Results of a multinational study suggest the need for rapid diagnosis and early antiviral treatment at the onset of herpetic meningoencephalitis

Herpes simplex encephalitis in France: incidence, 6-month rehospitalizations and mortality

BACKGROUND

Herpes simplex encephalitis (HSE) is a disease with unfavorable vital and functional prognoses. There are no recent epidemiological data on HSE at a national level using real-life databases, especially in France. This study aimed to report the incidence, the clinical characteristics and outcomes of the patients with HSE.

METHODS

We conducted a comprehensive retrospective cohort study on all patients hospitalized for HSE in France between 2015 and 2022 using national hospital discharge databases. Incidence, socio-demographic and clinical characteristics (including comorbidities, seizure, stays' features, intensive care supports) were described. The short- (first stay) and long-term (6-month) outcomes were reported, in terms of mortality and rehospitalizations.

RESULTS

1425 HSE patients were included (median age 67 [54-77] years old, M/F sex ratio 1.07), giving a mean yearly hospital incidence of 2.3 [2.1-2.5] per 1,000,000 inhabitants. 51.2% of the patients were admitted in ICU (n = 730), of whom 59.0% were mechanically ventilated. The overall mortality during the first stay was 14.3% (n = 204), up to 17.9% for ICU patients. Within 6 months, among the survivors, 10.1% had at least one rehospitalization related to HSE. At 6 months, 16.5% of all patients had died (n = 235), 20.8% for ICU patients.

CONCLUSION

In France, the incidence of hospitalizations for HSE was 2.3 per 1,000,000 inhabitants with more than half of the patients admitted in ICU and a 6-month in-hospital mortality about 16.5%. This real-life update on the characteristics and severe outcomes of the disease raises awareness among care practitioners, of the serious nature of the disease, and thus can lead to higher vigilance.

Profiles of primary brain abscesses and their impact on survival: An international ID-IRI study

OBJECTIVES

This study of 331 primary brain abscess (PBA) patients aimed to understand infecting agents, predisposing factors, and outcomes, with a focus on factors affecting mortality.

METHODS

Data were collected from 39 centers across 16 countries between January 2010 and December 2022, and clinical, radiological, and microbiological findings, along with their impact on mortality, were analyzed.

RESULTS

The patients had a mean ± SD age of 46.8 ± 16.3 years, with a male predominance of 71.6%. Common symptoms included headache (77.9%), fever (54.4%), and focal neurological deficits (53.5%). Gram-positive cocci were the predominant pathogens, with Viridans group streptococci identified as the most frequently isolated organisms. All patients received antimicrobial therapy and 71.6% underwent interventional therapies. The 42-day and 180-day survival rates were 91.9% and 86.1%, respectively. Significant predictors of 42-day mortality included intravenous drug addiction (HR: 6.02, 95% CI: 1.38-26.26), malignancy (HR: 3.61, 95% CI: 1.23-10.58), confusion (HR: 2.65, 95% CI: 1.19-5.88), and unidentified bacteria (HR: 4.68, 95% CI: 1.76-12.43). Significant predictors of 180-day mortality included malignancy (HR: 2.70, 95% CI: 1.07-6.81), confusion (HR: 2.14, 95% CI: 1.11-4.15), temporal lobe involvement (HR: 2.10, 95% CI: 1.08-4.08), and unidentified bacteria (HR: 3.02, 95% CI: 1.49-6.15).

CONCLUSION

The risk of death in PBA extends beyond the infection phase, with different factors influencing the 42-day and 180-day mortality rates. Intravenous drug addiction was associated with early mortality, while temporal lobe involvement was associated with late mortality.

Acute hemorrhagic leukoencephalopathy: a case report and literature review

Introduction and importance

Acute hemorrhagic leukoencephalopathy (AHLE) is a rare and devastating condition that can present with various neurological symptoms. The predisposing and initiating factors of AHLE are not fully understood. AHLE has a high morbidity and significant mortality rates, however, our case presents a surviving young girl.

Case presentation

Thirteen years old previously healthy girl was referred to the emergency department due to drowsiness, preceded by an upper respiratory infection 10 days earlier. Firstly, she was treated empirical with antiviral medication (Acyclovir) directed to herpes simplex virus and intravenous (IV) methylprednisolone pulses. When she did not respond well, intravenous immunoglobulin was administrated, which helped with the end-result diagnosis based on clinical and imaging findings.

Clinical discussion

AHLE is a fatal rare demyelinating disease characterized by an acute rapidly progressive fulminant inflammation of the white matter, it is usually misdiagnosed due to being a diagnosis of exclusion, and the much more common other diseases, including infectious encephalitis, meningitis, fulminant multiple sclerosis, other causes of acute disseminated encephalomyelitis. Different types of CNS infiltrates, such as neutrophils in AHLE and lymphocytes in acute disseminated encephalomyelitis, do not support the idea of differentiating the two diseases. The process of differentiating between these two diseases relies mostly on laboratory and imaging findings, which are well demonstrated in this case report.

Conclusion

The authors conclude this report by highlighting the dearth in published knowledge about this disease, and encouraging further studies be conducted about this topic.

Clinical characteristics and outcomes of patients with Herpes Simplex Encephalitis in Vietnam: a retrospective study

BACKGROUND

Herpes simplex encephalitis (HSE) is an important central nervous infection with severe neurological sequelae. The aim of this study was to describe clinical characteristic and outcomes of patients with HSE in Vietnam.

METHODS

This was a retrospective study of 66 patients with herpes simplex encephalitis who admitted to the National Hospital for Tropical Diseases, Hanoi, Vietnam from 2018 to 2021. The detection of herpes simplex virus (HSV) in cerebrospinal fluid was made by the real-time PCR assay. We reported the clinical manifestation on admission and evaluated clinical outcomes at the hospital discharge by modified Rankin Scale (mRS). Multivariate logistic regression analysis was used to analyze the independent risk factors of severe outcomes.

RESULTS

Of the 66 patients with laboratory confirmed HSE, the median age was 53 years (IQR 38-60) and 44 patients (69.7%) were male. The most common manifestations included fever (100%), followed by the consciousness disorder (95.5%). Other neurological manifestation were seizures (36.4%), memory disorders (31.8%), language disorders (19.7%) and behavioral disorders (13.6%). Conventional magnetic resonance imaging (MRI) showed 93.8% patients with temporal lobe lesions, followed by abnormalities in insula (50%), frontal lobe (34.4%) and 48.4% of patients had bilateral lesions. At discharge, 19 patients (28.8%) completely recovered, 15 patients (22.7%) had mild sequelae, 28 patients (42.4%) had moderate to severe sequelae. Severe neurological sequelae were memory disorders (55.8%), movement disorders (53.5%), language disorders (30.2%). Multivariate logistic regression analysis showed that Glasgow score decrement at admission, seizures, and time duration from onset of symptoms to the start of Acyclovir treatment > 4 days were independent factors associated with severe outcomes in HSE patients.

CONCLUSION

Glasgow score decrement, seizures and delay treatment with Acyclovir were associated with the poor outcome of patients with HSE.

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.

