Contributing factors of spontaneous intracerebral hemorrhage development in young adults

OBJECTIVE

The incidence of spontaneous intracerebral hemorrhage (ICH) in young people is relatively low; however, it leads to devastating lifelong neurologic deficits. We focused on spontaneous ICH occurring in young adults between 30 and 50 years of age.

METHODS

We retrospectively reviewed the records of 139 patients, aged 30-50 years, diagnosed with spontaneous ICH between 2011 and 2021. Cases of ICH attributable to discernible causative lesions were excluded. Demographic data, laboratory results, image findings, and clinical outcome were analyzed.

RESULTS

After exclusions, 73 patients were included in this study. Common characteristics among the study patients included male sex (83.6%), high body mass index (>25 kg/m2, 45.8%), smoking history (47.2%), heavy alcohol consumption (30.6%), previously diagnosed hypertension (41.1%), high serum triglyceride level (>150 mg/dL, 33.3%), and microbleeds or white matter changes observed on magnetic resonance images (51.3%). In the multivariate analysis, previously diagnosed hypertension was the sole significant risk factor for cerebral small vessel (OR 7.769, P=0.031). Age, brain stem location, Glasgow Coma Scale score at admission, and hematoma volume were associated with poor outcomes.

CONCLUSIONS

Hypertension, obesity, smoking, and cerebral small vessel disease were important factors associated with non-lesional spontaneous intracerebral hemorrhage in young patients. Radiologic changes corresponding to cerebral small vessel disease appeared in young patients (in their 30s) and they were associated with hypertension.

Vaccine value profile for herpes simplex virus

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are chronic, highly prevalent viral infections that cause significant morbidity around the world. HSV-2 is sexually transmitted and is the leading cause of genital ulcer disease (GUD). It also increases the risk of HIV acquisition, fueling the HIV epidemic. HSV-1 is typically acquired in childhood through nonsexual contact and contributes to oral and ocular disease, but it can also be sexually transmitted to cause GUD. Both HSV-1 and HSV-2 cause neonatal herpes and neurologic disease. Given the ubiquitous nature of HSV-1 and HSV-2 infections and the limited existing prevention and control measures, vaccination would be the most efficient strategy to reduce the global burden of morbidity related to HSV infection. Vaccine strategies include prophylactic vaccination, which would prevent infection among susceptible persons and would likely be given to adolescents, and therapeutic vaccinations, which would be given to people with symptomatic genital HSV-2 infection. This document discusses the vaccine value profile of both types of vaccines. This 'Vaccine Value Profile' (VVP) for HSV is intended to provide a high-level, holistic assessment of the information and data that are currently available to inform the potential public health, economic and societal value of pipeline vaccines and vaccine-like products. This VVP was developed by subject matter experts from academia, non-profit organizations, government agencies and multi-lateral organizations. All contributors have extensive expertise on various elements of the HSV VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using only existing and publicly available information.

Long-term sequelae after viral meningitis and meningoencephalitis are frequent, even in mildly affected patients, a prospective observational study

Introduction

An increasing number of studies demonstrate that viral meningitis and meningoencephalitis, even those with a mild course of meningitis, can result in residual sequelae.

Methods

We aimed to investigate the long-term outcome in both viral meningitis and meningoencephalitis/encephalitis patients and impact of long-term sequelae on patients' social and professional daily lives in a prospective observational study with a follow-up period of 20 months.

Results

A total of 50 patients (12% encephalitis, 58% meningoencephalitis and 30% meningitis) and 21 control persons participated in the study. The most common cause was the tick-borne encephalitis (TBE) virus. The most important persistent signs and symptoms after 2 years were subjective cognitive impairment (36%), fatigue and/or excessive daytime sleepiness (31%), disturbed nighttime sleep (31%) and headaches (13%), as well as feeling more rapidly exhausted after cognitive effort (53%). Independent of disease severity in the acute phase, almost one third of patients still reported mildly impaired social and/or professional life due to the long-term sequelae, with scores in the health status assessment still significantly lower compared to healthy controls.

Discussion

Regardless of the severity of the acute illness and despite constant improvement within 2 years, 67% of patients still had persistent signs and symptoms, but these were only relevant to everyday social or professional life in about 30% of these patients.

Characteristics, management and outcome of Herpes Simplex and Varicella-Zoster virus encephalitis: a multicentre prospective cohort study

OBJECTIVE

To characterize differences between Herpes Simplex virus encephalitis and Varicella-Zoster virus encephalitis (HSVE and VZVE) and other aetiologies of infectious encephalitis (IE), and to investigate the impact of time-to-aciclovir (ACV) start, ACV dose and duration on outcome.

METHODS

We compared 132 HSVE, 65 VZVE and 297 other IE enrolled in a prospective cohort (ENCEIF). We estimated associations between time-to-ACV start, dose or duration and outcome through adjusted odds ratio (aOR) using logistic regression analysis.

RESULTS

Prevalence of immunodepression differed among aetiologies: 15/65 (23%) for VZVE, 13/132 (10%) for HSVE and 30/297 (10%) for other IE (p <0.05), as was presence of seizure at admission: 27/132 (20%) for HSVE, 4/65 (6%) for VZVE and 43/297 (14%) for other IE (p <0.05). Poor outcome at hospital discharge (Glasgow outcome scale ≤3) differed among the three groups: 40/127 (31%) for HSVE, 12/65 (18%) for VZVE and 38/290 (13%) for other IE (p <0.05). Time-to-ACV start was associated with outcome in HSVE (aOR 3.61 [1.25-10.40]), but not in VZVE (aOR 0.84 [0.18-3.85]). Increased ACV dose was not associated with outcome among HSVE (aOR 1.25 [0.44-3.64]) nor VZVE (aOR 1.16 [0.24-5.73]).

DISCUSSION

HSVE and VZVE are distinct in clinical presentation, outcome and prognostic factors. The impact of early ACV initiation was more apparent for HSVE than for VZVE; however, this could be because of VZVE's smaller sample size and lower outcome rate leading to low statistical power or because of potential distinct IE pathophysiology.

Predictors of mortality and poor outcome for patients with severe infectious encephalitis in the intensive care unit: a cross-sectional study

BACKGROUND

There are few thorough studies assessing predictors of severe encephalitis, despite the poor prognosis and high mortality associated with severe encephalitis. The study aims to evaluate the clinical predictors of mortality and poor outcomes at hospital discharge in patients with severe infectious encephalitis in intensive care units.

METHOD

In two Chinese hospitals, a retrospective cohort study comprising 209 patients in intensive care units suffering from severe infectious encephalitis was carried out. Univariate and multivariate logistic regression analyses were used to identify the factors predicting mortality in all patients and poor outcomes in all survivors with severe infectious encephalitis.

RESULTS

In our cohort of 209 patients with severe encephalitis, 22 patients died, yielding a mortality rate of 10.5%. Cerebrospinal fluid pressure ≥ 400mmH2O (OR = 7.43), abnormal imaging (OR = 3.51), abnormal electroencephalogram (OR = 7.14), and number of rescues (OR = 1.12) were significantly associated with an increased risk of mortality in severe infectious encephalitis patients. Among the 187 survivors, 122 (65.2%) had favorable outcomes, defined as the modified Rankine Scale (mRS) score (0 ~ 3), and 65(34.8%) had poor outcomes (mRS scores 4 ~ 5). Age (OR = 1.02), number of rescues (OR = 1.43), and tubercular infection (OR = 10.77) were independent factors associated with poor outcomes at discharge in all survivors with severe infectious encephalitis.

CONCLUSIONS

Multiple clinical, radiologic, and electrophysiological variables are independent predictive indicators for mortality and poor outcomes in patients with severe encephalitis in intensive care units. Identifying these outcome predictors early in patients with severe encephalitis may enable the implementation of appropriate medical treatment and help reduce mortality rates.

Elevated levels of β2-microglobulin in cerebrospinal fluid in adult patients with viral encephalitis/meningitis

BACKGROUND

Increased cerebrospinal fluid (CSF) β2-microglobulin (β2-MG) values are attributed to immune activation, lymphoid cell turnover and release of tissue destruction in the central nervous system (CNS). We investigated plasma and CSF β2-MG levels in adult patients with viral encephalitis/meningitis and their correlations with clinical parameters.

METHOD

CSF samples from 26 patients with viral encephalitis/meningitis were collected. Moreover, 24 CSF samples from patients with non-inflammatory neurological disorders (NIND) as controls were collected. Plasma samples from 22 enrolled patients and 20 healthy individuals were collected. The β2-MG levels were measured by immunoturbidimetry on an automatic biochemical analyzer. Clinical data were extracted from an electronic patient documentation system.

RESULT

CSF levels of β2-MG, adenosine deaminase (ADA), white blood cell (WBC), lactate dehydrogenase (LDH), protein and lactate were significantly increased in patients with viral encephalitis/meningitis respectively (p < 0.001, p < 0.001, p < 0.001, p = 0.001, p < 0.001, p = 0.013). In contrast, no statistically significant difference was found in plasma levels of β2-MG. Furthermore, CSF levels of β2-MG were weakly correlated with WBC (r = 0.426, p = 0.030), lymphocyte percentage (r = 0.599, p = 0.018), ADA (r = 0.545, p = 0.004) and LDH (r = 0.414, p = 0.036), but not with lactate (r = 0.381, p = 0.055), protein (r = 0.179, p = 0.381) and plasma levels of β2-MG (r = -0.156, p = 0.537) in viral encephalitis/meningitis patients.

