New estimates of incidence of encephalitis in England

Current epidemiology of infectious encephalitis: a narrative review

BACKGROUND

Infectious encephalitis poses a global health challenge with high mortality and severe neurological consequences in survivors. Emerging pathogens and outbreaks are reshaping the patterns of the disease.

OBJECTIVES

The objective of this study is to understand the current epidemiology for improving prevention, diagnosis, and treatment.

SOURCES

Medline/PubMed was searched using 'encephalitis' and related MeSH terms from 2020 to September 2024. Population-based and case-control studies on encephalitis were searched without time restrictions. Other studies known by the authors were also included.

CONTENT

The incidence of infectious encephalitis ranged from 1.4 to 13.8 cases per 100 000 per year with a bimodal peak in infants and older adults. Herpes viruses remain the most common causes of sporadic encephalitis with herpes simplex virus type 1 and varicella zoster virus reported most frequently. In endemic regions, arboviruses such as Japanese encephalitis virus and West Nile virus contribute significantly to the disease burden. Climate change is adding to the spread of these vector-borne viruses thereby both altering the geographical distribution of causative agents and increasing the frequency of outbreaks. Evidence on risk factors associated with encephalitis is scarce and hampered by the absence of population-based case-control studies. The prognosis of infectious encephalitis remains unchanged during recent decades with high case-fatality rates and may vary according to, e.g. aetiology, age, and presence of immunocompromising conditions or other comorbidities. Importantly, a substantial proportion of survivors are left with disabling neurological sequelae.

IMPLICATIONS

The findings underscore the importance of public health surveillance and prevention strategies to address the changing epidemiology of encephalitis. This can be pursued through vaccination programmes and vector control efforts. Future research should focus on identifying risk factors, improving diagnostic tools, optimizing current treatment as well as exploring novel therapies for patients with encephalitis. Timely treatment and specialised post-hospital rehabilitation remain essential for patient management.

Clinical features and outcomes in children with seronegative autoimmune encephalitis

AIM

To characterize the presenting features and outcomes in children with seronegative autoimmune encephalitis, and to evaluate whether scores at nadir for the Modified Rankin Scale (mRS) and Clinical Assessment Scale for Autoimmune Encephalitis (CASE) or its paediatric-specific modification (ped-CASE) are predictive of outcomes.

METHOD

This observational study included children younger than 18 years of age with seronegative autoimmune encephalitis. Demographics and clinical data were collected. The mRS and CASE/ped-CASE scores were used to evaluate disease severity. Descriptive statistics and logistic regression were used for data analysis and to evaluate associations between scale scores and outcomes.

RESULTS

Sixty-three children were included (39 [62%] females, median age 7 years, interquartile range [IQR] 4 years 1 months-11 years 6 months), with follow-up available for 56 out of 63 patients (median follow-up 12.2 months, IQR 13.4-17.8). The most frequent presenting neurological manifestation was encephalopathy (81%). Median CASE/ped-CASE and mRS scores at nadir were 12.0 (IQR 7.0-17.0) and 1.0 (IQR 0-2.0) respectively. Thirty-three patients (59%) had persistent neurological deficits at follow-up. Both scoring systems suggested good functional recovery (mRS score ≤2, 95%; CASE/ped-CASE score <5, 91%). CASE/ped-CASE score was more likely than mRS to distinguish children with worse outcomes.

INTERPRETATION

Children with seronegative autoimmune encephalitis are likely to have neurological deficits at follow-up. CASE/ped-CASE is more likely to distinguish children with worse outcomes than MRS.

WHAT THIS PAPER ADDS

Encephalopathy was the most common reason for presentation in children with seronegative autoimmune encephalitis. Children with seronegative autoimmune encephalitis are likely to have neurological deficits at follow-up. The Clinical Assessment Scale for Autoimmune Encephalitis or its paeditric version at nadir was better at distinguishing children with poor outcomes than the Modified Rankin Scale.

Validation of the encephalitis criteria in adults with a suspected central nervous system infection: An updated score

OBJECTIVES

We aimed to validate and refine the encephalitis criteria proposed by the International Encephalitis Consortium in a cohort of adults initially suspected of a central nervous system (CNS) infection.

METHODS

We included patients from two prospective cohort studies consisting of adults suspected of a CNS infection whom underwent a diagnostic lumbar puncture. We evaluated the test characteristics of the criteria for both possible and probable encephalitis. The reference standard was a final clinical diagnosis of encephalitis. Recalibration of the criteria was done by adjusting the weight of each criterion based on their respective odds.

RESULTS

In total 1446 episodes were evaluated, of whom 162 (11%) had a clinical diagnosis of encephalitis. Possible encephalitis had a sensitivity of 41% (95% CI 33-49) and a specificity of 88% (95% CI 86-90). Probable encephalitis had a sensitivity and specificity of respectively 27% (95% CI 20-34) and 95% (95% CI 94-96). Through odds-based weighting, we recalibrated the weight of each individual criterion, resulting in a model consisting of an altered mental status (weight of 2), seizures (weight of 3), elevated CSF leukocytes (weight of 5) and abnormalities on neuroimaging (weight of 9). We proposed a cut-off at 5 for possible encephalitis, (sensitivity 93% [95% CI 88-96]; specificity 51% [95% 49-54]), and at 8 for probable encephalitis (sensitivity 51% [95% CI 44-59]; specificity 91% [95% CI 89-92]).

CONCLUSIONS

We validated and refined the existing diagnostic criteria for encephalitis, leading to a substantially enhanced sensitivity. These updated criteria hold promise to facilitate the accurate identification of encephalitis.

Epidemiology of autoimmune encephalitis and comparison to infectious causes-Experience from a tertiary center

OBJECTIVES

The incidence of autoimmune encephalitis (AIE) has risen in the last decade, yet recent studies are lacking. We compared the epidemiology of autoimmune and infectious encephalitis cases in Tel-Aviv Sourasky Medical Center (TASMC) between 2010 and 2020.

METHODS

All encephalitis cases, aged 18 and above, admitted to TASMC between the years 2010 and 2020 were reviewed for demographic, clinical, laboratory, and imaging data and categorized based on etiology.

RESULTS

Two hundred and twenty-five patients with encephalitis were identified. The most common identifiable cause was viral (42%), followed by autoimmune encephalitis (35%), bacterial (18%), and fungal/parasitic (5%). The incidence of AIE cases out of the yearly admitted cases increased substantially, from 3.8/100 K in 2010 to 18.8/100 K in 2020. The incidence of viral cases also increased while those of bacterial and fungal/parasitic infections remained stable. Patients with AIE were younger compared to infectious patients (p-value <0.001) and had lower markers of systemic and cerebrospinal fluid inflammation (p-value for all <0.001). Seizures were more common among AIE patients (p-value <0.001), yet one-year mortality rates were higher among infectious patients (p-value <0.001).

INTERPRETATION

AIE incidence has risen significantly in our institution during the past decade, with current rates comparable to those of all infectious causes combined. Based on this cohort, clinical clues for an autoimmune etiology include a non-inflammatory cerebrospinal fluid profile, the presence of seizures, and temporal lobe imaging abnormalities (also common in herpetic encephalitis). In light of its rising incidence and the importance of early treatment, AIE should be considered in the differential diagnosis of all encephalitis cases.

Estimating prevalence of post-war health disorders using multiple systems data

Effective surveillance on the long-term public health impact due to war and terrorist attacks remains limited. Such health issues are commonly under-reported, specifically for a large group of individuals. For this purpose, efficient estimation of the size or undercount of the population under the risk of physical and mental health hazards is of utmost necessity. A novel trivariate Bernoulli model is developed allowing heterogeneity among the individuals and dependence between the sources of information, and an estimation methodology using a Monte Carlo-based EM algorithm is proposed. Simulation results show the superiority of the performance of the proposed method over existing competitors and robustness under model mis-specifications. The method is applied to analyse two real case studies on monitoring amyotrophic lateral sclerosis (ALS) cases for the Gulf War veterans and the 9/11 terrorist attack survivors at the World Trade Center, USA. The average annual cumulative incidence rate for ALS disease increases by 33 % and 16 % for deployed and no-deployed military personnel, respectively, after adjusting the undercount. The number of individuals exposed to the risk of physical and mental health effects due to WTC terrorist attacks increased by 42 % . These results provide interesting insights that can assist in effective decision-making and policy formulation for monitoring the health status of post-war survivors.

