brighton criteria, and the relationship to the vaccine was examined using modified WHO Causality Assessment criteria. We compared age distribution of cases with that of prepandemic GBS cases and clinical features with the International GBS Outcome Study (IGOS).ResultsBetween 1 January and 30 June 2021, we received 67 reports of GBS following the ChAdOx1 vaccine (65 first doses) and three reports following the BNT162b2 vaccine (all first doses). The causal association with the vaccine was classified as probable for 56 (80%, all ChAdOx1), possible for 12 (17%, 10 ChAdOx1) and unlikely for two (3%, 1 ChAdOx1). A greater proportion of cases occurred in the 50–59 age group in comparison with prepandemic GBS. Most common clinical variants were sensorimotor GBS (n=55; 79%) and facial diplegia with paraesthesias (n=10; 14%). 10% (n=7/69) of patients reported an antecedent infection, compared with 77% (n=502/652) of the IGOS cohort (pInterpretationMost reports of GBS followed the first dose of ChAdOx1 vaccine. While our study cannot confirm or refute causation, this observation, together with the absence of alternative aetiologies, different than expected age distribution and the presence of unusual clinical features support a causal link. Clinicians and surveillance bodies should remain vigilant to the possibility of this very rare adverse event and its atypical variants.

ObjectivesNeuropsychiatric presentations of monkeypox (MPX) infection have not been well characterised, Despite evidence of nervous system involvement associated with two relatedOrthopoxviruses, in the case of smallpox infection (with the variola virus) and smallpox vaccination (which contains live vaccinia virus). In this systematic review and meta-analysis, we aim to determine the prevalence and describe the spectrum of neurological and psychiatric presentations of MPX.DesignSystematic review and meta-analysisData sourcesMEDLINE, EMBASE, PsycINFO, AMED and pre-print server (MedRxiv) searched up to 31/05/2022Eligibility criteria for study selection and analysisAny study design of humans infected with MPX that reported neurological or psychiatric presentation. Studies which included more than ten individuals, and symptoms that were reported in a minimum of two separate studies were eligible for meta-analysisData synthesisResults were pooled with random-effects meta-analysis to calculate generalised linear mixed models and corresponding 95% confidence intervals for each prevalence outcome. Heterogeneity was measured with the I2statistic. All included studies are summarised through a narrative synthesis. Risk of bias was assessed with the Newcastle Ottawa Scale and the Joanna Briggs Institute quality assessment tool.ResultsFrom 1,702 unique studies, we extracted data on 19 eligible studies (1,512 participants, 1,031 with confirmed infection using CDC criteria or PCR testing) most of which were cohort studies and case series with no controlled populations. Study quality was generally moderate. Six clinical features were eligible for meta-analysis, of which the most prevalent were myalgia in 55.5% [95%CI 12.1-91.9%], headache 53.8% [30.6-75.4%], fatigue 36.2% [2.0-94.0%], seizure 2.7% [0.6-10.2%], confusion 2.4% [1.1-5.2%] and encephalitis 2.0% [0.5-8.2%]. Heterogeneity significantly varied across clinical features (I2=0%-98.7%). Other reported presentations not eligible for meta-analysis included sensory-perceptual disturbance (altered vision, dizziness, and photophobia) and psychiatric symptoms (anxiety and depression).ConclusionsThere is preliminary evidence for a range of neurological and psychiatric presentations of MPX, ranging from commonly reported and nonspecific neurological symptoms (myalgia and headache) to rarer but more severe neurological complications, such as encephalitis and seizures. There is less evidence regarding the psychiatric sequelae of MPX, and although there are multiple reports of anxiety and depression the prevalence of these symptoms is unknown. MPX-related nervous system presentations may warrant surveillance within the current MPX outbreak, with prospective longitudinal studies evaluating the mid to long-term sequelae of the virus. Robust methods to evaluate the potential causality of MPX with these clinical features are required at an individual and epidemiological level.Systematic review registrationPROSPERO ID 336649SUMMARY BOXWhat is already known on this topicNeuropsychiatric symptoms can be highly disabling and have a detrimental effect on quality of life.Neuropsychiatric manifestations of monkeypox virus infection have not been well characterised, however, there is evidence of nervous system involvement with the related smallpox virus and vaccinia vaccine.What this study addsPreliminary evidence for a range of neurological and psychiatric presentations of monkeypox infection, ranging from commonly reported and nonspecific neurological symptoms (myalgia and headache) to rarer but more severe neurological complications, such as encephalitis and seizures.There is less evidence regarding the psychiatric sequelae of monkeypox infection, and although there are multiple reports of anxiety and depression the prevalence of these symptoms is unknown.This preliminary suspicion that there are monkeypox-related nervous system manifestations may warrant both surveillance within the current monkeypox outbreak and robust methods to evaluate the potential causality.

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.

Although SARS-CoV-2 causes a respiratory viral infection, there is a large incidence of neurological complications occurring in COVID-19 patients. These range from headaches and loss of smell to encephalitis and strokes. Little is known about the likely diverse mechanisms causing these pathologies and there is a dire need to understand how to prevent and treat them. This review explores recent research from the perspective of investigating how the immune system could play a role in neurological complications, including cytokines, blood biomarkers, immune cells, and autoantibodies. We also discuss lessons learnt from animal models. Overall, we highlight two key points that have emerged from increasing evidence: (1) SARS-CoV-2 does not invade the brain in the majority of cases and so the associated neurological complications might arise from indirect effects, such as immune activation (2) although the immune system plays a critical role in controlling the virus, its dysregulation can cause pathology.

Coronavirus disease 2019 (COVID-19) is a primarily respiratory disease with variable clinical courses for which animal models are needed to gather insights into the pathogenesis of its causative virus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), in human patients. SARS-CoV-2 not only affects the respiratory tract but also the central nervous system (CNS), leading to neurological symptoms such as loss of smell and taste, headache, fatigue or severe complications like cerebrovascular diseases. Transgenic mice expressing human angiotensin-converting enzyme 2 (hACE2) under the cytokeratin 18 promoter (K18-hACE2) represent a well-known model of SARS-CoV-2 infection. In the present study, it served to investigate the spatiotemporal distribution and pathomorphological features in the CNS following intranasal infection with relatively low SARS-CoV-2 doses and after prior influenza A virus infection. In K18-hACE2 mice, SARS-CoV-2 was found to frequently spread to and within the CNS during the later phase (day 7) of infection. Infection was restricted to neurons and appeared to first affect the olfactory bulb and spread from there mainly in basally orientated regions in the brain and into the spinal cord, in a dose dependent manner and independent of ACE2 expression. Neuronal infection was not associated with cell death, axonal damage or demyelination. However, microglial activation, microgliosis and a mild macrophage and T cell dominated inflammatory response was consistently observed. This was accompanied by apoptotic death of endothelial, microglial and immune cells, without evidence of viral infection of glial cells, endothelial cells and leukocytes. Taken together, microgliosis and immune cell apoptosis indicate a potential important role of microglial cells for the pathogenesis and viral effect in COVID-19 and possible impairment of neurological functions, especially in long COVID. These data may also be informative for the selection of therapeutic candidates, and broadly support investigation of agents with adequate penetration into relevant regions of the CNS.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the aetiologic agent of the coronavirus disease 2019 (COVID-19), is now rapidly disseminating throughout the world with 147,443,848 cases reported so far. Around 30-80% of cases (depending on COVID-19 severity) are reported to have neurological manifestations including anosmia, stroke, and encephalopathy. In addition, some patients have recognised autoimmune neurological disorders, including both central (limbic and brainstem encephalitis, acute disseminated encephalomyelitis [ADEM], and myelitis) and peripheral diseases (Guillain-Barré and Miller Fisher syndrome). We systematically describe data from 133 reported series on the Neurology and Neuropsychiatry of COVID-19 blog ( https://blogs.bmj.com/jnnp/2020/05/01/the-neurology-and-neuropsychiatry-of-covid-19/ ) providing a comprehensive overview concerning the diagnosis, and treatment of patients with neurological immune-mediated complications of SARS-CoV-2. In most cases the latency to neurological disorder was highly variable and the immunological or other mechanisms involved were unclear. Despite specific neuronal or ganglioside antibodies only being identified in 10, many had apparent responses to immunotherapies. Although the proportion of patients experiencing immune-mediated neurological disorders is small, the total number is likely to be underestimated. The early recognition and improvement seen with use of immunomodulatory treatment, even in those without identified autoantibodies, makes delayed or missed diagnoses risk the potential for long-term disability, including the emerging challenge of post-acute COVID-19 sequelae (PACS). Finally, potential issues regarding the use of immunotherapies in patients with pre-existent neuro-immunological disorders are also discussed.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the aetiologic agent of the coronavirus disease 2019 (COVID-19), is now rapidly disseminating throughout the world with 147,443,848 cases reported so far. Around 30–80% of cases (depending on COVID-19 severity) are reported to have neurological manifestations including anosmia, stroke, and encephalopathy. In addition, some patients have recognised autoimmune neurological disorders, including both central (limbic and brainstem encephalitis, acute disseminated encephalomyelitis [ADEM], and myelitis) and peripheral diseases (Guillain–Barré and Miller Fisher syndrome). We systematically describe data from 133 reported series on the Neurology and Neuropsychiatry of COVID-19 blog (https://blogs.bmj.com/jnnp/2020/05/01/the-neurology-and-neuropsychiatry-of-covid-19/) providing a comprehensive overview concerning the diagnosis, and treatment of patients with neurological immune-mediated complications of SARS-CoV-2. In most cases the latency to neurological disorder was highly variable and the immunological or other mechanisms involved were unclear. Despite specific neuronal or ganglioside antibodies only being identified in 10, many had apparent responses to immunotherapies. Although the proportion of patients experiencing immune-mediated neurological disorders is small, the total number is likely to be underestimated. The early recognition and improvement seen with use of immunomodulatory treatment, even in those without identified autoantibodies, makes delayed or missed diagnoses risk the potential for long-term disability, including the emerging challenge of post-acute COVID-19 sequelae (PACS). Finally, potential issues regarding the use of immunotherapies in patients with pre-existent neuro-immunological disorders are also discussed.