CONCLUSION

CSF β2-MG may be a potential inflammatory marker for viral encephalitis/meningitis in adult patients diagnosed with viral encephalitis/meningitis.

Encephalitis in HIV-negative immunodeficient patients: a prospective multicentre study, France, 2016 to 2019

BackgroundData on infectious encephalitis in immunodeficient (ID) individuals are scarce. This population may present with atypical clinical symptoms, be infected by uncommon pathogens and develop poor outcomes.AimWe aimed to describe the epidemiology of infectious encephalitis among HIV-negative ID patients.MethodsPatients from the ENCEIF (Etude Nationale de Cohorte des Encéphalites Infectieuses en France) prospective cohort meeting criteria for infectious encephalitis between January 2016 and December 2019 were included. We compared clinical presentation, magnetic resonance imaging (MRI) results, biological results, infection causes and outcome of ID patients with immunocompetent (IC) patients using Pearson's chi-squared test and Student's t-test. We carried out logistic regression to assess the role of immunodeficiency as risk factor for poor outcome.ResultsID patients (n = 58) were older (mean 72 vs 59 years), had higher prevalence of diabetes (26% vs 12%), pre-existing neurological disorders (12% vs 5%) and higher case-fatality rate (23.6% vs 5.6%) compared to IC patients (n = 436). Varicella zoster virus was the primary cause of encephalitis in ID patients (this aetiology was more frequent in ID (25.9%) than in IC patients (11.5%)), with herpes simplex virus second (22.4% in ID patients vs 27.3% in IC patients). Immunodeficiency was an independent risk factor for death or major sequelae (odds ratio: 3.41, 95%CI: 1.70-6.85).ConclusionsVaricella zoster virus is the most frequent cause of infectious encephalitis in ID patients. Immunodeficiency is a major risk factor for poor outcome. ID encephalitis patients should benefit from stringent investigation of cause and early empiric treatment.

Magnetic resonance imaging in acute meningoencephalitis of viral and unknown origin: frequent findings and prognostic potential

Background

Magnetic resonance imaging (MRI) findings in meningoencephalitis have mainly been described in terms of their diagnostic value rather than their prognostic potential, except for herpes simplex virus (HSV) encephalitis. The aims of our study were to describe frequency and anatomic locations of MRI abnormalities specific to limbic, circadian and motor systems in a cohort of meningoencephalitis patients, as well as to investigate the prognostic value of these MRI findings.

Methods

A secondary, selective analysis of a retrospective database including all meningitis, meningoencephalitis and encephalitis cases treated between 2016 and 2018 in the University hospital of Bern, Switzerland was performed. Patients with meningitis of any cause, bacterial or autoimmune causes of encephalitis were excluded.

Results

MRI scans and clinical data from 129 meningoencephalitis cases found that the most frequent causes were tick-borne encephalitis (TBE, 42%), unknown pathogens (40%), VZV (7%), and HSV1 (5%). At discharge, median modified Rankin Score (mRS) was 3 (interquartile range, IQR, 1), 88% of patients had persisting signs and symptoms. After a median of 17 months, median Glasgow Outcome Score (GOS) was 5 (IQR 1), 39% of patients still had residual signs or symptoms. All patients with HSV, 27% with TBE and 31% of those with meningoencephalitis of unknown etiology had fluid-attenuated inversion recovery (FLAIR) and to a lesser extent diffusion-weighted imaging (DWI) lesions in their initial MRI, with highly overlapping anatomical distribution. In one fifth of TBE patients the limbic system was affected. Worse outcome was associated with presence of DWI and/or FLAIR lesions and lower normalized apparent diffusion coefficient (ADC) signal intensities.

Conclusion

Presence of FLAIR lesions, restricted diffusion as well as the extent of ADC hypointensity in initial MRI are parameters which might be of prognostic value regarding the longterm clinical outcome for patients with meningoencephalitis of viral and of unknown origin. Although not described before, affection of limbic structures by TBE is possible as shown by our results: A substantial proportion of our TBE patients had FLAIR signal abnormalities in these regions.

Outcome and Sequelae of Infectious Encephalitis

Acute infectious encephalitis is a widely studied clinical syndrome. Although identified almost 100 years ago, its immediate and delayed consequences are still neglected despite their high frequency and possible severity. We reviewed the available data on sequelae and persisting symptoms following infectious encephalitis with the aim of characterizing the clinical picture of these patients at months to years after hospitalization. We searched PubMed for case series involving sequelae after infectious encephalitis. We carried out a narrative review of the literature on encephalitis caused by members of the Herpesviridae family (herpes simplex virus, varicella zoster virus, and human herpesvirus-6), members of the Flaviviridae family (West Nile virus, tick-borne encephalitis virus, and Japanese encephalitis virus), alphaviruses, and Nipah virus. We retrieved 41 studies that yielded original data involving 3,072 adult patients evaluated after infectious encephalitis. At least one of the five domains of cognitive outcome, psychiatric disorders, neurological deficits, global functioning, and quality of life was investigated in the reviewed studies. Various tests were used in the 41 studies and the investigation took place at different times after hospital discharge. The results showed that most patients are discharged with impairments, with frequent deficits in cognitive function such as memory loss or attention disorders. Sequelae tend to improve within several years following flavivirus or Nipah virus infection, but long-term data are scarce for other pathogens. Further research is needed to better understand the extent of sequelae after infectious encephalitis, and to propose a standardized assessment method and assess the rehabilitation efficacy in these patients.

Clinical Outcome Assessments in Encephalitis: A Systematic Review

BACKGROUND AND OBJECTIVES

Most patients with encephalitis experience persisting neurocognitive and neuropsychiatric sequelae in the years following this acute illness. Reported outcomes are often based on generic clinical outcome assessments that rarely capture the patient perspective. This may result in an underestimation of disease-specific sequelae. Disease-specific clinical outcome assessments can improve clinical relevance of reported outcomes and increase the power of research and trials. There are no patient-reported outcome measures (PROMs) developed or validated specifically for patients with encephalitis. The primary objective of this systematic literature review was to identify PROMs that have been developed for or validated in patients with encephalitis.

METHODS

We performed a systematic review of the literature published from inception until May 2023 in 3 large international databases (MEDLINE, EMBASE and Cochrane libraries). Eligible studies should have developed or validated a PROM in patients with encephalitis or encephalopathy. Methodologic quality was evaluated using the Consensus-based Standards for the selection of health status Measurement Instruments study design checklist for PROMs.

RESULTS

We identified no disease-specific PROMs developed or validated for patients with encephalitis. We identified one study on the development and validation of a disease-specific PROM for hepatic encephalopathy, although this disease course is substantially different to that of patients with encephalitis. The methodologic quality of the included study was generally rated as "doubtful." We identified 30 PROMs that have been applied in 46 studies on encephalitis or encephalopathy, although not validated in these populations. The most commonly applied PROMs for measuring Health-Related Quality of Life were the Medical Outcomes Study Short Form-36 and the Sickness Impact Profile. Emotional well-being was often assessed with the Beck Depression Inventory (BDI-II). Sporadically, PROMs were applied to address other aspects of outcome including daily functioning and sleep quality.

DISCUSSION

This systematic review confirms a critical gap in clinical outcome assessments in patients with encephalitis, failing to identify a validated measuring tool for detecting neurocognitive, functional, and health status. It is therefore essential to develop and/or validate disease-specific PROMs for the population with encephalitis to capture relevant information for patient management and clinical trials about the effects of disease that are at risk of being overlooked.

Mental health outcomes of encephalitis: An international web-based study

BACKGROUND AND PURPOSE

Acute encephalitis is associated with psychiatric symptoms. Despite this, the extent of mental health problems following encephalitis has not been systematically reported.

METHODS

We recruited adults who had been diagnosed with encephalitis of any aetiology to complete a web-based questionnaire.

RESULTS

In total, 445 respondents from 31 countries (55.1% UK, 23.1% USA) responded. Infectious encephalitis constituted 65.4% of cases, autoimmune 29.7%. Mean age was 50.1 years, 65.8% were female, and median time since encephalitis diagnosis was 7 years. The most common self-reported psychiatric symptoms were anxiety (75.2%), sleep problems (64.4%), mood problems (62.2%), and unexpected crying (35.2%). Self-reported psychiatric diagnoses were common: anxiety (44.0%), depression (38.6%), panic disorder (15.7%), and posttraumatic stress disorder (PTSD; 21.3%). Severe mental illnesses such as psychosis (3.3%) and bipolar affective disorder (3.1%) were reported. Self-reported diagnosis rates were broadly consistent with results from the Psychiatric Diagnostic Screening Questionnaire. Many respondents also reported they had symptoms of anxiety (37.5%), depression (28.1%), PTSD (26.8%), or panic disorder (20.9%) that had not been diagnosed. Rates of psychiatric symptoms did not differ between autoimmune and infectious encephalitis. In total, 37.5% respondents had thought about suicide, and 4.4% had attempted suicide, since their encephalitis diagnosis. More than half of respondents (53.5%) reported they had no, or substandard, access to appropriate mental health care. High rates of sensory hypersensitivities (>75%) suggest a previously unreported association.

CONCLUSIONS

This large international survey indicates that psychiatric symptoms following encephalitis are common and that mental health care provision may be inadequate. We highlight a need for proactive psychiatric input.

