Accuracy of the cerebrospinal fluid results to differentiate bacterial from non bacterial meningitis, in case of negative gram-stained smear

Role of inflammatory markers in the assessment of meningitis in adult patients with fever and headache

BACKGROUND

Meningitis, especially of bacterial origin, is a medical emergency that must be diagnosed promptly. However, due to the associated risks of complications of lumbar puncture, it is crucial to identify individuals who truly need it. The aim of this study was to assess the diagnostic role of inflammatory markers in distinguishing among patients without meningitis, those with aseptic meningitis, and those with bacterial meningitis.

METHODS

This was a retrospective, diagnostic study at an acute care hospital, involving adult patients who presented to either ambulatory care or the emergency department with fever and headache, but without altered mental status or neurological deficits. Inflammatory markers (C-reactive protein [CRP], mean platelet volume, neutrophil-lymphocyte ratio, and red cell distribution width) were assessed as index tests. An expert panel classified patients into three groups: no meningitis, aseptic meningitis, and bacterial meningitis using predefined criteria.

RESULTS

Of the 80 patients, 52 had no meningitis, 27 had aseptic meningitis, and 1 had bacterial meningitis. Of the inflammatory markers investigated, only CRP showed potential usefulness in differentiating these three diagnostic groups, with median values of 5.6 (interquartile range [IQR] 2.1, 11.3) mg/dL in those without meningitis, 0.2 (IQR 0.1, 1.2) mg/dL in those with aseptic meningitis, and notably elevated at 21.7 mg/dL in the patient with bacterial meningitis.

CONCLUSION

In adult patients presenting with fever and headache in an emergency setting, CRP was the only marker that demonstrated potential diagnostic utility in distinguishing among those with no meningitis, aseptic meningitis, and bacterial meningitis.

Diagnostic accuracy of procalcitonin for bacterial infection in the Emergency Department: a systematic review

INTRODUCTION AND OBJECTIVE

The care of patients with a suspected infectious process in hospital emergency departments (ED) accounts for 15%-35% of all daily care in these healthcare areas in Spain and Latin America. The early and adequate administration of antibiotic treatment (AB) and the immediate making of other diagnostic-therapeutic decisions have a direct impact on the survival of patients with severe bacterial infection. The main objective of this systematic review is to investigate the diagnostic accuracy of PCT to predict bacterial infection in adult patients treated with clinical suspicion of infection in the ED, as well as to analyze whether the different studies manage to identify a specific value of PCT as the most relevant from the diagnostic point of view of clinical decision that can be recommended for decision making in ED.

METHOD

A systematic review is carried out following the PRISMA regulations in the database of PubMed, Web of Science, EMBASE, Lilacs, Cochrane, Epistemonikos, Tripdatabase and ClinicalTrials.gov from January 2005 to May 31, 2023 without language restriction and using a combination of MESH terms: "Procalcitonin", "Infection/Bacterial Infection/Sepsis", "Emergencies/Emergency/Emergency Department", "Adults" and "Diagnostic". Observational cohort studies (diagnostic performance analyses) were included. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the method used and the risk of bias of the included articles. Observational cohort studies were included. No meta-analysis techniques were performed, but results were compared narratively.

RESULTS

A total of 1,323 articles were identified, of which 21 that met the inclusion criteria were finally analyzed. The studies include 10,333 patients with 4,856 bacterial infections (47%). Eight studies were rated as high, 9 as moderate, and 4 as low. The AUC-ROC of all studies ranges from 0.68 (95% CI: 0.61-0.72) to 0.99 (95% CI: 0.98-1). The value of PCT 0.2-0.3 ng/ml is the most used and proposed in up to twelve of the works included in this review whose average estimated performance is an AUC-ROC of 0.79. If only the results of the 5 high-quality studies using a cut-off point of 0.2-0.3 ng/ml PCT are taken into account, the estimated mean AUC-COR result is 0.78 with Se:69 % and Es:76%.

CONCLUSIONS

PCT has considerable diagnostic accuracy for bacterial infection in patients treated in ED for different infectious processes. The cut-off point of 0.25 (0.2-0.3) ng/ml has been positioned as the most appropriate to predict the existence of bacterial infection and can be used to help reasonably rule it out.

A Prospective Observational Study of Children with FS-Associated Hospitalization: The Implication and Outcomes of Pathogen Detection in Cerebrospinal Fluid

Background

Febrile seizures (FS) are a common cause of paediatric emergencies, but research on their aetiology and epidemiology are limited. The aim of this study was to investigate the prevalence of central nervous system (CNS) pathogenic infections in patients with FS-associated hospitalization.

Methods

A prospective observational study was conducted in children under 16 years of age with FS-associated hospitalization. Demographic, clinical and laboratory data were recorded. Multiplex-PCR was performed on cerebrospinal fluid (CSF) samples for nine viruses, nine bacteria and one fungus.

Results

A total of 119 children were enrolled between June 2021 and June 2022. Of these, 83.2% had a final diagnosis of FS (69.7%) or FS plus (13.4%). In addition, epilepsy and encephalitis/meningitis were also found in 16.8% (20/119). Seven pathogens were identified from 9 CSF samples (7.6%), including viruses (EV, EBV, HHV-6) and bacteria (H. influenzae, S. pneumoniae, M. tuberculosis, S. putrefaciens). There were no significant clinical or laboratory differences between children who tested positive or negative for pathogens in the CSF, except for the presentation of herpes pharyngitis. Children with encephalitis/meningitis had longer hospital stays compared with those diagnosed with FS at discharge; abnormal EEG findings were significantly more common in patients with epilepsy.

Conclusion

FS-associated hospitalized children may have viral or bacterial intracranial infections. Pathogen testing of CSF is an important basis for timely antibiotic or antiviral therapy when clinical and laboratory findings make FS indistinguishable from other CNS disorders.

Aseptic Meningitis and Its Viral Etiologies, Clinical Characteristics and Management Practices in Children: A Retrospective Hospital-Based Study From Jordan