BACKGROUND: Neurocysticercosis is the most common parasitic infection of the brain. Epilepsy is the most common clinical presentation, though people may also present with headache, symptoms of raised intracranial pressure, hydrocephalus, and ocular symptoms depending upon the localisation of the parasitic cysts. Anthelmintic drugs, antiepileptic drugs (AEDs), and anti‐oedema drugs, such as steroids, form the mainstay of treatment. This is an updated version of the Cochrane Review previously published in 2019. OBJECTIVES: To assess the effects (benefits and harms) of AEDs for the primary and secondary prevention of seizures in people with neurocysticercosis. For the question of primary prevention, we examined whether AEDs reduce the likelihood of seizures in people who had neurocysticercosis but had not had a seizure. For the question of secondary prevention, we examined whether AEDs reduce the likelihood of further seizures in people who had had at least one seizure due to neurocysticercosis. As part of primary prevention studies, we also aimed to examine which AED was beneficial in people with neurocysticercosis in terms of duration, dose, and side‐effect profile. SEARCH METHODS: For the 2021 update of this review, we searched the Cochrane Register of Studies (CRS Web), MEDLINE, and LILACS to January 2021. CRS Web includes randomised or quasi‐randomised, controlled trials from CENTRAL, the Specialised Registers of Cochrane Review Groups, including Epilepsy, PubMed, Embase, ClinicalTrials.gov, and the World Health Organisation International Clinical Trials Registry Platform. We also checked the reference lists of identified studies, and contacted experts and colleagues in the field to search for additional and ongoing studies. SELECTION CRITERIA: Randomised and quasi‐randomised controlled trials. Single‐blind, double‐blind, or unblinded studies were eligible for inclusion. DATA COLLECTION AND ANALYSIS: We followed standard methodological procedures expected by Cochrane. Two review authors independently selected trials for inclusion and extracted the relevant data. The primary outcomes of interest were: proportion of individuals experiencing seizures, and time to first seizure post randomisation. Secondary outcomes included: seizure freedom, number of withdrawals, side effects, number of people seizure free with short or long durations of treatment, quality of life, therapy costs, hospitalisations, and mortality. We used an intention‐to‐treat analysis for the primary analysis. We calculated odds ratio (OR) for dichotomous data (proportion of individuals who experienced seizures, were seizure free for a specific time period (12 or 24 months), withdrew from treatment, developed drug‐related side effects or complications, were seizure‐free with each treatment policy, mortality), and planned to use mean difference (MD) for continuous data, if any continuous data were identified (quality of life, cost of treatment). We intended to evaluate time to first seizure after randomisation by calculating hazard ratios (HRs). We assessed precision using 95% confidence intervals (CIs). We stratified the analysis by treatment comparison. We also considered the duration of drug usage, co‐medications, and the length of follow‐up. MAIN RESULTS: We did not find any trials that investigated the role of AEDs in preventing seizures among people with neurocysticercosis, presenting with symptoms other than seizures. We did not find any trials that directly compared individual AEDs for primary prevention in people with neurocysticercosis. We included four trials that evaluated the efficacy of short‐term versus longer‐term AED treatment for people with solitary neurocysticercosis (identified on computed tomography (CT) scan) who presented with seizures. In total, 466 people were enrolled. These studies compared AED treatment durations of 6, 12, and 24 months. The risk of seizure recurrence with six months of treatment compared with 12 to 24 months of treatment was inconclusive (odds ratio (OR) 1.34, 95% confidence interval (CI) 0.73 to 2.47; three studies, 360 participants; low‐certainty evidence). The risk of seizure recurrence with six to 12 months of treatment compared with 24 months of treatment was inconclusive (OR 1.36, 95% CI 0.72 to 2.57; three studies, 385 participants; very low‐certainty evidence). Two studies compared seizure recurrence with CT findings, and suggested that persistent and calcified lesions had a higher recurrence risk, and suggest longer duration of treatment with AEDs. One study reported no side effects, while the rest did not comment on side effects of the drugs. None of the studies addressed the quality of life of the participants. These studies had methodological deficiencies, such as small sample sizes, and a possibility of bias due to lack of blinding, which affect the results of the review. AUTHORS' CONCLUSIONS: Despite neurocysticercosis being the most common cause of epilepsy worldwide, there is currently no evidence available regarding the use of AEDs as seizure prophylaxis among people presenting with symptoms other than seizures. For those presenting with seizures, there is no reliable evidence regarding the duration of treatment required. Therefore, there is a need for large scale randomised controlled trials to address these questions.