Cerebrospinal fluid in Borna disease virus 1 (BoDV-1) encephalitis

Borna disease virus 1 (BoDV-1) has been recognized as a rare cause of very severe encephalitis with rapid onset in central Europe. Data on cerebrospinal fluid (CSF) analysis have not yet been analyzed in detail. Here, we present the first study on CSF changes in BoDV-1 encephalitis. We retrospectively analyzed CSFs from 18 BoDV-1 encephalitis cases from Bavaria, Germany, an endemic region, from 1996 to 2021. Data were obtained through review of medical records and institutional databases. We found that white blood cell count (WBC) in CSF is elevated in 13 of our 18 patients at first examination (average 83.2 ± 142.3 leukocytes/μl) and cytology showed predominance of lymphocytes. Patients with typical symptoms of meningoencephalitis had higher WBC in first CSF analyzation (133.5 ± 163.1 vs 4.0 ± 3.2/μl; p = 0.065). BoDV-1 PCR of CSF is not always positive when tested (7 of 9 cases). Four of five patients tested showed a polyvalent reaction against multiple viruses in the CSF suggesting that BoDV-1 may trigger autoimmune mechanisms. CSF changes in BoDV-1 encephalitis seem similar to those of other viral encephalitis and at the beginning WBC can be normal in up to 28%, making the diagnosis even more challenging. All in all, BoDV-1 should be included in the diagnostic workup of patients with rapidly evolving and/or severe encephalitis and patients with severe neuropathy and secondary encephalopathy with and without CSF changes. Repeated CSF examinations as well as BoDV-1 serology and CSF PCR have to be considered in endemic areas.

Empirical intravenous aciclovir therapy in a suspected case of acute encephalitis

Herpes simplex encephalitis is the most common cause of sporadic viral encephalitis worldwide but presents as a diagnostic challenge at many settings due to its non-specific symptoms, which can be easily mistaken for systemic infection or metabolic encephalopathy. It has diverse range of presentations from fever, altered sensorium, nausea, vomiting, meningismus to seizures, neurological deficits and coma in advanced stages. It is associated with significant morbidity and mortality if treatment is delayed or inadequate. We here discuss a case of Herpes simplex virus (HSV) encephalitis which rapidly progressed to result in irreversible neurological insult due to delayed diagnosis and treatment.

Biofire FilmArray Meningitis/Encephalitis panel for the aetiological diagnosis of central nervous system infections: A systematic review and diagnostic test accuracy meta-analysis

BACKGROUND

The FilmArray Meningitis/Encephalitis(FA/ME) panel brings benefits in clinical practice, but its diagnostic test accuracy (DTA) remains unclear. We aimed to determine the DTA of FA/ME for the aetiological diagnostic in patients with suspected central nervous system(CNS) infection.

METHODS

We performed a systematic review with DTA meta-analysis (PROSPERO: CRD42020139285). We searched Embase, Medline (Ovid), and Web of Science from inception until September 1st, 2021. We assessed the study-level risk of bias with the QUADAS-2 tool and applied the GRADE approach to assess the certainty of the synthesised evidence. We included studies that simultaneously measured the reference test (CSF/blood culture for bacteria, and specific polymerase chain reaction for viruses) and the FA/ME in patients with suspected CNS infection. We performed random-effects bivariate meta-analysis models of combined sensitivity and specificity using CSF/blood cultures(reference test 1) and a final diagnosis adjudication based on clinical/laboratory criteria (reference test 2).

FINDINGS

We included 19 studies (11,351 participants). For all bacteria with reference test 1 (16 studies/6183 patients) sensitivity was estimated at 89·5% (95%CI 81·1-94·4), and specificity at 97·4% (95%CI 94-98·9). With reference test 2 (15 studies/5,524 patients), sensitivity was estimated at 92·1%(95%CI 86·8-95·3) and specificity at 99.2(95%CI 98·3-99·6) For herpes simplex virus-2(HSV-2), enteroviruses, and Varicella-Zoster virus (VZV), we obtained sensitivities between 75·5 and 93·8%, and specificities above 99% (reference test 1). Certainty of the evidence was low.

INTERPRETATION

FA/ME may have acceptable-to-high sensitivities and high specificities for identifying bacteria, especially for S.pneumoniae, and viruses, especially for HSV-2, and enteroviruses. Sensitivities for L.monocytogenes, H.influenzae, E.coli, and HSV-1 were suboptimal.

FUNDING

None.

Assessment of Magnetic Resonance Imaging Changes and Functional Outcomes Among Adults With Severe Herpes Simplex Encephalitis

Importance

Current guidelines recommend brain magnetic resonance imaging (MRI) for clinical management of patients with severe herpes simplex encephalitis (HSE). However, the prognostic value of brain imaging has not been demonstrated in this setting.

Objective

To investigate the association between early brain MRI data and functional outcomes of patients with HSE at 90 days after intensive care unit (ICU) admission.

Design, Setting, and Participants

This multicenter cohort study was conducted in 34 ICUs in France from 2007 to 2019 and recruited all patients who received a clinical diagnosis of encephalitis and exhibited cerebrospinal fluid positivity for herpes simplex virus DNA in the polymerase chain reaction analysis. Data analysis was performed from January to April 2020.

Exposures

All patients underwent a standard brain MRI during the first 30 days after ICU admission.

Main Outcomes and Measures

MRI acquisitions were analyzed by radiologists blinded to patients' outcomes, using a predefined score. Multivariable logistic regression and supervised hierarchical classifiers methods were used to identify factors associated with poor outcome at 90 days, defined by a score of 3 to 6 (indicating moderate-to-severe disability or death) on the Modified Rankin Scale.

Results

Overall, 138 patients (median [interquartile range {IQR}] age, 62.6 [54.0-72.0] years; 75 men [54.3%]) with an admission median (IQR) Glasgow Coma Scale score of 9 (6-12) were studied. The median (IQR) delay between ICU admission and MRI was 1 (1-7) days. At 90 days, 95 patients (68.8%) had a poor outcome, including 16 deaths (11.6%). The presence of fluid-attenuated inversion recovery MRI signal abnormalities in more than 3 brain lobes (odds ratio [OR], 25.71; 95% CI, 1.21-554.42), age older than 60 years (OR, 7.62; 95% CI, 2.02-28.91), and the presence of diffusion-weighted MRI signal abnormalities in the left thalamus (OR, 6.90; 95% CI, 1.12-43.00) were independently associated with poor outcome. Machine learning models identified bilateral diffusion abnormalities as an additional factor associated with poor outcome (34 of 39 patients [87.2%] with bilateral abnormalities had poor outcomes) and confirmed the functional burden of left thalamic lesions, particularly in older patients (all 11 patients aged >60 years had left thalamic lesions).

Conclusions and Relevance

These findings suggest that in adult patients with HSE requiring ICU admission, extensive MRI changes in the brain are independently associated with poor functional outcome at 90 days. Thalamic diffusion signal changes were frequently observed and were associated with poor prognosis, mainly in older patients.

Volatile Organic Compounds to Identify Infectious (Bacteria/Viruses) Diseases of the Central Nervous System: A Pilot Study

BACKGROUND

Central nervous system (CNS) infectious diseases are common diseases in emergency rooms and neurology departments. CNS pathogen identification methods are time consuming and expensive and have low sensitivity and poor specificity. Some studies have shown that bacteria and viruses can produce specific volatile organic compounds (VOCs). The aim of this study is to find potential biomarkers by VOC analysis of cerebrospinal fluid (CSF) in patients with bacterial and viral meningitis/encephalitis (ME).

