Viral meningitis-associated hospitalizations in the United States, 1988-1999

An Outbreak of Coxsackievirus B Type 2 Acute Meningoencephalitis in Children, Israel, July-September 2022

During July-September 2022, 14 children suffering from meningoencephalitis tested positive for Coxsackievirus B2 (8 cerebrospinal fluid, 9 stool samples). Mean age 22 months (range 0-60 months); 8 were males. Seven of the children presented with ataxia and 2 had imaging features of rhombencephalitis, not previously described in association with Coxsackievirus B2.

The Cost of Suspected and Confirmed Bacterial Meningitis Cases Treated at Jimma University Medical Center, Ethiopia

Background

Infections of the central nervous system (CNS) such as meningitis or encephalitis can be caused by myriad of microorganisms and may be life-threatening. In Ethiopia, it is an important cause of premature death and disability, being the 9^th most common cause of years of life lost and loss of disability-adjusted life years.

The objective of this study was to estimate the cost of suspected and confirmed bacterial meningitis among inpatient managed patients at JUMC.

Methods

A facility-based cross-sectional study was conducted from July 28 to September 12, 2018. A semi-structured questionnaire was used in this study. Checklists were used to collect the types of laboratory tests performed and prescribed medications. This cost of illness study was conducted from the patient perspectives. We employed a micro-costing bottom-up approach to estimate the direct cost of meningitis. The human capital approach was used for estimating wages lost.

Result

Among total patients admitted and treated in JUMC, higher proportions (69.8%) were suspected bacterial meningitis but have been treated as confirmed cases. Total median costs for both suspected and confirmed bacterial meningitis patients were estimated to be ETB 98,812.32 (US $ 3,593.2; IQR 1,303.0 to 5,734.0). Total median direct cost was ETB 79,248.02 (US $ 2,881.75; IQR 890.7 to 3,576.7). Moreover, 45.3% of the patients reported that they were either admitted or given medication at JUMC or nearby health facility before their current admissions.

Conclusion

These findings indicate that most cases of bacterial meningitis were treated only empirically, and the cost of the treatment was high, especially for resource-limited countries like Ethiopia. To minimize the burden of meningitis and avoid unnecessary hospitalizations, the availability of diagnostic techniques is vitally important.

Etiology, Clinical Phenotypes, Epidemiological Correlates, Laboratory Biomarkers and Diagnostic Challenges of Pediatric Viral Meningitis: Descriptive Review

Meningitis is an inflammation of the brain and spinal cord meninges caused by infectious and non-infectious agents. Infectious agents causing meningitis include viruses, bacteria, and fungi. Viral meningitis (VM), also termed aseptic meningitis, is caused by some viruses, such as enteroviruses (EVs), herpesviruses, influenza viruses, and arboviruses. However, EVs represent the primary cause of VM. The clinical symptoms of this neurological disorder may rapidly be observed after the onset of the disease, or take prolonged time to develop. The primary clinical manifestations of VM include common flu-like symptoms of headache, photophobia, fever, nuchal rigidity, myalgia, and fatigue. The severity of these symptoms depends on the patient's age; they are more severe among infants and children. The course of infection of VM varies between asymptomatic, mild, critically ill, and fatal disease. Morbidities and mortalities of VM are dependent on the early recognition and treatment of the disease. There were no significant distinctions in the clinical phenotypes and symptoms between VM and meningitis due to other causative agents. To date, the pathophysiological mechanisms of VM are unclear. In this scientific communication, a descriptive review was performed to give an overview of pediatric viral meningitis (PVM). PVM may occasionally result in severe neurological consequences such as mental retardation and death. Clinical examinations, including Kernig's, Brudzinski's, and nuchal rigidity signs, were attempted to determine the clinical course of PVM with various success rates revealed. Some epidemiological correlates of PVM were adequately reviewed and presented in this report. They were seen depending mainly on the causative virus. The abnormal cytological and biochemical features of PVM were also discussed and showed potentials to distinguish PVM from pediatric bacterial meningitis (PBM). The pathological, developmental, behavioral, and neuropsychological complications of PVM were also presented. All the previously utilized techniques for the etiological diagnosis of PVM which include virology, serology, biochemistry, and radiology, were presented and discussed to determine their efficiencies and limitations. Finally, molecular testing, mainly PCR, was introduced and showed 100% sensitivity rates.

Innovations in infectious disease testing: Leveraging COVID-19 pandemic technologies for the future

Innovations in infectious disease testing have improved our abilities to detect and understand the microbial world. The 2019 novel coronavirus infectious disease (COVID-19) pandemic introduced new innovations including non-prescription “over the counter” infectious disease tests, mass spectrometry-based detection of COVID-19 host response, and the implementation of artificial intelligence (AI) and machine learning (ML) to identify individuals infected by the severe acute respiratory syndrome - coronavirus – 2 (SARS-CoV-2). As the world recovers from the COVID-19 pandemic; these innovative solutions will give rise to a new era of infectious disease tests extending beyond the detection of SARS-CoV-2. To this end, the purpose of this review is to summarize current trends in infectious disease testing and discuss innovative applications specifically in the areas of POC testing, MS, molecular diagnostics, sample types, and AI/ML.

Evolving Applications of Artificial Intelligence and Machine Learning in Infectious Diseases Testing

Background

Artificial intelligence (AI) and machine learning (ML) are poised to transform infectious disease testing. Uniquely, infectious disease testing is technologically diverse spaces in laboratory medicine, where multiple platforms and approaches may be required to support clinical decision-making. Despite advances in laboratory informatics, the vast array of infectious disease data is constrained by human analytical limitations. Machine learning can exploit multiple data streams, including but not limited to laboratory information and overcome human limitations to provide physicians with predictive and actionable results. As a quickly evolving area of computer science, laboratory professionals should become aware of AI/ML applications for infectious disease testing as more platforms are become commercially available.