A retrospective analysis of 20,178 adult neurological infection admissions to United Kingdom critical care units from 2001 to 2020

BACKGROUND

Neurological infection is an important cause of critical illness, yet little is known on the epidemiology of neurological infections requiring critical care.

METHODS

We analysed data on all adults with proven or probable neurological infection admitted to UK (NHS) critical care units between 2001 and 2020 reported to the Intensive Care National Audit and Research Centre. Diagnoses, physiological variables, organ support and clinical outcomes were analysed over the whole period, and for consecutive 5-year intervals within it. Predictors of in-hospital mortality were identified using a backward stepwise regression model.

RESULTS

We identified 20,178 critical care admissions for neurological infection. Encephalitis was the most frequent presentation to critical care, comprising 6725 (33.3%) of 20,178 cases. Meningitis- bacterial, viral or unspecified cases - accounted for 10,056 (49.8%) of cases. In-hospital mortality was high, at 3945/19,765 (20.0%) overall. Over the four consecutive 5-year periods, there were trends towards higher Glasgow Coma Scale scores on admission, longer critical care admissions (from median 4 [IQR 2-8] to 5 days [IQR 2-10]), and reduced in-hospital mortality (from 24.9 to 18.1%). We identified 12 independent predictors of in-hospital death which when used together showed good discrimination between patients who die and those who survive (AUC = 0.79).

CONCLUSIONS

Admissions with neurological infection to UK critical care services are increasing and the mortality, although improving, remains high. To further improve outcomes from severe neurological infection, novel approaches to the evaluation of risk stratification, monitoring and management strategies are required.

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.

Clinical predictors of encephalitis in UK adults-A multi-centre prospective observational cohort study

OBJECTIVES

Encephalitis, brain inflammation and swelling, most often caused by an infection or the body's immune defences, can have devastating consequences, especially if diagnosed late. We looked for clinical predictors of different types of encephalitis to help clinicians consider earlier treatment.

METHODS

We conducted a multicentre prospective observational cohort study (ENCEPH-UK) of adults (> 16 years) with suspected encephalitis at 31 UK hospitals. We evaluated clinical features and investigated for infectious and autoimmune causes.

RESULTS

341 patients were enrolled between December 2012 and December 2015 and followed up for 12 months. 233 had encephalitis, of whom 65 (28%) had HSV, 38 (16%) had confirmed or probable autoimmune encephalitis, and 87 (37%) had no cause found. The median time from admission to 1st dose of aciclovir for those with HSV was 14 hours (IQR 5-50); time to 1st dose of immunosuppressant for the autoimmune group was 125 hours (IQR 45-250). Compared to non-HSV encephalitis, patients with HSV more often had fever, lower serum sodium and lacked a rash. Those with probable or confirmed autoimmune encephalitis were more likely to be female, have abnormal movements, normal serum sodium levels and a cerebrospinal fluid white cell count < 20 cells x106/L, but they were less likely to have a febrile illness.

CONCLUSIONS

Initiation of treatment for autoimmune encephalitis is delayed considerably compared with HSV encephalitis. Clinical features can help identify patients with autoimmune disease and could be used to initiate earlier presumptive therapy.

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.

Imaging Spectrum of HTLV-1–Related Neurologic Disease

Purpose of Review

Human T-cell lymphotropic virus type 1 (HTLV-1)–associated myelopathy (HAM) is a well-recognized neurologic complication of HTLV-1. Beyond HAM, several other neurologic manifestations are increasingly recognized, including acute myelopathy, encephalopathy, and myositis. The clinical and imaging features of these presentations are less well understood and potentially underdiagnosed. In this study, we summarize the imaging features of HTLV-1–related neurologic disease, providing both a pictorial review and pooled series of the less well-recognized presentations.

Recent Findings

35 cases of acute/subacute HAM and 12 cases of HTLV-1–related encephalopathy were found. In subacute HAM, cervical and upper thoracic longitudinally extensive tranverse myelitis was noted, while in HTLV-1–related encephalopathy, confluent lesions in the frontoparietal white matter and along the corticospinal tracts were the most prevalent finding.

Summary

There are varied clinical and imaging presentations of HTLV-1–related neurologic disease. Recognition of these features aids early diagnosis where therapy may have the greatest benefit.

Perspectives on Diagnosis and Management of All-Cause Encephalitis: A National Survey of Adult Infectious Diseases Physicians

Background

Encephalitis is widely recognized as a challenging condition to diagnose and manage. The care of patients with encephalitis typically involves multiple disciplines, including neurologists and infectious disease (ID) physicians. Our objective was to describe the perspectives and needs of ID physicians regarding encephalitis, using a cross-sectional questionnaire survey.

Methods

We performed a survey among physician members of the Infectious Diseases Society of America's (IDSA) Emerging Infections Network (EIN).

Results

Response rate was 33% (480 among 1472 active EIN physician members). More than 75% of respondents reported caring for patients with suspected encephalitis. Although one-third were involved in the care of multiple patients with autoimmune encephalitis (AE) annually, comfort in diagnosing and managing encephalitis, and in particular AE, was low. Experience with advanced diagnostic tools was variable, as were approaches toward deployment of such tools. Respondents noted that training could be improved by incorporating a multidisciplinary approach taking advantage of online and virtual platforms. ID physicians report a heavy reliance on the 2008 IDSA guidelines for the management of encephalitis, and indicated strong support for a formal update.

Conclusions

ID physicians play an important role in the diagnosis and management of all-cause encephalitis. Despite exposure to AE, few ID physicians are comfortable in recognizing, diagnosing, and treating AE. Moreover, comfort with and use of advanced diagnostic tools for infectious encephalitis was highly variable. Training in encephalitis should include a focus on use and stewardship of advanced diagnostic tools and on collaborative approaches with neurologists and other practitioners on mechanisms and clinical presentations of AE. There is a need for a formal update of 2008 guidelines on the management of encephalitis.

Seasonal Trends in the Prevalence and Incidence of Viral Encephalitis in Korea (2015-2019)

Viral infections are a common cause of encephalitis. This study investigated the relationship between the incidence of encephalitis and that of respiratory and enteric viral infections in all age groups from 2015 to 2019, using the Health Insurance Review and Assessment (HIRA) Open Access Big Data Platform. We identified monthly incidence patterns and seasonal trends using the autoregressive integrated moving average (ARIMA). The Granger causality test was used to analyze correlations between encephalitis incidence and the positive detection rate (PDR) at 1-month intervals. A total of 42,775 patients were diagnosed with encephalitis during the study period. The incidence of encephalitis was highest in the winter (26.8%). The PDRs for respiratory syncytial virus (HRSV) and coronavirus (HCoV) were associated with the trend in encephalitis diagnosis in all age groups, with a 1-month lag period. In addition, an association with norovirus was observed in patients aged over 20 years, and with influenza virus (IFV) in patients aged over 60 years. This study found that HRSV, HCoV, IFV, and norovirus tended to precede encephalitis by 1 month. Further research is required to confirm the association between these viruses and encephalitis.

Encephalitis in travellers: A prospective multicentre study

BACKGROUND

As the epidemiology of encephalitis varies from one country to another, international travel may be an important clue for the diagnostic workout of this puzzling disease.