Cerebrospinal fluid proteomics in meningitis patients with reactivated varicella zoster virus

OBJECTIVE

This study investigated the proteomic characteristics of cerebrospinal fluid (CSF) in patients with varicella zoster virus (VZV) meningitis to understanding the pathogenesis of central nervous system (CNS) infection by reactivated VZV.

METHOD

We used data-independent acquisition model to analyze the CSF proteomic differences of 28 patients with VZV meningitis and 11 herpes zoster (HZ) patients. According to the clinical manifestations at discharge, 28 VZV meningitis patients were divided into favorable outcome group and unfavorable outcome (UO) group and their differences in CSF proteome were also analyzed.

RESULTS

Compared with the HZ group, the proteins (CXCL10, ELANE, IL-1RN, MPO, PRTN3, etc.) related to inflammation and immune cell activation were significantly upregulated in the VZV meningitis group (p < .01). The protein related to the nerve function and energy metabolism (CKMT1B, SLITRK3, Synaptotagmin-3, KIF5B, etc.) were significantly downregulated (p < .05). The levels of a pro-inflammatory factor, IL-18, in CSF were significantly higher in patients in the UO group as compared to patients with favorable prognosis (p < .05).

CONCLUSION

Inflammatory immune response is an important pathophysiological mechanism of CNS infection by VZV, and the CSF IL-18 levels might be a potential prognostic indicator of the outcomes of VZV meningitis.

Anti-NMDAR encephalitis secondary to acute necrotizing encephalopathy caused by herpes simplex virus infection in infants: Case series

BACKGROUND

To describe the clinical characteristics of anti-NMDAR encephalitis secondary to acute necrotizing encephalopathy caused by herpes simplex virus encephalitis in infants, and aid in its early recognition, diagnosis and treatment.

CASE PRESENTATION

A total of 4 infants were included; all presented with fever, seizures, and progressive disturbances of consciousness and were diagnosed with herpes simplex virus (HSV-1) encephalitis. Cerebrospinal fluid (CSF) protein levels progressively increased, and the head MRI showed necrotizing encephalopathy. There was no significant improvement or recurrence after treatment with acyclovir, dexamethasone, or immunoglobulins. CSF reexamination at 3 weeks to 3 months showed positive anti-NMDAR IgG antibodies and gradual improvement after high-dose methylprednisolone therapy.

CONCLUSION

Infants with ANE associated with HSV can develop secondary anti-NMDAR encephalitis, recognition of which is critical to ensure the appropriate institution of immunotherapy after active CNS infection has been ruled out.

Diagnostic value of cerebrospinal fluid Neutrophil Gelatinase-Associated Lipocalin for differentiation of bacterial meningitis from tuberculous meningitis or cryptococcal meningitis: a prospective cohort study

BACKGROUND

The early differential diagnosis between bacterial meningitis (BM) and tuberculous meningitis (TBM) or cryptococcal meningitis (CM) remains a significant clinical challenge. Neutrophil Gelatinase-Associated Lipocalin (NGAL) has been reported as a novel inflammatory biomarker in the early stages of infection. This study aimed to investigate whether cerebrospinal fluid (CSF) NGAL can serve as a potential biomarker for distinguishing between BM and TBM or CM.

METHODS

We prospectively enrolled the patients with suspected CNS infections at admission and divided them into three case groups: BM (n = 67), TBM (n = 55), CM (n = 51), and an age- and sex-matched hospitalized control (HC, n = 58). Detected the CSF NGAL and assessed its diagnostic accuracy in distinguishing between BM and TBM or CM. Additionally, longitudinally measured the CSF NGAL levels in patients with BM to evaluate its potential as a monitoring tool for antibacterial treatment.

RESULTS

The concentration of CSF NGAL in BM was significantly higher than in TBM, CM, and HC (all P < 0.05), while the serum NGAL did not show significant differences among the three case groups. The ROC analysis demonstrated that CSF NGAL presented a good diagnostic performance with an AUC of 0.834 (0.770-0.886) and at the optimal cutoff value of 74.27 ng/mL with 70.15% sensitivity and 77.36% specificity for discriminating BM with TBM and CM. Additionally, the CSF NGAL in the convalescent period of BM was significantly lower than in the acute period (P < 0.05).

CONCLUSIONS

CSF NGAL may serve as a potential biomarker for distinguishing between acute BM and TBM or CM. Additionally, it holds clinical significance in monitoring the effectiveness of antibiotic therapy for BM.

Can we forecast poor outcome in herpes simplex and varicella zoster encephalitis? A narrative review

Herpes simplex virus (HSV) and varicella zoster virus (VZV) are among the most commonly diagnosed infectious causes of sporadic encephalitis worldwide. Despite treatment, mortality and morbidity rates remain high, especially for HSV encephalitis. This review is intended to provide an overview of the existing scientific literature on this topic from the perspective of a clinician who is confronted with serious decisions about continuation or withdrawal of therapeutic interventions. We performed a literature review searching two databases and included 55 studies in the review. These studies documented or investigated specifically outcome and predictive parameters of outcome of HSV and/or VZV encephalitis. Two reviewers independently screened and reviewed full-text articles meeting the inclusion criteria. Key data were extracted and presented as a narrative summary. Both, HSV and VZV encephalitis have mortality rates between 5 and 20% and complete recovery rates range from 14 to 43% for HSV and 33 to 49% for VZV encephalitis. Prognostic factors for both VZV and HSV encephalitis are older age and comorbidity, as well as severity of disease and extent of magnetic resonance imaging (MRI) lesions on admission, and delay in treatment initiation for HSV encephalitis. Although numerous studies are available, the main limiting factors are the inconsistent patient selection and case definitions as well as the non-standardised outcome measures, which hampers the comparability of the studies. Therefore, larger and standardised observational studies applying validated case definitions and outcome measures including quality of life assessment are required to provide solid evidence to answer the research question.

Characteristics, management, and outcomes of patients with infectious encephalitis requiring intensive care: A prospective multicentre observational study

PURPOSE

Infectious encephalitis (IE) is a severe disease which requires intensive care unit (ICU) admission in up to 50% of cases. We aimed to describe characteristics, management and outcomes of IE patients who required ICU admission.

MATERIALS AND METHODS

Ancillary study focusing on patients with ICU admission within the ENCEIF cohort, a French prospective observational multicentre study. The primary criteria for outcome was the functional status at hospital discharge, categorized using the Glasgow outcome scale (GOS). Logistic regression model was used to identify risk factors for poor outcome, defined as a GOS ≤ 3.

RESULTS

We enrolled 198 ICU patients with IE. HSV was the primary cause (n = 72, 36% of all IE, 53% of IE with microbiological documentation). Fifty-two patients (26%) had poor outcome at hospital discharge, including 22 deaths (11%). Immunodeficiency, supratentorial focal signs on admission, lower cerebrospinal fluid (CSF) white cells count (<75/mm3), abnormal brain imaging, and time from symptoms onset to acyclovir start >2 days were independent predictors of poor outcome.

CONCLUSION

HSV is the primary cause of IE requiring ICU admission. IE patients admitted in ICU have a poor prognosis with 11% of in-hospital mortality and 15% of severe disabilities in survivors at discharge.

Encephalitis and poor neuronal death-mediated control of herpes simplex virus in human inherited RIPK3 deficiency

Inborn errors of TLR3-dependent type I IFN immunity in cortical neurons underlie forebrain herpes simplex virus-1 (HSV-1) encephalitis (HSE) due to uncontrolled viral growth and subsequent cell death. We report an otherwise healthy patient with HSE who was compound heterozygous for nonsense (R422*) and frameshift (P493fs9*) RIPK3 variants. Receptor-interacting protein kinase 3 (RIPK3) is a ubiquitous cytoplasmic kinase regulating cell death outcomes, including apoptosis and necroptosis. In vitro, the R422* and P493fs9* RIPK3 proteins impaired cellular apoptosis and necroptosis upon TLR3, TLR4, or TNFR1 stimulation and ZBP1/DAI-mediated necroptotic cell death after HSV-1 infection. The patient's fibroblasts displayed no detectable RIPK3 expression. After TNFR1 or TLR3 stimulation, the patient's cells did not undergo apoptosis or necroptosis. After HSV-1 infection, the cells supported excessive viral growth despite normal induction of antiviral IFN-β and IFN-stimulated genes (ISGs). This phenotype was, nevertheless, rescued by application of exogenous type I IFN. The patient's human pluripotent stem cell (hPSC)-derived cortical neurons displayed impaired cell death and enhanced viral growth after HSV-1 infection, as did isogenic RIPK3-knockout hPSC-derived cortical neurons. Inherited RIPK3 deficiency therefore confers a predisposition to HSE by impairing the cell death-dependent control of HSV-1 in cortical neurons but not their production of or response to type I IFNs.

Electroencephalography for prognostication of outcome in adults with severe herpes simplex encephalitis

BACKGROUND

Electroencephalography (EEG) is recommended for the practical approach to the diagnosis and prognosis of encephalitis. We aimed to investigate the prognostic value of standard EEG (_stdEEG) in adult patients with severe herpes simplex encephalitis.

METHODS

We performed a retrospective analysis of consecutive ICU patients with severe herpes simplex encephalitis in 38 French centers between 2006 and 2016. Patients with at least one _stdEEG study performed at ICU admission were included. _stdEEG findings were reviewed independently by two investigators. The association between _stdEEG findings (i.e., background activity, lateralized periodic discharges, seizures/status epilepticus, and reactivity to painful/auditory stimuli) and poor functional outcome, defined by a score on the modified Rankin Scale (mRS) of 3 to 6 (moderate to severe disability or death) at 90 days, were investigated.