Purpose In this study, we aimed to describe the clinical characteristics, laboratory findings, aetiologies, and role of PCR in the decision on the management plan and duration of hospital stay in Jordanian children diagnosed with aseptic meningitis. Methods This retrospective observational cohort study included children diagnosed with meningitis who were admitted to the paediatric ward at Jordan University Hospital (JUH) during the period from January 2016 to August 2020. Patients were identified through the ICD9 discharge code of meningitis. Patients diagnosed with aseptic meningitis (defined as a patient with signs and symptoms of meningitis with a cerebrospinal fluid (CSF) white cell count of >5 cells/mm3, and a negative CSF Gram stain) were included, while patients who had low CSF glucose (<50% of serum) positive cerebrospinal fluid Gram stain and/or culture for bacterial meningitis were excluded. Files were reviewed to collect data on the clinical picture, viruses identified by the CSF viral polymerase chain reaction (PCR) panel, duration of medication, and hospital stay in patients with identified virus versus those with negative viral PCR. Results One hundred and thirty-one patients were included: 87 males (66.4%) and 44 females (33.5%). Fever was the most common presenting symptom, followed by headache, vomiting, and excessive sleep in 48.0%, 42.7%, and 35.8% of the patients, respectively. Prior oral antibiotic use was reported in 48/125 (38.4%) patients. White blood cell count (WBC) ranged from 4.800 to 22.000. cells/mL, 45 patients (34.3%) had counts above 15.000 cells/mL. C-reactive protein level was high in 61/103 (59.2%) patients. CSF WBC count was <100 in 62 (47.3%) patients while neutrophils predominance of >70% was present in 27 (20.6%) patients. Viral panel PCR was done for 100/131 (76.3%) patients and was positive in 66/100 (66%) patients; with enterovirus being the most common identified viruses (60/100; 60%). The average duration of hospital stay was 5.9 and 5.5 days for those with negative and positive PCR respectively. Ten (7.6%) patients had seizures upon presentation. None of the patients had any neurological sequel related to his meningitis. Conclusion Enteroviruses are the most common identified cause of paediatric aseptic meningitis in Jordan. Although PCR revealed an identified virus in around half of the patients, nevertheless, there was no adjustment in the management plan regarding duration of empirical antibiotic use and hospital stay. Increasing knowledge and awareness among clinicians on viral meningitis' lab characteristics might have great impact on duration of hospital stay and thus would be reflected on the patient and the healthcare system as well.

Herpes simplex viruses (1 and 2) and varicella-zoster virus infections in an adult population with aseptic meningitis or encephalitis: A nine-year retrospective clinical study

Three α-herpesviruses are known to be associated with central nervous system (CNS) infection; however, there are limited data on the incidence and clinical characteristics of α-herpesviruses CNS infections. This study aimed to assess the clinical manifestations, laboratory findings, and outcomes in patients with human herpes simplex virus 1 (HSV-1), human herpes simplex virus 2 (HSV-2), and varicella-zoster virus (VZV) CNS infections.We identified cases of HSV-1, HSV-2, and VZV CNS infections and reviewed their clinical and laboratory characteristics. The study population was drawn from patients with HSV-1, HSV-2, and VZV polymerase chain reaction positivity in cerebrospinal fluid (CSF) who visited Pusan National University Hospital between 2010 and 2018.During the 9-year study period, a total of 727 CSF samples were examined, with 72.2% (525/727) patients identified as having a CNS infection. Of 471 patients with aseptic meningitis and encephalitis, the causative virus was identified in 145 patients, and no virus was detected in 337 patients. A total of 15.2% (80/525) were diagnosed with one of the 3 herpesviruses as causative agents, 59 patients had meningitis, and 21 patients had encephalitis. Eleven patients with HSV-1, 27 patients with HSV-2, and 42 patients with VZV CNS infections were included. The distribution of cases by age showed different patterns depending on the type of herpesvirus infection. Compared with the HSV-1 group, the median age in the HSV-2 group was younger (HSV-1: 58 years; HSV-2: 38 years; P = .004), and patients with VZV infections showed a bimodal age distribution. Encephalitis was more common in the HSV-1 group, and HSV-1 infection was associated with a poor prognosis at discharge. CSF white blood cell counts were significantly lower in patients infected with HSV-1 (117 × 106 cells/L) than in patients infected with VZV (301 × 106 cells/L) (P = .008).These 3 herpesviruses are important causes of CNS infections regardless of immunologic status. HSV-1 infection was commonly associated with encephalitis and poor prognosis; HSV-2 and VZV CNS infections were associated with a low risk of mortality and neurological sequelae.

Ability of Procalcitonin and C-Reactive Protein for Discriminating between Bacterial and Enteroviral Meningitis in Children Using Decision Tree

Bacterial meningitis (BM) is a public health burden in developing countries, including Central Asia. This disease is characterized by a high mortality rate and serious neurological complications. Delay with the start of adequate therapy is associated with an increase in mortality for patients with acute bacterial meningitis. Cerebrospinal fluid culture, as a gold standard in bacterial meningitis diagnosis, is time-consuming with modest sensitivity, and this is unsuitable for timely decision-making. It has been shown that bacterial meningitis differentiation from viral meningitis could be done through different parameters such as clinical signs and symptoms, laboratory values, such as PCR, including blood and cerebrospinal fluid (CSF) analysis. In this study, we proposed the method for distinguishing the bacterial form of meningitis from enteroviral one. The method is based on the machine learning process deriving making decision rules. The proposed fast-and-frugal trees (FFTree) decision tree approach showed an ability to determine procalcitonin and C-reactive protein (CRP) with cut-off values for distinguishing between bacterial and enteroviral meningitis (EVM) in children. Such a method demonstrated 100% sensitivity, 96% specificity, and 98% accuracy in the differentiation of all cases of bacterial meningitis in this study. These findings and proposed method may be useful for clinicians to facilitate the decision-making process and optimize the diagnostics of meningitis.

Microbial aspects and potential markers for differentiation between bacterial and viral meningitis among adult patients

OBJECTIVES

Meningitis is a medical emergency with permanent disabilities and high mortality worldwide. We aimed to determine causative microorganisms and potential markers for differentiation between bacterial and viral meningitis.

METHODOLOGY

Adult patients with acute meningitis were subjected to lumber puncture. Cerebrospinal fluid (CSF) microorganisms were identified using Real-time PCR. PCT and CRP levels, peripheral and CSF-leucocyte count, CSF-protein and CSF-glucose levels were assessed.

RESULTS

Out of 80 patients, infectious meningitis was confirmed in 75 cases; 38 cases were bacterial meningitis, 34 cases were viral meningitis and three cases were mixed infection. Higher PCT, peripheral and CSF-leukocytosis, higher CSF-protein and lower CSF-glucose levels were more significant in bacterial than viral meningitis patients. Neisseria meningitides was the most frequent bacteria and varicella-zoster virus was the most common virus. Using ROC analyses, serum PCT and CSF-parameters can discriminate bacterial from viral meningitis. Combined ROC analyses of PCT and CSF-protein significantly improved the effectiveness in predicting bacterial meningitis (AUC of 0.998, 100%sensitivity and 97.1%specificity) than each parameter alone (AUC of 0.951 for PCT and 0.996 for CSF-protein).

CONCLUSION

CSF-protein and serum PCT are considered as potential markers for differentiating bacterial from viral meningitis and their combination improved their predictive accuracy to bacterial meningitis.