METHODS

We performed an ancillary study using the ENCEIF prospective cohort conducted in 62 clinical sites in France from 2016 to 2019. All cases of encephalitis in adults that fulfilled a case definition derived from the International Encephalitis Consortium were included. Travellers were defined as patients who spent at least one night in a foreign country within the last six months.

RESULTS

Of the 494 encephalitis patients enrolled, 69 (14%) were travellers. As compared to non-travellers, they were younger (median age, 48 years [interquartile range, 36-69] vs. 66 [49-76], P < 0.001), less likely to be immunocompromised: 2/69 (3%) vs 56/425 (13%), P = 0.02, and reported more arthralgia: 7/69 (10%) vs. 11/425 (3%), P = 0.007. The risk of poor outcome at hospital discharge (Glasgow outcome scale ≤ 3), was similar for travellers and for non-travellers after adjustment (aOR 0.80 [0.36-1.80], P = 0.594). Arboviruses were the main causes of encephalitis in travellers: 15/69 (22%) vs. 20/425 (5%) in non-travellers, P < 0.001, and Herpes simplex virus (HSV) was the second (9/69, 13%). Of note, in 19% (13/69) of cases, the risk of encephalitis in travellers may have been decreased with a vaccine.

CONCLUSION

The two primary causes of encephalitis in travellers are arboviruses, and HSV. Empirical treatment of encephalitis in travellers must include aciclovir. Pre-travel advice and vaccination may decrease the risk of encephalitis in travellers.

Detection and significance of neuronal autoantibodies in patients with meningoencephalitis in Vientiane, Lao PDR

BACKGROUND

The importance of autoimmune encephalitis and its overlap with infectious encephalitides are not well investigated in South-East Asia.

METHODS

We report autoantibody testing, using antigen-specific live cell-based assays, in a series of 134 patients (cerebrospinal fluid and sera) and 55 blood donor controls (sera), undergoing lumbar puncture for suspected meningoencephalitis admitted in Vientiane, Lao People's Democratic Republic (PDR).

RESULTS

Eight of 134 (6%) patients showed detectable serum neuronal autoantibodies, against the N-methyl-D-aspartate and gamma-aminobutyric acid A receptors (NMDAR and GABAAR), and contactin-associated protein-like 2 (CASPR2). Three of eight patients had accompanying autoantibodies in cerebrospinal fluid (two with NMDAR and one with GABAAR antibodies), and in two of these the clinical syndromes were typical of autoimmune encephalitis. Three of the other five patients had proven central nervous system infections, highlighting a complex overlap between diverse infectious and autoimmune causes of encephalitis. No patients in this cohort were treated with immunotherapy, and the outcomes were poor, with improvement observed in a single patient.

CONCLUSIONS

In Lao PDR, autoimmune encephalitis is underdiagnosed and has a poor prognosis. Empiric immunotherapy should be considered after treatable infectious aetiologies are considered unlikely. Awareness and diagnostic testing resources for autoimmune encephalitis should be enhanced in South-East Asia.

Borrelia miyamotoi Meningoencephalitis in an Immunocompetent Patient

Borrelia miyamotoi is an underdiagnosed cause of tick-borne illness in endemic regions and, in rare cases, causes neurological disease in immunocompetent patients. Here, we present a case of serologically confirmed Borrelia miyamotoi meningoencephalitis in an otherwise healthy patient who rapidly improved following initiation of antibiotic therapy.

Outcomes of implementation of the FilmArray meningoencephalitis panel in a tertiary hospital between 2017 and 2020

Background

Acute meningoencephalitis is encountered commonly in the acute hospital setting and is associated with significant morbidity and mortality, in addition to significant healthcare costs. Multiplex PCR panels now allow syndromic testing for central nervous system infection. The BioFire® FilmArray® Meningoencephalitis (ME) allows testing of 14 target pathogens using only 0.2mls of cerebrospinal fluid (CSF). We conducted a retrospective observational study to assess the performance of the assay and secondarily to observe the clinical utility of negative results by comparing clinical outcomes of aseptic meningitis to bacterial and viral meningoencephalitis.

Methods

Data for CSF samples tested using the FilmArray ME panel from October 2017 to October 2020 were analysed. Detection of bacterial and viral targets was analysed. Admission to critical care area, 90-day readmission rates, average length of stay and 30-day and 90-day mortality were analysed for three groups with following diagnoses: bacterial meningitis, viral meningoencephalitis, or aseptic meningitis.

Results

From October 2017 to October 2020, 1926 CSF samples were received in the Clinical Microbiology laboratory. Of those, 543 CSF samples from 512 individual patients were tested using the FilmArray ME panel. Twenty-one bacterial targets and 56 viral targets were detected during the study period. For viral targets, the cumulative specificity was 98.9% (95% confidence interval: 93.1–99.9) when compared to the reference laboratory methods. The outcomes for 30- and 90-day mortality of the aseptic meningitis group were non-inferior relative to the viral meningoencephalitis and bacterial meningitis group. Patients with bacterial meningitis had a longer average length of stay. Aseptic meningitis was associated with a higher 90-day readmission rate than the other 2 groups, but without statistical significance.

Conclusion

In our hands, implementation of the FilmArray ME panel was relatively straightforward. We experienced a transition in our workflow processes that enabled streamlining of CSF diagnostics and the safe removal of Gram staining in those samples being tested by this molecular assay. Coupled to this improvement, there was a positive clinical impact on patient care due to rapid turnaround time to results.

Neurological and cognitive outcomes after antibody-negative autoimmune encephalitis in children

AIM

To characterize the neurological and cognitive outcomes in children with antibody-negative autoimmune encephalitis (Ab-negative AE).

METHOD

A cohort of children presenting to our institution over a 10-year period with autoimmune encephalitis was identified by structured retrospective review of medical records. Clinical features at presentation and final follow-up were recorded. Neuropsychological testing was performed in a subset of patients. Outcomes after Ab-negative AE were compared with outcomes after N-methyl-D-aspartate receptor antibody encephalitis (NMDARE).

RESULTS

Forty-four patients (26 females, 18 males, median age 9y 2mo [interquartile range 4y 5mo-11y 8mo], 23 with NMDARE) with a diagnosis of autoimmune encephalitis were included. Postencephalitic epilepsy was more frequent after Ab-negative AE compared to NMDARE (61% vs 14%, p=0.002). Cognitive testing was performed in a subset of patients (n=21; Ab-negative AE=11, NMDARE=10). Full-scale IQ was lower after Ab-negative AE than NMDARE (mean IQ 75 vs 92, p=0.02), primarily because of reduced verbal comprehension index (80 vs 98, p=0.01) and working memory index (77 vs 95, p=0.09). The cognitive function most commonly impaired was executive function (80% [8/10] vs 22% [2/9]).

INTERPRETATION

Ab-negative AE was associated with poorer cognitive outcomes than NMDARE at 1-year follow-up. Further studies are required to evaluate if immunotherapy can be optimized to improve outcome.

A critical review and update on autoimmune encephalitis: understanding the alphabet soup

Autoimmune encephalitis (AE) comprises a group of diseases mediated by antibodies against neuronal cell surface or synaptic antigens, such as ion channels or neurotransmitter receptors. New clinical syndromes and their associated antibodies were and are still being characterized over the last two decades. The fact that their main clinical features are interdisciplinary, - encompassing neuropsychiatric symptoms, cognitive dysfunction, epileptic seizures, movement and sleep disorders - has led to a surge of interest in this field. Some of these diseases present with a well-defined syndrome, being recognizable on clinical grounds. Correct diagnosis is important since AE are potentially treatable diseases, despite their severity. On the other hand, an increasing number of neuronal antibodies being described casts doubt upon the way we should utilize antibody testing and interpret results. In this article we review, summarize and update the current knowledge on antibody mediated encephalitis.

Global magnitude of encephalitis burden and its evolving pattern over the past 30 years

OBJECTIVE

We aimed to estimate the spatiotemporal patterns of the encephalitis burden along with its attributable risk factors at the national, regional, and global levels, which may be helpful in guiding targeted prevention and treatment programs.