Content

In this review we: (a) define both AI/ML, (b) provide an overview of common ML approaches used in laboratory medicine, (c) describe the current AI/ML landscape as it relates infectious disease testing, and (d) discuss the future evolution AI/ML for infectious disease testing in both laboratory and point-of-care applications.

Summary

The review provides an important educational overview of AI/ML technique in the context of infectious disease testing. This includes supervised ML approaches, which are frequently used in laboratory medicine applications including infectious diseases, such as COVID-19, sepsis, hepatitis, malaria, meningitis, Lyme disease, and tuberculosis. We also apply the concept of “data fusion” describing the future of laboratory testing where multiple data streams are integrated by AI/ML to provide actionable clinical knowledge.

Bulging fontanelle in febrile infants as a predictor of bacterial meningitis

It is common practice to perform a lumbar puncture in infants presenting with fever and a bulging fontanelle in order to rule out bacterial meningitis. However, most of these infants have benign, self-limiting diseases. The objective was to determine whether there is an association between bulging fontanelle and bacterial meningitis in febrile infants. This retrospective cohort study included febrile children with a bulging fontanelle who underwent lumbar puncture at Meir Medical Center from 2005 through 2015. A total of 764 children ages 2-18 months underwent lumbar puncture during the study period. Among them, 304 had a bulging fontanelle and fever on evaluation and cerebrospinal fluid pleocytosis was found in 115 (37.8%), including 1 case of bacterial meningitis (0.3%). None of the infants described on admission as appearing well on presentation was found to have bacterial meningitis. Of the 764 children who underwent lumbar puncture, 10 infants were diagnosed with bacterial meningitis, and only one (10%) presented with a bulging fontanelle.Conclusion: The finding of a bulging fontanelle has very low sensitivity and specificity for bacterial meningitis. Most causes of a bulging fontanelle in febrile infants are self-limiting diseases. The routine approach of performing a lumbar puncture in febrile infants with a bulging fontanelle should be reconsidered. What is Known: • It is common to perform a lumbar puncture in febrile infants with a bulging fontanelle, to rule out bacterial meningitis. • However, there are only few researches regarding the relationship between bulging fontanelle and bacterial meningitis. What is New: • The finding of a bulging fontanelle has very low sensitivity and specificity for bacterial meningitis • The need for routine lumbar puncture in these cases should be reconsidered.

Etiology, Clinical Presentation and Incidence of Infectious Meningitis and Encephalitis in Polish Children

Little is known about the causes and the frequency of meningitis and encephalitis in Poland. We did a retrospective single-center cohort study of children under 18 years old hospitalized with infectious meningitis or encephalitis. Incidence rates were calculated using collected data from patients from the North-East Poland only. A total of 374 children hospitalized between 1 January 2015 and 31 December 2019 were included in the study. A total of 332 (89%) children had meningitis, and 42 (11%) had encephalitis. The etiology of the infection was established in 331 (89%) cases. Enteroviruses accounted for 224 (60%) of all patients. A total of 68 (18%) cases were tick-borne infections. Bacterial pathogens were detected in 26 (7%) children. The median length of hospital stay for children with enteroviral meningitis was 7 days (IQR 7–9), increasing to 11 days (8–13) in those treated with antibiotics. The incidence of meningitis was estimated to be 32.22 (95% CI, 25.33–40.98) per 100,000 and that of encephalitis to be 4.08 (95% CI, 2.07–8.02) per 100,000. By the broad use of molecular diagnostic methods, we managed to identify etiology of the infection in the majority of children. Our data suggest that thorough diagnostics of central nervous system infections are needed to rationalize treatment.

Early Entry Events in Echovirus 30 Infection

Echovirus 30 (E30), a member of the enterovirus B species, is a major cause of viral meningitis, targeting children and adults alike. While it is a frequently isolated enterovirus and the cause of several outbreaks all over the world, surprisingly little is known regarding its entry and replication strategy within cells. In this study, we used E30 strain Bastianni (E30B) generated from an infectious cDNA clone in order to study early entry events during infection in human RD cells. E30B required the newly discovered Fc echovirus receptor (FcRn) for successful infection, but not the coxsackievirus and adenovirus receptor (CAR) or decay-accelerating factor (DAF), although an interaction with DAF was observed. Double-stranded RNA replication intermediate was generated between 2 and 3 h postinfection (p.i.), and viral capsid production was initiated between 4 and 5 h p.i. The drugs affecting Rac1 (NSC 23766) and cholesterol (filipin III) compromised infection, whereas bafilomycin A1, dyngo, U-73122, wortmannin, and nocodazole did not, suggesting the virus follows an enterovirus-triggered macropinocytic pathway rather than the clathrin pathway. Colocalization with early endosomes and increased infection due to constitutively active Rab5 expression suggests some overlap and entry to classical early endosomes. Taken together, these results suggest that E30B induces an enterovirus entry pathway, leading to uncoating in early endosomes.IMPORTANCE Echovirus 30 (E30) is a prevalent enterovirus causing regular outbreaks in both children and adults in different parts of the world. It is therefore surprising that relatively little is known of its infectious entry pathway. We set out to generate a cDNA clone and gradient purified the virus in order to study the early entry events in human cells. We have recently studied other enterovirus B group viruses, like echovirus 1 (EV1) and coxsackievirus A9 (CVA9), and found many similarities between those viruses, allowing us to define a so-called "enterovirus entry pathway." Here, E30 is reminiscent of these viruses, for example, by not relying on acidification for infectious entry. However, despite not using the clathrin entry pathway, E30 accumulates in classical early endosomes.

Outcomes measures in children after acute central nervous system infections and malaria

PURPOSE OF REVIEW

Acute central nervous system (CNS) infections in children result in significant mortality and neurologic morbidity worldwide. This article summarizes the recent pediatric literature published on outcomes measures used after acute infectious meningitis, encephalitis, and cerebral malaria, and highlights ongoing research efforts to standardize outcomes measurements. Search terms were geared toward functional, cognitive, behavioral, and other outcome assessments.