CD169 and CD64 could help differentiate bacterial from CoVID-19 or other viral infections in the Emergency Department

The identification of a bacterial, viral, or even noninfectious cause is essential in the management of febrile syndrome in the emergency department (ED), especially in epidemic contexts such as flu or CoVID-19. The aim was to assess discriminative performances of two biomarkers, CD64 on neutrophils (nCD64) and CD169 on monocytes (mCD169), using a new flow cytometry procedure, in patients presenting with fever to the ED during epidemics. Eighty five adult patients presenting with potential infection were included during the 2019 flu season in the ED of La Timone Hospital. They were divided into four diagnostic outcomes according to their clinical records: no-infection, bacterial infection, viral infection and co-infection. Seventy six patients with confirmed SARS-CoV-2 infection were also compared to 48 healthy volunteers. For the first cohort, 38 (45%) patients were diagnosed with bacterial infections, 11 (13%) with viral infections and 29 (34%) with co-infections. mCD169 was elevated in patients with viral infections, with a majority of Flu A virus or Respiratory Syncytial Virus, while nCD64 was elevated in subjects with bacterial infections, with a majority of Streptococcus pneumoniae and Escherichia coli. nCD64 and mCD169 showed 90% and 80% sensitivity, and 78% and 91% specificity, respectively, for identifying patients with bacterial or viral infections. When studied in a second cohort, mCD169 was elevated in 95% of patients with SARS-CoV-2 infections and remained at normal level in 100% of healthy volunteers. nCD64 and mCD169 have potential for accurately distinguishing bacterial and acute viral infections. Combined in an easy and rapid flow cytometry procedure, they constitute a potential improvement for infection management in the ED, and could even help for triage of patients during emerging epidemics.

A 2020 review on the role of procalcitonin in different clinical settings: an update conducted with the tools of the Evidence Based Laboratory Medicine

Biomarkers to guide antibiotic treatment decisions have been proposed as an effective way to enhancing a more appropriate use of antibiotics. As a biomarker, procalcitonin (PCT) has been found to have good specificity to distinguish bacterial from non-bacterial inflammations. Decisions regarding antibiotic use in an individual patient are complex and should be based on the pre-test probability for bacterial infection, the severity of presentation and the results of PCT serum concentration. In the context of a high pre-test probability for bacterial infections and/or a high-risk patient with sepsis, monitoring of PCT over time helps to track the resolution of infection and decisions regarding early stop of antibiotic treatment. As outlined by the Evidence Based Laboratory Medicine (EBLM), not only the pre-test probability but also the positive likelihood ratio influence the performance of a test do be really diagnostic. This aspect should be taken into account in the interpretation of the results of clinical trials evaluating the performance of PCT in guiding antibiotic therapy.

Flow cytometry evaluation of infection-related biomarkers in febrile subjects in the emergency department

Aim: In an Emergency Department (ED), the etiological identification of infected subjects is essential. 13 infection-related biomarkers were assessed using a new flow cytometry procedure. Materials & methods: If subjects presented with febrile symptoms at the ED, 13 biomarkers' levels, including CD64 on neutrophils (nCD64) and CD169 on monocytes (mCD169), were tested and compared with clinical records. Results: Among 50 subjects, 78% had bacterial infections and 8% had viral infections. nCD64 showed 82% sensitivity and 91% specificity for identifying subjects with bacterial infections. mCD169, HLA-ABC ratio and HLA-DR on monocytes had high values in subjects with viral infections. Conclusion: Biomarkers showed promising performances to improve the ED's infectious stratification.

Meningitis in adults: diagnosis and management

Bacterial meningitis is a medical emergency. All clinicians who provide acute medical care require a sound understanding of the priorities of managing a patient with suspected meningitis during the first hour. These include obtaining blood cultures, performing lumbar puncture and initiating appropriate therapy, while avoiding harmful delays such as those that result from not administering treatment until neuroimaging has been performed. Despite the increasing availability of newer diagnostic techniques, the interpretation of cerebrospinal fluid parameters remains a vital skill for clinicians. International and local guidelines differ with regard to initial empirical therapy of bacterial meningitis in adults; the North American guideline recommends ceftriaxone and vancomycin for all patients, while the Australian, UK and European guidelines recommend that vancomycin only be added for patients who are more likely to have pneumococcal meningitis or who have a higher likelihood of being infected with a strain of Streptococcus pneumoniae with reduced susceptibility to ceftriaxone. Patients with risk factors for Listeria meningitis also require an anti-Listeria agent, such as benzylpenicillin, to be added to this treatment regimen. Dexamethasone should be a routine component of empirical therapy due to its proven role in reducing morbidity and mortality from pneumococcal meningitis.

To what extent can clinical characteristics be used to distinguish encephalitis from encephalopathy of other causes? Results from a prospective observational study

Background

Recognizing patients with encephalitis may be challenging. The cardinal symptom, encephalopathy, has a wide array of differential diagnoses. In this prospective study we aimed to explore the etiology of encephalitis and to assess the diagnostic accuracy of symptoms and clinical findings in patients with encephalitis in an encephalopathic population.

Methods

Patients with acute onset of encephalopathy (n = 136) were prospectively enrolled from January 2014–December 2015 at Oslo University Hospital, Ullevaal. Clinical and biochemical characteristics of patients who met the case definition of encephalitis were compared to patients with encephalopathy of other causes.

Results

Among 136 patients with encephalopathy, 19 (14%) met the case-definition of encephalitis. For 117 patients other causes of encephalopathy were found, infection outside the CNS was the most common differential diagnosis. Etiology of encephalitis was confirmed in 53% (4 bacterial, 4 viral, 1 parasitic, and 1 autoimmune). Personality change, nausea, fever, focal neurology, recent travel history, and low inflammation markers were significantly more abundant in patients with encephalitis, but the diagnostic accuracy for individual parameters were low (area under the curve (AUC) < 0.7). The combination of fever (OR = 6.6, 95% CI, 1.6–28), nausea (OR = 8.9, 95% CI, 1.7–46) and a normal level of ESR (erythrocyte sedimentation rate < 17 mm/hr, OR = 6.9, 95% CI, 1.5–33) was significant in multivariate analysis with an AUC (area under the curve) of 0.85 (95% CI, 0.76–0.94). Moderately increased pleocytosis in CSF (5-100 × 10⁶/L) further increased the diagnostic accuracy of this combination, AUC 0.90 (95% CI, 0.81–0.98).

Conclusions

There is a wide diversity in differential diagnoses in patients with encephalopathy, and no single symptom or finding can be used to predict encephalitis with high accuracy in this group. The combination of fever, nausea and a low ESR in an encephalopathic population, increased the diagnostic accuracy of encephalitis compared to solitary parameters. The triad could be a useful clinical tool for early diagnosis of encephalitis, and these patients should be considered for further diagnostics such as lumbar puncture (LP).

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3570-2) contains supplementary material, which is available to authorized users.

Utility of urine reagent strips in cerebrospinal fluid analysis: An aid to bedside diagnosis of meningitis

Context

The provision of initial treatment to a patient with suspected meningitis depends greatly on early recognition and rapid diagnostic evaluation of cerebrospinal fluid (CSF) leukocytes, proteins, and glucose. The diagnosis is time critical and timely intervention has an implication on the prognosis and outcome. Reasonably, sound laboratorial setups are not available in our country in the primary health-care level and, even in the settings where they are available, long waiting periods precede the availability of results.

Aims

We conducted this study to emphasize the role of urine reagent strip test as a rapid diagnostic tool in CSF analysis.

Settings and Design:

This is a prospective single-blinded study on 100 consecutive CSF samples received with in 1h of tap.