BackgroundMagnetic resonance imaging (MRI) of the brain could be a key diagnostic and research tool for understanding the neuropsychiatric complications of COVID-19. For maximum impact, multi-modal MRI protocols will be needed to measure the effects of SARS-CoV2 infection on the brain by diverse potentially pathogenic mechanisms, and with high reliability across multiple sites and scanner manufacturers.MethodsA multi-modal brain MRI protocol comprising sequences for T1-weighted MRI, T2-FLAIR, diffusion MRI (dMRI), resting-state functional MRI (fMRI), susceptibility-weighted imaging (swMRI) and arterial spin labelling (ASL) was defined in close approximation to prior UK Biobank (UKB) and C-MORE protocols for Siemens 3T systems. We iteratively defined a comparable set of sequences for General Electric (GE) 3T systems. To assess multi-site feasibility and between-site variability of this protocol, N=8 healthy participants were each scanned at 4 UK sites: 3 using Siemens PRISMA scanners (Cambridge, Liverpool, Oxford) and 1 using a GE scanner (King’s College London). Over 2,000 Imaging Derived Phenotypes (IDPs) measuring both data quality and regional image properties of interest were automatically estimated by customised UKB image processing pipelines. Components of variance and intra-class correlations were estimated for each IDP by linear mixed effects models and benchmarked by comparison to repeated measurements of the same IDPs from UKB participants.ResultsIntra-class correlations for many IDPs indicated good-to-excellent between-site reliability. First considering only data from the Siemens sites, between-site reliability generally matched the high levels of test-retest reliability of the same IDPs estimated in repeated, within-site, within-subject scans from UK Biobank. Inclusion of the GE site resulted in good-to-excellent reliability for many IDPs, but there were significant between-site differences in mean and scaling, and reduced ICCs, for some classes of IDP, especially T1 contrast and some dMRI-derived measures. We also identified high reliability of quantitative susceptibility mapping (QSM) IDPs derived from swMRI images, multi-network ICA-based IDPs from resting-state fMRI, and olfactory bulb structure IDPs from T1, T2-FLAIR and dMRI data.ConclusionThese results give confidence that large, multi-site MRI datasets can be collected reliably at different sites across the diverse range of MRI modalities and IDPs that could be mechanistically informative in COVID brain research. We discuss limitations of the study and strategies for further harmonization of data collected from sites using scanners supplied by different manufacturers. These protocols have already been adopted for MRI assessments of post-COVID patients in the UK as part of the COVID-CNS consortium.

Background:The spectrum of neurological and psychiatric complications associated with paediatric SARS-CoV-2 infection is poorly understood. We aimed to analyse the range and prevalence of these complications in hospitalised children and adolescents. Methods:We did a prospective national cohort study in the UK using an online network of secure rapid-response notification portals established by the CoroNerve study group. Paediatric neurologists were invited to notify any children and adolescents (age Findings:Between April 2, 2020, and Feb 1, 2021, 52 cases were identified; in England, there were 51 cases among 1334 children and adolescents hospitalised with COVID-19, giving an estimated prevalence of 3·8 (95% CI 2·9–5·0) cases per 100 paediatric patients. 22 (42%) patients were female and 30 (58%) were male; the median age was 9 years (range 1–17). 36 (69%) patients were Black or Asian, 16 (31%) were White. 27 (52%) of 52 patients were classified into the COVID-19 neurology group and 25 (48%) were classified into the PIMS-TS neurology group. In the COVID-19 neurology group, diagnoses included status epilepticus (n=7), encephalitis (n=5), Guillain-Barré syndrome (n=5), acute demyelinating syndrome (n=3), chorea (n=2), psychosis (n=2), isolated encephalopathy (n=2), and transient ischaemic attack (n=1). The PIMS-TS neurology group more often had multiple features, which included encephalopathy (n=22 [88%]), peripheral nervous system involvement (n=10 [40%]), behavioural change (n=9 [36%]), and hallucinations at presentation (n=6 [24%]). Recognised neuroimmune disorders were more common in the COVID-19 neurology group than in the PIMS-TS neurology group (13 [48%] of 27 patientsvs1 [vssix [22%] of 27 patients, p=0·0001) and received immunomodulatory treatment (22 [88%] patientsvs12 [44%] patients, p=0·045). 17 (33%) patients (10 [37%] in the COVID-19 neurology group and 7 [28%] in the PIMS-TS neurology group) were discharged with disability; one (2%) died (who had stroke, in the PIMS-TS neurology group). Interpretation:This study identified key differences between those with a primary neurological disorder versus those with PIMS-TS. Compared with patients with a primary neurological disorder, more patients with PIMS-TS needed intensive care, but outcomes were similar overall. Further studies should investigate underlying mechanisms for neurological involvement in COVID-19 and the longer-term outcomes.

Background: A high prevalence of antiphospholipid antibodies has been reported in case series of patients with neurological manifestations and COVID-19; however, the pathogenicity of antiphospholipid antibodies in COVID-19 neurology remains unclear. Methods: This single-centre cross-sectional study included 106 adult patients: 30 hospitalised COVID-neurological cases, 47 non-neurological COVID-hospitalised controls, and 29 COVID-non-hospitalised controls, recruited between March and July 2020. We evaluated nine antiphospholipid antibodies: anticardiolipin antibodies [aCL] IgA, IgM, IgG; anti-beta-2 glycoprotein-1 [aβ2GPI] IgA, IgM, IgG; anti-phosphatidylserine/prothrombin [aPS/PT] IgM, IgG; and anti-domain I β2GPI (aD1β2GPI) IgG. Findings: There was a high prevalence of antiphospholipid antibodies in the COVID-neurological (73.3%) and non-neurological COVID-hospitalised controls (76.6%) in contrast to the COVID-non-hospitalised controls (48.2%). aPS/PT IgG titres were significantly higher in the COVID-neurological group compared to both control groups (p

The scientific community rapidly responded to the COVID-19 pandemic by developing novel SARS-CoV-2 vaccines (table 1). As of early June 2021, an estimated 2 billion doses have been administered worldwide.1 Neurological adverse events following immunisation (AEFI), such as cerebral venous sinus thrombosis and demyelinating episodes, have been reported. In some countries, these have led to the temporary halting of both vaccine trials and roll-out programmes. In the absence of clear evidence of causal associations between the vaccine and adverse events, or the rarity of the AEFIs themselves, programmes have thus far been restarted, although sometimes with modifications to recommendations.2 View this table: Table 1 SARS-CoV-2 vaccines approved for use by at least one regulatory body at the time of submission (early June 2021)71 Transient influenza-like symptoms such as headache, myalgia and fatigue have been reported in up to 5% of SARS-CoV-2 vaccine recipients in clinical trials,3 4 although these symptoms often indicate an appropriate immune response to vaccination.5 More severe potential adverse effects in the open-label phase of vaccine roll-outs are being collected through national surveillance systems. In the USA, roughly 372 adverse events have been reported per million doses, which is a lower rate than expected based on the clinical trials.6 In the UK, adverse events are reported via the Coronavirus Yellow Card reporting website. As of early June 2021, approximately 250 000 Yellow Cards have been submitted, equating to around three to seven Yellow Cards per 1000 doses.7 For comparison, the 2010 Pandemrix vaccination had a rate of around 0.6 Yellow Card submissions per 1000 doses.8 Increased pharmacovigilance surrounding SARS-CoV-2 vaccinations may lead to surveillance bias,9 safety alerts may lead to notoriety bias10 and recall bias may also occur. Nevertheless, with large numbers of people being vaccinated, often with a two-dose schedule, rare complications …

There is accumulating evidence of the neurological and neuropsychiatric features of infection with SARS-CoV-2. In this systematic review and meta-analysis, we aimed to describe the characteristics of the early literature and estimate point prevalences for neurological and neuropsychiatric manifestations. We searched MEDLINE, Embase, PsycINFO and CINAHL up to 18 July 2020 for randomised controlled trials, cohort studies, case-control studies, cross-sectional studies and case series. Studies reporting prevalences of neurological or neuropsychiatric symptoms were synthesised into meta-analyses to estimate pooled prevalence. 13 292 records were screened by at least two authors to identify 215 included studies, of which there were 37 cohort studies, 15 case-control studies, 80 cross-sectional studies and 83 case series from 30 countries. 147 studies were included in the meta-analysis. The symptoms with the highest prevalence were anosmia (43.1% (95% CI 35.2% to 51.3%), n=15 975, 63 studies), weakness (40.0% (95% CI 27.9% to 53.5%), n=221, 3 studies), fatigue (37.8% (95% CI 31.6% to 44.4%), n=21 101, 67 studies), dysgeusia (37.2% (95% CI 29.8% to 45.3%), n=13 686, 52 studies), myalgia (25.1% (95% CI 19.8% to 31.3%), n=66 268, 76 studies), depression (23.0% (95% CI 11.8% to 40.2%), n=43 128, 10 studies), headache (20.7% (95% CI 16.1% to 26.1%), n=64 613, 84 studies), anxiety (15.9% (5.6% to 37.7%), n=42 566, 9 studies) and altered mental status (8.2% (95% CI 4.4% to 14.8%), n=49 326, 19 studies). Heterogeneity for most clinical manifestations was high. Neurological and neuropsychiatric symptoms of COVID-19 in the pandemic’s early phase are varied and common. The neurological and psychiatric academic communities should develop systems to facilitate high-quality methodologies, including more rapid examination of the longitudinal course of neuropsychiatric complications of newly emerging diseases and their relationship to neuroimaging and inflammatory biomarkers.