RECENT FINDINGS

Recent data suggest that, depending on microbiological cause, there are differences in currently used outcome measures following acute CNS infections. Outcomes assessments include a variety of formal psychological tests (structured interviews and neuropsychological tests of cognitive and motor functioning) and dichotomized or ordinal scales. Standardization of outcome measures, however, is lacking. Global efforts to standardize outcomes that encompass both the child and family are ongoing.

SUMMARY

Centers worldwide can track and measure a variety of cognitive, behavioral, and functional outcomes after acute CNS infections. Standardized documentation and coding of clinically important outcomes is needed. Further research to evaluate effective practices using acute adjunctive and rehabilitation therapies will be aided by outcome measure standardization.

Meningitis gone viral: description of the echovirus wave 2013 in Germany

Background

Aseptic meningitis epidemics may pose various health care challenges.

Methods

We describe the German enterovirus meningitis epidemics in the university hospital centers of Düsseldorf, Cologne and Berlin between January 1st and December 31st, 2013 in order to scrutinize clinical differences from other aseptic meningitis cases.

Results

A total of 72 enterovirus (EV-positive) meningitis cases were detected in our multicenter cohort, corresponding to 5.8% of all EV-positive cases which were voluntarily reported within the National Enterovirus surveillance (EVSurv, based on investigation of patients with suspected aseptic meningitis/encephalitis and/or acute flaccid paralysis) by physicians within this period of time. Among these 72 patients, 38 (52.8%) were enterovirus positive and typed as echovirus (18 pediatric and 20 adult cases, median age 18.5 years; echovirus 18 (1), echovirus 2 (1), echovirus 30 (31), echovirus 33 (1), echovirus 9 (4)). At the same time, 45 aseptic meningitis cases in our cohort were excluded to be due to enteroviral infection (EV-negative). Three EV-negative patients were tested positive for varicella zoster virus (VZV) and 1 EV-negative patient for herpes simplex virus 2. Hospitalization was significantly longer in EV-negative cases. Cerebrospinal fluid analysis did not reveal significant differences between the two groups. After discharge, EV-meningitis resulted in significant burden of sick leave in our pediatric cohort as parents had to care for the children at home.

Conclusions

Voluntary syndromic surveillance, such as provided by the EVSurv in our study may be a valuable tool for epidemiological research. Our analyses suggest that EV-positive meningitis predominantly affects younger patients and may be associated with a rather benign clinical course, compared to EV-negative cases.

Diagnostic Practices for Suspected Community-Acquired Central Nervous System Infection in the Post-Conjugate Vaccine Era

OBJECTIVE

The aim of this study was to evaluate diagnostic practices for suspected community-acquired central nervous system (CNS) infection in an urban pediatric population.

METHODS

This is an observational, retrospective single-center review of cerebrospinal fluid (CSF) studies in children, 1 month to 21 years old, evaluated for suspected CNS infection from 2004 to 2014. Cases of suspected nosocomial meningitis were excluded. The frequency of N-methyl-D-aspartate receptor antibody (NMDAR ab) encephalitis was analyzed from 2010 to 2014.

RESULTS

A total of 940 unique patient visits with CSF studies were included in the final analysis. There were 940 bacterial cultures sent; 4 (0.42%) grew suspected CSF bacterial pathogens, and 18 (1.9%) grew organisms that were suspected contaminants. Bacterial pathogens included late-onset group B Streptococcus in 3 infants younger than 3 months and Streptococcus pneumoniae in an unvaccinated 9-year-old child. Viral CNS infection was 7.5 times more frequent than bacterial infection. Enterovirus was the only virus isolated. Five cases positive for NMDAR ab were identified since 2010.

CONCLUSIONS

Bacterial studies were performed more frequently than viral and other studies. Cerebrospinal fluid bacterial culture was nearly 5 times more likely to yield a contaminant than a pathogen. The frequency of viral infection was likely underestimated as only 20% were tested, mainly by culture, which is suboptimal. These data suggest diagnostic practices for the evaluation of suspected community-acquired CNS infections in children need to be modified to reflect current epidemiology and highlight the need for greater accessibility to polymerase chain reaction for viral diagnostics. Furthermore, NMDAR ab-mediated encephalitis should be considered early in children presenting with suggestive symptoms.

Viral (aseptic) meningitis: A review

Viral meningitis is an inflammation of the meninges associated with acute onset of meningeal symptoms and fever, pleocytosis of the cerebrospinal fluid, and no growth on routine bacterial culture. It is sometimes associated with viral encephalitis and meningoencephalitis. Viruses reach the central nervous system (CNS) hematogenously or in a retrograde manner from nerve endings. The viral etiology varies according to age and country. Molecular diagnostics technology has helped improve the rate of pathogen detection reducing unnecessary antibiotic use and length of hospitalization. Most of the viral infections detailed in this article have no specific treatment other than supportive care. Many of the viruses discussed are preventable by vaccination and proper skin protection against transmitting vectors.

Risk Classification for Enteroviral Infection in Children With Meningitis and Negative Gram Stain

OBJECTIVES

Enterovirus is the most common cause of aseptic meningitis in children. This study aimed at identifying baseline variables associated with a positive cerebrospinal fluid (CSF) Enterovirus polymerase chain reaction (PCR) to aid clinicians in targeting patients who could be tested and treated as outpatients.

METHODS

We performed a retrospective review of children (2 months to 17 years old) admitted to the Children's Memorial Hermann Hospital in Houston, TX, between January 2005 and December 2010 with symptoms of meningitis, CSF white cell count of greater than 5 cells/mm, and a negative CSF Gram stain, who had a CSF Enterovirus PCR.