METHODS

Based on available data sources, the incidence, mortality, and disability-adjusted life years (DALYs) of encephalitis in 204 countries and regions from 1990 to 2019 were reconstructed by the Global Burden of Disease Study 2019 using the Cause of Death Ensemble model, spatiotemporal Gaussian process regression, and DisMod-MR 2.1. We conducted a systematic analysis on the epidemiological characteristics of encephalitis in detail by gender, region, and age over the past three decades.

RESULTS

Globally, 1,444,720 incident cases, 89,900 deaths, and 4.80 million DALYs related to encephalitis were estimated in 2019. The age-standardized incidence rate and age-standardized mortality rate (ASMR) decreased from 23.17 and 2.18 to 19.33 and 1.19 per 100,000 person-years over the past 30 years, respectively. However, beginning in 2011-2013, the burden of encephalitis has shown an inflection point, with a further decline of the ASRs ceasing. Lower socio-demographic index (SDI) regions in South Asia, Western and Eastern Sub-Saharan Africa had the highest burden of encephalitis in 2019. During the past three decades, most countries of South Asia achieved significant control of the burden. In contrast, developed countries with a higher SDI have shown a notable increase in ASMR and age-standardized DALYs rate. Children and older adults have always been high-risk groups for encephalitis.

CONCLUSION

Although the global burden of encephalitis has decreased in the past 30 years, a further decline stopped from 2011-2013. The diverse burden in different regions calls for differentiated management, and the persistent high burden in some low-SDI regions and the increased burden in developed countries with higher SDIs deserve more attention.

ABBREVIATIONS

ASDR: age-standardized DALY rate, ASIR: age-standardized incidence rate, ASMR: age-standardized mortality rate, ASR: age-standardized rate, CI: confidence interval, DALY: disability-adjusted life-year, EAPC: estimated annual percentage change, GBD: Global Burden of Disease Study, HAP: household air pollution from solid fuels, HSE: herpes simplex encephalitis, HSV: herpes simplex virus, ICD: International Classification of Diseases, JE: Japanese encephalitis, PCR: polymerase chain reaction, SDI: socio-demographic index, TBE: tick-borne encephalitis, UI: uncertainty interval.

Challenges for nurses in caring for patients with acute encephalitis: lack of knowledge, time and rehabilitation

AIM

To explore the experiences of registered nurses providing care to adult patients affected by encephalitis, from admission into hospital through to discharge.

STUDY DESIGN

A qualitative phenomenological methodology was used. Sample and setting: Eight registered nurses in a city centre teaching hospital.

METHODS

Data collection took place using in-depth, semi-structured interviews. Data were analysed and themes identified using framework analysis.

FINDINGS

Three key findings were identified: nurses felt that they lacked knowledge of encephalitis, lacked time to give these patients the care they needed, and they lacked access to rehabilitation for patients with encephalitis.

CONCLUSION

This study provides the first evidence on nurses' experiences of providing care to patients affected by encephalitis. It has shown that they often lack the knowledge and time to give adequate support to patients. They also lack access to rehabilitation for these patients.

[Disease Characteristics, Treatment, and Prognosis of Chinese Patients with Autoimmune Encephalitis: A Retrospective Study]

OBJECTIVE

To investigate the clinical features and prognosis of autoimmune encephalitis (AE).

METHODS

Accessing data from the electronic medical records of patients receiving care at West China Hospital, Sichuan University, China between 2013 and 2019, we conducted a retrospective study of the disease characteristics, laboratory examinations, treatment, and prognosis of AE patients. Before they were discharged, modified Rankin Scale (mRS) was used to assess the prognosis of AE patients and their mRS scores were then used to categorize patients as having good prognosis (mRS scores of 0-2) or poor prognosis (mRS scores of 3-6). Multivariate logistic regression was used to analyze risk factors associated with poor prognosis.

RESULTS

A total of 121 patients were included in the study. The male-to-female ratio was 1∶1.1. At the time of diagnosis, patients were mainly from the age group of young to middle-aged individuals. Among the 121 patients, 64.5% (78 patients) had anti-N-methyl D-aspartate receptor (NMDAR) encephalitis, accounting for the largest proportion. 33.1% (40 patients) first visited the Department of Psychiatry for medical assistance. 62.8% (76 patients ) showed prodromal symptoms. The common clinical manifestations of the AE patients at the time of admission included cognitive dysfunction (104 patients, 86.0%), thought disorder (90 patients, 74.4%), and altered behaviors (88 patients, 72.7%). The NMDAR antibody titers were higher in the cerebrospinal fluid (CSF) than those in the serum. Double-positive antibodies were detected in 6 patients. No abnormality was observed in the brain magnetic resonance imaging (MRI) of 42 patients (34.7%) . Electroencephalography abnormalities were observed in 71 patients (58.7%). 111 patients (91.7%) received first-line immunotherapy and 61 patients (50.4%) still had neuropsychiatric deficits when they were discharged. Multivariate logistic regression revealed that consciousness disorder (odds ratio [ OR] =4.230, 95% confidence interval [ CI] : 1.540-11.617; P=0.005), altered behavior ( OR=2.997, 95% CI: 1.068-8.406; P=0.037) and movement disorder ( OR=7.753, 95% CI: 1.446-41.578; P=0.017) were risk factors for poor clinical prognosis of AE patients.

CONCLUSIONS

Patients with AE mainly manifest cognitive damage. Half of the patients left neuropsychiatric deficits. The relationship between CSF titers and serum titers is unparalleled. The options of immunotherapy show no difference in their influence on prognosis. Cognitive dysfunction, altered behavior and movement disorder are independent risk factors for a poor prognosis at discharge.

Temporal rank of clinical characteristics and prognosis of anti-N-methyl-d-aspartate receptor encephalitis

OBJECTIVES

Early recognition and intervention of patients with the anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis are important to achieve a better prognosis. The study aims to summarize the real-world perspectives of anti-NMDAR encephalitis patients in China via electronic medical records (EMRs).

METHODS

Using EMRs of patients from 2013 to 2019 from West China Hospital in China, a retrospective research was conducted to demonstrate the temporary rank of clinical characteristics and disease prognosis of anti-NMDAR encephalitis. The modified Rankin Scale (mRS) scores were used to divide the anti-NMDAR-encephalitis into two groups (poor prognosis vs. good prognosis). Chi-square test and logistic regression were used to analyze factors associated with prognosis.

RESULTS

Here, 78 patients were included. The most common clinical characteristics are cognitive dysfunction (86.0%) and thought disorder (86.0%). Cognitive dysfunction, thought disorder, and seizures tended to appear soon after prodrome symptoms. Logistics analysis results showed that cognitive dysfunction (OR = 4.48, 95% CI = 1.09-18.47), the score of (GCS ≤ 8) (OR = 4.52, 95% CI = 1.18-17.32), positive antibodies in serum (OR = 4.89, 95% CI = 1.19-20.13) and delay immunotherapy (OR = 4.76, 95% CI = 1.79-12.60) were risk factors of poor clinical outcomes.

CONCLUSIONS

There are two peaks in the development of autoimmune encephalitis (AE). The first peak is cognitive dysfunction, and the second peak is autonomic dysfunction. Cognitive dysfunction and GCS score ≤8 at admission, antibodies positive in serum, and delay immunotherapy were risk factors for a poor prognosis at discharge.

Protocol for DexEnceph: a randomised controlled trial of dexamethasone therapy in adults with herpes simplex virus encephalitis

INTRODUCTION

Herpes simplex virus (HSV) encephalitis is a rare severe form of brain inflammation that commonly leaves survivors and their families with devastating long-term consequences. The virus particularly targets the temporal lobe of the brain causing debilitating problems in memory, especially verbal memory. It is postulated that immunomodulation with the corticosteroid, dexamethasone, could improve outcomes by reducing brain swelling. However, there are concerns (so far not observed) that such immunosuppression might facilitate increased viral replication with resultant worsening of disease. A previous trail closed early because of slow recruitment.