SUMMARYBackgroundThe nature and extent of persistent neuropsychiatric symptoms after COVID-19 are not established. To help inform mental health service planning in the pandemic recovery phase, we systematically determined the prevalence of neuropsychiatric symptoms in survivors of COVID-19.MethodsFor this pre-registered systematic review and meta-analysis (PROSPERO ID CRD42021239750) we searched PubMed, EMBASE, CINAHL and PsycINFO to 20th February 2021, plus our own curated database. We included peer-reviewed studies reporting neuropsychiatric symptoms at post-acute or later time-points after COVID-19 infection, and in control groups where available. For each study a minimum of two authors extracted summary data. For each symptom we calculated a primary pooled prevalence using generalised linear mixed models. Heterogeneity was measured withI2. Subgroup analyses were conducted for COVID-19 hospitalisation, severity, and duration of follow-up.FindingsFrom 2,844 unique titles we included 51 studies (n=18,917 patients). The mean duration of follow-up after COVID-19 was 77 days (range 14-182 days). Study quality was generally moderate. The most frequent neuropsychiatric symptom was sleep disturbance (pooled prevalence=27·4% [95%CI 21·4- 34·4%]), followed by fatigue (24·4% [17·5-32·9%]), objective cognitive impairment (20·2% [10·3-35·7%]), anxiety (19·1%[13·3-26·8%]), and post-traumatic stress (15·7% [9·9-24·1%]). Only two studies reported symptoms in control groups, both reporting higher frequencies in Covid-19 survivors versus controls. Between-study heterogeneity was high (I2=79·6%-98·6%). There was little or no evidence of differential symptom prevalence based on hospitalisation status, severity, or follow-up duration.InterpretationNeuropsychiatric symptoms are common and persistent after recovery from COVID-19. The literature on longer-term consequences is still maturing, but indicates a particularly high frequency of insomnia, fatigue, cognitive impairment, and anxiety disorders in the first six months after infection.FundingJPR is supported by the Wellcome Trust (102186/B/13/Z).IK is funded through the NIHR (Oxford Health Biomedical Research Facility, Development and Skills Enhancement Award) and the Medical Research Council (Dementias Platform UK and Deep and Frequent Phenotyping study project grants).HH is funded by the German Research Foundation (DFG, Grant: HO 1286/16-1). The funders played no role in the design, analysis or decision to publish.RESEARCH IN CONTEXTEvidence before this studyNeuropsychiatric symptoms like cognitive impairment, fatigue, insomnia, depression and anxiety can be highly disabling. Recently there has been increasing awareness of persistent neuropsychiatric symptoms after COVID-19 infection, but a systematic synthesis of these symptoms is not available. In this review we searched five databases up to 20th February 2021, to establish the pooled prevalence of individual neuropsychiatric symptoms up to six months after COVID-19.Added value of this studyThis study establishes which of a range of neuropsychiatric symptoms are the most common after COVID-19. We found high rates in general, with little convincing evidence that these symptoms lessen in frequency during the follow-up periods studied.ImplicationsPersistent neuropsychiatric symptoms are common and appear to be limited neither to the post-acute phase, nor to recovery only from severe COVID-19. Our results imply that health services should plan for high rates of requirement for multidisciplinary services (including neurological, neuropsychiatric and psychological management) as populations recover from the COVID-19 pandemic.

SARS-CoV-2 is associated with new-onset neurological and psychiatric conditions. Detailed clinical data, including factors associated with recovery, are lacking, hampering prediction modelling and targeted therapeutic interventions. In a UK-wide cross-sectional surveillance study of adult hospitalized patients during the first COVID-19 wave, with multi-professional input from general and sub-specialty neurologists, psychiatrists, stroke physicians, and intensivists, we captured detailed data on demographics, risk factors, pre-COVID-19 Rockwood frailty score, comorbidities, neurological presentation and outcome. A priori clinical case definitions were used, with cross-specialty independent adjudication for discrepant cases. Multivariable logistic regression was performed using demographic and clinical variables, to determine the factors associated with outcome. A total of 267 cases were included. Cerebrovascular events were most frequently reported (131, 49%), followed by other central disorders (95, 36%) including delirium (28, 11%), central inflammatory (25, 9%), psychiatric (25, 9%), and other encephalopathies (17, 7%), including a severe encephalopathy (n = 13) not meeting delirium criteria; and peripheral nerve disorders (41, 15%). Those with the severe encephalopathy, in comparison to delirium, were younger, had higher rates of admission to intensive care and a longer duration of ventilation. Compared to normative data during the equivalent time period prior to the pandemic, cases of stroke in association with COVID-19 were younger and had a greater number of conventional, modifiable cerebrovascular risk factors. Twenty-seven per cent of strokes occurred in patients 60 years old, the younger stroke patients presented with delayed onset from respiratory symptoms, higher rates of multi-vessel occlusion (31%) and systemic thrombotic events. Clinical outcomes varied between disease groups, with cerebrovascular disease conferring the worst prognosis, but this effect was less marked than the pre-morbid factors of older age and a higher pre-COVID-19 frailty score, and a high admission white cell count, which were independently associated with a poor outcome. In summary, this study describes the spectrum of neurological and psychiatric conditions associated with COVID-19. In addition, we identify a severe COVID-19 encephalopathy atypical for delirium, and a phenotype of COVID-19 associated stroke in younger adults with a tendency for multiple infarcts and systemic thromboses. These clinical data will be useful to inform mechanistic studies and stratification of patients in clinical trials., Ross Russell et al. report novel details of COVID-19 neurological complications: multiple overlapping diagnoses in the same patients, a severe encephalopathy atypical for delirium, and a lowered threshold for stroke in younger adults. Higher age, pre-morbid frailty score and white cell count predicted clinical outcome., Graphical Abstract Graphical Abstract