RESULTS

One hundred thirty-seven children were reviewed; median age was 4.7 (0.1-17.1) years, and 79 (58%) were male. Fifty patients (37%) had positive CSF Enterovirus PCR. Only 13 (15%) of the Enterovirus PCR-negative patients had an identifiable etiology. All patients were hospitalized. The mean hospital stay for patients with Enterovirus was 2.9 days; 88% received empiric antibiotics. Rates of antibiotic administration were not different between PCR-positive and PCR-negative groups (P > 0.05). All patients with Enterovirus had a favorable clinical outcome.A predictive model was created using 3 baseline variables independently associated with a positive Enterovirus PCR (P < 0.05): May to November presentation, CSF protein of less than 100 mg/dL, and absence of focal neurologic signs. The model classified patients into 2 risk categories for a positive Enterovirus PCR (low risk, 0% [0/17 patients]; high risk, 42% [50/120 patients]; P < 0.001).

CONCLUSIONS

Our predictive model can be used to identify children for whom Enterovirus PCR testing is warranted. Such testing could avoid unnecessary hospitalization and antibiotic administration.

Incidence, aetiology, and sequelae of viral meningitis in UK adults: a multicentre prospective observational cohort study

BACKGROUND

Viral meningitis is increasingly recognised, but little is known about the frequency with which it occurs, or the causes and outcomes in the UK. We aimed to determine the incidence, causes, and sequelae in UK adults to improve the management of patients and assist in health service planning.

METHODS

We did a multicentre prospective observational cohort study of adults with suspected meningitis at 42 hospitals across England. Nested within this study, in the National Health Service (NHS) northwest region (now part of NHS England North), was an epidemiological study. Patients were eligible if they were aged 16 years or older, had clinically suspected meningitis, and either underwent a lumbar puncture or, if lumbar puncture was contraindicated, had clinically suspected meningitis and an appropriate pathogen identified either in blood culture or on blood PCR. Individuals with ventricular devices were excluded. We calculated the incidence of viral meningitis using data from patients from the northwest region only and used these data to estimate the population-standardised number of cases in the UK. Patients self-reported quality-of-life and neuropsychological outcomes, using the EuroQol EQ-5D-3L, the 36-Item Short Form Health Survey (SF-36), and the Aldenkamp and Baker neuropsychological assessment schedule, for 1 year after admission.

FINDINGS

1126 patients were enrolled between Sept 30, 2011, and Sept 30, 2014. 638 (57%) patients had meningitis: 231 (36%) cases were viral, 99 (16%) were bacterial, and 267 (42%) had an unknown cause. 41 (6%) cases had other causes. The estimated annual incidence of viral meningitis was 2·73 per 100 000 and that of bacterial meningitis was 1·24 per 100 000. The median length of hospital stay for patients with viral meningitis was 4 days (IQR 3-7), increasing to 9 days (6-12) in those treated with antivirals. Earlier lumbar puncture resulted in more patients having a specific cause identified than did those who had a delayed lumbar puncture. Compared with the age-matched UK population, patients with viral meningitis had a mean loss of 0·2 quality-adjusted life-years (SD 0·04) in that first year.

INTERPRETATION

Viruses are the most commonly identified cause of meningitis in UK adults, and lead to substantial long-term morbidity. Delays in getting a lumbar puncture and unnecessary treatment with antivirals were associated with longer hospital stays. Rapid diagnostics and rationalising treatments might reduce the burden of meningitis on health services.

FUNDING

Meningitis Research Foundation and UK National Institute for Health Research.

Management of acute meningitis

Acute meningitis remains a devastating disease. Clinicians need a low threshold for suspecting meningitis, to undertake appropriate investigations and provide treatment in a timely manner, to minimise the risk of poor outcome in bacterial disease, while limiting unnecessary treatment in viral meningitis.

Viral meningitis: current issues in diagnosis and treatment

PURPOSE OF REVIEW

The purpose of this review is to give an overview of viral meningitis and then focus in on some of the areas of uncertainty in diagnostics, treatment and outcome.

RECENT FINDINGS

Bacterial meningitis has been declining in incidence over recent years. Over a similar time period molecular diagnostics have increasingly been used. Because of both of these developments viral meningitis is becoming relatively more important. However, there are still many unanswered questions. Despite improvements in diagnostics many laboratories do not use molecular methods and even when they are used many cases still remain without a proven viral aetiology identified. There are also no established treatments for viral meningitis and the one potential treatment, aciclovir, which is effective in vitro for herpes simplex virus, has never been subjected to a clinical trial.

SUMMARY

Viruses are in increasingly important cause of meningitis in the era of declining bacterial disease. The exact viral aetiology varies according to age and country. Molecular diagnostics can not only improve the rate of pathogen detection but also reduce unnecessary antibiotics use and length of hospitalization. Further research is required into treatments for viral meningitis and the impact in terms of longer term sequelae.

Incidence, Predictors, and Outcomes of Ventriculostomy-Associated Infections in Spontaneous Intracerebral Hemorrhage

BACKGROUND

The impact of ventriculostomy-associated infections (VAI) on intracerebral hemorrhage (ICH) outcomes has not been clearly established, although prior studies have attempted to address the incidence and predictors of VAI. We aimed to explore VAI characteristics and its effect on ICH outcomes at a population level.

METHODS

ICH patients requiring ventriculostomy with and without VAI were identified from 2002 to 2011 Nationwide Inpatient Sample using ICD-9 codes. A retrospective cohort study was performed. Demographics, comorbidities, hospital characteristics, inpatient outcomes, and resource utilization measures were compared between the two groups. Pearson's Chi-square and Wilcoxon-Mann-Whitney tests were used for categorical and continuous variables, respectively. Logistic regression was used to analyze the predictors of VAI.

RESULTS

We included 34,238 patients in the analysis, of whom 1934 (5.6 %) had VAI. The rate of ventriculostomy utilization in ICH increased from 5.7 % in 2002-2003 to 7.0 % in 2010-2011 (trend p < 0.001) and the rate of VAI also showed a gradual upward trend from 6.1 to 7.0 % across the same interval (trend p < 0.001). The VAI group had significantly higher inpatient mortality (41.2 vs. 36.5 %, p < 0.001) and it remained higher after controlling for baseline demographics, hospital characteristics, comorbidity, and systemic infections (adjusted OR 1.38, 95 % CI 1.22-1.46, p < 0.001). The VAI group had longer length of hospital stay and higher inflation adjusted cost of care. Predictors of VAI included higher age, males, higher Charlson's comorbidity scores, longer length of stay, and presence of systemic infections mainly pneumonia and sepsis.