METHODS

CSF samples from 16 patients with bacterial ME and 42 patients with viral ME were collected, and solid-phase microextraction combined with gas chromatography-mass spectrometry was used to analyze the metabolites in the CSF.

RESULTS

There are 2 substances (ethylene oxide and phenol) that were found to be different between the 2 groups. Ethylene oxide was significantly greater in the group of bacterial ME patients than in the viral ME group of patients (p < 0.05). In addition, phenol was remarkably increased in the group of ME patients compared with the bacterial ME patients (p < 0.05).

CONCLUSIONS

Ethylene oxide and phenol may be potential biomarkers to distinguish bacterial ME and viral ME. VOC analysis of CSF may be used as a supporting tool for clinical diagnosis.

Prevalence and clinical manifestations of herpes simplex virus infection among suspected patients of herpes simplex encephalitis in Shiraz, Iran

Encephalitis has infectious and noninfectious etiology. Among infectious agents, viruses are the main causes of encephalitis; Herpes simplex virus (HSV) is known as the most common causative agent of viral encephalitis. In this current cross-sectional investigation, we aimed to assess the prevalence of HSV in the cerebrospinal fluid (CSF) specimens of Herpes Simplex Encephalitis (HSE) suspected patients and also determining the clinical symptoms and laboratory findings of this viral complication. Two hundred consecutive HSE suspected patients with clinical diagnosis of encephalitis were included in the study and then the presence of HSV DNA in their CSF was applied by Polymerase Chain Reaction (PCR) assay. Molecular detection of two hundred (117 males with mean age: 43 years, 83 females with mean age: 39 years) CSF samples showed that 22 (11.11%) cases were positive for HSV infection. 15(68.18%) of the positive samples were more than 50 years old, however, there was no significant correlation between age distribution, gender and HSE clinical manifestations. Fever (91%), headache (72.7%), seizer (59%), and weakness (59%) were the most common symptoms in positive patients and also mortality rate was (18.18%). CSF laboratory abnormalities of HSE cases were as follows; lymphocytic pleocytosis 19 (86.3%), leukocytosis 19 (86.3%), elevated protein level 16 (72.7%), and hypoglycorrhachia 3(13.6%). Screening of HSE suspected patients is crucial in the treatment of patients and reduce the mobility and morbidity of patients. Qualitative PCR as an available method in most developing countries could be a reliable method to monitor consecutive HSE suspected patients.

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).

Clinical utility of the FilmArray meningitis/encephalitis panel in children at a tertiary center in South Korea

BACKGROUND

We retrospectively evaluated the pathogens in the cerebrospinal fluid (CSF) of pediatric meningitis/encephalitis (M/E) by FilmArray meningitis/encephalitis panel (FA-MEP), and the characteristics of children showing positive and negative FA-MEP results.

METHOD

FA-MEP along with conventional tests (bacterial/viral cultures, and polymerase chain reaction tests) was performed in children who presented symptoms of M/E. Clinical and laboratory data were reviewed to evaluate the characteristics of children with pathogens detected by FA-MEP.

RESULTS

The CSF specimens from 110 pediatric M/E patients were enrolled. Mean age of the patients was 5.9 ± 5.2 years. Overall positive rate of FA-MEP was 46.4% (51/110). The pathogens detected in the patients were enterovirus (23/51, 45.1%), parechovirus (10/51, 19.6%), S. pneumoniae (7/51, 13.7%), human herpesvirus type 6 (6/51, 11.8%), S. agalactiae (3/51, 5.9%), herpes simplex virus type 2 (1/51, 2.0%), and E. coli (1/51, 2.0%). Aseptic meningitis (OR, 3.24, 95% CI, 1.18-12.73) and a duration of <2 days from onset of symptoms to CSF test (OR, 3.56, 95% CI, 0.1-0.91) significantly contributed to detection of pathogens by the FA-MEP. Among the 14 children who were administered empiric antibiotics before the CSF test, the detection rate was significantly higher in the FA-MEP than in the conventional test (28.6 vs. 0.0%, p = 0.031).

CONCLUSIONS

FA-MEP had a higher detection rate in children with M/E compared with conventional tests, particularly aseptic meningitis, and in case of shorter duration of time-to-test. This test was more effective than the conventional test in pediatric M/E patients that had been administered empiric antibiotics.

The Use of Adjunctive Steroids in Central Nervous Infections

Central nervous system (CNS) infections continue to be associated with significant neurological morbidity and mortality despite various existing therapies. Adjunctive steroid therapy has been employed clinically to reduce inflammation in the treatment of CNS infections across various causative pathogens. Steroid therapy can potentially improve clinical outcomes including reducing mortality rates, provide no significant benefit, or cause worsened outcomes, based on the causative agent of infection. The data on benefits or harms of adjunctive steroid therapy is not consistent in outcome or density through CNS infections, and varies based on the disease diagnosis and pathogen. We summarize the existing literature on the effects of adjunctive steroid therapy on outcome for a number of CNS infections, including bacterial meningitis, herpes simplex virus, West Nile virus, tuberculosis meningitis, cryptococcal meningitis, Angiostrongylus cantonensis, neurocysticercosis, autoimmune encephalitis, toxoplasmosis, and bacterial brain abscess. We describe that while steroid therapy is beneficial and supported in pathogens such as pneumococcal meningitis and tuberculosis, for other diseases, like Listeria monocytogenes and Cryptococcus neoformans they are associated with worse outcomes. We highlight areas of consistent and proven findings and those which need more evidence for supported beneficial clinical use of adjunctive steroid therapy.

Long-Term Survival, Morbidity, Social Functioning and Risk of Disability in Patients with a Herpes Simplex Virus Type 1 or Type 2 Central Nervous System Infection, Denmark, 2000-2016

Background

The long-term prognosis following herpes simplex virus (HSV) central nervous system (CNS) infection is still debated.

Patients and Methods

We examined outcomes in all Danish residents who, during 2000–2016, tested PCR positive for HSV-1 (n=208) or HSV-2 (n=283) in the cerebrospinal fluid, compared to comparison cohorts from the general population (n=2080 and n=2830).

Results

One-year mortality was increased among HSV-1 patients (difference 19.3%; 95% CI: 13.6% to 25.0%) and HSV-2 patients (difference 5.3%; 95% CI: 2.5% to 8.1%), but thereafter mortality was not increased. After exclusion of persons diagnosed with cancer prior to study inclusion, one-year mortality difference for HSV-2 patients was 1.7% (−0.1% to 3.5%). After five years, HSV-1 patients had lower employment (difference −19.8%; 95% CI: −34.7% to −4.8%) and higher disability pension rates (difference 22.2%; 95% CI: 8.4% to 36.0%) than the comparison cohort, but similar number of inpatient days, outpatient visits, and sick leave. HSV-2 patients had employment and disability pension rates comparable to the comparison cohort, but more inpatient days (difference 1.5/year; 95% CI: −0.2 to 3.2), outpatient visits (difference 1.3/year; 95% CI: 0.3 to 3.2), and sick leave days (difference 9.1/year; 95% CI: 7.9 to 10.4).

Conclusion

HSV-1 and HSV-2 CNS infections differ substantially with respect to prognosis. HSV-1 CNS infection is followed by increased short-term mortality and long-term risk of disability. HSV-2 CNS infection has no substantial impact on mortality or working capability but is associated with increased morbidity.