Background This is an updated version of the Cochrane review published in 2015. Around half of people with epilepsy will not achieve seizure freedom on their first antiepileptic drug; many will require add-on therapy. Around a third of people fail to achieve complete seizure freedom despite multiple antiepileptic drugs. Lacosamide has been licenced as an add-on therapy for drug-resistant focal epilepsy. Objectives To evaluate the efficacy and tolerability of lacosamide as an add-on therapy for children and adults with drug-resistant focal epilepsy. Search methods We searched the following databases (22 August 2019): the Cochrane Register of Studies (CRS Web), including the Cochrane Epilepsy Group Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid, 1946 to 20 August 2019), ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP), with no language restrictions. We contacted UCB Pharma (sponsors of lacosamide). Selection criteria Randomised controlled trials of add-on lacosamide in people with drug-resistant focal epilepsy. Data collection and analysis We used standard Cochrane methodology, assessing the following outcomes: 50% or greater reduction in seizure frequency; seizure freedom; treatment withdrawal; adverse events; quality of life; and cognitive changes. The primary analyses were intention-to-treat. We estimated summary risk ratios (RR) for each outcome presented with 99% confidence intervals (CI), except for 50% or greater seizure reduction, seizure freedom and treatment withdrawal which were presented with 95% CIs. We performed subgroup analyses according to lacosamide dose and sensitivity analyses according to population age, whereby data from children were excluded from the meta-analysis. Main results We included five trials (2199 participants). The risk of bias for all studies was low to unclear. All studies were placebo-controlled and assessed doses from 200 mg to 600 mg per day. One study evaluated lacosamide in children; all other studies were in adults. Trial duration ranged from 24 to 26 weeks. All studies used adequate methods of randomisation and were double-blind. Overall, the certainty of the evidence for the outcomes was judged as moderate to high, with the exception of seizure freedom which was low. The RR for a 50% or greater reduction in seizure frequency for all doses of lacosamide compared with placebo was 1.79 (95% CI 1.55 to 2.08; 5 studies; 2199 participants; high-certainty evidence). The RR for seizure freedom for all doses of lacosamide compared with placebo was 2.27 (95% CI 1.35 to 3.83; 5 studies; 2199 participants; low-certainty evidence). The RR for treatment withdrawal for all doses of lacosamide compared with placebo was 1.57 (95% CI 1.24 to 1.98; 5 studies; 2199 participants; moderate-certainty evidence). The estimated effect size for most outcomes did not change considerably following sensitivity analysis. For seizure freedom, however, the RR nearly doubled upon the exclusion of data from children (RR 4.04, 95% CI 1.52 to 10.73). Adverse events associated with lacosamide included: abnormal co-ordination (RR 6.12, 99% CI 1.35 to 27.77), blurred vision (RR 4.65, 99% CI 1.24 to 17.37), diplopia (RR 5.59, 99% CI 2.27 to 13.79), dizziness (RR 2.96, 99% CI 2.09 to 4.20), nausea (RR 2.35, 99% CI 1.37 to 4.02), somnolence (RR 2.04, 99% CI 1.22 to 3.41), vomiting (RR 2.94, 99% CI 1.54 to 5.64), and number of participants experiencing one or more adverse events (RR 1.12, 99% CI 1.01 to 1.24). Adverse events that were not significant were: vertigo (RR 3.71, 99% CI 0.86 to 15.95), rash (RR 0.58, 99% CI 0.17 to 1.89), nasopharyngitis (RR 1.41, 99% CI 0.87 to 2.28), headache (RR 1.34, 99% CI 0.90 to 1.98), fatigue (RR 2.11, 99% CI 0.92 to 4.85), nystagmus (RR 1.47, 99% CI 0.61 to 3.52), and upper respiratory tract infection (RR 0.70, 99% CI 0.43 to 1.15). Authors' conclusions Lacosamide is effective and well-tolerated in the short term when used as add-on treatment for drug-resistant focal epilepsy. Lacosamide increases the number of people with 50% or greater reduction in seizure frequency and may increase seizure freedom, compared to placebo. Higher doses of lacosamide may be associated with higher rates of adverse events and treatment withdrawal. Additional evidence is required assessing the use of lacosamide in children and on longer-term efficacy and tolerability.

SummaryObjectiveTo summarize the frequency of neurological manifestations reported in COVID-19 patients and investigate the association of these manifestations with disease severity and mortality.DesignSystematic review and meta-analysisEligibility criteriaStudies enrolling consecutive COVID-19 patients (probable or confirmed) presenting with neurological manifestations.Data sourcesPubMed, Medline, Cochrane library, clinicaltrials.gov and EMBASE from 31st December 2019 to 15th December 2020.Data extraction and analysisTwo authors independently screened titles and abstracts retrieved by literature search. Risk of bias was examined using Joanna Briggs Institute (JBI) scale. A random-effects meta-analysis was performed, and pooled prevalence and 95% Confidence Intervals (CI) were calculated for neurological manifestations. Odds ratio (OR) and 95%CI were calculated to determine the association of neurological manifestations with disease severity and mortality. Presence of heterogeneity was assessed using I-square, meta-regression, and subgroup analyses. Statistical analyses were conducted in R version 3.6.2.ResultsOf 2,455 citations, 350 studies were included in this review, providing data on 145,634 COVID-19 patients, 89% of whom were hospitalized. Forty-one neurological manifestations (24 symptoms and 17 diagnoses) were identified. Pooled prevalence of the most common neurological symptoms included: fatigue (32%), myalgia (20%), taste impairment (21%), smell impairment (19%) and headache (13%). A low risk of bias was observed in 85% of studies; studies with higher risk of bias yielded higher prevalence estimates. Stroke was the most common neurological diagnosis (pooled prevalence-2%). In COVID-19 patients aged >60, the pooled prevalence of acute confusion/delirium was 34% and the presence of any neurological manifestations in this age group was associated with mortality (OR 1.80; 95%CI 1.11 to 2.91).ConclusionsUp to one-third of COVID-19 patients analysed in this review experienced at least one neurological manifestation. One in 50 patients experienced stroke. In those over 60, more than one-third had acute confusion/delirium; the presence of neurological manifestations in this group was associated with near doubling of mortality. Results must be interpreted keeping in view the limitations of observational studies and associated bias.Systematic review registrationPROSPERO CRD42020181867.What is already known on this topicThe frequency of neurological manifestations including fatigue, myalgia, taste and smell impairments, headache and dizziness in COVID-19 patients has been reported in a few systematic reviews and meta-analyses. However, considerable heterogeneity has been observed in terms of methodological quality of the studies, severity of the disease, mean age and hospitalization status of the patients. The evidence regarding the frequency of neurological diagnoses including stroke, encephalitis, Guillain Barré syndrome (GBS) is also limited to case reports and case series and no data exists thus far on the pooled prevalence estimates for neurological diagnoses in COVID-19 patients.What this study addsTo the best of the authors’ knowledge, this is the largest systematic review and meta-analysis to date (including 350 studies with data on 145,634 cases) summarizing the evidence on the frequency of the full spectrum of neurological manifestations in COVID-19 patients in the overall, young and elderly populations. For the first time, our review reports the pooled prevalence of stroke in COVID-19 patients. Risk of bias, old age and disease severity were potential determinants of the frequency and nature of neurological manifestations as well as its association with mortality. Our review also highlights the need to develop reporting standards for studies describing the frequency of clinical features. Moreover, we note that this will be the first systematic review and meta-analysis on this subject to include studies reported in all languages.

Background and ObjectivesThe utility of the Glasgow Coma Scale (GCS) in intubated patients is limited due to reliance on language function evaluation. The Full Outline of Unresponsiveness (FOUR) Score was designed to circumvent this shortcoming, instead adding evaluations of brainstem reflexes (FOUR B) and specific respiratory patterns (FOUR R). We aimed to determine whether the verbal component of the GCS (GCS V) among nonintubated patients with encephalopathy significantly contributes to mortality prediction and to assess GCS vs FOUR Score performance.MethodsAll prospectively consented patients ≥18 years of age admitted to the Internal Medicine service at Zambia's University Teaching Hospital from October 3, 2017, to May 21, 2018, with a GCS score ≤10 have undergone simultaneous GCS and FOUR Score assessments. The patients were not eligible for mechanical ventilatory support per local standards. Patients' demographics and clinical characteristics were presented as either percentage frequencies or numerical summaries of spread. The predictive power of the GCS without the Verbal component vs total GCS vs FOUR Score on mortality was estimated with the area under the receiver operating characteristic curve (AU ROC).ResultsTwo hundred thirty-five patients (50% women, mean age 47.5 years) were enrolled. All patients were Black. Presumed etiology was CNS infection (64, 27%), stroke (63, 27%), systemic infection (39, 16.6%), and metabolic encephalopathy (3, 14.5%); 14.9% had unknown etiology. In-hospital mortality was 83%. AU ROC for GCS Eye + Motor score (0.662) vs total GCS score (0.641) vs total FOUR Score (0.657) did not differ. Odds ratio mortality for GCS score >6 vs ≤6 was 0.32 (95% confidence interval [CI] 0.14–0.72, p = 0.01); for FOUR Score >10 vs ≤10, it was 0.41 (95% CI 0.19–0.86, p = 0.02).DiscussionAbsence of a verbal component of GCS had no significant impact on the performance of the total GCS, and either GCS or FOUR Score is an acceptable scoring tool for mortality prediction in the resource-limited setting. These findings need further validation in the countries with readily available mechanical ventilatory support.Classification of EvidenceThis study provides Class I evidence that the verbal component of the GCS does not significantly contribute to a total GCS score in mortality prediction among patients with encephalopathy who are not intubated.