METHOD

DexEnceph is a pragmatic multicentre, randomised, controlled, open-label, observer-blind trial to determine whether adults with HSV encephalitis who receive dexamethasone alongside standard antiviral treatment with aciclovir for have improved clinical outcomes compared with those who receive standard treatment alone. Overall, 90 patients with HSV encephalitis are being recruited from a target of 45 recruiting sites; patients are randomised 1:1 to the dexamethasone or control arms of the study. The primary outcome measured is verbal memory as assessed by the Weschler Memory Scale fourth edition Auditory Memory Index at 26 weeks after randomisation. Secondary outcomes are measured up to 72 weeks include additional neuropsychological, clinical and functional outcomes as well as comparison of neuroimaging findings. Patient safety monitoring occurs throughout and includes the detection of HSV DNA in cerebrospinal fluid 2 weeks after randomisation, which is indicative of ongoing viral replication. Innovative methods are being used to ensure recrutiment targets are met for this rare disease.

DISCUSSION

DexEnceph aims to be the first completed randomised controlled trial of corticosteroid therapy in HSV encephalitis. The results will provide evidence for future practice in managing adults with the condition and has the potential to improve outcomes .

ETHICS AND DISSEMINATION

The trial has ethical approval from the UK National Research Ethics Committee (Liverpool Central, REF: 15/NW/0545, 10 August 2015). Protocol V.2.1, July 2019. The results will be published and presented as soon as possible on completion.

TRIAL REGISTRATION NUMBERS

ISRCTN11774734, EUDRACT 2015-001609-16.

A Prospective Cohort Study to Identify Clinical, Biological, and Imaging Features That Predict the Etiology of Acute Encephalitis

BACKGROUND

New diagnostic tools have been developed to improve the diagnosis of infectious encephalitis. Using a prospective cohort of encephalitis patients, our objective was to identify possible clusters of patients with similar patterns among encephalitis of unknown cause (EUC) and to describe to what extent a patient's initial presentation may be predictive of encephalitis etiology, particularly herpes simplex virus (HSV) and varicella-zoster virus (VZV).

METHODS

The National Cohort of Infectious Encephalitis in France is an ongoing prospective cohort study implemented in France in 2016. Patients who present with documented or suspected acute infectious encephalitis were included. Focusing on the variables that describe the initial presentation, we performed a factor analysis of mixed data (FAMD) to investigate a pattern of association between the initial presentation of a patient and the etiologic pathogen.

RESULTS

As of 1 August 2018, data from 349 patients were analyzed. The most frequent pathogens were HSV (25%), VZV (11%), tick-borne encephalitis virus (6%), Listeria (5%), influenza virus (3%), and EUC (34%). Using the FAMD, it was not possible to identify a specific pattern related to the group of EUC. Age, temporal or hemorrhagic lesions, and cerebral spinal fluid lymphocytosis were significantly associated with HSV/VZV encephalitis.

CONCLUSIONS

No initial clinical/imaging/biology pattern was identified at admission among EUC, despite the improvement in diagnostic tools. In this context, the recommendation for a universal, early, probabilistic, initial treatment against HSV and VZV is still relevant, regardless of the initial clinical presentation of the encephalitis.

Update on the diagnosis and management of autoimmune encephalitis

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.

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.

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.

Mood, Activity Participation, and Leisure Engagement Satisfaction (MAPLES): a randomised controlled pilot feasibility trial for low mood in acquired brain injury

Background

Acquired brain injury (ABI) affects approximately 79.3 million individuals annually and is linked with elevated rates of depression and low mood. Existing methods for treating depression in ABI have shown mixed efficacy. Behavioural activation (BA) is a potentially promising intervention. Its premise is that individuals with low mood avoid planning and engaging in activities due to low expectations of a positive outcome. Consequently, their exposure to positive reinforcement is reduced, exacerbating low mood. BA aims to break this cycle by encouraging activity planning and engagement. It is unknown whether cognitive demands of traditional BA may undermine efficacy in ABI. Here, we assess the feasibility and acceptability of two groups designed to increase activity engagement. In the activity planning group (traditional BA), the importance of meaningful and positive activity will be discussed and participants encouraged to plan/engage in activities in everyday life. The activity engagement group (experiential BA) instead focuses on engagement in positive experiences (crafts, games, discussion) within the group. The primary aims are to evaluate the feasibility and acceptability of the two groups in ABI. A secondary aim is to explore relative efficacy of the groups compared to an equivalent period of waitlist controls.

Method

This study outlines a parallel-arm pilot feasibility trial for individuals with low mood and ABI that compares a traditional vs experiential BA group vs waitlist controls. Adults (≥ 18 years) will be recruited from local ABI services and randomised to condition. Feasibility and acceptability will be assessed via recruitment, retention, attendance and participant feedback. Groups will be compared (pre- and post-intervention and 1 month follow-up) by assessing self-reported activity engagement. Secondary outcomes include self-report measures of depression, anxiety, post-traumatic distress related to the ABI, motivation, participation and sense of control over one’s life.

Ethics and dissemination

The trial has been approved by the Health Research Authority of the NHS in the UK (East of England—Cambridge Central, REF 18/EE/0305). Results will inform future research on interventions for mood in ABI and be disseminated broadly via peer-reviewed journals, conference presentations and social media.

Trial registration

ClinicalTrials.gov, NCT03874650 pre-results. Protocol version 2.1, March 5, 2019

Immune-mediated encephalitis for the infectious disease specialist

PURPOSE OF REVIEW

Autoimmune encephalitis is increasingly recognized and must be distinguished from infectious forms of encephalitis. Moreover, physicians should be aware of infectious triggers of autoimmune encephalitis and of infectious complications associated with treatment.

RECENT FINDINGS

Recent epidemiological studies suggest that the incidence of autoimmune encephalitis may rival that of infectious encephalitis. Although distinguishing autoimmune from infectious forms of encephalitis on clinical grounds can be challenging, recently proposed diagnostic criteria can provide some assistance. There has been an explosion in our knowledge of autoimmune encephalitis associated with antibodies to neuronal cell surface antigens, and two of the most common forms, anti-NMDA receptor encephalitis and anti-LGI1 encephalitis, are typically associated with distinctive clinical features. Although tumors have long been known to trigger autoimmune encephalitis, it has been recently recognized that herpes simplex encephalitis may trigger the generation of antineuronal autoantibodies resulting in an autoimmune neurologic relapse. Both first and second-line therapies for autoimmune encephalitis are associated with infectious complications, whereas emerging treatments, including anakinra and tocilizumab, may also result in increased susceptibility to certain infections.

SUMMARY

The diagnosis and management of autoimmune encephalitis is complex, and awareness of diagnostic criteria and modalities, typical clinical syndromes, infectious triggers of disease, and infectious complications of therapies is critical in optimizing care for affected patients.

Epidemiology and Etiology of Severe Childhood Encephalitis in The Netherlands

BACKGROUND

Limited data are available on childhood encephalitis. Our study aimed to increase insight on clinical presentation, etiology, and clinical outcome of children with severe encephalitis in the Netherlands.

METHODS

We identified patients through the Dutch Pediatric Intensive Care Evaluation database and included children diagnosed with encephalitis <18 years of age admitted to 1 of the 8 pediatric intensive care units (PICU) in the Netherlands between January 2003 and December 2013. We analyzed demographic characteristics, clinical symptoms, neurologic imaging, etiology, treatment and mortality.

