Cerebrospinal fluid lactate as a marker to differentiate between community-acquired acute bacterial meningitis and aseptic meningitis/encephalitis in adults: a Danish prospective observational cohort study

Reliability of a point of care testing blood gas analyzer for measurement of lactate levels in cerebrospinal fluid

Analysis of cerebrospinal fluid (CSF), including lactate, is key for diagnosis of acute meningitis. Since blood gas analyzers (BGA) enable rapid and safe blood-lactate measurements, we evaluated the reliability of RAPIDPoint 500 BGA to provide a fast and accurate measure of CSF lactate. In this study, CSF lactate levels were measured by a reference assay and on RAPIDPoint 500 BGA. Comparability was evaluated through difference analysis, using Bland Altman test, and linear regression analysis, using the Passing Bablok test. Agreement rate according to CSF lactate (≥3.5 and <3.5 mmol/L) was calculated using kappa (κ) statistic. Population study included 98 CSF samples. Concerning difference analysis, according to Bland-Altman test, bias was 0.13 mmol/L (CI 95%: -0.26 to 0.52 mmol/L. In regression analysis, according to Passing-Bablok equation a systematic difference between both assays was found. In concordance analysis, the interrate realibility was very high (κ: 0.964). According to our resuls, although a systematic difference was detected when lactate levels were measured on RAPIDPoint 500 BGA, the results from Bland-Altman test and the high agreement rate support that this POCT analyzer could be useful for a early and safe detection of patients with high probability of increased CSF lactate level.

Factors influencing procalcitonin in the cerebrospinal fluid of patients after neurosurgery and its diagnostic value for intracranial infection

OBJECTIVE

This study aimed to investigate the factors influencing Procalcitonin (PCT) in the cerebrospinal fluid (CSF) of patients with high fever and suspected intracranial infection after neurosurgery and its clinical application value.

METHODS

Between February 2021 and August 2022, CSF and serum samples were collected via lumbar puncture from patients with high fever and suspected intracranial infection in the Intensive Care Unit(ICU) of our hospital. Multivariate logistic regression analysis was performed to analyze the factors influencing elevated PCT in CSF. The diagnostic efficacy of each index was assessed using receiver operating characteristic (ROC) curves.

RESULTS

A total of 183 CSF samples were collected, of which 148 had increased PCT levels, including 73 cases of intracranial infection and 75 cases in the case‒control group. Multivariate logistic regression analysis showed that intracranial infection [OR = 0.117, 95% CI: 0.025-0.559; p < 0.01] and hemorrhagic CSF [OR = 0.162, 95% CI: 0.029-0.916; p < 0.04] were factors influencing CSF PCT, while trauma [OR = 3.43, 95% CI: 0.76-15.45; p < 0.12], epileptic seizure [OR = 0.00, 95% CI: 0.00; p < 0], age [OR = 1.02, 95% CI: 0.98-1.52; p < 0.32] and Glasgow Coma Scale (GCS) score [OR = 1.03, 95% CI: 0.78-1.32; p < 0.83] did not influence CSF PCT. The CSF PCT and serum PCT levels in the intracranial infection group and the case‒control group were 0.13 (0.11, 0.25) ng/ml and 0.14 (0.07, 0.25) ng/ml and 0.14 (0.08,0.32) ng/ml and 0.23 (0.13,0.48)ng/ml, respectively, with no statistically significant difference. The median values of CSF lactate in the intracranial infection group and the case‒control group were 6.45 (4.475, 8.325) mmol/l and 3.2 (2.02, 4.200) mmol/l, respectively, with a statistically significant difference between the groups.The areas under the ROC curve of CSF PCT, serum PCT,CSF lactate, CSF PCT combined with lactate were 0.59, 0.63, 0.82,and 0.83,respectively.

CONCLUSION

Intracranial infection and hemorrhagic CSF are influencing factors for elevated CSF PCT following neurosurgery. It should be noted that the diagnostic value of intracranial infection by CSF PCT elevated alone is limited, but the combination it with other indicators can help improve diagnostic efficacy.

Cerebrospinal Fluid-Basic Concepts Review

Cerebrospinal fluid plays a crucial role in protecting the central nervous system (CNS) by providing mechanical support, acting as a shock absorber, and transporting nutrients and waste products. It is produced in the ventricles of the brain and circulates through the brain and spinal cord in a continuous flow. In the current review, we presented basic concepts related to cerebrospinal fluid history, cerebrospinal fluid production, circulation, and its main components, the role of the blood-brain barrier and the blood-cerebrospinal fluid barrier in the maintenance of cerebrospinal fluid homeostasis, and the utility of Albumin Quotient (Q_Alb) evaluation in the diagnosis of CNS diseases. We also discussed the collection of cerebrospinal fluid (type, number of tubes, and volume), time of transport to the laboratory, and storage conditions. Finally, we briefly presented the role of cerebrospinal fluid examination in CNS disease diagnosis of various etiologies and highlighted that research on identifying cerebrospinal fluid biomarkers indicating disease presence or severity, evaluating treatment effectiveness, and enabling understanding of pathogenesis and disease mechanisms is of great importance. Thus, in our opinion, research on cerebrospinal fluid is still necessary for both the improvement of CNS disease management and the discovery of new treatment options.