Subjects and Methods

All the 100 samples were subjected to definitive test being CSF microscopy and biochemical analysis of proteins and sugar and index test being a semi quantitative analysis of CSF leukocytes, proteins, and sugar by urinary reagent strips.

Statistical Analysis Used

The diagnostic accuracy of the reagent strip for different cutoff levels was estimated and tabulated in the form of sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio.

Results

77% of cases were in the pediatric age group and 23% cases were adults. The sensitivity and specificity for leukocytes by the strip method for ≥15 cells/cumm were 89.28% and 98.61%, respectively, which increased to 100% with an increase in the counts. The reagent strip test had a sensitivity of 85.71% and a specificity of 95.65% for the protein levels >30 mg/dl which increased to 100% with an increase in protein levels. The reagent strip test for glucose was highly specific (100%) but less sensitive.

Conclusions

The results indicate that urine reagent strip is instrumental in bedside CSF analysis and has a future stand in the diagnosis of meningitis.

The Role of Procalcitonin in the Diagnosis of Meningitis: A Literature Review

OBJECTIVE

To review the current published literature on the use of procalcitonin as a diagnostic and prognostic marker in adult patients with meningitis.

METHODS

We conducted a PubMed search to identify all relevant publications regarding the diagnostic and prognostic value of serum procalcitonin in patients with a known or suspected central nervous system infection. We also reviewed the bibliographies of all identified manuscripts in an attempt to identify additional relevant references.

RESULTS

A significant body of evidence suggests that serum procalcitonin has a promising role and can be a useful biomarker in the assessment of patients with meningitis.

CONCLUSIONS

Our literature review suggests that data on the role of Cerebrospinal Fluid (CSF) procalcitonin are limited, whereas serum procalcitonin (S⁻PCT) is probably a useful tool in the evaluation of patients with a known or suspected central nervous system infection and can help distinguish between bacterial and viral meningitis.

Vector-Borne Disease is a Common Cause of Hospitalized Febrile Illness in India

Acute febrile illness (AFI) is a major cause of morbidity and mortality in India and other resource-limited settings, yet systematic etiologic characterization of AFI has been limited. We prospectively enrolled adults (N = 970) and children (age 6 months to 12 years, N = 755) admitted with fever from the community to Sassoon General Hospital in Pune, India, from July 2013 to December 2015. We systematically obtained a standardized clinical history, basic laboratory testing, and microbiologic diagnostics on enrolled participants. Results from additional testing ordered by treating clinicians were also recorded. A microbiological diagnosis was found in 549 (32%) participants; 211 (12%) met standardized case definitions for pneumonia and meningitis without an identified organism; 559 (32%) were assigned a clinical diagnosis in the absence of a confirmed diagnosis; and 406 (24%) had no diagnosis. Vector-borne diseases were the most common cause of AFI in adults including dengue (N = 188, 19%), malaria (N = 74, 8%), chikungunya (N = 15, 2%), and concurrent mosquito-borne infections (N = 23, 2%) occurring most frequently in the 3 months after the monsoon. In children, pneumonia was the most common cause of AFI (N = 214, 28%) and death. Bacteremia was found in 68 (4%) participants. Central nervous system infections occurred in 58 (6%) adults and 64 (8%) children. Etiology of AFI in India is diverse, highly seasonal, and difficult to differentiate on clinical grounds alone. Diagnostic strategies adapted for season and age may reduce diagnostic uncertainty and identify causative organisms in treatable, fatal causes of AFI.

Pleocytosis is not fully responsible for low CSF glucose in meningitis

Objective

The mechanism of hypoglycorrhachia-low CSF glucose-in meningitis remains unknown. We sought to evaluate the relative contribution of CSF inflammation vs microorganisms (bacteria and fungi) in lowering CSF glucose levels.

Methods

We retrospectively categorized CSF profiles into microbial and aseptic meningitis and analyzed CSF leukocyte count, glucose, and protein concentrations. We assessed the relationship between these markers using multivariate and stratified linear regression analysis for initial and repeated CSF sampling. We also calculated the receiver operating characteristics of CSF glucose and CSF-to-serum glucose ratios to presumptively diagnose microbial meningitis.

Results

We found that increasing levels of CSF inflammation were associated with decreased CSF glucose levels in the microbial but not aseptic category. Moreover, elevated CSF protein levels correlated more strongly than the leukocyte count with low CSF glucose levels on initial (R² = 36%, p < 0.001) and repeated CSF sampling (R² = 46%, p < 0.001). Hypoglycorrhachia (<40 mg/dL) was observed in 50.1% of microbial cases, but only 9.6% of aseptic cases, most of which were neurosarcoidosis. Absolute CSF glucose and CSF-to-serum glucose ratios had similar low sensitivity and moderate-to-high specificity in diagnosing microbial meningitis at thresholds commonly used.

Conclusions

The main driver of hypoglycorrhachia appears to be a combination of microbial meningitis with moderate to high degrees of CSF inflammation and proteins, suggesting that the presence of microorganisms capable of catabolizing glucose is a determinant of hypoglycorrhachia in meningitis. A major notable exception is neurosarcoidosis. Low CSF glucose and CSF-to-serum glucose ratios are useful markers for the diagnosis of microbial meningitis.

Procalcitonin-guided antibiotic therapy in critically ill adults: a meta-analysis

Background

As a novel biomarker of inflammation, procalcitonin (PCT) has proven useful to guide antibiotic therapy in intensive care unit (ICU). However, there are controversial on mortality. The aim of this study was to evaluate the utility of PCT-guided antibiotic therapy in critically ill adults and determine whether studies are sufficient.

Methods

A systematic search in PubMed, Embase and Cochrane was performed. We included only randomized controlled trials which compared the safety and efficacy between PCT-guided or standard antibiotic therapy groups in ICU adults. Trial sequential analysis and GARDE approach were performed.

Results

Fifteen studies met our criteria for inclusion finally, with a cumulative number of 5486 ICU patients. There was no difference in 28-day mortality between two compared groups (P = 0.626), but significant decreases were observed in the duration of antibiotic therapy for the first episode of infection (P < 0.001) and length of hospitalization (P = 0.049). No significant deference was found in secondary endpoints except total duration of antibiotic therapy (P < 0.001). TSA revealed that the pooled sample sizes of 28-day mortality and the duration of antibiotic therapy for the first episode of infection exceeded the estimated required information size, but not the length of hospitalization.

Conclusions

PCT-guided therapy is a better and safer algorithm to be applied into ICU patients, which appears no effect on 28-day mortality while performing preferable utility in reducing the duration of antibiotic therapy for the first episode of infection. More studies on these endpoints were not recommended.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2622-3) contains supplementary material, which is available to authorized users.

Diagnosis and Treatment of Central Nervous System Infections in the Emergency Department

Central nervous system (CNS) infections, including meningitis, encephalitis, and brain abscess, are rare but time-sensitive emergency department (ED) diagnoses. Patients with CNS infection can present to the ED with nonspecific signs and symptoms, including headache, fever, altered mental status, and behavioral changes. Neuroimaging and CSF fluid analysis can appear benign early in the course of disease. Delaying therapy negatively impacts outcomes, particularly with bacterial meningitis and herpes simplex virus encephalitis. Therefore, diagnosis of CNS infection requires vigilance and a high index of suspicion based on the history and physical examination, which must be confirmed with appropriate imaging and laboratory evaluation.