CONCLUSION

VAI resulted in higher inpatient mortality, more unfavorable discharge disposition, and higher resource utilization measures in ICH patients. Steps to mitigate VAI may help improve ICH outcomes and decrease hospital costs.

The UK joint specialist societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults

Bacterial meningitis and meningococcal sepsis are rare conditions with high case fatality rates. Early recognition and prompt treatment saves lives. In 1999 the British Infection Society produced a consensus statement for the management of immunocompetent adults with meningitis and meningococcal sepsis. Since 1999 there have been many changes. We therefore set out to produce revised guidelines which provide a standardised evidence-based approach to the management of acute community acquired meningitis and meningococcal sepsis in adults. A working party consisting of infectious diseases physicians, neurologists, acute physicians, intensivists, microbiologists, public health experts and patient group representatives was formed. Key questions were identified and the literature reviewed. All recommendations were graded and agreed upon by the working party. The guidelines, which for the first time include viral meningitis, are written in accordance with the AGREE 2 tool and recommendations graded according to the GRADE system. Main changes from the original statement include the indications for pre-hospital antibiotics, timing of the lumbar puncture and the indications for neuroimaging. The list of investigations has been updated and more emphasis is placed on molecular diagnosis. Approaches to both antibiotic and steroid therapy have been revised. Several recommendations have been given regarding the follow-up of patients.

Epidemiology of meningitis with a negative CSF Gram stain: under-utilization of available diagnostic tests

Meningitis with a negative cerebrospinal fluid Gram stain (CSF-GS) poses a diagnostic challenge as more than 50% of patients remain without an aetiology. The introduction of polymerase chain reaction (PCR) and arboviral serologies have increased diagnostic capabilities, yet large scale epidemiological studies evaluating their use in clinical practice are lacking. We conducted a prospective observational study in New Orleans between November 1999 and September 2008 (early era) when PCR was not widely available, and in Houston between November 2008 and June 2013 (modern era), when PCR was commonly used. Patients presenting with meningitis and negative CSF-GS were followed for 4 weeks. All investigations, PCR used, and results were recorded as they became available. In 323 patients enrolled, PCR provided the highest diagnostic yield (24·2%) but was ordered for 128 (39·6%) patients; followed by serology for arboviruses (15%) that was ordered for 100 (31%) of all patients. The yield of blood cultures was (10·3%) and that of CSF cultures was 4%; the yield for all other tests was <10%. Overall, 65% of the patients remained without a diagnosis at 4 weeks: 72·1% in early era vs. 53·4% (P < 0·01) in modern era; this change was attributed to diagnosing more viral pathogens, 8·3% and 26·3% (P < 0·01), respectively. The introduction of PCR and arboviral serologies has improved the yield of diagnosing patients with meningitis and a negative CSF-GS, but both tests are being under-utilized.

Neuroepidemiology and the epidemiology of viral infections of the nervous system

The field of neurovirology will undoubtedly experience evolution and change in the years to come. The epidemiology of viral CNS diseases continues to change, and as our understanding of the pathogenesis and pathophysiology associated with viral agents grows, so does our understanding of the behavior of these pathogens among populations. The appearance of viral pathogens in newsettings, new or unrecognized modes of transmission,and the emergence of previously unrecognized pathogens will continue to challenge our laboratory diagnostic and epidemiologic capabilities. However, each lesson that is learned from this evolving epidemiology will hopefully result in improved surveillance, diagnostic,and treatment and prevention capabilities.

Enterovirus infections in England and Wales, 2000-2011: the impact of increased molecular diagnostics

There have recently been significant changes in diagnostic practices for detecting enterovirus (EV) infections across England and Wales. Reports of laboratory-confirmed EV infections submitted by National Health Service (NHS) hospital laboratories to Public Health England (PHE) over a 12-year period (2000-2011) were analysed. Additionally, the PHE Virus Reference Department (VRD) electronic database containing molecular typing data from 2004 onwards was interrogated. Of the 13,901 reports, there was a decline from a peak of 2254 in 2001 to 589 in 2006, and then an increase year-on-year to 1634 in 2011. This increase coincided with increasing PCR-based laboratory diagnosis, which accounted for 36% of reported cases in 2000 and 92% in 2011. The estimated annual incidence in 2011 was 3.9/100,000 overall and 238/100,000 in those aged <3 months, who accounted for almost one-quarter of reported cases (n = 2993, 23%). During 2004-2011, 2770 strains were submitted for molecular typing to the VRD, who found no evidence for a predominance of any particular strain. Thus, the recent increase in reported cases closely reflects the increase in PCR testing by NHS hospitals, but is associated with a lower proportion of samples being submitted for molecular typing. The high EV rate in young infants merits further investigation to inform evidence-based management guidance.

Underreporting of viral encephalitis and viral meningitis, Ireland, 2005-2008

Viral encephalitis (VE) and viral meningitis (VM) have been notifiable infectious diseases under surveillance in the Republic of Ireland since 1981. Laboratories have reported confirmed cases by detection of viral nucleic acid in cerebrospinal fluid since 2004. To determine the prevalence of these diseases in Ireland during 2005–2008, we analyzed 3 data sources: Hospital In-patient Enquiry data (from hospitalized following patients discharge) accessed through Health Intelligence Ireland, laboratory confirmations from the National Virus Reference Laboratory, and events from the Computerised Infectious Disease Reporting surveillance system. We found that the national surveillance system underestimates the incidence of these diseases in Ireland with a 10-fold higher VE hospitalization rate and 3-fold higher VM hospitalization rate than the reporting rate. Herpesviruses were responsible for most specified VE and enteroviruses for most specified VM from all 3 sources. Recommendations from this study have been implemented to improve the surveillance of these diseases in Ireland.