An Association of Varicella Zoster Virus, Facial Palsy, and Meningitis in a Young Immunocompetent Male

Varicella zoster is a secondary infection caused by the virus of chickenpox, after becoming latent in neurons of dorsal root ganglia or trigeminal ganglia. Varicella zoster virus (VZV) can be reactivated years later to produce shingles (zoster), generally in immunocompromised adults to produce neurological deficits and rash. Meningeal involvement of VZV is also reported and can be diagnosed. Herein, we report a 39-year-old immunocompetent male adult with a rare manifestation caused by VZV. The report is an association between facial nerve palsy and a polymerase chain reaction-confirmed VZV meningitis, even without the dermal typical rash. The patient eventually recovered after receiving acyclovir intravenously.

Compliance with international guidelines in adults with encephalitis

Background

Encephalitis is associated with significant neurological disability and mortality. Many guidelines are published for encephalitis management but compliance with them is unknown.

Objectives

To evaluate the appropriate management and compliance to the current guidelines in adults with encephalitis.

Study design

A retrospective multicenter study at 17 hospitals in the Greater Houston area from August 1, 2008 through September 30, 2017. All cases met the definition for possible or probable encephalitis as per the international encephalitis consortium guidelines.

Results

A total of 241 adults (age >17 years) with encephalitis were enrolled. The most common etiologies were unknown (41.9 %), viral (27.8 %) and autoimmune (21.2 %). An adverse clinical outcome was seen in 49 % with 12.4 % in hospital mortality. A high compliance with guidelines (>90 %) was only seen in obtaining a brain computerized tomography (CT) scan, blood cultures and cerebrospinal fluid (CSF) gram stain and culture. A CSF herpes virus simplex (HSV) polymerase chain reaction (PCR) was done in 84 % and only repeated in 14.2 % of patients with an initial negative result. Furthermore, only two-thirds of patients were started empirically on intravenous acyclovir and antibiotics. Evaluation for other etiologies were not uniformly performed: arboviral serologies (57.3 %), CSF anti-N-Methyl-d-Aspartate Receptor (NMDA) receptor antibody (35.7 %), and CSF varicella zoster virus (VZV) PCR (32 %). The highest yield for the tests were arboviral serologies (42 %), anti-NMDA antibodies (41.2 %) and VZV PCR (16.4 %).

Conclusion

The management of encephalitis as per current guidelines is suboptimal leading to underutilization of currently available diagnostic tests and empirical therapy.

Immunomodulatory Strategies in Herpes Simplex Virus Encephalitis

Herpes simplex virus 1 (HSV-1) can be responsible for life-threatening HSV encephalitis (HSE). The mortality rate of patients with HSE who do not receive antiviral treatment is 70%, with most survivors suffering from permanent neurological sequelae. The use of intravenous acyclovir together with improved diagnostic technologies such as PCR and magnetic resonance imaging has resulted in a reduction in the mortality rate to close to 20%. However, 70% of surviving patients still do not recover complete neurological functions. Thus, there is an urgent need to develop more effective treatments for a better clinical outcome. It is well recognized that cerebral damage resulting from HSE is caused by viral replication together with an overzealous inflammatory response. Both of these processes constitute potential targets for the development of innovative therapies against HSE. In this review, we discuss recent progress in therapy that may be used to ameliorate the outcome of patients with HSE, with a particular emphasis on immunomodulatory agents. Ideally, the administration of adjunctive immunomodulatory drugs should be initiated during the rise of the inflammatory response, and its duration should be limited in time to reduce undesired effects. This critical time frame should be optimized by the identification of reliable biomarkers of inflammation.

Herpes Simplex Virus Encephalitis: Patterns of Epidemiology and Outcomes of Patients Admitted to the Intensive Care Unit in Texas, 2008 - 2016

Background

Patients with herpes simplex virus encephalitis (HSVE) often require admission to the intensive care unit (ICU) and have considerably worse outcomes than those not critically ill. The short-term outcomes of critically ill patients in the general population have markedly improved over the past decades. However, the population-level patterns of demand for critical care services among patients with HSVE have not been examined, and it is unknown whether there were corresponding outcome gains among those admitted to the ICU.

Methods

The Texas Inpatient Public Use Data File was used to identify hospitalizations with HSVE aged ≥ 18 years during 2008 - 2016. ICU admissions were identified using unit-specific revenue codes. The patterns of ICU utilization and those of short-term outcomes (with short-term mortality defined as in-hospital death or discharge to hospice) were examined across demographic strata and over time.

Results

Among 1,964 hospitalizations with HSVE, 1,176 (59.9%) were admitted to ICU (45.8% aged ≥ 65 years; 53.1% female, among ICU admissions). ICU utilization increased with age (from 47.9% (age 18 - 44 years) through 61.2% (older adults (age ≥ 65 years)); P = 0.0003 for trend), and increased over time only among older adults (odds ratio: 1.06/year (95% confidence interval (CI): 1.01 - 1.12)). Among ICU admissions, routine home discharge, transfer to a post-acute care facility, and short-term mortality occurred in 26.8%, 39.5%, and 18.7%, respectively; the corresponding outcomes for older adults were 10.6%, 51.4%, and 26.2%, respectively. The outcomes for the whole cohort of ICU admissions remained unchanged over time.

Conclusions

Adults with HSVE had high demand for critical care services, and those admitted to ICU had high short-term mortality and substantial residual morbidity among survivors, which remained unchanged over time. These findings can inform clinicians’ decision-making and discussions about goals of care with affected patients and their surrogates.

Treatable causes of adult-onset rapid cognitive impairment

OBJECTIVES

Acute and subacute cognitive decline, defined collectively as rapid cognitive impairment (RCI), is attributed to diverse disorders and brings great challenges for differential diagnosis. In this study we investigated the RCI patients to determine the underlying causes and the cognitive outcome of the treatable RCI.

PATIENTS AND METHODS

We reviewed medical records of consecutively hospitalized patients (n = 346) with significant and new cognitive dysfunction between January 2014 and December 2015. Based on the duration of their cognitive dysfunction, patients were divided into two groups with the RCI (< 12 months) and the chronic cognitive impairment (CCI, ≥ 12 months), respectively. Etiologies of the RCI and the CCI were analyzed; the cognitive outcomes of the RCI patients with the treatable disorders were assessed in the follow-up visits.

RESULTS

Potentially treatable or reversible causes were identified in 134 (72%) of 187 RCI patients and in 34 (21%) of 159 CCI patients. The causes in the 134 (72%) RCI patients were immune/inflammation (50, 37%), infection (30, 22%), vascular diseases (29, 22%), neoplasm (16, 12%), metabolic/toxic disorders (7, 5%), and others (2, 1%). The treatable disorders found in both the RCI and the CCI patients were vascular diseases, autoimmune encephalitis, viral encephalitis, inflammatory demyelinating diseases, Hashimoto encephalopathy, neurosyphilis, hydrocephalus, and Vitamin B12 deficiency. Total 114 RCI patients with the treatable disorders were followed up for 6∼39 (median 21) months. Poor cognitive outcomes were found in 24 (21%) of the 114 followed-up patients, comprising patients with infection (1, 3%), immune/inflammation (12, 25%), vascular diseases (8, 28%), and metabolic/toxic disorders (3, 43%).