Usefulness of blood and cerebrospinal fluid laboratory testing to predict bacterial meningitis in the emergency department

INTRODUCTION

The classic clinical presentation of bacterial meningitis (BM) is observed in less than half of the cases in adults, and symptoms are less specific in children, the elderly or immunocompromised, and other chronic patients. The usual signs and symptoms do not provide optimal sensitivity and specificity for distinguishing possible BM from viral meningitis (VM), which may lead to a delay in the appropriate antimicrobial therapy. Society therefore stands to benefit from the development of effective, objective, and rapid tools able to predict and identify patients with BM. These tools include laboratory tests for blood and cerebrospinal fluid (CSF). The aim of this review is to summarise recently published scientific evidence in order to clarify existing controversies and compare the usefulness and diagnostic ability of the different parameters used to predict BM.

DEVELOPMENT

Systematic search of the main bibliographic databases and platforms to identify articles published between January 2000 and January 2016. We selected 59 articles that meet the objectives of this review.

CONCLUSIONS

CSF lactate, proportion of polymorphonuclear leukocytes, and CSF glucose, as well as serum procalcitonin (PCT), are the independent factors most predictive of bacterial aetiology. The model that combines serum PCT and CSF lactate achieves the highest predictive power for BM, with a sensitivity and specificity exceeding 99%. We should consider BM when CSF lactate >33 md/dL and/or PCT>0.25ng/mL.

Procalcitonin testing to guide antibiotic therapy for the treatment of sepsis in intensive care settings and for suspected bacterial infection in emergency department settings: a systematic review and cost-effectiveness analysis

BACKGROUND

Determination of the presence or absence of bacterial infection is important to guide appropriate therapy and reduce antibiotic exposure. Procalcitonin (PCT) is an inflammatory marker that has been suggested as a marker for bacterial infection.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of adding PCT testing to the information used to guide antibiotic therapy in adults and children (1) with confirmed or highly suspected sepsis in intensive care and (2) presenting to the emergency department (ED) with suspected bacterial infection.

METHODS

Twelve databases were searched to June 2014. Randomised controlled trials were assessed for quality using the Cochrane Risk of Bias tool. Summary relative risks (RRs) and weighted mean differences (WMDs) were estimated using random-effects models. Heterogeneity was assessed visually using forest plots and statistically using the I (2) and Q statistics and investigated through subgroup analysis. The cost-effectiveness of PCT testing in addition to current clinical practice was compared with current clinical practice using a decision tree with a 6 months' time horizon.

RESULTS

Eighteen studies (36 reports) were included in the systematic review. PCT algorithms were associated with reduced antibiotic duration [WMD -3.19 days, 95% confidence interval (CI) -5.44 to -0.95 days, I (2) = 95.2%; four studies], hospital stay (WMD -3.85 days, 95% CI -6.78 to -0.92 days, I (2) = 75.2%; four studies) and a trend towards reduced intensive care unit (ICU) stay (WMD -2.03 days, 95% CI -4.19 to 0.13 days, I (2) = 81.0%; four studies). There were no differences for adverse clinical outcomes. PCT algorithms were associated with a reduction in the proportion of adults (RR 0.77, 95% CI 0.68 to 0.87; seven studies) and children (RR 0.86, 95% CI 0.80 to 0.93) receiving antibiotics, reduced antibiotic duration (two studies). There were no differences for adverse clinical outcomes. All but one of the studies in the ED were conducted in people presenting with respiratory symptoms. Cost-effectiveness: the base-case analyses indicated that PCT testing was cost-saving for (1) adults with confirmed or highly suspected sepsis in an ICU setting; (2) adults with suspected bacterial infection presenting to the ED; and (3) children with suspected bacterial infection presenting to the ED. Cost-savings ranged from £368 to £3268. Moreover, PCT-guided treatment resulted in a small quality-adjusted life-year (QALY) gain (ranging between < 0.001 and 0.005). Cost-effectiveness acceptability curves showed that PCT-guided treatment has a probability of ≥ 84% of being cost-effective for all settings and populations considered (at willingness-to-pay thresholds of £20,000 and £30,000 per QALY).

CONCLUSIONS

The limited available data suggest that PCT testing may be effective and cost-effective when used to guide discontinuation of antibiotics in adults being treated for suspected or confirmed sepsis in ICU settings and initiation of antibiotics in adults presenting to the ED with respiratory symptoms and suspected bacterial infection. However, it is not clear that observed costs and effects are directly attributable to PCT testing, are generalisable outside people presenting with respiratory symptoms (for the ED setting) and would be reproducible in the UK NHS. Further studies are needed to assess the effectiveness of adding PCT algorithms to the information used to guide antibiotic treatment in children with suspected or confirmed sepsis in ICU settings. Additional research is needed to examine whether the outcomes presented in this report are fully generalisable to the UK.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014010822.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Clinical decision rules for acute bacterial meningitis: current insights

Acute community-acquired bacterial meningitis (BM) requires rapid diagnosis so that suitable treatment can be instituted within 60 minutes of admitting the patient. The cornerstone of diagnostic examination is lumbar puncture, which enables microbiological analysis and determination of the cerebrospinal fluid (CSF) cytochemical characteristics. However, microbiological testing is not sufficiently sensitive to rule out this diagnosis. With regard to the analysis of standard CSF cytochemical characteristics (polymorphonuclear count, CSF glucose and protein concentration, and CSF:serum glucose), this is often misleading. Indeed, the relatively imprecise nature of the cutoff values for these BM diagnosis markers can make their interpretation difficult. However, there are two markers that appear to be more efficient than the standard ones: CSF lactate and serum procalcitonin levels. Scores and predictive models are also available; however, they only define a clinical probability, and in addition, their use calls for prior validation on the population in which they are used. In this article, we review current methods of BM diagnosis.

Diagnostic Accuracy of Procalcitonin in Bacterial Meningitis Versus Nonbacterial Meningitis: A Systematic Review and Meta-Analysis

Several studies have investigated the diagnostic accuracy of procalcitonin (PCT) levels in blood or cerebrospinal fluid (CSF) in bacterial meningitis (BM), but the results were heterogeneous. The aim of the present study was to ascertain the diagnostic accuracy of PCT as a marker for BM detection. A systematic search of the EMBASE, Scopus, Web of Science, and PubMed databases was performed to identify studies published before December 7, 2015 investigating the diagnostic accuracy of PCT for BM. The quality of the eligible studies was assessed using the revised Quality Assessment for Studies of Diagnostic Accuracy method. The overall diagnostic accuracy of PCT detection in CSF or blood was pooled using the bivariate model. Twenty-two studies involving 2058 subjects were included in this systematic review and meta-analysis. The overall specificities and sensitivities were 0.86 and 0.80 for CSF PCT, and 0.97 and 0.95 for blood PCT, respectively. Areas under the summary receiver operating characteristic curves were 0.90 and 0.98 for CSF PCT and blood PCT, respectively. The major limitation of this systematic review and meta-analysis was the small number of studies included and the heterogeneous diagnostic thresholds adopted by eligible studies. Our meta-analysis shows that PCT is a useful biomarker for BM diagnosis.