RESULTS

We included 214 patients with at least one available _stdEEG study. The first _stdEEG was performed after a median time of one (interquartile range (IQR) 0 to 2) day from ICU admission. At the time of recording, 138 (64.5%) patients were under invasive mechanical ventilation. Lateralized periodic discharges were recorded in 91 (42.5%) patients, seizures in 21 (9.8%) and status epilepticus in 16 (7.5%). In the whole population, reactivity to auditory/noxious stimuli was tested in 140/214 (65.4%) patients and was absent in 71/140 (33.2%) cases. In mechanically ventilated patients, _stdEEG reactivity was tested in 91/138 (65.9%) subjects, and was absent in 53/91 (58.2%) cases. Absence of reactivity was the only independent _stdEEG finding associated with poor functional outcome in the whole population (OR 2.80, 95% CI 1.19 to 6.58) and in the subgroup of mechanically ventilated patients (OR 4.99, 95% CI 1.6 to 15.59). Adjusted analyses for common clinical predictors of outcome and sedation at time of _stdEEG revealed similar findings in the whole population (OR 2.03, 95% CI 1.18 to 3.49) and in mechanically ventilated patients (OR 2.62, 95% CI 1.25 to 5.50).

CONCLUSIONS

Absence of EEG reactivity to auditory/noxious stimuli is an independent marker of poor functional outcome in severe herpes simplex encephalitis.

Increased volume of cerebral oedema is associated with risk of acute seizure activity and adverse neurological outcomes in encephalitis - regional and volumetric analysis in a multi-centre cohort

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.

Neuroimaging and neurological outcome of children with acute encephalitis

AIM

To investigate the severity of acute phase magnetic resonance imaging (MRI) findings and severity of acute illness as risk factors for disability after recovery from encephalitis.

METHOD

Children with encephalitis (n = 98; median age 6 years 10 months, interquartile range 3 years-11 years 6 months; 59 males, 39 females) treated in Turku University Hospital during the years 1995 to 2016 were identified in this retrospective cohort study. The acute phase (<2 months of symptom onset) brain MRIs were re-evaluated and classified based on the severity of neuroimaging finding by a neuroradiologist. Neurological outcome at discharge, at short-term (<3 months from discharge) follow-up, and at long-term (>1 year from discharge) follow-up was assessed from medical records using the Glasgow Outcome Scale.

RESULTS

Long-term recovery was poor in 24 of 82 (29%) children with follow-up data. Two children died, eight had severe disability, and 14 had moderate disability. Acute phase MRI was available for re-evaluation from 74 of 82 patients with follow-up data. The increasing severity of MRI findings was associated with need for ventilator therapy and with poor recovery.

INTERPRETATION

The risk for poor recovery in paediatric encephalitis is high, and it is associated with the severity of MRI findings.

WHAT THIS PAPER ADDS

Poor long-term recovery was found in 29% of children with encephalitis. Severe disability measured by Glasgow Outcome Scale was found in 8%. The most severe neuroimaging findings were a risk factor for severe acute illness and poor long-term recovery.

Infectious encephalitis in elderly patients: a prospective multicentre observational study in France 2016-2019

PURPOSE

Data on encephalitis in elderly patients are scarce. We aimed to describe the characteristics, aetiologies, management, and outcome of encephalitis in patients older than 65 years.

METHODS

We performed an ancillary study of ENCEIF, a prospective cohort that enrolled all cases of encephalitis managed in 46 clinical sites in France during years 2016-2019. Cases were categorized in three age groups: (1) 18-64; (2) 65-79; (3) ≥ 80 years.

RESULTS

Of the 494 adults with encephalitis enrolled, 258 (52%) were ≥ 65 years, including 74 (15%) ≥ 80 years. Patients ≥ 65 years were more likely to present with coma, impaired consciousness, confusion, aphasia, and rash, but less likely to present with fever, and headache (P < 0.05 for each). Median cerebrospinal fluid (CSF) white cells count was 61/mm³[13-220] in 65-79 years, 62 [17-180] in ≥ 80 years, vs. 114 [34-302] in < 65 years (P = 0.01). The proportion of cases due to Listeria monocytogenes and VZV increased after 65 years (P < 0.001), while the proportion of tick-borne encephalitis and Mycobacterium tuberculosis decreased with age (P < 0.05 for each). In-hospital mortality was 6/234 (3%) in < 65 years, 18/183 (10%) in 65-79 years, and 13/73 (18%) in ≥ 80 years (P < 0.001). Age ≥ 80 years, coma on admission, CSF protein ≥ 0.8 g/L and viral encephalitis were independently predictive of 6 month mortality.

CONCLUSION

Elderly patients represent > 50% of adults with encephalitis in France, with higher proportion of L. monocytogenes and VZV encephalitis, increased risk of death, and sequels. The empirical treatment currently recommended, aciclovir and amoxicillin, is appropriate for this age group.

Diagnostic Value of the Electroencephalogram and Cerebrospinal Fluid in Viral Encephalitis

BACKGROUND

Electroencephalogram (EEG) and cerebrospinal fluid (CSF) are widely used in the clinical diagnosis of viral encephalitis (VE), but their value in the diagnosis of VE and the detection rate of abnormal indicators need to be further supported by more clinical data.

METHODS

In this study, routine laboratory testing, biochemical examinations of cerebrospinal fluid (CSF) and EEG characteristics were performed in patients with VE to guide the diagnosis and treatment of VE in clinical settings. A total of 330 patients with VE were enrolled in the Department of Neurology of the Third Affiliated Hospital of Zunyi Medical University from January 1, 2015 to January 30, 2020. EEG, routine testing and assessment of biochemical indicators of CSF were performed within 10 days after admission, and the results were analyzed by paired χ 2 test to compare the diagnostic value of EEG and CSF for VE.

RESULTS

In 330 cases of VE, 283 cases (85.76%) had abnormal EEG, and 189 cases (57.27%) had abnormal CSF indicators. The incidence of EEG abnormalities was higher than that of CSF indicators, and the difference was statistically significant ( P <0.05).

CONCLUSIONS

Both the EEG and CSF analysis are valuable indicators in the diagnosis of VE patients. Compared with the CSF examination, the EEG examination had a better diagnostic efficacy for the diagnosis of VE. In addition, a normal EEG or a normal CSF level cannot exclude VE, and it is still necessary to develop new diagnostic indicators to cover all viral encephalitides.

Incident Herpes Zoster and Risk of Dementia: A Population-Based Danish Cohort Study

BACKGROUND AND OBJECTIVES

Herpes zoster (HZ) is caused by reactivation of the neurotrophic varicella-zoster virus (VZV). Zoster may contribute to development of dementia through neuroinflammation, cerebral vasculopathy, or direct neural damage, but epidemiologic evidence is limited. We used data from linked nationwide Danish registries to conduct a cohort study of the association between zoster and dementia during 1997-2017. As secondary aims, we examined whether associations were more pronounced for zoster involving cranial nerves (mainly ophthalmic zoster) or the CNS and Alzheimer disease as an outcome.

METHODS

We included people aged ≥40 years with zoster and a general population comparison cohort matched 5:1 by sex and birth year. We identified zoster and dementia in the registries using prescription records in the community and hospital diagnoses. We used Cox regression to compute confounder-adjusted hazard ratios (HRs) with 95% CIs for dementia associated with zoster during 0-1 year and 1-21 years of follow-up. We compared the cumulative incidence of dementia, inverse probability weighted for confounders.

RESULTS

The study included 247,305 people with zoster and 1,235,890 matched general population comparators (median age 64 years; 61% female). The HR of all-cause dementia was 0.98 (95% CI 0.92-1.04) during the first year and 0.93 (95% CI 0.90-0.95) thereafter in people with zoster vs matched comparators. Dementia was diagnosed in 9.7% of patients with zoster and 10.3% of matched comparators by the end of follow-up. We observed no increased long-term risk of dementia in subgroup analyses, except possibly in people with CNS infection (HR 1.94; 95% CI 0.78-4.80). Analyses of Alzheimer disease as a separate outcome showed similar results.

DISCUSSION

HZ is not associated with an increased risk of dementia, and contrary to expectation, we found a small decrease in the risk. The explanation for this finding is unclear, and systematic errors should be considered. Patients with CNS involvement had an almost 2-fold increased relative risk of dementia. The population attributable fraction of dementia due to this rare complication is estimated at 0.014%. Therefore, universal vaccination against VZV in the elderly is unlikely to reduce dementia risk.

Short- and long-term mortality of subarachnoid hemorrhage according to hospital volume and severity using a nationwide multicenter registry study

Introduction

Recent improvements in treatment for subarachnoid hemorrhage (SAH) have decreased the mortality rates; however, the outcomes of SAH management are dependent on many other factors. In this study, we used nationwide, large-scale, observational data to investigate short- and long-term mortality rates after SAH treatment and the influence of patient severity and hospital volume.

Patients and methods

We selected patients with SAH treated with clipping and coiling from the South Korean Acute Stroke Assessment Registry. High- and low-volume hospitals performed ≥20 clipping and coiling procedures and <20 clipping and coiling procedures per year, respectively. Short- and long-term mortality were tracked using data from the Health Insurance Review and Assessment Service.