RESULTS

We included 121 children with a median age of 4.6 years (IQR 1.3-9.8). The most frequently described clinical features were headache (82.1%), decreased consciousness (79.8%) and seizures (69.8%). In 44.6% of the children, no causative agent was identified. Viral- and immune-mediated encephalitis were diagnosed in 33.1% and 10.7% of the patients. A herpes simplex virus infection (13.2%) was mainly seen in children <5 years of age, median age, 1.73 years (IQR 0.77-5.01), while immune-mediated encephalitis mostly affected older children, median age of 10.4 years (IQR, 3.72-14.18). An age of ≥ 5 years at initial presentation was associated with a lower mortality (OR 0.2 [CI 0.08-0.78]). The detection of a bacterial (OR 9.4 [CI 2.18-40.46]) or viral (OR 3.7 [CI 1.16-11.73]) pathogen was associated with a higher mortality.

CONCLUSIONS

In almost half of the Dutch children presenting with severe encephalitis, a causative pathogen could not be identified, underlining the need for enhancement of microbiologic diagnostics. The detection of a bacterial or viral pathogen was associated with a higher mortality.

Clinical Features, Diagnosis, and Outcome of Encephalitis in French Guiana

The aim of our study was to describe the clinical features, the etiologies, and the factors associated with poor outcome of encephalitis in French Guiana. Our study was retrospective, including all cases of encephalitis hospitalized in the Cayenne General Hospital, from January 2007 to July 2017. Patients were included through the 2013 encephalitis consortium criteria and the outcome was evaluated using the Glasgow outcome scale at 3 months from the diagnosis of encephalitis. We included 108 patients, giving an approximate incidence rate of four cases/100,000 inhabitants/year. The origin of the encephalitis was diagnosed in 81 cases (75%), and 72 of them (66.7%) were from an infectious origin. The most common infectious causes were Cryptococcus sp. (18.5%) independently of the immune status, Toxoplasma gondii (13.9%), and Streptococcus pneumoniae (5.5%). In the follow-up, 48 patients (46.6%) had poor outcome. Independent risk factors associated with poor outcome at 3 months were “coming from inside area of the region” (P = 0.036, odds ratio [OR] = 4.19; CI 95% = 1.09–16.06), need for mechanical ventilation (P = 0.002, OR = 5.92; CI 95% = 1.95–17.95), and age ≥ 65 years (P = 0.049, OR = 3.99; CI 95% = 1.01–15.89). The most identified cause of encephalitis in French Guiana was Cryptococcus. The shape of the local epidemiology highlights the original infectious situation with some local specific pathogens.

A Population-based Observational Study of Childhood Encephalitis in Children Admitted to Pediatric Intensive Care Units in England and Wales

BACKGROUND

Encephalitis is a serious neurologic condition that can result in admission to intensive care. Yet, there are no studies on pediatric intensive care unit (PICU) admission rates and usage of intensive care resources by children with encephalitis in England and Wales. The objectives of this study were to (1) define the PICU incidence and mortality rates for childhood encephalitis, (2) describe the usage of intensive care resources by children with encephalitis admitted to PICU and (3) explore the associated cost from PICU encephalitis admissions.

METHODS

Retrospective analysis of anonymized data for 1031 children (0-17 years) with encephalitis admitted (January 2003 to December 2013) to PICU in England and Wales.

RESULTS

The PICU encephalitis incidence was 0.79/100,000 population/yr (95% confidence interval [CI]: 0.74-0.84), which gives an annual total of 214 bed days of intensive care occupancy for children admitted with encephalitis and an estimated annual PICU bed cost of £414,230 (interquartile range: 198,111-882,495) for this cohort. PICU encephalitis admissions increased during the study period (annual percentage change = 4.5%, 95% CI: 2.43%-6.50%, P ≤ 0.0001). In total, 808/1024 (78.9%) cases received invasive ventilation while 216/983 (22.0%) and 50/890 (5.6%) cases received vasoactive treatment and renal support, respectively. There were 87 deaths (8.4%), giving a PICU encephalitis mortality rate of 0.07/100,000 population (0-17 years)/yr (95% CI: 0.05-0.08).

CONCLUSIONS

These data suggest that encephalitis places a significant burden to the healthcare service. More work is needed to improve outcomes for children with encephalitis.

Tools for the Diagnosis of Herpes Simplex Virus 1/2: Systematic Review of Studies Published Between 2012 and 2018

Background

Herpes simplex virus (HSV)-1 and HSV-2 are common infections affecting the global population, with HSV-1 estimated to affect 67% of the global population. HSV can have rare but severe manifestations, such as encephalitis and neonatal herpes, necessitating the use of reliable and accurate diagnostic tools for the detection of the viruses. Currently used HSV diagnostic tools require highly specialized skills and availability of a laboratory setting but may lack sensitivity. The numerous recently developed HSV diagnostic tools need to be identified and compared in a systematic way to make the best decision about which diagnostic tool to use. The diagnosis of HSV is essential for prompt treatment with antivirals. To select the best test for a patient, knowledge of the performance and limitations of each test is critical.

Objective

This systematic review has summarized recent studies evaluating HSV-1 and HSV-2 diagnostic tools.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, selection criteria, data extraction, and data analysis were determined before the commencement of the study. Studies assessing the specificity/sensitivity of HSV-1 or HSV-2 diagnostic tools published between 2012 and 2018 were included. Quality assessment of included studies was performed using the quality assessment of diagnostic accuracy studies (QUADAS-2) tool.

Results

Searches of the PubMed database yielded 264 studies; 11 studies included 11 molecular assays, and 8 studies included 19 different serological assays for the detection of HSV-1, HSV-2, or both. A greater proportion of molecular assay–based tools are being developed by commercial entities. Studies that tested molecular assays mostly focused on cutaneous and mucosal HSV infections (n=13); 2 studies focused on ocular disease, whereas only 1 study focused on the central nervous system manifestations. The Simplexa HSV 1 & 2 Direct is currently the only Food and Drug Administration–approved device for use on cerebrospinal fluid. No tools focused on prenatal screening. We also present performance metrics of tests for benchmarking of future technology. Most of the included studies had a high risk of bias rating in half of the QUADAS-2 tool risk of bias domains.

Conclusions

The use of serologic tests to diagnose genital lesions is inappropriate because positive results may be due to chronic infection, whereas negative results may overlook recent infection. The incidence of acute infections is rising. As these infections present the greatest risk to fetuses, work needs to be done to prevent vertical transfer. Prenatal screening for primary infection and subsequent medical intervention will assist in lowering the rate of neonatal herpes. In conclusion, HSV diagnosis is moving away from culture-based methods to serology-based or polymerase chain reaction–based methods. Sensitive, rapid, and efficient HSV diagnostic tools should be adopted for the prevention of acute infections and neonatal herpes.

Encephalitis on deployment in Kenya: think beyond the infections

A 34-year-old female soldier presented with fever and behavioural changes while deployed in Kenya and was diagnosed with encephalitis. The patient underwent urgent aeromedical evacuation to the Queen Elizabeth Hospital, Birmingham for further management. Microbiology tests excluded common infectious causes that are endemic in the East Africa region. However, an autoantibody screen was positive for antibodies against the N-methyl-D-aspartate receptor (NMDAR). Full body imaging confirmed the presence of limbic encephalitis and an ovarian mass suggestive of a teratoma. The patient was diagnosed with ovarian teratoma-associated anti-NMDAR encephalitis, a potentially fatal disease. The patient underwent surgery to remove the teratoma and commenced immunotherapy with steroids, plasma exchange and rituximab. This case highlights the diagnostic challenges of fever with behavioural changes in military personnel deployed in a tropical environment.

Epidemiology of central nervous system infectious diseases: a meta-analysis and systematic review with implications for neurosurgeons worldwide

OBJECTIVE

Central nervous system (CNS) infections cause significant morbidity and mortality and often require neurosurgical intervention for proper diagnosis and treatment. However, neither the international burden of CNS infection, nor the current capacity of the neurosurgical workforce to treat these diseases is well characterized. The objective of this study was to elucidate the global incidence of surgically relevant CNS infection, highlighting geographic areas for targeted improvement in neurosurgical capacity.