A Population-Based Acute Meningitis and Encephalitis Syndromes Surveillance in Guangxi, China, May 2007-June 2012

Objectives

Acute meningitis and encephalitis (AME) are common diseases with the main pathogens being viruses and bacteria. As specific treatments are different, it is important to develop clinical prediction rules to distinguish aseptic from bacterial or fungal infection. In this study we evaluated the incidence rates, seasonal variety and the main etiologic agents of AME, and identified factors that could be used to predict the etiologic agents.

Methods

A population-based AME syndrome surveillance system was set up in Guigang City, Guangxi, involving 12 hospitals serving the study communities. All patients meeting the case definition were investigated. Blood and/or cerebrospinal fluid were tested for bacterial pathogens using culture or RT-PCR and serological tests for viruses using enzyme-linked immunosorbent assays. Laboratory testing variables were grouped using factor analysis. Multinomial logistic regression was used to predict the etiology of AME.

Results

From May 2007 to June 2012, the annual incidence rate of AME syndrome, and disease specifically caused by Japanese encephalitis (JE), other viruses, bacteria and fungi were 12.55, 0.58, 4.57, 0.45 and 0.14 per 100,000 population, respectively. The top three identified viral etiologic agents were enterovirus, mumps virus, and JE virus, and for bacteria/fungi were Streptococcus sp., Cryptococcus neoformans and Staphylococcus sp. The incidence of JE and other viruses affected younger populations and peaked from April to August. Alteration of consciousness and leukocytosis were more likely to be caused by JE, bacteria and fungi whereas CSF inflammation was associated with bacterial/fungal infection.

Conclusions

With limited predictive validity of symptoms and signs and routine laboratory tests, specific tests for JE virus, mumps virus and enteroviruses are required to evaluate the immunization impact and plan for further intervention. CSF bacterial culture cannot be omitted in guiding clinical decisions regarding patient treatment.

The role of serum procalcitonin in the diagnosis of bacterial meningitis in adults: a systematic review and meta-analysis

OBJECTIVE

Clinically, it is often difficult to differentiate between bacterial and viral aetiologies in adults with suspected meningitis. Several studies have demonstrated the potential use of serum procalcitonin (PCT) in making this differentiation. The aim was to pool these studies into a meta-analysis to determine the diagnostic accuracy of PCT.

METHODS

Major electronic databases were searched for articles studying the use of serum PCT in the differentiation of bacterial and viral meningitis in adult patients. No date or language restrictions were applied. Data analysis was performed using Meta-DiSc 1.4 and MIX 2.0.

RESULTS

Nine studies (n=725 patients) were included in the meta-analysis. Serum PCT was found to be a highly accurate test for diagnosing meningitis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio (DOR) for PCT were 0.90 (95% confidence interval (CI) 0.84-0.94), 0.98 (95% CI 0.97-0.99), 27.3 (95% CI 8.2-91.1), 0.13 (95% CI 0.07-0.26), and 287.0 (95% CI 58.5-1409.0), respectively. PCT was found to be far superior to C-reactive protein, which had a pooled DOR of only 22.1 (95% CI 12.7-38.3).

CONCLUSIONS

Serum PCT is a highly accurate diagnostic test that can be used by physicians for rapid differentiation between bacterial and viral causes of meningitis in adults.

Methods of rapid diagnosis for the etiology of meningitis in adults

Infectious meningitis may be due to bacterial, mycobacterial, fungal or viral agents. Diagnosis of meningitis must take into account numerous items of patient history and symptomatology along with regional epidemiology and basic cerebrospinal fluid testing (protein, etc.) to allow the clinician to stratify the likelihood of etiology possibilities and rationally select additional diagnostic tests. Culture is the mainstay for diagnosis in many cases, but technology is evolving to provide more rapid, reliable diagnosis. The cryptococcal antigen lateral flow assay (Immuno-Mycologics) has revolutionized diagnosis of cryptococcosis and automated nucleic acid amplification assays hold promise for improving diagnosis of bacterial and mycobacterial meningitis. This review will focus on a holistic approach to diagnosis of meningitis as well as recent technological advances.

Community-acquired meningitis in older adults: clinical features, etiology, and prognostic factors

OBJECTIVES

To investigate the epidemiology and outcomes of community-acquired meningitis in older adults.

DESIGN

Retrospective study.

SETTING

Participants adults in Houston, Texas, with community-acquired meningitis hospitalized between January 1, 2005, and January 1, 2010 (N = 619; n = 54, 8.7%, aged ≥65; n = 565 aged <65).

METHODS

An adverse clinical outcome was defined as a Glasgow Outcome Scale score of 4 or less.

RESULTS

Older adults had higher rates of comorbidities, abnormal neurological and laboratory (serum white blood cell count >12,000/μL, and cerebrospinal fluid protein >100 mg/dL) findings (P < .001), abnormalities on computed tomography and magnetic resonance imaging of the head (P = .002), and adverse clinical outcomes (ACOs) (P < .001). The majority of participants (65.8%) had meningitis of unknown etiology. Bacterial meningitis was an infrequent cause of community-acquired meningitis (7.4%). Of the known causes, bacterial meningitis and West Nile virus were more common in older than younger adults; younger participants more frequently had cryptococcal and viral meningitis. On logistic regression, female sex was predictive of a poor outcome in the older participants (P = .002), whereas abnormal neurological examination (P < .001), fever (P = .01), and a cerebrospinal fluid glucose level less than 45 mg/dL (P = .002) were significant poor prognostic factors in younger participants.

CONCLUSION

Most cases of community-acquired meningitis are of unknown origin. Older adults are more likely than younger adults to have bacterial meningitis and West Nile virus infection when a cause can be identified. They also have more neurological abnormalities, laboratory and imaging abnormalities, and adverse clinical outcomes.

Ability of procalcitonin to predict bacterial meningitis in the emergency department

INTRODUCTION

The aim of this study was to analyse and compare procalcitonin (PCT) and C-reactive protein (CRP) as tools for detecting bacterial meningitis and predicting bacteraemia.

METHODS

Prospective, observational, and descriptive analytical study of 98 consecutive patients aged ≥15 years and diagnosed with acute meningitis in an emergency department between August 2009 and July 2013.