Results

Among 2,634 patients treated using clipping and coiling, 1,544 (58.6%) and 1,090 (41.4%) were hospitalized in high- and low-volume hospitals, respectively, and 910 (34.5%) and 1,724 (65.5%) were treated with clipping and coiling, respectively. Mortality rates were 13.5, 14.4, 15.2, and 16.1% at 3 months, 1, 2, and 4 years, respectively. High-volume hospitals had a significantly lower 3-month mortality rate. Patients with mild clinical status had a significantly lower 3-month mortality rate in high-volume hospitals than in low-volume hospitals. Patients with severe clinical status had significantly lower 1- and 2-year mortality rates in high-volume hospitals than in low-volume hospitals.

Conclusion

Short- and long-term mortality in patients with SAH differed according to hospital volume. In the modern endovascular era, clipping and coiling can lead to better outcomes in facilities with high stroke-care capabilities.

Childhood encephalitis in the Greater Mekong region (the SouthEast Asia Encephalitis Project): a multicentre prospective study

BACKGROUND

Encephalitis is a worldwide public health issue, with a substantially high burden among children in southeast Asia. We aimed to determine the causes of encephalitis in children admitted to hospitals across the Greater Mekong region by implementing a comprehensive state-of-the-art diagnostic procedure harmonised across all centres, and identifying clinical characteristics related to patients' conditions.

METHODS

In this multicentre, observational, prospective study of childhood encephalitis, four referral hospitals in Cambodia, Vietnam, Laos, and Myanmar recruited children (aged 28 days to 16 years) who presented with altered mental status lasting more than 24 h and two of the following minor criteria: fever (within the 72 h before or after presentation), one or more generalised or partial seizures (excluding febrile seizures), a new-onset focal neurological deficit, cerebrospinal fluid (CSF) white blood cell count of 5 per mL or higher, or brain imaging (CT or MRI) suggestive of lesions of encephalitis. Comprehensive diagnostic procedures were harmonised across all centres, with first-line testing was done on samples taken at inclusion and results delivered within 24 h of inclusion for main treatable causes of disease and second-line testing was done thereafter for mostly non-treatable causes. An independent expert medical panel reviewed the charts and attribution of causes of all the included children. Using multivariate analyses, we assessed risk factors associated with unfavourable outcomes (ie, severe neurological sequelae and death) at discharge using data from baseline and day 2 after inclusion. This study is registered with ClinicalTrials.gov, NCT04089436, and is now complete.

FINDINGS

Between July 28, 2014, and Dec 31, 2017, 664 children with encephalitis were enrolled. Median age was 4·3 years (1·8-8·8), 295 (44%) children were female, and 369 (56%) were male. A confirmed or probable cause of encephalitis was identified in 425 (64%) patients: 216 (33%) of 664 cases were due to Japanese encephalitis virus, 27 (4%) were due to dengue virus, 26 (4%) were due to influenza virus, 24 (4%) were due to herpes simplex virus 1, 18 (3%) were due to Mycobacterium tuberculosis, 17 (3%) were due to Streptococcus pneumoniae, 17 (3%) were due to enterovirus A71, 74 (9%) were due to other pathogens, and six (1%) were due to autoimmune encephalitis. Diagnosis was made within 24 h of admission to hospital for 83 (13%) of 664 children. 119 (18%) children had treatable conditions and 276 (42%) had conditions that could have been preventable by vaccination. At time of discharge, 153 (23%) of 664 children had severe neurological sequelae and 83 (13%) had died. In multivariate analyses, risk factors for unfavourable outcome were diagnosis of M tuberculosis infection upon admission (odds ratio 3·23 [95% CI 1·04-10·03]), coma on day 2 (2·90 [1·78-4·72]), supplementary oxygen requirement (1·89 [1·25-2·86]), and more than 1 week duration between symptom onset and admission to hospital (3·03 [1·68-5·48]). At 1 year after inclusion, of 432 children who were discharged alive from hospital with follow-up data, 24 (5%) had died, 129 (30%) had neurological sequelae, and 279 (65%) had completely recovered.

INTERPRETATION

In southeast Asia, most causes of childhood encephalitis are either preventable or treatable, with Japanese encephalitis virus being the most common cause. We provide crucial information that could guide public health policy to improve diagnostic, vaccination, and early therapeutic guidelines on childhood encephalitis in the Greater Mekong region.

FUNDING

Institut Pasteur, Institut Pasteur International Network, Fondation Merieux, Aviesan Sud, INSERM, Wellcome Trust, Institut de Recherche pour le Développement (IRD), and Fondation Total.

Next-Generation Sequencing Technology Combined With Multiplex Polymerase Chain Reaction as a Powerful Detection and Semiquantitative Method for Herpes Simplex Virus Type 1 in Adult Encephalitis: A Case Report

Background

Traditional testing for specific microbes or categories of central nervous system (CNS) infectious diseases is often limited in sensitivity and timeliness. However, failure to initiate a timely etiological diagnosis and corresponding treatment in patients with neurologic infections contribute to poor outcomes.

Case Summary

A 58 year-old male presented acutely with fever, abnormal mental behavior, seizures and decreased consciousness. Brain magnetic resonance imaging (MRI) showed an abnormal FLAIR/T2 signal mainly in the left thalamus, temporal lobe, insular lobe, and bilateral hippocampus. To identify the pathogen, the cerebrospinal fluid (CSF) sample of the patient was used for metagenomic next-generation sequencing (mNGS) analysis and multiplex polymerase chain reaction (mPCR). The results showed 188 herpes simplex virus (HSV-1)-specific sequences. After acyclovir and foscarnet sodium treatment, the ratio of HSV-1/internal reference reads decreased from 813/493 to 695/1961, which coincided with clinical remission.

Conclusion

This study indicates that mNGS combined with mPCR may be an effective method for etiological diagnostic and dynamic clinical surveillance for HSV-1 encephalitis.

How should we define a 'good' outcome from encephalitis? A systematic review of the range of outcome measures used in the long-term follow-up of patients with encephalitis

INTRODUCTION

Encephalitis is typically caused by infection or autoimmunity. Most survivors suffer complex neurological and psychiatric sequelae. Standardised outcome measures are needed for accurate interpretation of observational studies and clinical trials. Step one in this process is understanding the strengths and weaknesses of those in use.

METHODS

We performed a systematic literature review searching six databases. One reviewer screened titles and abstracts, and two reviewers determined if shortlisted full-text articles met inclusion criteria. Key data were extracted from these papers and presented as a narrative summary.

RESULTS

Thirty-seven outcome measures were used for 3,133 patients across the 35 included papers, of which, only one was developed for encephalitis. The outcome measures used in most patients were the Glasgow Outcome Score used in 1,436 (46%), Barthel Index used in 1,173 (37%), Euro-QoL-5D used in 1,107 (35%) and modified Rankin Scale used in 1,034 (33%).

CONCLUSION

Most of the 37 measures assessed a single category of sequelae using 5-8-point scales and were not validated for use in encephalitis. Research is needed to develop a composite outcome measure for use in clinical practice and a core-outcomes set for use in clinical trials. For now, the Liverpool Outcome Score offers a good choice for clinicians.

Cognitive decline following acute viral infections: literature review and projections for post-COVID-19

Recently, much attention has been drawn to the importance of the impact of infectious disease on human cognition. Several theories have been proposed, to explain the cognitive decline following an infection as well as to understand better the pathogenesis of human dementia, especially Alzheimer's disease. This article aims to review the state of the art regarding the knowledge about the impact of acute viral infections on human cognition, laying a foundation to explore the possible cognitive decline followed coronavirus disease 2019 (COVID-19). To reach this goal, we conducted a narrative review systematizing six acute viral infections as well as the current knowledge about COVID-19 and its impact on human cognition. Recent findings suggest probable short- and long-term COVID-19 impacts in cognition, even in asymptomatic individuals, which could be accounted for by direct and indirect pathways to brain dysfunction. Understanding this scenario might help clinicians and health leaders to deal better with a wave of neuropsychiatric issues that may arise following COVID-19 pandemic as well as with other acute viral infections, to alleviate the cognitive sequelae of these infections around the world.

Comparison of functional outcome scales in paediatric acute encephalitis: Responsiveness and outcome predictors

PURPOSE

To compare scoring systems and their ability to capture short and long-term recovery of paediatric patients with acute encephalitis. To identify clinical predictors of short-term outcomes by correlating functional outcome measures at 1 month post diagnosis of acute encephalitis.

METHODS

Patients with encephalitis diagnosed between July 2011 and 2016 based on Granerod's criteria were studied in this retrospective cohort study. Functional outcome scores on WeeFIM, LOS, GOS-E, mRS and ICF at initial presentation and 1, 3, 6 and 12 months later were compared.

RESULTS

WeeFIM and LOS scores both showed maximum change in the first 3 months, reflecting highest recovery in this period. With WeeFIM, the greatest change occurred within the first month following diagnosis. On univariate analysis, seizure frequency in the first month, presence of movement disorder, presence of autonomic dysfunction and lower baseline functional score was associated with poorer WeeFIM scores at 1 month. The latter three variables remained statistically significant on multivariate analysis.

CONCLUSION

WeeFIM is a potentially preferred functional outcome assessment tool as it demonstrated greatest recovery within the first month due to a trend of high responsiveness and relatively low ceiling effect. Presence of autonomic dysfunction and movement disorders at diagnosis correlated with poorer outcome at 1 month post diagnosis.