METHODS

A systematic literature review and meta-analysis were performed to capture studies published between 1990 and 2016. PubMed, EMBASE, and Cochrane databases were searched using variations of terms relating to CNS infection and epidemiology (incidence, prevalence, burden, case fatality, etc.). To deliver a geographic breakdown of disease, results were pooled using the random-effects model and stratified by WHO region and national income status for the different CNS infection types.

RESULTS

The search yielded 10,906 studies, 154 of which were used in the final qualitative analysis. A meta-analysis was performed to compute disease incidence by using data extracted from 71 of the 154 studies. The remaining 83 studies were excluded from the quantitative analysis because they did not report incidence. A total of 508,078 cases of CNS infections across all studies were included, with a total sample size of 130,681,681 individuals. Mean patient age was 35.8 years (range: newborn to 95 years), and the male/female ratio was 1:1.74. Among the 71 studies with incidence data, 39 were based in high-income countries, 25 in middle-income countries, and 7 in low-income countries. The pooled incidence of studied CNS infections was consistently highest in low-income countries, followed by middle- and then high-income countries. Regarding WHO regions, Africa had the highest pooled incidence of bacterial meningitis (65 cases/100,000 people), neurocysticercosis (650/100,000), and tuberculous spondylodiscitis (55/100,000), whereas Southeast Asia had the highest pooled incidence of intracranial abscess (49/100,000), and Europe had the highest pooled incidence of nontuberculous vertebral spondylodiscitis (5/100,000). Overall, few articles reported data on deaths associated with infection. The limited case fatality data revealed the highest case fatality for tuberculous meningitis/spondylodiscitis (21.1%) and the lowest for neurocysticercosis (5.5%). In all five disease categories, funnel plots assessing for publication bias were asymmetrical and suggested that the results may underestimate the incidence of disease.

CONCLUSIONS

This systematic review and meta-analysis approximates the global incidence of neurosurgically relevant infectious diseases. These results underscore the disproportionate burden of CNS infections in the developing world, where there is a tremendous demand to provide training and resources for high-quality neurosurgical care.

Autoimmune Encephalitides

Autoimmune encephalitis is a severe inflammatory disorder of the brain with diverse causes and a complex differential diagnosis. Recent advances in the past decade have led to the identification of new syndromes and biological markers of limbic encephalitis, the commonest presentation of autoimmune encephalitis. The successful use of serum and intrathecal antibodies to diagnose affected patients has resulted in few biopsy and postmortem examinations. In those available, there can be variable infiltrating inflammatory T cells with cytotoxic granules in close apposition to neurons, consistent with an inflammatory autoimmune basis, but true vasculitis is rarely seen. The exception is Hashimoto encephalopathy.

Acute encephalitis in immunocompetent adults

Encephalitis is a condition of inflammation of the brain parenchyma, occurs as a result of infectious or autoimmune causes, and can lead to encephalopathy, seizures, focal neurological deficits, neurological disability, and death. Viral causes account for the largest proportion, but in the last decade there has been growing recognition of anti-neuronal antibody syndromes. This Seminar focuses on the diagnosis and management of acute encephalitis in adults. Although viral and autoimmune causes are highlighted because of their prominent roles in encephalitis, other infectious pathogens are also considered. The role of cerebrospinal fluid studies, MRI, and novel diagnostic modalities (eg, next-generation sequencing) are discussed. Management approaches, including treatment of acute neurological complications and the use of immune suppressive and modulatory drugs for cases of suspected or confirmed autoimmune cause, are covered. Additionally, we discuss the remaining challenges in the diagnosis, management, and prognosis of encephalitis.

Predictive Role of Electroencephalography in Regard to Neurological and Cognitive Sequelae After Acute Central Nervous System Infection

Introduction:

Electroencephalography can also be used to monitor long-term recovery of the patient after acute phase of the disease. Impaired neurocognitive function after infection, similar to brain injury, may present a transient but also prolonged problem for the functioning of an individual. Some studies have shown that importance of EEG may not be significant in sequel monitoring, because the extensive changes in EEG seen with severe forms of CNS infection do not necessarily imply a longer-term poor outcome.

Aim:

To examine the predictive potential of electroencephalography (EEG) in regard to the emergence of neurological and cognitive sequelae of acute central nervous system (CNS) infection.

Methods:

The study included 62 patients treated at the Clinic for Infectious Diseases, Clinical Center of Sarajevo University, who were diagnosed with acute CNS infection. The EEG record was characterized as: normal, non-specific changes of mild, moderate and severe degree and specific changes. The sequelae (headache, cognitive dysfunction, neurological and neurophysiological disorders, audiological and behavioral disorders) was evaluated by combining neurological, psychiatric, pediatric, otolaryngological, ophthalmic and infectological examination in the Neuroinfective Counseling Department for up to 6 months after discharge.

Results:

After a treatment of an acute CNS infection 25 (40.3%) patients had no sequelae and 37 (59.7%) were with sequelae. The EEG in the initial stage of the disease (Wald’s coefficient = 12.8), followed by the age of the patients (Wald = 6.4), had the greatest influence on the prediction of sequela (p=0.0001). For each additional degree of verified pathological changes in the EEG, the risk of sequelae was increased by 5 degrees (OR = 5.3), respectively. There was no statistically significant association between changes in cerebrospinal fluid (CSF) findings, meningeal symptoms, and signs with sequelae development.

Conclusion:

Younger age, as well as severe clinical status of a patient, which implies a disorder of consciousness and seizures on admission, are associated with irreversible consequences on a previously mentally healthy individual. Pathological changes (Delta and Theta waves, spike slow complex wave) on the EEG finding significantly predicted presence of sequelae. .

A pragmatic cluster randomised controlled trial of a tailored intervention to improve the initial management of suspected encephalitis

OBJECTIVE

To determine whether a tailored multifaceted implementation strategy improves the initial management of patients with suspected encephalitis.

DESIGN

Pragmatic two arm cluster randomised controlled trial.

SETTING

Hospitals within the United Kingdom.

PARTICIPANTS

Twenty-four hospitals nested within 12 postgraduate deaneries. Patients were identified retrospectively by searching discharge, microbiology, radiology and pharmacy records and included if they met clinical criteria or had a recorded suspicion of encephalitis.

INTERVENTION

An implementation strategy designed to overcome barriers to change, comprising local action planning, education and training, feedback on performance, a lumbar puncture pack and a range of optional components.

OUTCOMES

The primary outcome was the proportion of patients with suspected encephalitis undergoing diagnostic lumbar puncture within 12 hours of admission and starting aciclovir treatment within six hours. Secondary outcomes included the proportions of adults and children who had a lumbar puncture, who had appropriate cerebrospinal fluid investigations, and who had appropriate radiological imaging within 24 hours of admission. Data were collected from patient records for 12 months before and 12 months during the intervention period, and analysed blind to allocation.

RESULTS

13 hospitals were randomised to intervention and 11 to control (no intervention), with 266 and 223 patients with suspected encephalitis identified respectively. There was no significant difference in primary outcome between intervention and control hospitals (13.5% and 14.8% respectively, p = 0.619; treatment effect -0.188, 95% confidence interval -0.927 to 0.552), but both had improved compared to pre-intervention (8.5%).

CONCLUSION

The improvement in both intervention and control arms may reflect overall progress in management of encephalitis through wider awareness and education.

TRIAL REGISTRATION

Controlled Trials: ISRCTN06886935.

Systematic review of rehabilitation intervention outcomes of adult and paediatric patients with infectious encephalitis

OBJECTIVE

Although a range of rehabilitation interventions have been applied to restore function after infectious encephalitis, there is a lack of literature summarising the benefits of these interventions. This systematic review aims to synthesise current scientific knowledge on outcome measures following rehabilitative interventions among children and adults with infectious encephalitis, with a specific focus on the influence of the age, sex, baseline status and intervention type.