RESULTS

We analysed 98 patients with AM (66 males [67%]); mean age was 44±21 years. The diagnosis was bacterial meningitis in 38 patients (20 with bacteraemia); viral meningitis in 33; probable viral meningitis in 15; and presumptively diagnosed partially treated acute meningitis in 12. PCT had the highest area under the ROC curve (AUC) (0.996; 95% CI, 0.987-1; p<0.001). With a cutoff of ≥ 0.74 ng/ml, PCT achieved 94.7% sensitivity, 100% specificity, negative predictive value (NPV) of 93.9%, and positive predictive value (PPV) of 100%. The mean levels for PCT were11.47±7.76 ng/ml in bacterial meningitis vs. 0.10±0.15 ng/ml in viral meningitis (p <0.001). The AUC for CRP was 0.916 and a cutoff of ≥ 90 mg/L achieved 67.5% sensitivity, 86.3% specificity, PPV of 89.2%, and NPV of 90.4%. As a predictor of bacteraemia in bacterial meningitis, only PCT delivered a significant difference (14.7±7.1 ng/mL vs. 4.68±3.54 ng/mL, p<0.001). A cutoff of ≥ 1.1 ng/mL achieved 94.6% sensitivity, 72.4% specificity, NPV of 95.4%, and PPV of 69.2%; the AUC was 0.965 (95% CI, 0.921-1; p<0.001).

CONCLUSIONS

PCT has a high diagnostic power for acute meningitis in emergency department patients. PCT outperforms CRP in the detection of bacterial aetiology and is a good predictor of bacteraemia in bacterial meningitis.

Can Procalcitonin in Cerebrospinal Fluid be a Diagnostic Tool for Meningitis?

BACKGROUND

To study the levels of procalcitonin (PCT) in patients with meningitis and control group and compare them with established markers of infection--such as C-reactive protein (CRP), high-sensitivity CRP, and WBC--in cerebrospinal fluid (CSF) and assess the possible discriminative role of PCT in the differential diagnosis of meningitis from other noninfectious diseases.

METHODS

We studied CSF samples of patients from Intensive Care Unit, Internal Medicine, Neurology, Hematology, and Pediatric departments. The total number of patients included in the study was 58. The samples were divided into three groups: group 1 with bacterial meningitis (BM) central nervous system (n = 19); group 2 with viral meningitis (VM, n = 11); and group 3, control group, with noninfectious diseases (n = 28).

RESULTS

Values of PCT levels >0.5 ng/ml were considered as abnormal. In group 1, mean PCT levels were 4.714 ± 1.59 ng/ml. In group 2, all patients had PCT <0.5 ng/ml (0.1327 ± 0.03 ng/ml). In group 3, the mean PCT levels were <0.1 ng/ml.

CONCLUSION

PCT values in CSF can be very helpful in distinguishing BM from VM and other noninfectious diseases.

Role of Clinical Presentations and Routine CSF Analysis in the Rapid Diagnosis of Acute Bacterial Meningitis in Cases of Negative Gram Stained Smears

Background and Aim. Bacterial meningitis is a lethal, disabling endemic disease needing prompt antibiotic management. Gram stained smears is rapid accurate method for diagnosis of bacterial meningitis. In cases of negative gram stained smears diagnosis is delayed till culture results. We aim to assess the role of clinical presentations and routine CSF analysis in the cost-effective rapid diagnosis of negative gram stained smears bacterial meningitis. Methods. Cross sectional study including 623 acute meningitis patients divided into two groups: bacterial meningitis and nonbacterial meningitis groups. The clinical presentations, systemic inflammatory parameters, and CSF analysis were evaluated and compared in both groups. Results. Altered conscious level, localizing neurological signs, Kernig's and Brudzinski's signs together with peripheral leucocytosis (>10.000/mm(3)), high CRP (>6) together with high CSF protein (>50 gl/dL), CSF neutrophilic count (≥50% of total CSF leucocytic count), and low CSF glucose level (<45 gm/dL) and CSF/serum glucose ≤0.6 were significantly diagnostic in bacterial meningitis patients. From the significant CSF analysis variables CSF protein carried the higher accuracy of diagnosis 78% with sensitivity 88% and specificity 72%. Conclusions. High CSF protein (>50 mg/dL) together with plasma inflammatory markers and CSF cytochemical parameters can diagnose bacterial meningitis in gram stain negative smear till culture results.

Cerebrospinal fluid/blood glucose ratio as an indicator for bacterial meningitis

BACKGROUND

Bacterial meningitis is an emergent disease requiring prompt diagnosis and treatment with appropriate antimicrobials. Although the lumbar puncture is widely used as a diagnostic tool for bacterial meningitis, it remains unclear which value in cerebrospinal fluid (CSF) analysis in emergency laboratory tests precisely predicts the presence of bacterial meningitis.

METHODS

This is a single-center, retrospective review of medical records to determine which emergency laboratory CSF test results are useful for predicting bacterial meningitis. The diagnosis of meningitis is made when the white blood cell count in CSF exceeds 5 cells/μL, while the diagnosis of bacterial meningitis additionally requires the growth of a pathogen from a CSF culture or the identification of a pathogen in Gram staining of CSF specimen.

RESULTS

We identified 15 patients with bacterial meningitis and 129 patients with aseptic meningitis. While neutrophil-predominant pleocytosis and a decreased glucose level in CSF can predict the presence of bacterial meningitis, the CSF/blood glucose ratio is more precise (optimal cut-off=0.36, sensitivity=92.9%, specificity=92.9%, area under the curve=.97) even after administration of antimicrobials prior to examination in the emergency department.

CONCLUSION

This study suggests that the CSF/blood glucose ratio may be a better single indicator for bacterial meningitis. Since the CSF glucose and blood glucose values are promptly and easily obtained from a lumbar puncture, the CSF/blood glucose ratio should be considered as a timely diagnostic indicator of bacterial meningitis. It may also help exclude the diagnosis of bacterial meningitis especially in cases in which no microorganisms can be cultured.

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.

Photoacoustic and photothermal detection of circulating tumor cells, bacteria and nanoparticles in cerebrospinal fluid in vivo and ex vivo

Circulating cells, bacteria, proteins, microparticles, and DNA in cerebrospinal fluid (CSF) are excellent biomarkers of many diseases, including cancer and infections. However, the sensitivity of existing methods is limited in their ability to detect rare CSF biomarkers at the treatable, early-stage of diseases. Here, we introduce novel CSF tests based on in vivo photoacoustic flow cytometry (PAFC) and ex vivo photothermal scanning cytometry. In the CSF of tumor-bearing mice, we molecularly detected in vivo circulating tumor cells (CTCs) before the development of breast cancer brain metastasis with 20-times higher sensitivity than with current assays. For the first time, we demonstrated assessing three pathways (i.e., blood, lymphatic, and CSF) of CTC dissemination, tracking nanoparticles in CSF in vivo and their imaging ex vivo. In label-free CSF samples, we counted leukocytes, erythrocytes, melanoma cells, and bacteria and imaged intracellular cytochromes, hemoglobin, melanin, and carotenoids, respectively. Taking into account the safety of PAFC, its translation for use in humans is expected to improve disease diagnosis beyond conventional detection limits.