Time trends of viral meningitis among young adults in Israel: 1978-2012

Viral meningitis (VM) is a medical condition of public health concern, as it is a common sporadic and epidemic illness. However, there is limited data on the epidemiology of VM. The purpose of this study was to analyze long-term and seasonal trends of VM in a young adult military population. VM is a obligatory notifiable disease in the Israel Defense Forces. For the present study, the archives of the Army Health Branch were reviewed for all cases of VM from January 1, 1978 to December 31, 2012, and the annual, monthly, and seasonal rates were calculated. The annual incidence over the 35-year period showed a high peak every 3-5 years followed by a quiescent period of 2-3 years, reaching as high as 58.4 per 100,000 in 1980 and as low as 3.0 per 100,000 in 2005. This cyclic pattern has diminished over the last decade, reflected by a decline in mean incidence (10.46 per 100,000 in 2003-2012 compared to 19.79 per 100,000 in 1978-2002). Average monthly rates ranged from 1.0 cases per 100,000 soldiers in January/February to 2.2 per 100,000 in July/August. The difference in average rates between winter (1.2 cases per 100,000) and summer (1.9 cases per 100,000) was statistically significant (p < 0.001). Analysis of the long-term epidemiology of VM shows an epidemic pattern, with predominance in the warmer months. Identifying viral causes of meningitis may spare patients unnecessary treatment while prompting the introduction of public health interventions and control measures, especially in crowded settings.

Cerebrospinal fluid TNF-α, IL-6, and IL-8 in children with bacterial meningitis

OBJECTIVE

We evaluated the levels of cerebrospinal fluid concentrations of tumor necrosis factor-α, interleukin-6, and interleukin-8 in bacterial meningitis in children.

METHODS

The study included children up to 14 years of age admitted to a pediatric ward with fever, headache, vomiting, and seizures. The diagnosis of bacterial meningitis was based on clinical features: physical examination, blood and cerebrospinal fluid cytochemical findings, Gram stain, and bacterial culture. The cerebrospinal fluid levels of tumor necrosis factor-α, interleukin-6, and interleukin-8 were measured in 57 children with bacterial meningitis, 15 with viral meningitis, and 15 controls by enzyme-linked immunosorbent assay methods.

RESULTS

The mean concentrations of cerebrospinal fluid, tumor necrosis factor-α, interleukin-6, and interleukin-8 were 1108 ± 183, 652 ± 287, and 442 ± 120 pg/mL, respectively, in children with bacterial meningitis and were significantly increased in those in the viral meningitis group (tumor necrosis factor-α : 711 ± 105, IL-6 : 272 ± 161, IL-8 : 175 ± 62 pg/mL; P < 0.001) or control (390 ± 37, 59 ± 17, 19 ± 13 pg/mL, respectively, P < 0.001). At optimum cutoff level based on the receiver operating characteristic curve, cerebrospinal fluid cytokines (tumor necrosis factor-α, interleukin-6, and interleukin-8) showed sensitivity and specificity of 100% for the diagnosis of bacterial meningitis. For differentiation of bacterial from viral meningitis, cerebrospinal fluid level of tumor necrosis factor-α, IL-6, and IL-8 showed sensitivity and specificity of 94.7% and 86.7%, 80.7% and 53.3%, and 89.5% and 86.7%, respectively.

CONCLUSION

The increased concentration of cerebrospinal fluid tumor necrosis factor-α, interleukin-6, and interleukin-8 in children with meningitis suggests a role in the pathogenesis of bacterial meningitis and these levels might prove to be useful in children whose diagnosis is in question.

Meningitis

Meningitis is defined as inflammation of the meninges, in almost all cases identified by an abnormal number of white blood cells in the cerebrospinal fluid and specific clinical signs/symptoms. Onset may be acute or chronic, and clinical symptoms of acute disease develop over hours to days. This article reviews the epidemiology, pathophysiology, clinical manifestations, diagnosis, and management of acute meningitis, and provides a list of key points for primary care practitioners. Aseptic and bacterial meningitis vary significantly and are discussed separately.

Role of biomarkers in the management of antibiotic therapy: an expert panel review II: clinical use of biomarkers for initiation or discontinuation of antibiotic therapy

Biomarker-guided initiation of antibiotic therapy has been studied in four conditions: acute pancreatitis, lower respiratory tract infection (LRTI), meningitis, and sepsis in the ICU. In pancreatitis with suspected infected necrosis, initiating antibiotics best relies on fine-needle aspiration and demonstration of infected material. We suggest that PCT be measured to help predict infection; however, available data are insufficient to decide on initiating antibiotics based on PCT levels. In adult patients suspected of community-acquired LRTI, we suggest withholding antibiotic therapy when the serum PCT level is low (<0.25 ng/mL); in patients having nosocomial LRTI, data are insufficient to recommend initiating therapy based on a single PCT level or even repeated measurements. For children with suspected bacterial meningitis, we recommend using a decision rule as an aid to therapeutic decisions, such as the Bacterial Meningitis Score or the Meningitest®; a single PCT level ≥0.5 ng/mL also may be used, but false-negatives may occur. In adults with suspected bacterial meningitis, we suggest integrating serum PCT measurements in a clinical decision rule to help distinguish between viral and bacterial meningitis, using a 0.5 ng/mL threshold. For ICU patients suspected of community-acquired infection, we do not recommend using a threshold serum PCT value to help the decision to initiate antibiotic therapy; data are insufficient to recommend using PCT serum kinetics for the decision to initiate antibiotic therapy in patients suspected of ICU-acquired infection. In children, CRP can probably be used to help discontinue therapy, although the evidence is limited. In adults, antibiotic discontinuation can be based on an algorithm using repeated PCT measurements. In non-immunocompromised out- or in- patients treated for RTI, antibiotics can be discontinued if the PCT level at day 3 is < 0.25 ng/mL or has decreased by >80-90%, whether or not microbiological documentation has been obtained. For ICU patients who have nonbacteremic sepsis from a known site of infection, antibiotics can be stopped if the PCT level at day 3 is < 0.5 ng/mL or has decreased by >80% relative to the highest level recorded, irrespective of the severity of the infectious episode; in bacteremic patients, a minimal duration of therapy of 5 days is recommended.