CONCLUSIONS

Treatable or reversible causes are common underlying RCI. Poor outcomes with severe cognitive deficits are considerably present in the treatable RCI patients and result in permanent dementia.

Early clinical management of acute CNS infections: a prospective cohort study

Aim: To explore early management and clinical predictors of patients with suspected CNS infections. Methods: In a prospective cohort study of 125 adult patients with suspected CNS infections, clinical features and early management time points were compared between groups with and without confirmed CNS infections. Results: The door-to-lumbar puncture time was associated with the initial Glasgow Coma Scale score, the confirmed diagnosis and the time to change empirical treatment. Multivariate analysis indicated that the initial Glasgow Coma Scale score was an independent risk factor for prognosis. Conclusion: Lumbar puncture plays a crucial role in early management of CNS infections. Patients with CNS infection who have disturbances of consciousness should receive particular attention.

Herpesvirus Infections of the Nervous System

PURPOSE OF REVIEW

This article reviews the spectrum of neurologic disease associated with human herpesvirus infections.

RECENT FINDINGS

As more patients are becoming therapeutically immunosuppressed, human herpesvirus infections are increasingly common. Historically, infections with human herpesviruses were described as temporal lobe encephalitis caused by herpes simplex virus type 1 or type 2. More recently, however, additional pathogens, such as varicella-zoster virus, Epstein-Barr virus, cytomegalovirus, and human herpesvirus 6 have been identified to cause serious neurologic infections. As literature emerges, clinical presentations of herpesvirus infections have taken on many new forms, becoming heterogeneous and involving nearly every location along the neuraxis. Advanced diagnostic methods are now available for each specific pathogen in the herpesvirus family. As data emerge on viral resistance to conventional therapies, newer antiviral medications must be considered.

SUMMARY

Infections from the herpesvirus family can have devastating neurologic outcomes without prompt and appropriate treatment. Clinical recognition of symptoms and appropriate advanced testing are necessary to correctly identify the infectious etiology. Knowledge of secondary neurologic complications of disease is equally important to prevent additional morbidity and mortality. This article discusses infections of the central and peripheral nervous systems caused by herpes simplex virus type 1 and type 2, varicella-zoster virus, Epstein-Barr virus, cytomegalovirus, and human herpesvirus 6. The pathophysiology, epidemiology, clinical presentations of disease, diagnostic investigations, imaging characteristics, and treatment for each infectious etiology are discussed in detail.

Infectious causes and outcomes in patients presenting with cerebral spinal fluid pleocytosis

To evaluate the infectious etiologies, clinical features, and outcomes of patients with CNS infections at a tertiary care center. Patients that present with a pleocytosis in the cerebral spinal fluid (CSF), defined as a CSF WBC count > 5 cells/mm³, from July 2015 to June 2016 at a tertiary care hospital were analyzed for this report. Data from patients with confirmed (n = 43) and presumed (n = 51) CNS infections were analyzed. CNS infection was the leading known cause of CSF pleocytosis (n = 43, 18% of all patients with a pleocytosis in the CSF), and HSV-2 was identified as the leading causative pathogen (n = 10) followed by varicella zoster virus (n = 5). Fifty-three percent of patients with a pleocytosis in the CSF did not receive a diagnosis. In the patients that did not receive a diagnosis, CNS infection was presumed to be the cause in 51 patients (21% of patients with CSF pleocytosis). The mean time to diagnosis for patients with confirmed CNS infection was 16 days, but time to diagnosis was highly variable depending on the causative pathogen. There was a significant overlap in CSF parameters and peripheral white blood cell counts in patients diagnosed with a viral, bacterial, or fungal infection. Neuroimaging changes were present in only 44% of CNS infections. The overall mortality was 7% for CNS infections, and 17% of patients with a CNS infection had a severe neurologic deficit at presentation while only 3% had a severe deficit at the last neurologic assessment. This study provides new insights into the infectious causes of disease in a cohort of patients with pleocytosis in the CSF. The study provides new insights into the time to diagnosis and outcomes in patients that present with pleocytosis in the CSF.

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.

Missing Cases of Herpes Simplex Virus (HSV) Infection of the Central Nervous System When the Reller Criteria Are Applied for HSV PCR Testing: a Multicenter Study

Previous studies suggested that herpes simplex virus (HSV) PCR testing can be safely deferred in patients with normal cerebrospinal fluid (CSF) white blood cell (WBC) counts and protein levels as long as they are older than 2 years of age and are not immunocompromised, the so-called Reller criteria. In this multicenter study, we retrospectively assessed the validity of these screening criteria in our setting. A total of 4,404 CSF specimens submitted for HSV PCR testing to the respective microbiology laboratories at the participating hospitals between 2012 and 2018 were included. Six commercially available HSV PCR assays were used across the participating centers. Ninety-one of the 4,404 CSF specimens (2.1%) tested were positive for HSV DNA (75 samples for HSV-1 and 16 for HSV-2). Nine patients failed to meet the Reller criteria, of whom seven were deemed to truly have HSV encephalitis. Overall, no significant correlation between HSV PCR cycle threshold (C_T ) values and WBC counts or total protein levels was found. In addition, median HSV PCR C_T s were comparable between patients who met the Reller criteria and those who did not (P = 0.531). In summary, we show that HSV DNA may be detected in CSF specimens with normal WBC and protein levels collected from immunocompetent individuals older than 2 years with HSV encephalitis. Nevertheless, the data also indicate that the number of cases detected could be lowered at least by half if CSF specimens with borderline WBC counts (4 cells/mm³) as well as children of any age are systematically tested.

Epidemiology of Meningitis and Encephalitis in Infants and Children in the United States, 2011-2014

BACKGROUND

Large epidemiologic studies evaluating the etiologies, management decisions and outcomes of infants and children with meningitis and encephalitis in the United States are lacking.

METHODS

Children 0-17 years of age with meningitis or encephalitis as assessed by International Classification of Diseases, Ninth Revision, codes available in the Premier Healthcare Database during 2011-2014 were analyzed.

RESULTS

Six thousand six hundred sixty-five patients with meningitis or encephalitis were identified; 3030 (45.5%) were younger than 1 year of age, 295 (4.4%) were 1-2 years of age, 1460 (21.9%) were 3-9 years of age, and 1880 (28.2%) were 10-17 years of age. Etiologies included enterovirus (58.4%), unknown (23.7%), bacterial (13.0%), noninfectious (3.1%), herpes simplex virus (1.5%), other viruses (0.7%), arboviruses (0.5%) and fungal (0.04%). The majority of patients were male [3847 (57.7%)] and healthy [6094 (91.4%)] with no reported underlying conditions. Most underwent a lumbar puncture in the emergency department [5363 (80%)] and were admitted to the hospital [5363 (83.1%)]. Antibiotic therapy was frequent (92.2%) with children younger than 1 year of age with the highest rates (97.7%). Antiviral therapy was less common (31.1%). Only 539 (8.1%) of 6665 of patients received steroids. Early administration of adjunctive steroids was not associated with a reduction in mortality (P = 0.266). The overall median length of stay was 2 days. Overall mortality rate (0.5%) and readmission rates (<1%) was low for both groups.

CONCLUSION

Meningitis and encephalitis in infants and children in the United States are more commonly caused by viruses and are treated empirically with antibiotic therapy and antiviral therapy in a significant proportion of cases. Adjunctive steroids are used infrequently and are not associated with a benefit in mortality.