Prediction of bacterial meningitis based on cerebrospinal fluid pleocytosis in children

Children with cerebrospinal fluid pleocytosis are frequently treated with parenteral antibiotics, but only a few have bacterial meningitis. Although some clinical prediction rules, such as bacterial meningitis score, are of well-known value, the cerebrospinal fluid white blood cells count can be the initial available information. Our aim was to establish a cutoff point of cerebrospinal fluid white blood cell count that could distinguish bacterial from viral and aseptic meningitis. A retrospective study of children aged 29 days to 17 years who were admitted between January 1st and December 31th, 2009, with cerebrospinal fluid pleocytosis (white blood cell≥7μL(-1)) was conducted. The cases of traumatic lumbar puncture and of antibiotic treatment before lumbar puncture were excluded. There were 295 patients with cerebrospinal fluid pleocytosis, 60.3% females, medium age 5.0±4.3 years distributed as: 12.2% 1-3 months; 10.5% 3-12 months; 29.8% 12 months to 5 years; 47.5% >5 years. Thirty one children (10.5%) were diagnosed with bacterial meningitis, 156 (52.9%) viral meningitis and 108 (36.6%) aseptic meningitis. Bacterial meningitis was caused by Neisseria meningitidis (48.4%), Streptococcus pneumoniae (32.3%), other Streptococcus species (9.7%), and other agents (9.7%). cerebrospinal fluid white blood cell count was significantly higher in patients with bacterial meningitis (mean, 4839cells/μL) compared to patients with aseptic meningitis (mean, 159cells/μL, p<0.001), with those with aseptic meningitis (mean, 577cells/μL, p<0.001) and with all non-bacterial meningitis cases together (p<0.001). A cutoff value of 321white blood cell/μL showed the best combination of sensitivity (80.6%) and specificity (81.4%) for the diagnosis of bacterial meningitis (area under receiver operating characteristic curve 0.837). Therefore, the value of cerebrospinal fluid white blood cell count was found to be a useful and rapid diagnostic test to distinguish between bacterial and nonbacterial meningitis in children.

Evaluation of IL-6 and High Sensitive C Reactive Protein Value in CSF and Serum Children Suspected Meningitis Referred to Pediatric Emergency Room

Background

Acute bacterial meningitis which is a pediatric emergency with high mortality and morbidity must be diagnosed and treat promptly. Often diagnosis of bacterial meningitis from viral meningitis is difficult after some days. Determination of some inflammatory mediators’ example IL-6 and HS-CRP were useful in differential diagnosis of bacterial and viral meningitis.

Objectives

This study attempted to Determining HS-CRP and IL6 in serum and CSF in children suspected meningitis and Comparing value HS-CRP and IL6 in bacterial/viral meningitis.

Patients and Methods

Of children that hospitalized in pediatric emergency ward (Ghaem Hospital Mashhad university of medical science, in duration 01 Dec 2010-01 Dec 2011) and for they performed lumbar puncture, 1cc serum and CSF of they were taken to laboratory and have measured IL-6 with Elisa method and HS-CRP with immunoturbidometry method, patients were followed up and finally we compared levels of this two mediators.

Results

Finally, this study performed on 81 children and infants. From 81 cases, 27 cases (33.3%) had bacterial meningitis 27 cases (33.3%) viral meningitis and 27 cases (33.3%) had normal CSF. IL-6 concentration in the CSF and serum were significantly raised in cases of bacterial meningitis (P = 0.001, P = 0.01) but HS-CRP concentration in the CSF and serum were not significantly raised in cases of bacterial meningitis (P = 0.46, P = 0.29). Mean IL-6 concentration in the CSF in bacterial meningitis was (180.74) and in viral meningitis was (39.08) .Mean HS-CRP in CSF in bacterial meningitis was (2.22) and viral meningitis was (1.29). Mean HS-CRP in serum in bacterial meningitis was (8.23) and viral meningitis was (6.36).

Conclusions

The measurement of IL-6 in the CSF and serum in potentially a very useful diagnostic tool for differential diagnosis of bacterial and viral meningitis.

Meningitis with a negative cerebrospinal fluid Gram stain in adults: risk classification for an adverse clinical outcome

OBJECTIVE

To derive and validate a risk score for an adverse clinical outcome in adults with meningitis and a negative cerebrospinal fluid (CSF) Gram stain.

PATIENTS AND METHODS

We conducted a retrospective study of 567 adults from Houston, Texas, with meningitis evaluated between January 1, 2005, and January 1, 2010. The patients were divided into derivation (N=292) and validation (N=275) cohorts. An adverse clinical outcome was defined as a Glasgow Outcome Scale score of 4 or less.

RESULTS

Of the 567 patients, 62 (11%) had an adverse clinical outcome. A predictive model was created using 3 baseline variables that were independently associated with an adverse clinical outcome (P<.05): age greater than 60 years, abnormal findings on neurologic examination (altered mental status, focal neurologic deficits, or seizures), and CSF glucose level of less than 2.4975 mmol/L (to convert CSF glucose to mmol/L, multiply by 0.05551). The model classified patients into 2 categories of risk for an adverse clinical outcome--derivation sample: low risk, 0.6% and high risk, 32.8%; P<.001; and validation sample: low risk, 0.5% and high risk, 21.1%; P<.001.

CONCLUSION

Adults with meningitis and a negative CSF Gram stain can be accurately stratified for the risk of an adverse clinical outcome using clinical variables available at presentation.

The spectrum of central nervous system infections in an adult referral hospital in Hanoi, Vietnam

Objectives

To determine prospectively the causative pathogens of central nervous system (CNS) infections in patients admitted to a tertiary referral hospital in Hanoi, Vietnam.

Methods

From May 2007 to December 2008, cerebrospinal fluid (CSF) samples from 352 adults with suspected meningitis or encephalitis underwent routine testing, staining (Gram, Ziehl-Nielsen, India ink), bacterial culture and polymerase chain reaction targeting Neisseria meningitidis, Streptococcus pneumoniae, S. suis, Haemophilus influenzae type b, Herpes simplex virus (HSV), Varicella Zoster virus (VZV), enterovirus, and 16S ribosomal RNA. Blood cultures and clinically indicated radiology were also performed. Patients were classified as having confirmed or suspected bacterial (BM), tuberculous (TBM), cryptococcal (CRM), eosinophilic (EOM) meningitis, aseptic encephalitis/meningitis (AEM), neurocysticercosis and others.

Results

352 (male: 66%) patients were recruited: median age 34 years (range 13–85). 95/352 (27.3%) diagnoses were laboratory confirmed and one by cranial radiology: BM (n = 62), TBM (n = 9), AEM (n = 19), CRM (n = 5), and neurocysticercosis (n = 1, cranial radiology). S. suis predominated as the cause of BM [48/62 (77.4%)]; Listeria monocytogenese (n = 1), S. pasteurianus (n = 1) and N. meningitidis (n = 2) were infrequent. AEM viruses were: HSV (n = 12), VZV (n = 5) and enterovirus (n = 2). 5 patients had EOM. Of 262/352 (74.4%) patients with full clinical data, 209 (79.8%) were hospital referrals and 186 (71%) had been on antimicrobials. 21 (8%) patients died: TBM (15.2%), AEM (10%), and BM (2.8%).

Conclusions

Most infections lacked microbiological confirmation. S. suis was the most common cause of BM in this setting. Improved diagnostics are needed for meningoencephalitic syndromes to inform treatment and prevention strategies.