The COVID-19 pandemic death toll now surpasses two million individuals and there is a need for early identification of individuals at increased risk of mortality. Host genetic variation partially drives the immune and biochemical responses to COVID-19 that lead to risk of mortality. We identify and prioritise blood proteins and biomarkers that may indicate increased risk for severe COVID-19, via a proteome Mendelian randomization approach by collecting genome-wide association study (GWAS) summary statistics for >4,000 blood proteins. After multiple testing correction, troponin I3, cardiac type (TNNI3) had the strongest effect (odds ratio (O.R.) of 6.86 per standard deviation increase in protein level), with proteinase 3 (PRTN3) (O.R.=2.48), major histocompatibility complex, class II, DQ alpha 2 (HLA-DQA2) (O.R.=2.29), the C4A-C4B heterodimer (O.R.=1.76) and low-density lipoprotein receptor-related protein associated protein 1 (LRPAP1) (O.R.=1.73) also being associated with higher odds of severe COVID-19. Conversely, major histocompatibility complex class I polypeptide-related sequence A (MHC1A) (O.R.=0.6) and natural cytotoxicity triggering receptor 3 (NCR3) (O.R.=0.46) were associated with lower odds. These proteins are involved in heart muscle contraction, natural killer and antigen presenting cells, and the major histocompatibility complex. Based on these findings, it may be possible to better predict which patients may develop severe COVID-19 and to design better treatments targeting the implicated mechanisms.

ObjectivesThere is accumulating evidence of the neurological and neuropsychiatric features of infection with SARS-CoV-2. In this systematic review and meta-analysis, we aimed to describe the characteristics of the early literature and estimate point prevalences for neurological and neuropsychiatric manifestations.MethodsWe searched MEDLINE, Embase, PsycInfo and CINAHL up to 18 July 2020 for randomised controlled trials, cohort studies, case-control studies, cross-sectional studies and case series. Studies reporting prevalences of neurological or neuropsychiatric symptoms were synthesised into meta-analyses to estimate pooled prevalence.Results13,292 records were screened by at least two authors to identify 215 included studies, of which there were 37 cohort studies, 15 case-control studies, 80 cross-sectional studies and 83 case series from 30 countries. 147 studies were included in the meta-analysis. The symptoms with the highest prevalence were anosmia (43.1% [35.2—51.3], n=15,975, 63 studies), weakness (40.0% [27.9—53.5], n=221, 3 studies), fatigue (37.8% [31.6—44.4], n=21,101, 67 studies), dysgeusia (37.2% [30.0—45.3], n=13,686, 52 studies), myalgia (25.1% [19.8—31.3], n=66.268, 76 studies), depression (23.0 % [11.8—40.2], n=43,128, 10 studies), headache (20.7% [95% CI 16.1—26.1], n=64,613, 84 studies), anxiety (15.9% [5.6—37.7], n=42,566, 9 studies) and altered mental status (8.2% [4.4—14.8], n=49,326, 19 studies). Heterogeneity for most clinical manifestations was high.ConclusionsNeurological and neuropsychiatric symptoms of COVID-19 in the pandemic’s early phase are varied and common. The neurological and psychiatric academic communities should develop systems to facilitate high-quality methodologies, including more rapid examination of the longitudinal course of neuropsychiatric complications of newly emerging diseases and their relationship to neuroimaging and inflammatory biomarkers.

Historical epidemiological perspectives from past pandemics and recent neurobiological evidence link infections and psychoses, leading to concerns that COVID-19 will present a significant risk for the development of psychosis. But are these concerns justified, or mere sensationalism? In this article we review the historical associations between viral infection and the immune system more broadly in the development of psychosis, before critically evaluating the current evidence pertaining to SARS-CoV-2 and risk of psychosis as an acute or post-infectious manifestation of COVID-19. We review the 42 cases of psychosis reported in infected patients to date, and discuss the potential implications of in utero infection on subsequent neurodevelopment and psychiatric risk. Finally, in the context of the wider neurological and psychiatric manifestations of COVID-19 and our current understanding of the aetiology of psychotic disorders, we evaluate possible neurobiological and psychosocial mechanisms as well as the numerous challenges in ascribing a causal pathogenic role to the infection.

Background: Pre-existing diseases are considered risk factors for severe COVID-19 and death. However, there is lack of consolidated global data on this risk among individuals with pre-existing neurological disease. Aim: Investigate the impact of pre-existing neurological disease on the clinical course and outcome of COVID-19. Methods: A rapid review of literature from PubMed and the World Health Organization (WHO) COVID-19 database was conducted for articles published between 1st January 2020 and 4th April 2021. The review included individuals with COVID-19 and pre-existing neurological disease using pre-generated search terms to capture chronic neurological diseases in all age-groups. Articles included in the review were systematic reviews and meta-analysis, cohort studies, retrospective studies, case-control studies and case series. From the included studies, demographic data and Odds Ratios (OR) were extracted, and pooled ORs were generated for the outcomes of COVID-19 severity and death. Results: Twenty-six articles from 12 countries across three continents with a total of 379,947 COVID-19 patients was included. The mean age was 57 years (SD 10.93), 51.3% of whom were female. Pre-existing neurological disease, particularly cerebrovascular disease and dementia, was shown to be a risk factor for severe COVID-19 with a pooled OR of 1.99 (1.81 – 2.18). There was also an increased risk of death with a pooled OR for pre-existing neurological disease overall of 1.74 (1.56 – 1.94). Conclusion: The findings suggest that pre-existing neurological disease is a significant risk factor for severe COVID-19 and mortality. Further investigations to consolidate these findings are required through large multi-national cohort studies.

Background: Neurological COVID-19 disease has been reported widely, but often without using standard case definitions or detailed diagnostic work up. Several meta-analyses, based on such reports, describe the neurological diagnoses but give little information on outcomes and risk factors. Methods: We conducted an individual patient data meta-analysis of hospitalised patients with neurological COVID-19 disease, using standard case definitions. We invited authors of studies from the first pandemic wave, plus clinicians in the Global COVID-Neuro Network with unpublished data, to contribute, and extracted aggregate data from published reports. We analysed features associated with poor outcome (moderate to severe sequelae or death, 3-6, on the modified Rankin scale) using multivariable models. Findings: We identified 381 studies (31 unpublished) describing 4443 patients with COVID-19 and neurological disease: 83 of these provided IPD for 1979 (45%) patients. Encephalopathy (978 [49%]) and cerebrovascular events (506 [26%]), were the most common diagnoses in the IPD database and aggregate data. Respiratory and systemic symptoms preceded neurological features in 93% of patients; one third developed neurological disease after hospital admission. A poor outcome was more common in patients with cerebrovascular events (76% [95% CI 67-82]), than encephalopathy (54% [42-65]). Intensive care use was high (38% [35-41] overall), and also greater in the cerebrovascular patients. In the cerebrovascular, but not encephalopathic patients, risk factors for poor outcome included breathlessness on admission and elevated D-Dimer. Overall, 30-day mortality was 30% (27-32). The hazard of death was reduced for patients in the WHO European region, but increased in low- and lower-middle-income countries. Interpretation: Neurological COVID-19 disease poses a considerable burden in terms of disease outcomes and use of hospital resources. The different risk factors for encephalopathy and stroke suggest different disease mechanisms which may be amenable to intervention, especially in those who develop neurological symptoms after hospital admission. Funding This study was funded by the UK Medical Research Council’s Global Effort on COVID-19 Programme (MR/V033441/1); UK National Institute for Health Research (NIHR)-funded Global Health Research Group on Acute Brain Infections (17/63/110); and the NIHR Health Protection Research Unit in Emerging and Zoonotic Infections (NIHR200907), at University of Liverpool in partnership with Public Health England (PHE), in collaboration with Liverpool School of Tropical Medicine and the University of Oxford (Grant Nos. IS-HPU-1112-10117 and NIHR200907). Declaration of Interests: BS reports a grant from UKRI/DHSC Global Effort on COVID-19 Research (Medical Research Council) and non-financial support from UK National Institute for Health Research Global Health Research Group on Brain Infections. SL and TS are supported by a grant from the EU Zika Preparedness Latin American Network consortium (ZikaPLAN). ZikaPLAN has received funding from the EU's Horizon 2020 research and innovation programme under grant agreement number 734584. LCG reports non-financial support from Pfizer, non-financial support from Gilead. LB reports grants from GlaxoSmithKline, Research England and Wellcome Trust. AMBM reports grants from Conselho Nacional de Desenvolvimento Cientifico e Tecnologico CNPq/Brazil, and Sao Paulo Research Foundation FAPESP/Brazil. AP reports personal fees from ZAMBON, UCB , BIOMARIN, and ABBvie pharma. TS was an adviser to the GlaxoSmithKline Ebola Vaccine programme, chaired a Siemens Diagnostics clinical advisory board, and advises the WHO Brain Health Unit Forum on Neurology and COVID-19; TS has also previously filed a patent for a test for bacterial meningitis based on a blood test (GB 1606537.7, April 14, 2016), and has grants from the UK Medical Research Council and National Institute for Health Research. All other authors declare no conflict of interest