Serum procalcitonin in septic meningitis

OBJECTIVE

To evaluate the role of serum procalcitonin (PCT) in diagnosis of septic meningitis in children and its efficacy in differential diagnosis.

METHODS

The study included 40 children of septic meningitis admitted in pediatric ward with fever, headache, vomiting and seizure, up to 14 y of age. The diagnosis of septic meningitis was based on clinical features; physical examination, blood and cerebrospinal fluid (CSF) cytochemical findings, gram's stain and bacterial culture. Fifteen cases of aseptic meningitis admitted during same period were also included in the study, and 15 children with normal CSF were taken as control. Serum PCT was measured by ELISA Kit.

RESULTS

Serum PCT level was significantly higher in children with septic meningitis than those with aseptic meningitis or in controls (p < 0.001). In culture and gram's stain positive 7 cases, serum procalcitonin was significantly elevated (24,768.21 ± 6,567.45 pg/mL) than aseptic meningitis(14,451.24 ± 4,266.15 pg/mL) (p < 0.001). Further its level was found significantly elevated in partially treated septic meningitis as compared to aseptic meningitis cases (p < 0.001). At optimum cut off value of ≥ 5,000 pg/mL, based on area under ROC curve, PCT showed sensitivity, specificity, positive predictive value and negative predictive value of 98.5 %, 93.5 %, 98.6 % and 93.3 % respectively. Serum PCT with cut off level of 15,000 pg/ml showed sensitivity, specificity, PPV and NPV of 92 %, 67 %, 91.4 % and 71.4 % respectively for the differentiation of septic from aseptic meningitis.

CONCLUSIONS

Serum PCT may be used as diagnostic marker for septic meningitis and its differentiation from aseptic meningitis.

Central nervous system infections among individuals with and without end-stage renal disease

OBJECTIVES

Individuals with immunodeficiencies are at increased risk of central nervous system (CNS) infections. Data are limited on the risk of CNS infections in patients with end-stage renal disease (ESRD).

METHODS

We conducted a population-based, nationwide cohort study among ESRD patients from 1990 to 2009. Data on ESRD patients was obtained from the Danish Nephrology Registry database. Each ESRD patient was matched with up to 19 population controls. Using the National Hospital Registry we identified hospital admissions with CNS infection as primary discharge diagnosis.

RESULTS

The study included 13,374 ESRD patients and 245,397 population controls, providing 67,012 person-years and 2,237,237 person-years of observation, respectively. The overall incidence rate (IR) of first-time hospitalisation for CNS infection was 149 per 100,000 person-years (95%-confidence interval [CI], 123-181) among ESRD patients. The IR of CNS infection was comparable among dialysis and transplant patients. Compared to population controls, the incidence rate-ratio of first CNS infection was 5.58 (95%-CI, 4.47-6.91) for ESRD patients in general. The 30-day mortality following hospitalisation for CNS infections was 21% (95%-CI, 14-30) among ESRD patients and 13% (95%-CI, 10-16) among population controls.

CONCLUSIONS

ESRD patients have considerable excess risk and mortality from CNS infections, which is of great clinical and public health concern.

U.S. emergency department visits for meningitis, 1993-2008

OBJECTIVES

Large-scale epidemiologic studies of meningitis in the emergency department (ED) setting are lacking. Using a nationwide sample, the authors determined the frequency of meningitis visits and characterize management.

METHODS

Using National Hospital Ambulatory Medical Care Survey (NHAMCS) data, 1993 through 2008, meningitis diagnoses were studied and national rates were estimated via standard weighting procedures.

RESULTS

Meningitis was diagnosed at 1,048,000 visits (95% confidence interval [CI] = 893,000 to 1,203,000) during 1993 through 2008. This is 66,000 cases annually, or 62 per 100,000 visits, with no change over time (p = 0.20). ED diagnoses were unspecified (60%), viral (31%), bacterial (8%), and fungal (1%) meningitis. Median age was 24 years (interquartile range = 9 to 40 years). While 1.97 times as many adults were diagnosed with meningitis (95% CI = 1.83 to 2.13), meningitis accounted for a similar proportion of visits among children and adults (ratio = 1.33, 95% CI = 0.58 to 2.63). Per population, children were more likely to have a meningitis visit (31 vs. 21 per 100,000; ratio = 1.48, 95% CI =1.003 to 2.10); children aged younger than 3 years had the highest rate (98 per 100,000, 95% CI =63 to 133). Spring and summer visits were 1.25 times as numerous as fall a nd winter (95% CI= 1.15 to 1.36). Third-generation cephalosporins were administered in 42%, analgesics in 19%, and antiemetics in 15% of cases, and 66% were admitted to the hospital (95% CI= 58% to 73%).

CONCLUSIONS

Meningitis is rare, diagnosed at 62 per 100,000 ED visits. Rates have been stable over time. Children are 1.48 times more likely to have a visit for meningitis, although adults make twice as many visits. Absence of consensus guidelines for patients suspected of having viral meningitis but being tested for bacterial meningitis may lead to variability in admission and prescribing decisions.

Headaches attributable to infectious diseases

Headache is the most common symptom that humans experience. While the vast majority of headaches are due to benign primary headache disorders, a small but important minority of headaches are due to secondary causes. Whereas significant emphasis is placed on educating physicians regarding prompt recognition of subarachnoid hemorrhage and headaches secondary to brain tumors, attention toward headaches secondary to infectious causes is often neglected. Unfortunately, a missed or delayed diagnosis of a headache secondary to meningitis, encephalitis, brain abscess, subdural empyema, or other infectious etiologies can lead to dire consequences for both the patient and physician. Accordingly, this article provides an overview of headaches attributed to systemic and intracranial infectious causes.