Meningitis, meningoencephalitis and encephalitis in Bern: an observational study of 258 patients

Background

Depending on geographic location, causes of encephalitis, meningoencephalitis and meningitis vary substantially. We aimed to identify the most frequent causes, clinical presentation and long-term outcome of encephalitis, meningoencephalitis and meningitis cases treated in the Inselspital University Hospital Bern, Switzerland.

Methods

In this monocentric, observational study, we performed a retrospective review of clinical patient records for all patients treated within a 3-year period. Patients were contacted for a telephone follow-up interview and to fill out questionnaires, especially related to disturbances of sleep and wakefulness.

Results

We included 258 patients with the following conditions: encephalitis (18%), nonbacterial meningoencephalitis (42%), nonbacterial meningitis (27%) and bacterial meningoencephalitis/meningitis (13%). Herpes simplex virus (HSV) was the most common cause of encephalitis (18%); tick-borne encephalitis virus (TBEV) was the most common cause of nonbacterial meningoencephalitis (46%), enterovirus was the most common cause of nonbacterial meningitis (21%) and Streptococcus pneumoniae was the most common cause of bacterial meningoencephalitis/meningitis (49%). Overall, 35% patients remained without a known cause. After a median time of 16 months, 162 patients participated in the follow-up interview; 56% reported suffering from neurological long-term sequelae such as fatigue and/or excessive daytime sleepiness (34%), cognitive impairment and memory deficits (22%), headache (14%) and epileptic seizures (11%).

Conclusions

In the Bern region, Switzerland, TBEV was the overall most frequently detected infectious cause, with a clinical manifestation of meningoencephalitis in the majority of cases. Long-term neurological sequelae, most importantly cognitive impairment, fatigue and headache, were frequently self-reported not only in encephalitis and meningoencephalitis survivors but also in viral meningitis survivors up to 40 months after acute infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02502-3.

Viral metagenomic sequencing in the diagnosis of meningoencephalitis: a review of technical advances and diagnostic yield

INTRODUCTION

Meningoencephalitis patients are often severely impaired and benefit from early etiological diagnosis, though many cases remain without identified cause. Metagenomics as pathogen agnostic approach can result in additional etiological findings; however, the exact diagnostic yield when used as a secondary test remains unknown.

AREAS COVERED

This review aims to highlight recent advances with regard to wet and dry lab methodologies of metagenomic testing and technical milestones that have been achieved. A selection of procedures currently applied in accredited diagnostic laboratories is described in more detail to illustrate best practices. Furthermore, a meta-analysis was performed to assess the additional diagnostic yield utilizing metagenomic sequencing in meningoencephalitis patients. Finally, the remaining challenges for successful widespread implementation of metagenomic sequencing for the diagnosis of meningoencephalitis are addressed in a future perspective.

EXPERT OPINION

The last decade has shown major advances in technical possibilities for using mNGS in diagnostic settings including cloud-based analysis. An additional advance may be the current established infrastructure of platforms for bioinformatic analysis of SARS-CoV-2, which may assist to pave the way for global use of clinical metagenomics.

Herpes simplex encephalitis in a patient with a distinctive form of inherited IFNAR1 deficiency

Inborn errors of TLR3-dependent IFN-α/β- and IFN-λ-mediated immunity in the CNS can underlie herpes simplex virus 1 (HSV-1) encephalitis (HSE). The respective contributions of IFN-α/β and IFN-λ are unknown. We report a child homozygous for a genomic deletion of the entire coding sequence and part of the 3'-UTR of the last exon of IFNAR1, who died of HSE at the age of 2 years. An older cousin died following vaccination against measles, mumps, and rubella at 12 months of age, and another 17-year-old cousin homozygous for the same variant has had other, less severe, viral illnesses. The encoded IFNAR1 protein is expressed on the cell surface but is truncated and cannot interact with the tyrosine kinase TYK2. The patient's fibroblasts and EBV-B cells did not respond to IFN-α2b or IFN-β, in terms of STAT1, STAT2, and STAT3 phosphorylation or the genome-wide induction of IFN-stimulated genes. The patient's fibroblasts were susceptible to viruses, including HSV-1, even in the presence of exogenous IFN-α2b or IFN-β. HSE is therefore a consequence of inherited complete IFNAR1 deficiency. This viral disease occurred in natural conditions, unlike those previously reported in other patients with IFNAR1 or IFNAR2 deficiency. This experiment of nature indicates that IFN-α/β are essential for anti-HSV-1 immunity in the CNS.

Subacute Herpes Simplex Type 1 Encephalitis: Case Report With Literature Review

INTRODUCTION

The typical herpes simplex viral encephalitis (HSVE) course is an acute illness, less commonly it may present as a chronic course, mainly in children, and rarely may it be subacute. Subacute HSVE is rarely described in the literature being reported 4 times only.

CASE REPORT

We here report 2 cases of subacute HSV1 encephalitis diagnosed based on cerebrospinal fluid polymerase chain reaction and magnetic resonance imaging findings and review the literature trying to find any specific clinical, laboratory, radiologic diagnostic or prognostic criteria regarding this subacute form of HSVE.

CONCLUSION

There is subacute form of HSVE and should be suspected with any subacute febrile illness with nonspecific cognitive impairment even in the absence of focal neurological symptoms and in cases with rapidly progressive dementia. This form has similar radiologic finding and good response to acyclovir but carry even better prognosis than that the acute HSVE.

Varicella Zoster Virus Encephalitis in Denmark From 2015 to 2019-A Nationwide Prospective Cohort Study

BACKGROUND

Knowledge of the epidemiology and clinical characteristics of varicella zoster virus (VZV) encephalitis remains limited.

METHODS

Nationwide prospective cohort study of adults treated for microbiologically confirmed VZV encephalitis at Danish departments of infectious diseases from 2015 to 2019. Modified Poisson regression analysis was used to compute adjusted relative risks (RRs) of unfavorable outcome.

RESULTS

We identified 92 adults (49% female) with VZV encephalitis, yielding an incidence of 5.3/1 000 000 per year (95% CI, 4.2-6.6). Median age was 75 years (IQR, 67-83) and immunocompromising conditions were frequent (39%). Predominant symptoms were confusion (76%), headache (56%), nausea (45%), gait disturbance (42%), and personality changes (41%). Cranial imaging showed cerebral vasculitis (including infarction and hemorrhage) in 14 (16%) patients and encephalitic abnormalities in 11 (13%) with predilection for the brainstem and deep brain structures. Intravenous acyclovir treatment was initiated a median (IQR) of 13.4 hours (5.2-46.3) since admission, while cranial imaging and lumbar puncture were performed after 6.3 hours (2.5-31.0) and 18.5 hours (4.9-42.0). In-hospital, 1-month, and 3-month mortalities were 4%, 9%, and 11%, respectively. Unfavorable outcome (Glasgow Outcome Score of 1-4) was found in 69% at discharge, with age (adjusted RR [aRR], 1.02; 95% CI, 1.01-1.03), vasculitis (aRR, 1.38; 95% CI, 1.02-1.86), and Glasgow Coma Scale (GCS) <15 (aRR, 1.32; 95% CI, 1.01-1.73) identified as independent risk factors.

CONCLUSIONS

VZV encephalitis occurs primarily in elderly or immunocompromised patients with a higher incidence than previously estimated. The diagnosis is often delayed; risk factors for unfavorable outcome are age, cerebral vasculitis, and GCS <15.

Characteristics and outcome of varicella-zoster virus central nervous system infections in adults

We conducted an observational retrospective study of all adults hospitalized for documented varicella-zoster virus (VZV) meningitis or encephalitis during years 2000-2015 in one referral centre. Thirty-six patients (21 males, 15 females) were included, with meningitis (n = 21), or meningoencephalitis (n = 15). Median age was 51 years [interquartile range, 35-76], and 6 patients (17%) were immunocompromised. Aciclovir was started in 32 patients (89%), with a median dose of 11 mg/kg/8 h [10-15]. No patient died, but 12 (33%) had neurological sequelae at discharge. Age was the only variable associated with adverse outcome (OR 1.98 [1.17-3.35] per 10-year increment, P = 0.011).

Herpesvirus encephalitis diagnosed by polymerase chain reaction at the National Institute of Neurology of Mexico

The frequency of central nervous system infections due to herpesvirus have been studied in various populations; however, studies in Mexican mestizo patients are scant. This paper documents the frequency of herpesvirus encephalitis in Mexican mestizo patients from the National Institute of Neurology and Neurosurgery (NINN) of Mexico. To study the frequency of herpetic viral encephalitis at the NINN in the period from 2004 to 2009. We reviewed clinical records from patients with clinically suspected encephalitis; polymerase chain reaction assays were done for detection of herpesviruses in cerebrospinal fluid (CSF) samples. The total number of patients studied was 502; in 59 (12%), the diagnosis of herpetic encephalitis was confirmed by PCR-based testing of CSF. Of them, 21 (36%) were positive for herpes simplex virus type 1, 15 (25%) for Epstein-Barr virus, 10 (17%) for varicella zoster virus, 8 (14%) for cytomegalovirus, 3 (5%) for human herpesvirus 6, and 2 (3%) for herpes simplex virus 2. Our results show a varied frequency of viral encephalitis in mestizo patients due to herpesviruses in a tertiary neurological center and point out the importance of modern molecular technology to reach the etiological diagnosis in cases of encephalitis.