Worldwide SARS-CoV-2 vaccination campaigns for prevention of COVID-19 are currently underway. In clinical trials and in open-label monitoring the vaccines have shown efficacy against COVID-19 and there have been limited and transient side effects. Previous vaccination campaigns have taught us that neurological adverse events to vaccinations can occur. In this review, we summarise what is already known about neurological and neuropsychiatric adverse events of COVID-19 vaccinations, and place this in the context of historical vaccination campaigns. There have been a number of neurological and neuropsychiatric adverse events following immunisation (AEFI) in association with SARS-CoV-2 vaccinations, however in each case there is either no definitive evidence currently to support causality or recognised adverse events are extremely rare. Causality assessment aids such as the Causality Assessment of an Adverse Event Following Immunization from the World Health Organisation and the Bradford Hill criteria may help us better understand potential neurological and neuropsychiatric adverse events to COVID-19 vaccinations. Functional neurological disorder (FND) can be precipitated by the process of vaccination and has previously been noted to potentially spread between individuals, particularly in younger communities. Importantly FND does not implicate the vaccine constituents and therefore should not hamper ongoing vaccination campaigns. Although neurological and neuropsychiatric AEFI may occur after SARS-CoV-2 vaccinations, at present there are no common causally associated neurological adverse events. It is likely that some patients will develop FND in response to vaccination, although this does not implicate vaccine constituents. In cases of future serious neurological or neuropsychiatric AEFIs, judicious and rapid assessment of causality must occur. In general, the benefits of ARS-CoV-2 vaccination at present outweigh the risks from a neurological standpoint, although in specific situations the risk-benefit ratio will vary depending on geographic and demographic factors as well as population risk factors. Ensuring as minimal disruption as possible to ongoing swift worldwide vaccination campaigns is essential to establish the herd immunity required to end the COVID-19 pandemic.

Encephalopathy is a common complication of COVID-19 that can both be a challenge to manage and also negatively impacts prognosis. Whilst encephalopathy may be due to common systemic causes, such as hypoxia, COVID-19 has also been associated with more prolonged encephalopathy due to less common but nevertheless severe complications, such as inflammation of the brain parenchyma, cerebrovascular involvement and seizures, which may be disproportionate to COVID-19 severity and which require specific management. The aim of this review is to provide pragmatic guidance on the management of COVID-19 encephalopathy through a consensus agreement of the Global COVID-19 Neuro-Research Coalition. A systematic literature search of Medline, MedRxiv, and BioRx was conducted between 1st January 2020 and 11th June 2021 with additional review of references cited within the identified bibliographies. A modified Delphi-approach was then undertaken to develop recommendations along with a parallel approach to score the strength of both the recommendation and the supporting evidence. This manuscript presents analysis of contemporaneous evidence for definition, epidemiology, and pathophysiology of COVID-19 encephalopathy and practical guidance for clinical assessment, investigation, and acute and long-term management.

Background:Concerns regarding potential neurological complications of COVID-19 are being increasingly reported, primarily in small series. Larger studies have been limited by both geography and specialty. Comprehensive characterisation of clinical syndromes is crucial to allow rational selection and evaluation of potential therapies. The aim of this study was to investigate the breadth of complications of COVID-19 across the UK that affected the brain.Methods:During the exponential phase of the pandemic, we developed an online network of secure rapid-response case report notification portals across the spectrum of major UK neuroscience bodies, comprising the Association of British Neurologists (ABN), the British Association of Stroke Physicians (BASP), and the Royal College of Psychiatrists (RCPsych), and representing neurology, stroke, psychiatry, and intensive care. Broad clinical syndromes associated with COVID-19 were classified as a cerebrovascular event (defined as an acute ischaemic, haemorrhagic, or thrombotic vascular event involving the brain parenchyma or subarachnoid space), altered mental status (defined as an acute alteration in personality, behaviour, cognition, or consciousness), peripheral neurology (defined as involving nerve roots, peripheral nerves, neuromuscular junction, or muscle), or other (with free text boxes for those not meeting these syndromic presentations). Physicians were encouraged to report cases prospectively and we permitted recent cases to be notified retrospectively when assigned a confirmed date of admission or initial clinical assessment, allowing identification of cases that occurred before notification portals were available. Data collected were compared with the geographical, demographic, and temporal presentation of overall cases of COVID-19 as reported by UK Government public health bodies.Findings:The ABN portal was launched on April 2, 2020, the BASP portal on April 3, 2020, and the RCPsych portal on April 21, 2020. Data lock for this report was on April 26, 2020. During this period, the platforms received notification of 153 unique cases that met the clinical case definitions by clinicians in the UK, with an exponential growth in reported cases that was similar to overall COVID-19 data from UK Government public health bodies. Median patient age was 71 years (range 23–94; IQR 58–79). Complete clinical datasets were available for 125 (82%) of 153 patients. 77 (62%) of 125 patients presented with a cerebrovascular event, of whom 57 (74%) had an ischaemic stroke, nine (12%) an intracerebral haemorrhage, and one (1%) CNS vasculitis. 39 (31%) of 125 patients presented with altered mental status, comprising nine (23%) patients with unspecified encephalopathy and seven (18%) patients with encephalitis. The remaining 23 (59%) patients with altered mental status fulfilled the clinical case definitions for psychiatric diagnoses as classified by the notifying psychiatrist or neuropsychiatrist, and 21 (92%) of these were new diagnoses. Ten (43%) of 23 patients with neuropsychiatric disorders had new-onset psychosis, six (26%) had a neurocognitive (dementia-like) syndrome, and four (17%) had an affective disorder. 18 (49%) of 37 patients with altered mental status were younger than 60 years and 19 (51%) were older than 60 years, whereas 13 (18%) of 74 patients with cerebrovascular events were younger than 60 years versus 61 (82%) patients older than 60 years. Interpretation:To our knowledge, this is the first nationwide, cross-specialty surveillance study of acute neurological and psychiatric complications of COVID-19. Altered mental status was the second most common presentation, comprising encephalopathy or encephalitis and primary psychiatric diagnoses, often occurring in younger patients. This study provides valuable and timely data that are urgently needed by clinicians, researchers, and funders to inform immediate steps in COVID-19 neuroscience research and health policy. Funding: None.