Acute kidney injury (AKI) associated with intravenous aciclovir in adults: Incidence and risk factors in clinical practice

OBJECTIVES

This study sought to identify the incidence of, and risk factors for, acute kidney injury (AKI) in adults treated with parenteral aciclovir.

METHODS

A single-centre retrospective cohort study of prospectively acquired electronic clinical, pharmacy and laboratory data was performed with approval of the Caldicott guardian. AKI was defined by Kidney Disease Improving Global Outcomes (KDIGO) criteria, prior to analysis of baseline patient and treatment-related risk factors.

RESULTS

269 aciclovir treatment episodes were identified in 268 patients. Overall incidence of AKI was 13%. Half of AKI episodes were KDIGO grade 2/3. In univariate analysis, AKI occurred more frequently in patients with pre-existing chronic kidney disease (CKD), diabetes, and in patients treated with higher daily doses of aciclovir. There was also a trend to increased age in patients with AKI. In a binomial logistic regression model only CKD and daily dose remained significant independent factors.

CONCLUSIONS

AKI is an important side effect of parenteral aciclovir, the incidence of which is comparable to established nephrotoxic drugs such as aminoglycosides. Patients with pre-existing chronic kidney disease or receiving higher total doses are at greatest risk, reinforcing the clinical importance of appropriate dose adjustment for ideal body weight and baseline renal function.

Evaluation of a Commercial Multiplex Molecular Panel for Diagnosis of Infectious Meningitis and Encephalitis

Rapid and accurate laboratory tests are important for the timely diagnosis and treatment of central nervous system infections. The FilmArray meningitis/encephalitis (ME) panel (BioFire Diagnostics, Salt Lake City, UT) is an FDA-cleared, multiplex molecular panel that allows the detection of 14 pathogens (bacterial [n = 6], viral [n = 7], and fungal [n = 1] pathogens) from cerebrospinal fluid (CSF). In this study, we evaluated the performance characteristics of the FilmArray ME panel using clinical, residual CSF samples (n = 291) that tested positive by a routine method(s) (e.g., bacterial culture, individual real-time PCR assay) for a pathogen represented on the ME panel. Of note, a subset (n = 76) of the CSF specimens was collected during the prevaccine era and had been characterized as positive for a bacterial pathogen. The FilmArray ME panel demonstrated an overall percent positive agreement (PPA) of 97.5% (78/80) for bacterial pathogens, 90.1% (145/161) for viruses, and 52% (26/50) for Cryptococcusneoformans/C. gattii Despite the low overall agreement (52%) between the ME panel and antigen testing for detection of C. neoformans/C. gattii, the percent positive agreement of the FilmArray assay for C. neoformans/C. gattii was 92.3% (12/13) when the results were compared directly to the results of routine fungal smear or culture. The FilmArray ME panel offers a rapid (∼60-min), syndrome-based approach for the detection of select meningitis and encephalitis pathogens.

Prediction of unfavorable outcomes in cryptococcal meningitis: results of the multicenter Infectious Diseases International Research Initiative (ID-IRI) cryptococcal meningitis study

Cryptococcal meningitis (CM) is mostly seen in immunocompromised patients, particularly human immunodeficiency virus (HIV)-positive patients, but CM may also occur in apparently immunocompetent individuals. Outcome analyses have been performed in such patients but, due to the high prevalence of HIV infection worldwide, CM patients today may be admitted to hospitals with unknown HIV status, particularly in underdeveloped countries. The objective of this multicenter study was to analyze all types of CM cases in an aggregate cohort to disclose unfavorable outcomes. We retrospectively reviewed the hospitalized CM patients from 2000 to 2015 in 26 medical centers from 11 countries. Demographics, clinical, microbiological, radiological, therapeutic data, and outcomes were included. Death, neurological sequelae, or relapse were unfavorable outcomes. Seventy (43.8%) out of 160 study cases were identified as unfavorable and 104 (65%) were HIV infected. On multivariate analysis, the higher Glasgow Coma Scale (GCS) scores (p = 0.021), cerebrospinal fluid (CSF) leukocyte counts > 20 (p = 0.038), and higher CSF glucose levels (p = 0.048) were associated with favorable outcomes. On the other hand, malignancy (p = 0.026) was associated with poor outcomes. Although all CM patients require prompt and rational fungal management, those with significant risks for poor outcomes need to be closely monitored.

Central nervous system infections in the absence of cerebrospinal fluid pleocytosis

Previous multicenter/multinational studies were evaluated to determine the frequency of the absence of cerebrospinal fluid pleocytosis in patients with central nervous system infections, as well as the clinical impact of this condition. It was found that 18% of neurosyphilis, 7.9% of herpetic meningoencephalitis, 3% of tuberculous meningitis, 1.7% of Brucella meningitis, and 0.2% of pneumococcal meningitis cases did not display cerebrospinal fluid pleocytosis. Most patients were not immunosuppressed. Patients without pleocytosis had a high rate of unfavorable outcomes and thus this condition should not be underestimated.

HSV-1 Encephalitis: High Index of Clinical Suspicion, Prompt Diagnosis, and Early Therapeutic Intervention Are the Triptych of Success-Report of Two Cases and Comprehensive Review of the Literature

Herpes Simplex Virus (HSV) encephalitis is an acute infectious disease of the Central Nervous System (CNS), usually affecting the limbic structures, the median temporal cortex, and the orbitofrontal regions. Its annual incidence has significantly increased over the last 20 years and the mortality rate is 7%, if early diagnosed and treated, and 70%, if left untreated, while it is associated with high rates of morbidity. It should be noted that even when Cerebrospinal fluid (CSF) analysis seems normal, imaging studies are not specific and HSV Polymerase Chain Reaction (PCR) test is negative; the clinician should be more aggressive, if clinical presentation is indicative for HSV encephalitis, by administrating acyclovir early after patient's admission. The latter may be a vital intervention for the patient, modifying the patient's clinical course. Through the presentation of two cases of HSV-1 encephalitis that we managed in our department over the last 1 year and after systematic and comprehensive research of the relevant literature, we aim at showing the crucial role of medical history and physical examination, along with the high index of clinical suspicion, in order to make promptly the diagnosis and administer timely intravenous acyclovir, limiting the possibility of complications during the disease's course.

Etiology and prognosis of acute viral encephalitis and meningitis in Chinese children: a multicentre prospective study

BACKGROUND

In China, there were few studies about the pathogens of acute viral encephalitis and meningitis in children in recent years. The aims of this study were to characterize the etiology and prognosis of acute viral encephalitis and meningitis in Chinese children.

METHODS

This was a multicentre prospective study. Two hundred and sixty one viral encephalitis patients and 285 viral meningitis patients were enrolled. The mean age of viral encephalitis and meningitis were 5.88 ± 3.60 years and 6.39 ± 3.57 years, respectively. Real-time reverse transcription PCR and multiplex PCR were used to detect human enteroviruses and herpes viruses in cerebrospinal fluid (CSF) of patients with encephalitis or meningitis. The enzyme-linked immune absorbent assay (ELISA) was used for detecting IgM antibody against Japanese encephalitis virus (JEV) in CSF and against mumps virus, tick-borne encephalitis virus (TBEV), dengue virus and rubella virus in acute serum. The clinical and outcome data were collected during patients' hospitalization.