"Double Trouble": Severe Meningoencephalitis Due to Borrelia burgdorferi and Powassan Virus Co-Infection Successfully Treated with Intravenous Immunoglobulin

BACKGROUND Powassan virus (POWV) is an emerging tick-borne flavivirus transmitted to humans by ticks. While infection is asymptomatic in some people, others develop life-threatening encephalitis with high mortality rates. Co-infection between POWV and Borrelia burgdorferi is rare despite the fact that both pathogens can be transmitted through the same tick vector, Ixodes scapularis. It is unclear if co-infection leads to more severe clinical presentation and worse outcome. CASE REPORT A 76-year-old Wisconsin man was admitted for meningoencephalitis complicated by hypoxemic and hypercapnic respiratory failure requiring endotracheal intubation. The patient had no known tick bites but lived in a heavily wooded area. Extensive work-up for infectious, autoimmune, and paraneoplastic causes was positive for Borrelia burgdorferi and Powassan virus infection (POWV). Following treatment with ceftriaxone for neuroborreliosis and supportive care for POWV infection, the patient failed to improve. Intravenous immunoglobulins (IVIG) were started empirically, and the patient attained gradual neurological improvement and was successfully extubated. CONCLUSIONS Treatment for POWV infection is supportive, and at this time there are no approved targeted antivirals for this disease. At this time, it remains unclear if co-infection with 2 pathogens leads to a more severe clinical presentation and higher mortality. In the absence of contraindications, IVIG might be beneficial to patients with POWV infection who are not improving with supportive care.

Defence Medical Rehabilitation Centre (DMRC) COVID-19 Recovery Service

Coronavirus disease 2019 (COVID-19) causes significant mortality and morbidity, with an unknown impact in the medium to long term. Evidence from previous coronavirus epidemics indicates that there is likely to be a substantial burden of disease, potentially even in those with a mild acute illness. The clinical and occupational effects of COVID-19 are likely to impact on the operational effectiveness of the Armed Forces. Collaboration between Defence Primary Healthcare, Defence Secondary Healthcare, Defence Rehabilitation and Defence Occupational Medicine resulted in the Defence Medical Rehabilitation Centre COVID-19 Recovery Service (DCRS). This integrated clinical and occupational pathway uses cardiopulmonary assessment as a cornerstone to identify, diagnose and manage post-COVID-19 pathology.

Characteristics and long-term prognosis of Danish patients with varicella zoster virus detected in the cerebrospinal fluid, compared with the background population

BACKGROUND

Risk factors for and long-term outcomes following detection of varicella zoster virus (VZV) DNA in the cerebrospinal fluid (CSF) are unknown.

METHODS

We performed a nationwide population-based cohort study of all Danish residents who had VZV DNA detected in the CSF by polymerase chain reaction (PCR) between 1 January 1997 and 1 March 2016 (VZV cohort; n = 517) and an age- and sex- matched comparison cohort from the general Danish population (n = 9823). We examined potential risk factors and mortality, neurologic morbidity, psychiatric morbidity, redemption of medicine prescribed for the nervous system and social outcomes.

RESULTS

Prior hospital admission, redemption of immunosuppressive medicine, comorbidity and immunosuppressive conditions were associated with detection of VZV DNA in the CSF. Mortality was increased in the VZV cohort, especially during the first year of observation and among patients with encephalitis. Patients in the VZV cohort had an increased risk of dementia and epilepsy. The redemption of antiepileptics and antidepressants was increased in the VZV cohort.

CONCLUSIONS

Immunosuppression and comorbidity are associated with increased risk of detection of VZV DNA in the CSF and the condition is associated with increased mortality and neurological morbidity.

Cognitive impairment without altered levels of cerebrospinal fluid biomarkers in patients with encephalitis caused by varicella-zoster virus: a pilot study

Varicella-zoster virus (VZV) is one of the most common agents causing viral infections of the central nervous system (CNS). VZV encephalitis is associated with severe neurological sequelae, despite antiviral treatment. Cognitive impairment has been reported and VZV has been associated with dementia. Our aim was to investigate the cognitive impairment and cerebrospinal fluid biomarkers in a follow-up study of patients with VZV encephalitis. Thirteen patients with VZV encephalitis, diagnosed by detection of VZV DNA in cerebrospinal fluid (CSF) by PCR and concomitant symptoms of encephalitis, were included. Neuropsychological assessment in parallel with a lumbar puncture to obtain CSF was performed 1.5–7 years after acute disease. The CSF biomarkers neurofilament light chain (NFL), S100B, glial fibrillary acidic protein (GFAP), amyloid-β (Aβ) 40 and Aβ42, total tau (t-tau) and phosphorylated tau (p-tau) were analysed and compared to controls (n = 24). Cognitive impairment was shown in the domains of executive functions and speed/attention and to a minor degree in the domains of learning/memory and language, indicated by a significantly poorer performance on seven neuropsychological test variables. No convincing evidence of alterations in concentrations of biomarkers in the CSF were shown. Our results indicate that patients with VZV encephalitis suffer from cognitive impairment long time after acute disease. Importantly, these impairments do not seem to be accompanied by biomarker evidence of ongoing neuronal or astrocytic injury/activation or induction of dementia-related brain pathologies by the infection.

Innate immune responses to Listeria in vivo

Listeria monocytogenes (Lm) is a foodborne bacterial pathogen that causes listeriosis, a severe infection that manifests as bacteremia and meningo-encephalitis mostly in immunocompromised individuals, and maternal-fetal infection. A critical pathogenic determinant of Lm relies on its ability to actively cross the intestinal barrier, disseminate systemically and cross the blood-brain and placental barriers. Here we illustrate how Lm both evades innate immunity, favoring its dissemination in host tissues, and triggers innate immune defenses that participate to its control.

Prospective Evaluation of Childhood Encephalitis: Predisposing Factors, Prevention and Outcome

BACKGROUND

Acute encephalitis in childhood is a serious condition. The severity varies between studies, partly reflecting differences in study design where only severe cases from referral centers often are reported. The aim of this study was to prospectively study the clinical picture and etiology of acute encephalitis in childhood at a primary and tertiary pediatric hospital in Sweden.

METHODS

All children with acute encephalitis were prospectively included from 2011 to 2016. Laboratory tests, investigations and follow-up were performed according to standardized study protocols.

RESULTS

Eighty-nine children were included (46 female and 43 male) with a median age of 53 months. An etiology was established in 61/89. Tick-borne encephalitis virus, enterovirus and rotavirus dominated and 34% were caused by a virus preventable by vaccination. Immune-mediated encephalitis was seen in 7 children. An abnormal electroencephalography picture was seen in 77/86, pathologic findings on neuroimaging in 13/49, and 38/89 children had seizures. Sequelae were reported by 49%. A high prevalence of previous contact with child and adolescent psychiatry was seen and, although not statistically significant, the need for extra support at school before encephalitis and the presence of central nervous system disease in the family seemed to predispose for a longer hospital stay.

CONCLUSION

Encephalitis is a condition with long-term consequences. Most children need admission to hospital, and many need surveillance in the intensive care unit. The etiology can be determined in a majority of cases, and 1/3 could have been prevented by vaccination. This study corroborates electroencephalography as a cornerstone in diagnosis.

Predicting Inpatient Mortality Among Encephalitis Patients: A Novel Admission Risk Score

Background

Identifying underlying commonalities among all-cause encephalitis cases can be extraordinarily useful in predicting meaningful risk factors associated with inpatient mortality.

Methods

A retrospective cohort of patients with encephalitis was derived from a clinical chart review of adult patients (age ≥18 years) across 16 different hospitals in Houston, Texas, between January 2005 and July 2015. Clinical features at admission were assessed for their correlation with inpatient mortality and used to derive a final risk score prediction tool.

Results

The study included a total of 273 adult patients with all-cause encephalitis, 27 (9.9%) of whom died during hospitalization. A limited number of clinical features were substantially different between patients who survived and those who died (Charlson score, Glasgow coma scale [GCS], immunosuppression, fever on admission, multiple serologic studies, and abnormal imaging). A final multivariable logistic model was derived with the following risk factors, which were transformed into a scoring system: 1 point was assigned to the presence of a Charlson score >2, thrombocytopenia, or cerebral edema, and 2 points for a GCS value <8. Patients were then classified into different risk groups for inpatient mortality: 0 points (0%), 1 point (7%), 2 points (10.9%), 3 points (36.8%), and ≥4 points (81.8%).

Conclusions

The risk score developed from this study shows a high predictive value. This can be highly beneficial in alerting care providers to key clinical risk factors associated with in-hospital mortality in adults with encephalitis.

Acyclovir-induced neurotoxicity with a positive cerebrospinal fluid varicella zoster PCR result creating a management dilemma: a case report

BACKGROUND

Varicella zoster virus central nervous system infections can present as aseptic meningitis, encephalitis, myelitis, and vasculopathy. Diagnosis is based on identification of varicella zoster virus deoxyribonucleic acid (DNA) in the cerebrospinal fluid by polymerase chain reaction. Therapy for these infections is acyclovir or valacyclovir. However, acyclovir can have neurotoxic effects that can mimic the presentation of varicella zoster virus central nervous system disease. We present a rare presentation of a patient who had acyclovir-induced neurotoxicity who also had a false-positive cerebrospinal fluid varicella zoster virus polymerase chain reaction result, creating a management dilemma. We review the clinical characteristics of acyclovir-induced neurotoxicity. In addition, we present the diagnostic characteristics of the cerebrospinal fluid viral polymerase chain reaction and alternative methods to diagnose central nervous system varicella zoster virus disease.