Herpes simplex virus (HSV)-1 encephalitis has significant morbidity partly because of an over-exuberant immune response characterized by leukocyte infiltration into the brain and increased blood-brain barrier (BBB) permeability. Determining the role of specific leukocyte subsets and the factors that mediate their recruitment into the brain is critical to developing targeted immune therapies. In a murine model, we find that the chemokines CXCL1 and CCL2 are induced in the brain following HSV-1 infection. Ccr2 (CCL2 receptor)-deficient mice have reduced monocyte recruitment, uncontrolled viral replication, and increased morbidity. Contrastingly, Cxcr2 (CXCL1 receptor)-deficient mice exhibit markedly reduced neutrophil recruitment, BBB permeability, and morbidity, without influencing viral load. CXCL1 is produced by astrocytes in response to HSV-1 and by astrocytes and neurons in response to IL-1α, and it is the critical ligand required for neutrophil transendothelial migration, which correlates with BBB breakdown. Thus, the CXCL1-CXCR2 axis represents an attractive therapeutic target to limit neutrophil-mediated morbidity in HSV-1 encephalitis.

Reply by the current author to the comments made by Mark A Oldham et al (see record 2020-79526-008) and Dorothy Wade et al (see record 2020-79526-009) on the original article (see record 2020-71085-023) We thank Dorothy Wade and colleagues and Mark Oldham and colleagues for their recognition of the cross-speciality effort of members of the UK's major professional neuroscience bodies who undertook this challenging UK-wide study during the exponential phase of the COVID-19 pandemic We also welcome the involvement of geriatricians and psychologists in future research We agree that delirium is common, especially in severe infections and in the intensive care unit As stated in our Article, we acknowledge that the study might have not recorded all such cases Changes in mental status with clear and recognised risk factors were not the focus of this study We agree that if such commonly observed complications were included, they might have substantially increased the number of patients recruited, mirroring the situation in other critical illnesses In this situation, the burden of CNS complications arising from COVID-19 would be even greater than we found in our study (PsycInfo Database Record (c) 2020 APA, all rights reserved)

In recent years, autoimmunity has been increasingly recognised as an important cause of encephalitis. Many different antibodies are now known to target antigens on the neuronal surface, and some of these are associated with characteristic clinical presentations, although seronegative cases are also recognised. Autoimmune encephalitis may mimic other conditions, including primary psychiatric disorders, particularly early in the disease. Because early immune treatment of autoimmune encephalitis improves patient outcomes, and indeed many make a good recovery, it is important to recognise these syndromes promptly.

One hundred years ago, neurologists were faced with a surge of cases of uncertain cause manifesting a protean array of symptoms. Through careful semiological description, pattern recognition and histopathological analysis, von Economo and others unified these seemingly disparate cases, defining the epidemic of encephalitis lethargica. Several landmark papers in the Journal of Neurology and Psychopathology (now JNNP) helped to illuminate clinical and pathological aspects of this new disease. In the subsequent hundred years, there have been other infectious epidemics affecting the nervous system, with causative agents including flaviviruses, influenza, enteroviruses (eg, poliomyelitis) and coronaviruses (CoV). Neurologists seeing patients in the age of COVID-19 have much to gain from the historical lessons of the epidemics of the last 100 years in responding to these new challenges. A case of encephalitis lethargica involving chiefly the cerebral cortex Authors : Watson GA Year Published : 1920 Epidemic encephalitis: Clinical papers by various authors Authors : Horder T Year Published : 1920 The first systematic descriptions of encephalitis lethargica were those of von Economo in 1916–1917, who coined the term (figure 1),1 which is also known as ‘von Economo’s disease’.2 However, there were probable cases in 1915 predating the ‘influenza epidemic’, and von Economo and others suggested that earlier epidemics throughout modern history may also have been related.3 Figure 1 Constantin Freiherr Economo von San Serff (von Economo (1876–1931)) Austrian neurologist, psychiatrist, pilot and originator of the diagnosis encephalitis lethargica (https://commons.wikimedia.org/wiki/Category:Constantin\_von\_Economo). Encephalitis lethargica appears to have spread from Eastern Europe to Germany, France and Britain between 1916 and 1918 and and then to have affected much of the rest of the world in the following few years.1 4 It probably affected more than a million people during the first half of the twentieth century, before apparently disappearing, although some clinicians …

Summary Background The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is of a scale not seen since the 1918 influenza pandemic. Although the predominant clinical presentation is with respiratory disease, neurological manifestations are being recognised increasingly. On the basis of knowledge of other coronaviruses, especially those that caused the severe acute respiratory syndrome and Middle East respiratory syndrome epidemics, cases of CNS and peripheral nervous system disease caused by SARS-CoV-2 might be expected to be rare. Recent developments A growing number of case reports and series describe a wide array of neurological manifestations in 901 patients, but many have insufficient detail, reflecting the challenge of studying such patients. Encephalopathy has been reported for 93 patients in total, including 16 (7%) of 214 hospitalised patients with COVID-19 in Wuhan, China, and 40 (69%) of 58 patients in intensive care with COVID-19 in France. Encephalitis has been described in eight patients to date, and Guillain-Barre syndrome in 19 patients. SARS-CoV-2 has been detected in the CSF of some patients. Anosmia and ageusia are common, and can occur in the absence of other clinical features. Unexpectedly, acute cerebrovascular disease is also emerging as an important complication, with cohort studies reporting stroke in 2–6% of patients hospitalised with COVID-19. So far, 96 patients with stroke have been described, who frequently had vascular events in the context of a pro-inflammatory hypercoagulable state with elevated C-reactive protein, D-dimer, and ferritin. Where next? Careful clinical, diagnostic, and epidemiological studies are needed to help define the manifestations and burden of neurological disease caused by SARS-CoV-2. Precise case definitions must be used to distinguish non-specific complications of severe disease (eg, hypoxic encephalopathy and critical care neuropathy) from those caused directly or indirectly by the virus, including infectious, para-infectious, and post-infectious encephalitis, hypercoagulable states leading to stroke, and acute neuropathies such as Guillain-Barre syndrome. Recognition of neurological disease associated with SARS-CoV-2 in patients whose respiratory infection is mild or asymptomatic might prove challenging, especially if the primary COVID-19 illness occurred weeks earlier. The proportion of infections leading to neurological disease will probably remain small. However, these patients might be left with severe neurological sequelae. With so many people infected, the overall number of neurological patients, and their associated health burden and social and economic costs might be large. Health-care planners and policy makers must prepare for this eventuality, while the many ongoing studies investigating neurological associations increase our knowledge base.

Purpose: Status epilepticus (SE) is a severe condition of unrelenting seizures requiring urgent identification and treatment. SE may be unprovoked, occurring in someone with epilepsy, or may be provoked by acute intracranial disease or metabolic derangement. Increasingly encephalitis, particularly autoimmune types, is reported to cause refractory seizures. Whilst convulsive SE is readily identified, non-convulsive SE (NCSE) can be difficult to identify clinically, and electroencephalography (EEG) is required. Therefore, it is critical to identify the key clinical features associated with NCSE on EEG to inform future use of EEG. Methods: We conducted a multicentre, retrospective analysis of EEG requests from four general and one specialist neurology hospital in the Northwest of England (2015-2018). Cases were identified from EEG requests for patients with suspected NCSE or other indications such as encephalopathy. We compared demographic and clinical characteristics between EEG-confirmed cases of NCSE and a randomly selected sample of negative controls. Results: 358 EEGs were reviewed, and 8 positive cases of NCSE were identified. Epilepsy was identified as the aetiology in 2 of these cases, and autoimmune encephalitis another 2 cases (one patient with N-methyl-d-aspartate receptor antibodies and another with voltage gated potassium channel antibodies). Previous alcohol excess (p = 0.005) and subtle motor signs (p = 0.047) on examination were observed more frequently in patients with NCSE compared to controls. Conclusion: Physicians should have a low threshold for urgent EEG in patients with suspected or previous encephalitis, especially if autoimmunity is suspected or subtle motor signs are present. info:eu-repo/semantics/publishedVersion