RESULTS

The etiology of viral encephalitis was confirmed in 52.5% patients. The primary pathogen was human enteroviruses (27.7%) in viral encephalitis. The incidence of sequelae and the fatality rate of viral encephalitis with confirmed etiology were 7.5% and 0.8%, respectively. The etiology of viral meningitis was identified in 42.8% cases. The leading pathogen was also human enteroviruses (37.7%) in viral meningitis. The prognosis of viral meningitis was favorable with only 0.7% patients had neurological sequelae.

CONCLUSIONS

Human enteroviruses were the leading cause both in acute viral encephalitis and viral meningitis in children. The incidence of sequelae and fatality rate of viral encephalitis with confirmed etiology were 7.5% and 0.8%, respectively. The prognosis of viral meningitis was favorable compared to viral encephalitis.

Burden of herpes simplex virus encephalitis in the United States

Herpes simplex virus encephalitis (HSVE) is a disease of public health concern, but its burden on the healthcare of United States has not been adequately assessed recently. We aimed to define the incidence, complications and outcomes of HSVE in the recent decade by analyzing data from a nationally representative database. Healthcare Cost and Utilization Project databases were utilized to identify patients with primary discharge diagnosis of HSVE. Annual hospitalization rate was estimated and several preselected inpatient complications were identified. Regression analyses were used to identify mortality predictors. Key epidemiological factors were compared with those from other countries. Total 4871 patients of HSVE were included in our study. The annual hospitalization rate was 10.3 ± 2.2 cases/million in neonates, 2.4 ± 0.3 cases/million in children and 6.4 ± 0.4 cases/million in adults. Median age was 57 years and male:female incidence ratio was 1:1. Rates of some central nervous system complications were seizures (38.4%), status epilepticus (5.5%), acute respiratory failure (20.1%), ischemic stroke (5.6%) and intracranial hemorrhage (2.7%), all of which were significantly associated with mortality. In-hospital mortality in neonates, children and adults were 6.9, 1.2 and 7.7%, respectively. HSVE still remains a potentially lethal infectious disease with high morbidity and mortality. Most recent epidemiological data in this study may help understanding this public health disease, and the patient outcome data may have prognostic significance.

The burden and epidemiology of community-acquired central nervous system infections: a multinational study

Risk assessment of central nervous system (CNS) infection patients is of key importance in predicting likely pathogens. However, data are lacking on the epidemiology globally. We performed a multicenter study to understand the burden of community-acquired CNS (CA-CNS) infections between 2012 and 2014. A total of 2583 patients with CA-CNS infections were included from 37 referral centers in 20 countries. Of these, 477 (18.5%) patients survived with sequelae and 227 (8.8%) died, and 1879 (72.7%) patients were discharged with complete cure. The most frequent infecting pathogens in this study were Streptococcus pneumoniae (n = 206, 8%) and Mycobacterium tuberculosis (n = 152, 5.9%). Varicella zoster virus and Listeria were other common pathogens in the elderly. Although staphylococci and Listeria resulted in frequent infections in immunocompromised patients, cryptococci were leading pathogens in human immunodeficiency virus (HIV)-positive individuals. Among the patients with any proven etiology, 96 (8.9%) patients presented with clinical features of a chronic CNS disease. Neurosyphilis, neurobrucellosis, neuroborreliosis, and CNS tuberculosis had a predilection to present chronic courses. Listeria monocytogenes, Staphylococcus aureus, M. tuberculosis, and S. pneumoniae were the most fatal forms, while sequelae were significantly higher for herpes simplex virus type 1 (p < 0.05 for all). Tackling the high burden of CNS infections globally can only be achieved with effective pneumococcal immunization and strategies to eliminate tuberculosis, and more must be done to improve diagnostic capacity.

Infectious encephalitis: Management without etiological diagnosis 48hours after onset

Introduction

The etiological diagnosis of infectious encephalitis is often not established 48 hours after onset. We aimed to review existing literature data before providing management guidelines.

Method

We performed a literature search on PubMed using filters such as “since 01/01/2000”, “human”, “adults”, “English or French”, and “clinical trial/review/guidelines”. We also used the Mesh search terms “encephalitis/therapy” and “encephalitis/diagnosis”.

Results

With Mesh search terms “encephalitis/therapy” and “encephalitis/diagnosis”, we retrieved 223 and 258 articles, respectively. With search terms “encephalitis and corticosteroid”, we identified 38 articles, and with “encephalitis and doxycycline” without the above-mentioned filters we identified 85 articles. A total of 210 articles were included in the analysis.

Discussion

Etiological investigations must focus on recent travels, animal exposures, age, immunodeficiency, neurological damage characteristics, and potential extra-neurological signs. The interest of a diagnosis of encephalitis for which there is no specific treatment is also to discontinue any empirical treatments initially prescribed. Physicians must consider and search for autoimmune encephalitis.

Herpes Simplex Encephalitis: an Update

PURPOSE OF REVIEW

The goal of this review is to provide an update on current thinking regarding herpes simplex encephalitis (HSE), emphasizing new information about pathogenesis, diagnosis, and immune responses. Specific questions to be addressed are the following: (1) Is there a genetic predisposition to HSE? (2) What clinical approaches have the greatest impact on improving the long-term outcomes in patients with HSE? And (3) are there immune-mediated mechanisms that may account for relapsing HSE?

RECENT FINDINGS

Toll-like receptor 3 (TLR 3) plays an important role in innate immune responses, including generation of interferons. Multiple single-gene errors in TLR 3 interferon pathways have recently been described in children that result in increased susceptibility to HSE. Conversely, studies in both animal models and humans indicate that both cytolytic viral replication and immune-mediated responses (including cytotoxic T lymphocytes and immune mechanisms mediated by TLR 2) contribute to the pathology of HSV, suggesting possible new therapeutic approaches. In terms of treatment, data clearly indicate that a longer duration between onset of symptoms and initiation of effective antiviral therapy correlates directly with less favorable clinical outcome. Recurrent or relapsing HSE may occasionally occur, but recent observations indicate that many instances of "relapsing HSE", especially in children, are more often anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis triggered by the antecedent HSV infection. Innate immune responses are critical for defense against HSV; genetic defects in this system may predispose patients to HSE. During acute HSE, exuberant immune responses may contribute to the CNS pathology, suggesting that selective immunosuppressive therapy, coupled with potent antiviral drugs, may eventually play a role in the therapeutic management of HSV. While overall clinical outcomes of HSE remain suboptimal, the initiation of high-dose acyclovir therapy as early as possible in the course of the illness provides the best chance for a patient to survive with minimal neurologic damage. Distinguishing relapsing HSE from autoimmune anti-NMDAR antibody encephalitis is critically important because therapeutic approaches will be very different.

Herpes simplex type 2 encephalitis and methotrexate medication: a fortuitous or causative association in a patient with spondyloarthritis?

It is unclear whether immunosuppression is a risk factor for herpes encephalitis. Herein, we describe a rare case of herpes simplex virus type 2 encephalitis in a patient treated with low-dose methotrexate for HLA-B27-associated spondyloarthritis. The patient was successfully treated with acyclovir but presented sequelae of encephalitis. Here we discuss the possible role of low-dose methotrexate therapy as a risk factor of neurological herpes reactivation and severe disease. The host-related and viral risk factors are also addressed.