Acute Urinary Retention due to Aseptic Meningitis: Meningitis-Retention Syndrome

Acute urinary retention in aseptic meningitis is rarely encountered, and the diagnosis of aseptic meningitis may be less than straightforward, because its symptoms and neurological signs are occasionally mild or absent. We report a case in which acute urinary retention provided an appropriate indication for the diagnosis of aseptic meningitis as the cause of an undiagnosed fever.

Clinical decision rules for evaluating meningitis in children

PURPOSE OF REVIEW

Distinguishing between bacterial and aseptic meningitis in children is sometimes difficult. Guidelines recommend that patients with acute meningitis be systematically hospitalized and treated with antibiotics until the cerebrospinal fluid culture results are available. This strategy ensures rapid treatment for bacterial meningitis, but also involves unnecessary admissions and antibiotics for aseptic meningitis. Some authors have, therefore, proposed different combinations of predictors in clinical decision rules to distinguish as early as possible between bacterial and aseptic meningitis. To be useful, these rules must have near-100% sensitivity for bacterial meningitis, good specificity (to reduce unnecessary antibiotics and admissions), and easy bedside application.

RECENT FINDINGS

The present review examines the performance and level of validation of decision rules proposed after the Haemophilus influenzae vaccination entered widespread use. Most of these rules have been validated incompletely, if at all. Only one rule incorporates the best single validated predictive marker for distinguishing between bacterial and aseptic meningitis in children: serum procalcitonin level.

SUMMARY

Two rules are highly promising, meeting the three major conditions after a retrospective validation process in large samples. These rules can be applied cautiously to patients with the same inclusion and exclusion criteria as those in the derivation sets, while awaiting prospective multicenter validation studies.

Resolving ambiguities in genetic typing of human enterovirus species C clinical isolates and identification of enterovirus 96, 99 and 102

Molecular methods, based on sequencing the region encoding the VP1 major capsid protein, have recently become the gold standard for enterovirus typing. In the most commonly used scheme, sequences more than 75% identical (>85% amino acid identity) in complete or partial VP1 sequence are considered to represent the same type. However, as sequence data have accumulated, it has become clear that the '75%/85% rule' may not be universally applicable. To address this issue, we have determined nucleotide sequences for the complete P1 capsid region of a collection of 53 isolates from the species Human enterovirus C (HEV-C), comparing them with each other and with those of 20 reference strains. Pairwise identities, similarity plots and phylogenetic reconstructions identified three potential new enterovirus types, EV96, EV99 and EV102. When pairwise sequence comparisons were considered in aggregate, there was overlap in percentage identity between comparisons of homotypic strains and heterotypic strains. In particular, the differences between coxsackievirus (CV) A13 and CVA17, CVA24 and EV99, and CVA20 and EV102 were difficult to discern, largely because of intratypic sequence diversity. Closer inspection revealed the minimum intratypic values and maximum intratypic values varied by type, suggesting that the rules were at least consistent within a type. By plotting VP1 amino acid identity vs nucleotide identity for each sequence pair and considering each type separately, members of each type were fully resolved from those of other types. This study suggests that a more stringent value of 88% VP1 amino acid identity is more appropriate for routine typing and that other criteria may need to be applied, on a case by case basis, where lower values are seen.

Sensitivity of the bacterial meningitis score in 889 children with bacterial meningitis

OBJECTIVE

To validate sensitivity of the bacterial meningitis score (BMS) in a large population of children with bacterial meningitis (BM).

STUDY DESIGN

Secondary analysis of prospective data for children presenting with BM to a hospital emergency department between January 2001 and February 2005. The BMS was applied to all children with acute BM using the same inclusion criteria proposed by the authors of the rule. The sensitivity of the rule was calculated.

RESULTS

Of the 900 children aged 29 days to 18 years with acute BM who met all inclusion criteria, 889 had enough data for assigning the BMS. Use of the BMS correctly identified 884 children with BM, for 99.6% sensitivity (95% confidence interval: 98.9% to 99.8%).

CONCLUSIONS

The sensitivity of the BMS to detect disease was very high, but a few cases of BM were missed. Further refinements of the BMS may be warranted to lower the false-negative rate.

Increased detection rate in diagnosis of herpes simplex virus type 2 meningitis by real-time PCR using cerebrospinal fluid samples

Efficient and sensitive diagnostic methods are needed in the management of virus infections in the central nervous system. There is a demand for an evaluation of the sensitivity of PCR methods for early diagnosis of meningitis due to herpes simplex type 2 (HSV-2) and varicella-zoster virus (VZV). The objective of this study was to evaluate real-time PCR in the detection of HSV-2 and VZV DNA from cerebrospinal fluid (CSF) for etiological diagnoses in clinically well-characterized cases of primary and recurrent aseptic meningitis. Samples from 110 patients, 65 of whom were diagnosed with or were strongly suspected of having HSV-2 meningitis and 45 with acute aseptic meningitis of unknown causes, were analyzed. Results were compared with the outcome of nested PCR for HSV-2 infection. Clinical parameters were analyzed in relation to CSF viral load. With real-time PCR, HSV-2 DNA was found in CSF from 80% (52/65) of patients with clinical HSV-2 meningitis compared to 72% (47/65) found by nested PCR. The sensitivity of real-time HSV-2 PCR was found to be 87% (33/38) in primary and 70% (19/27) in recurrent meningitis. The HSV-2 viral load was significantly higher in primary than in recurrent meningitis and correlated with the degree of inflammation. VZV DNA was detected in 2 of 45 samples (4.4%). Real-time PCR for the diagnosis of HSV-2 meningitis was evaluated in a large, clinically well-characterized sample of material and found to identify more cases than nested PCR in the group of patients with recurrent meningitis. Quantification of DNA enables further research of disease prognosis and treatment.