CASE PRESENTATION

A 68-year-old Hispanic man with end-stage renal disease was diagnosed with cutaneous zoster at an outside facility and was started on acyclovir 4 days prior to admission. His family noted worsening confusion, agitation, speech difficulty, and hallucinations, leading them to bring him to the emergency department. His cerebrospinal fluid varicella zoster virus polymerase chain reaction result was positive, indicating the presence of varicella zoster virus deoxyribonucleic acid in the cerebrospinal fluid; however, he did not have cerebrospinal fluid pleocytosis typical of varicella zoster virus meningoencephalitis. Pharmacy records from the outside hospital revealed supratherapeutic acyclovir dosing. This led to a diagnostic dilemma over whether this patient had varicella zoster virus encephalitis or acyclovir-induced neurotoxicity. Acyclovir was discontinued, and the patient underwent two sessions of hemodialysis to remove acyclovir, which led to a full neurologic recovery.

CONCLUSIONS

Varicella zoster virus encephalitis and acyclovir-induced neurotoxicity can have similar presentations. Varicella zoster virus deoxyribonucleic acid can be present in the cerebrospinal fluid during active cutaneous zoster in the absence of central nervous system disease. If concern for central nervous system varicella zoster virus disease remains high, additional testing with cerebrospinal fluid serology can be performed. Compared with central nervous system varicella zoster virus disease, acyclovir-induced neurotoxicity has a more predictable clinical resolution once drug therapy is discontinued or the patient undergoes hemodialysis, which can aid in making the diagnosis. Clinicians should be aware of this rare and dangerous complication of acyclovir. In addition, clinicians should have an understanding of the diagnostic limitations of cerebrospinal fluid viral polymerase chain reaction and have alternative approaches available to diagnose central nervous system varicella zoster virus disease when it is suspected.

Serum and cerebrospinal fluid neurofilament light chain in patients with central nervous system infections caused by varicella-zoster virus

Varicella-zoster virus (VZV) is a common cause of viral central nervous system (CNS) infection, and patients may suffer from severe neurological sequelae. The biomarker neurofilament light chain (NFL) is used for assessment of neuronal damage and is normally measured in cerebrospinal fluid (CSF). Novel methods have given the possibility to measure NFL in serum instead, which could be a convenient tool to estimate severity of disease and prognosis in VZV CNS infections. Here, we investigate the correlation of serum and CSF NFL in patients with VZV CNS infection and the association of NFL levels in serum and CSF with different VZV CNS entities. NFL in serum and CSF was measured in 61 patients who were retrospectively identified with neurological symptoms and VZV DNA in CSF detected by PCR. Thirty-three herpes zoster patients and 40 healthy blood donors served as control groups. NFL levels in serum and CSF correlated strongly in the patients with VZV CNS infection. Encephalitis was associated with significantly higher levels of NFL in both serum and CSF compared with meningitis and Ramsay Hunt syndrome. Surprisingly, herpes zoster controls had very high serum NFL levels, comparable with those shown in encephalitis patients. We show that analysis of serum NFL can be used instead of CSF NFL for estimation of neuronal injury in patients with VZV CNS infection. However, high levels of serum NFL also in patients with herpes zoster, without signs of CNS involvement, may complicate the interpretation.

Predictors of Outcome in Clinically Diagnosed Viral Encephalitis Patients: A 5-Year Prospective Study

Background

Viral encephalitis is the most common infectious disease of the central nervous system and is associated with high morbidity, mortality, and disability. The objective of this study was to analyze the clinical characteristics, auxiliary examinations, therapeutic management, and outcomes of patients clinically diagnosed with viral encephalitis and identify the outcome predictors.

Methods

We conducted a prospective observational study by collecting information from patients clinically diagnosed with viral encephalitis at the First Affiliated Hospital of Chongqing Medical University and Yongchuan Hospital of Chongqing Medical University from January 2013 to December 2018. Univariate and multivariate analyses were performed to identify factors that influenced good patient outcomes (mRS < 3) and poor patient outcomes (mRS ≥ 3) at discharge.

Results

In total, 216 patients were enrolled in the study. The multivariate analysis suggested that the following factors were associated with a poor outcome: Glasgow Coma Scale (GCS) score (OR 0.154, 95% CI (0.078-0.302), and P < 0.001), focal neurological deficits (OR 9.403, 95% CI (1.581-55.928), and P = 0.014), and total length of hospital stay (OR 1.119, 95% CI (1.002-1.250), and P = 0.045). However, neurological intensive care unit (NICU) treatment, status epilepticus, and abnormal electroencephalogram (EEG) findings did not influence the prognosis of patients.

Conclusion

Our study suggests that low GCS scores at admission, focal neurological deficits at admission, and a prolonged total hospital stay are predictors of a poor outcome at discharge in clinically diagnosed viral encephalitis patients. Whether early and effective neurological rehabilitation can improve the prognosis of viral encephalitis patients with focal neurological deficits remains to be confirmed in further studies.

Herpes simplex virus encephalitis update

PURPOSE OF REVIEW

HSV is the most frequently identified cause of infectious encephalitis, in Western countries. This article is an update on the topic based on a review of recent studies from 2017 to 2018.

RECENT FINDINGS

Acyclovir is still the first line treatment, and no new drugs are currently available for clinical use. The major considerations for HSV encephalitis are as follows: point one, clinical evaluation remains the most important factor, as though CSF HSV PCR has a good sensitivity, in a small proportion of patients the initial testing might be negative. MRI brain is the first line imaging test, and mesial temporal lobe involvement and other typical findings are important for diagnosis; point 2, there should be emphasis on sequela, short-term, and long-term outcomes, and not just case fatality rated in future studies and clinical management. Auto-immune encephalitis can be triggered by HSV, and should be considered in patients who are not responding to treatment; point 3, future studies should be on better management of sequela, and better treatment regimens including those targeting the immune response.

SUMMARY

Autoimmune encephalitis is a clearly identified complication of HSV encephalitis. Inflammatory mechanisms are linked to the clinical presentation as well as severity and poor outcome. Initial corticosteroid therapy has to be evaluated in order to prevent complications.

Rhombencephalitis in Children: Diffusion Magnetic Resonance Imaging (MRI) Correlation With Clinical Outcomes

In children with rhombencephalitis, neuroimaging abnormalities have been infrequently correlated with clinical outcome. We investigated whether magnetic resonance (MR) neuroimaging studies could predict clinical outcomes and disturbance of consciousness in patients with rhombencephalitis. We retrospectively analyzed the MR studies of 19 pediatric patients with rhombencephalitis (median age: 4.2 years, range 0.5-17; sex: 32% male). Fluid-attenuated inversion recovery imaging and diffusion-weighted imaging findings were graded to create imaging scores according to the extent of imaging abnormality. Clinical outcomes in the first week and 12th month were graded by using Glasgow Outcome Scale scores (1-5) and dichotomized to unfavorable or favorable outcome. Correlations of the imaging scores with the clinical outcomes and with disturbance of consciousness were assessed by using multivariate logistic regression analysis. No significant correlation was found between fluid-attenuated inversion recovery score or diffusion-weighted imaging score (P = .608, P = .132, respectively) and disturbance of consciousness. In the first week, the unfavorable outcome group (n = 11) had significantly higher diffusion-weighted imaging score than did the favorable outcome group (n = 8) (Mann-Whitney U test, P = .005). Multivariate logistic regression analysis showed that the diffusion-weighted imaging score (odds ratio, 18.182; 95% confidence interval: 1.36, 243.01; P = .028) was significantly associated with unfavorable outcome. In the 12th month, the fluid-attenuated inversion recovery score or diffusion-weighted imaging score (P = .994, P = .997, respectively) were not significantly associated with unfavorable outcome. Patients with rhombencephalitis who have a higher diffusion-weighted imaging score are more likely to have an unfavorable 1-week clinical outcome.

A 9-month retrospective evaluation of the aetiology and management of patients presenting with encephalitis/meningoencephalitis at a South London hospital

Encephalitis causes high morbidity and mortality. An incidence of 4.3 cases of encephalitis/100 000 population has been reported in the UK. We performed a retrospective evaluation of the diagnosis and management of adults admitted to hospital with a clinical diagnosis of encephalitis/meningoencephalitis. Clinical, laboratory and radiological data were collated from electronic records. Thirty-six patients, median age 55 years and 24 (67%) male were included. The aetiology was confirmed over nine months in 25 (69%) of whom 16 were infections (six viral, seven bacterial, two parasitic and one viral and parasitic co-infection); 7 autoimmune; 1 metabolic and 1 neoplastic. Of 24 patients with fever, 15 (63%) had an infection. The median time to computed topography, magnetic resonance imaging and electroencephalography (EEG) was 1, 8 and 3 days respectively. Neuroimaging was abnormal in 25 (69%) and 17 (89%) had abnormal EEGs. Only 19 (53%) received aciclovir treatment. Six (17%) made good recoveries, 16 (44%) had moderate disability, 8 (22%) severe disability and 6 (17%) died. Outcomes were worse for those with an infectious cause. In summary, a diagnosis was made in 69.4% of patients admitted with encephalitis/meningoencephalitis. Autoimmune causes are important to consider at an early stage due to a successful response to treatment. Only 53% of patients received aciclovir on admission. Neuroimaging and EEG studies were delayed. The results of this work resulted in further developing the clinical algorithm for managing these patients.