Incidence and mortality of herpes simplex encephalitis in Denmark: A nationwide registry-based cohort study

OBJECTIVES

We aimed to investigate the incidence and mortality of herpes simplex encephalitis (HSE) in a nationwide cohort.

METHODS

From the Danish National Patient Registry, we identified all adults hospitalised with a first-time diagnosis of HSE in Denmark during 2004-2014. The HSE diagnoses were verified using medical records and microbiological data. Patients were followed for mortality through the Danish Civil Registry System. We estimated age-standardised incidence rates of HSE and 30-day, 60-day, and 1-year cumulative mortality. Furthermore, we assessed whether calendar year, age, gender, level of comorbidity, virus type, and department type was associated with HSE mortality.

RESULTS

We identified a total of 230 cases of HSE. Median age was 60.7 years (interquartile range: 49.3-71.6). The overall incidence rate was 4.64 cases per million population per year (95% confidence interval: 4.06-5.28). The cumulative mortality within 30 days, 60 days, and 1 year of the HSE admission was 8.3%, 11.3%, and 18.6%, respectively. Advanced age and presence of comorbidity were associated with increased 60-day and 1-year mortality.

CONCLUSIONS

This nationwide study of verified HSE found a higher incidence than reported in previous nationwide studies. Presence of comorbidity was identified as a novel adverse prognostic factor. Mortality rates following HSE remain high.

Sepsis and Other Infectious Disease Emergencies in the Elderly

Waning immunity and declining anatomic and physiologic defenses render the elder vulnerable to a wide range of infectious diseases. Clinical presentations are often atypical and muted, favoring global changes in mental status and function over febrile responses or localizing symptoms. This review encompasses early recognition, evaluation, and appropriate management of these common infections specifically in the context of elders presenting to the emergency department. With enhanced understanding and appreciation of the unique aspects of infections in the elderly, emergency physicians can play an integral part in reducing the morbidity and mortality associated with these often debilitating and life-threatening diseases.

Managing atypical and typical herpetic central nervous system infections: results of a multinational study

There have been many studies pertaining to the management of herpetic meningoencephalitis (HME), but the majority of them have focussed on virologically unconfirmed cases or included only small sample sizes. We have conducted a multicentre study aimed at providing management strategies for HME. Overall, 501 adult patients with PCR-proven HME were included retrospectively from 35 referral centres in 10 countries; 496 patients were found to be eligible for the analysis. Cerebrospinal fluid (CSF) analysis using a PCR assay yielded herpes simplex virus (HSV)-1 DNA in 351 patients (70.8%), HSV-2 DNA in 83 patients (16.7%) and undefined HSV DNA type in 62 patients (12.5%). A total of 379 patients (76.4%) had at least one of the specified characteristics of encephalitis, and we placed these patients into the encephalitis presentation group. The remaining 117 patients (23.6%) had none of these findings, and these patients were placed in the nonencephalitis presentation group. Abnormalities suggestive of encephalitis were detected in magnetic resonance imaging (MRI) in 83.9% of the patients and in electroencephalography (EEG) in 91.0% of patients in the encephalitis presentation group. In the nonencephalitis presentation group, MRI and EEG data were suggestive of encephalitis in 33.3 and 61.9% of patients, respectively. However, the concomitant use of MRI and EEG indicated encephalitis in 96.3 and 87.5% of the cases with and without encephalitic clinical presentation, respectively. Considering the subtle nature of HME, CSF HSV PCR, EEG and MRI data should be collected for all patients with a central nervous system infection.

State-of-the-Art Microbiologic Testing for Community-Acquired Meningitis and Encephalitis

Meningitis and encephalitis are potentially life-threatening diseases with a wide array of infectious, postinfectious, and noninfectious causes. Diagnostic testing is central to determining the underlying etiology, treatment, and prognosis, but many patients remain undiagnosed due to suboptimal testing and lack of tests for all pathogens. In this article, we summarize the epidemiology, barriers to diagnosis, and current best tests for meningitis and encephalitis in developed countries. We end with a brief discussion of new test methods, such as multiplex panel-based tests and metagenomic sequencing, which are likely to alter diagnostic strategies for these conditions in the near future.

Herpes simplex and varicella zoster CNS infections: clinical presentations, treatments and outcomes

OBJECTIVES

To describe the clinical manifestations, cerebrospinal fluid (CSF) characteristics, imaging studies and prognostic factors of adverse clinical outcomes (ACO) among adults with herpes simplex virus (HSV) or varicella zoster virus (VZV) CNS infections.

METHODS

Retrospective review of adult patients with positive HSV or VZV polymerase chain reaction on CSF from an observational study of meningitis or encephalitis in Houston, TX (2004-2014), and New Orleans, LA (1999-2008).

RESULTS

Ninety-eight adults patients were identified; 25 had encephalitis [20 (20.4 %) HSV, 5 (5.1 %) VZV], and 73 had meningitis [60 (61.1 %) HSV and 13 (13.3 %) VZV]. HSV and VZV had similar presentations except for nausea (P < 0.01) and rash (P < 0.001). The CSF profile did not differ between HSV and VZV infection. Abnormal neuroimaging findings were found in 11.6 % (10/86) brain CTs and 21.3 % (16/75) brain MRIs. The EEG was abnormal in 57.9 % (11/19). Sixteen patients (16.3 %) had an ACO (10 HSV encephalitis, 3 VZV encephalitis and 3 VZV meningitis). Intravenous acyclovir administered within 48 h was protective against an ACO [OR 0.19 (0.04-0.80), P = 0.02). However, on logistic regression only Charlson comorbidity score >1 and an encephalitis presentation were independently associated with an ACO. The treatment for HSV meningitis was variable, and all patients had a good clinical outcome.

CONCLUSION

Alpha herpes CNS infections due to HSV and VZV infections have similar clinical and laboratory manifestations. ACO was observed more frequently in those patients with comorbidities and an encephalitis presentation.

Innate immune response during herpes simplex virus encephalitis and development of immunomodulatory strategies

Herpes simplex viruses are large double-stranded DNA viruses. These viruses have the ability to establish a lifelong latency in sensory ganglia and to invade and replicate in the CNS. Apart from relatively benign mucosal infections, HSV is responsible for severe illnesses including HSV encephalitis (HSE). HSE is the most common cause of sporadic, potentially fatal viral encephalitis in Western countries. If left untreated, the mortality rate associated with HSE is approximately 70%. Despite antiviral therapy, the mortality is still higher than 30%, and almost 60% of surviving individuals develop neurological sequelae. It is suggested that direct virus-related and indirect immune-mediated mechanisms contribute to the damages occurring in the CNS during HSE. In this manuscript, we describe the innate immune response to HSV, the development of HSE in mice knock-out for proteins of the innate immune system as well as inherited deficiencies in key components of the signaling pathways involved in the production of type I interferon that could predispose individuals to develop HSE. Finally, we review several immunomodulatory strategies aimed at modulating the innate immune response at a critical time after infection that were evaluated in mouse models and could be combined with antiviral therapy to improve the prognosis of HSE. In conclusion, the cerebral innate immune response that develops during HSE is a "double-edged sword" as it is critical to control viral replication in the brain early after infection, but, if left uncontrolled, may also result in an exaggerated inflammatory response that could be detrimental to the host.