SEARCH STRATEGY

Five scholarly databases (MEDLINE, Embase, PsycINFO, CINAHL and Cochrane Central Register of Controlled Trials), three sources of grey literature (Google, Google Scholar and Grey Matters) and reference lists of included publications were systematically searched. Literature published before 15 December 2017 and focused on patients with infectious encephalitis in any rehabilitation setting were included. Quality assessment was completed using the Downs and Black rating scale.

RESULTS

Of the 12 737 reference titles screened, 20 studies were included in this review. All of the studies had sample sizes of less than 25 patients and received a score of less than 15 out of 31 points on the Downs and Black rating scale. Findings showed a variety of interventions has been applied to alleviate sequelae from infectious encephalitis, including using cognitive therapy (nine studies), behavioural therapy (five studies), physical therapy (two studies) or two or more therapies (four studies). There was inconclusive evidence on the effect of sex, age and baseline functional abilities on outcomes. Due to clinical and methodological heterogeneity between studies, meta-analyses were not performed.

CONCLUSION

Evidence suggests the potential for a beneficial effect of rehabilitation interventions in patients with infectious encephalitis. Future research is required to identify all effect modifiers and to determine the effect of time in the natural course of recovery. An enhanced set of known effect modifiers will support the process of future evaluation of a client-centred rehabilitation intervention.

TRIAL REGISTRATION NUMBER

CRD42015029217.

Under-reporting of pertussis in Ontario: A Canadian Immunization Research Network (CIRN) study using capture-recapture

Introduction

Under-reporting of pertussis cases is a longstanding challenge. We estimated the true number of pertussis cases in Ontario using multiple data sources, and evaluated the completeness of each source.

Methods

We linked data from multiple sources for the period 2009 to 2015: public health reportable disease surveillance data, public health laboratory data, and health administrative data (hospitalizations, emergency department visits, and physician office visits). To estimate the total number of pertussis cases in Ontario, we used a three-source capture-recapture analysis stratified by age (infants, or aged one year and older) and adjusting for dependency between sources. We used the Bayesian Information Criterion to compare models.

Results

Using probable and confirmed reported cases, laboratory data, and combined hospitalizations/emergency department visits, the estimated total number of cases during the six-year period amongst infants was 924, compared with 545 unique observed cases from all sources. Using the same sources, the estimated total for those aged 1 year and older was 12,883, compared with 3,304 observed cases from all sources. Only 37% of infants and 11% for those aged 1 year and over admitted to hospital or seen in an emergency department for pertussis were reported to public health. Public health reporting sensitivity varied from 2% to 68% depending on age group and the combination of data sources included. Sensitivity of combined hospitalizations and emergency department visits varied from 37% to 49% and of laboratory data from 1% to 50%.

Conclusions

All data sources contribute cases and are complementary, suggesting that the incidence of pertussis is substantially higher than suggested by routine reports. The sensitivity of different data sources varies. Better case identification is required to improve pertussis control in Ontario.

Acute encephalitis - diagnosis and management

Encephalitis, inflammation of the brain, is most commonly caused by a viral infection (especially herpes simplex virus [HSV] type 1 in the UK) although autoimmune causes, such as N-methyl D-aspartate receptor (NMDAR) antibody encephalitis, are increasingly recognised. Most patients present with a change in consciousness level and may have fever, seizures, movement disorder or focal neurological deficits. Diagnosis hinges crucially on lumbar puncture and cerebrospinal fluid (CSF) examination, but imaging and electroencephalography (EEG) may also be helpful. Treatment of HSV encephalitis with aciclovir dramatically improves outcome, but the optimal management of autoimmune encephalitis is still uncertain. Many patients with encephalitis are left with residual physical or neuropsychological deficits which require long-term multidisciplinary management. Here we review assessment of patients with suspected encephalitis, general aspects of management and areas of ongoing research.

Human T-cell lymphotropic virus (HTLV)-associated encephalopathy: an under-recognised cause of acute encephalitis? Case series and literature review

Human T-cell lymphotropic virus (HTLV)-1-associated myelopathy (HAM) is well described. Clinical features are predominantly consistent with cord pathology, though imaging and autopsy studies also demonstrate brain inflammation. In general, this is subclinical; however, six cases have previously been reported of encephalopathy in HTLV-1-infected patients, without alternative identified aetiology. We describe three further cases of encephalitis in the UK HAM cohort (n = 142), whereas the annual incidence of acute encephalitis in the general population is 0.07-12.6 per 100,000. Clinical features included reduced consciousness, fever/hypothermia, headaches, seizures, and focal neurology. Investigation showed: raised CSF protein; pleocytosis; raised CSF:peripheral blood mononuclear cell HTLV-1 proviral load ratio; and MRI either normal or showing white matter changes in brain and cord. Four of the six previous case reports of encephalopathy in HTLV-infected patients also had HAM. Histopathology, reported in three, showed perivascular predominantly CD8+ lymphocytic infiltrates in the brain. One had cerebral demyelination, and all had cord demyelination. We have reviewed the existing six cases in the literature, together with our three new cases. In all seven with HAM, the spastic paraparesis deteriorated sub-acutely preceding encephalitis. Eight of the nine were female, and four of the seven treated with steroids improved. We propose that HTLV-associated encephalopathy may be part of the spectrum of HTLV-1-induced central nervous system disease.

Increased serum vascular endothelial growth factor is associated with acute viral encephalitis in Bangladeshi children

Encephalitis causes significant global morbidity and mortality. A large number of viruses cause encephalitis, and their geographic and temporal distributions vary. In many encephalitis cases, the virus cannot be detected, even after extensive testing. This is one challenge in management of the encephalitis patient. Since cytokines are pivotal in any form of inflammation and vary according to the nature of the inflammation, we hypothesized cytokine levels would allow us to discriminate between encephalitis caused by viruses and other aetiologies. This pilot study was conducted in a tertiary care hospital in Dhaka, Bangladesh. Viral detection was performed by polymerase chain reaction using patient cerebrospinal fluid. Acute phase reactants and cytokines were detected in patient serum. Of the 29 biomarkers assessed using the Wilcoxon rank-sum test, only vascular endothelial growth factor (VEGF) was significantly higher (P = 0.0015) in viral-positive compared with virus–negative encephalitis patients. The area under the curve (AUC) for VEGF was 0.82 (95% confidence interval: 0.66–0.98). Serum VEGF may discriminate between virus-positive and virus-negative encephalitis. Further study will be needed to confirm these findings.

Care beyond the hospital ward: understanding the socio-medical trajectory of herpes simplex virus encephalitis

BACKGROUND

Herpes simplex virus (HSV) encephalitis is a life-threatening infection of the brain, which has significant physical, cognitive and social consequences for survivors. Despite increasing recognition of the long-term effects of encephalitis, research and policy remains largely focused on its acute management, meaning there is little understanding of the difficulties people face after discharge from acute care. This paper aims to chart the problems and challenges which people encounter when they return home after treatment for HSV encephalitis.

METHODS

The paper reports on data from 30 narrative interviews with 45 people affected by HSV encephalitis and their significant others. The study was conducted as part of the ENCEPH-UK programme grant on Understanding and Improving the Outcome of Encephalitis.

RESULTS

The findings show the diverse challenges which are experienced by people after treatment for HSV encephalitis. We first chart how peoples' everyday lives are fragmented following their discharge from hospital. Second, we document the social consequences which result from the longer-term effects of encephalitis. Finally, we show how the above struggles are exacerbated by the lack of support systems for the post-acute effects of encephalitis, and describe how people are consequently forced to devise their own care routines and strategies for managing their problems.

CONCLUSION

The paper argues that in order to improve long-term outcomes in encephalitis, it is vital that we develop pathways of support for the condition beyond the acute hospital setting. We conclude by making recommendations to enhance communication and care for the post-acute consequences of encephalitis, to ensure those affected are fully supported through the chronic effects of this devastating disease.