Pentraxin 3 in the cerebrospinal fluid during central nervous system infections: A retrospective cohort study

The present study describes diagnostic and prognostic abilities of Cerebrospinal fluid (CSF) Pentraxin 3 (PTX3) in central nervous system (CNS) infections. CSF PTX3 was measured retrospectively from 174 patients admitted under suspicion of CNS infection. Medians, ROC curves and Youdens index was calculated. CSF PTX3 was significantly higher among all CNS infections and undetectable in most of the patients in the control group, and significantly higher in bacterial infections compared to viral and Lyme infections. No association was found between CSF PTX3 and Glasgow Outcome Score. PTX3 in the CSF can distinguish bacterial infection from viral and Lyme infections and non-CNS infections. Highest levels were found in bacterial meningitis. No prognostic abilities were found.

High cerebrospinal fluid lactate concentration at 48 h of hospital admission predicts poor outcomes in patients with tuberculous meningitis: A multicenter retrospective cohort study

Objective

This study aimed to analyze the cerebrospinal fluid (CSF) parameters affecting the outcomes of patients with tuberculous meningitis (TBM).

Methods

This is a multi-center, retrospective, cohort study involving 81 patients who were diagnosed with TBM and treated in Haihe Clinical College of Tianjin Medical University, Tianjin Medical University General Hospital, and General Hospital of Air Force PLA from January 2016 to December 2019. Baseline data, Glasgow Coma Scale (GCS) score, and clinical presentations of all patients were collected at admission. CSF samples were collected at 48 h, 1, 2, and 3 weeks after admission. CSF lactate, adenosine deaminase, chloride, protein, glucose levels and intracranial pressure were measured. After a follow-up of 16.14 ± 3.03 months, all patients were assessed using the modified Rankin Scale (mRS) and divided into good (mRS scores of 0–2 points) and poor outcome groups (mRS scores of 3–6 points). The differences in patients' baseline data, GCS score, clinical presentations, and levels of CSF parameters detected at 48 h, 1, 2, and 3 weeks after admission between two groups were compared. Statistically significant variables were added to the binary logistic regression model to identify the factors impacting the outcomes of patients with TBM. Receiver operating characteristic (ROC) curve was used to assess the predictive ability of the model.

Results

The CSF lactate level exhibited a decreasing trend within 3 weeks of admission in the two groups. For the within-group comparison, statistically significant differences in the lactate level was found in both groups between four different time points. A binary logistic regression model revealed that CSF lactate level at 48 h after admission, age, and GSC score on admission were independently associated with the outcomes of patients with TBM. ROC curve analysis showed that the area under the ROC curve (AUC) was 0.786 for the CSF lactate level (48 h), 0.814 for GCS score, and 0.764 for age.

Conclusion

High CSF lactate level at 48 h after admission is one of the important factors for poor outcomes in patients with TBM.

Spatial and temporal variation of routine parameters: pitfalls in the cerebrospinal fluid analysis in central nervous system infections

The cerebrospinal fluid (CSF) space is convoluted. CSF flow oscillates with a net flow from the ventricles towards the cerebral and spinal subarachnoid space. This flow is influenced by heartbeats, breath, head or body movements as well as the activity of the ciliated epithelium of the plexus and ventricular ependyma. The shape of the CSF space and the CSF flow preclude rapid equilibration of cells, proteins and smaller compounds between the different parts of the compartment. In this review including reinterpretation of previously published data we illustrate, how anatomical and (patho)physiological conditions can influence routine CSF analysis. Equilibration of the components of the CSF depends on the size of the molecule or particle, e.g., lactate is distributed in the CSF more homogeneously than proteins or cells. The concentrations of blood-derived compounds usually increase from the ventricles to the lumbar CSF space, whereas the concentrations of brain-derived compounds usually decrease. Under special conditions, in particular when distribution is impaired, the rostro-caudal gradient of blood-derived compounds can be reversed. In the last century, several researchers attempted to define typical CSF findings for the diagnosis of several inflammatory diseases based on routine parameters. Because of the high spatial and temporal variations, findings considered typical of certain CNS diseases often are absent in parts of or even in the entire CSF compartment. In CNS infections, identification of the pathogen by culture, antigen detection or molecular methods is essential for diagnosis.

Existing Data Sources for Clinical Epidemiology: The Danish Study Group of Infections of the Brain Database (DASGIB)

Central nervous system (CNS) infections are rare diseases that are associated with considerable morbidity and mortality. Increased knowledge based on contemporary data is a prerequisite for improved management and prevention of these serious conditions. Yet, population-based databases of patients hospitalized with CNS infections remain scarce. The Danish Study Group of Infections of the Brain (DASGIB) has prospectively registered information on all adults ≥18 years of age admitted with CNS infections at departments of infectious diseases in Denmark since 2015. The main variables collected are baseline demographics, blood and cerebrospinal fluid tests, imaging results, and outcome using the Glasgow Outcome Scale score. To investigate important aspects for each type of CNS infections, additional variables are included specifically for bacterial meningitis, viral meningitis, encephalitis, brain abscess, neurosyphilis, and Lyme neuroborreliosis. From 2015 to 2020, a total of 3579 cases of CNS infections have been recorded in the DASGIB database. Using the unique civil registration number assigned to all Danish residents, the database can be unambiguously linked with nationwide healthcare registries at the individual level. This enables researchers to conduct detailed population-based and longitudinal observational studies of risk and prognosis of CNS infections and to compare them with matched population cohorts. The database is well-suited for epidemiological research and the DASGIB network forms a solid infrastructure for future national and international collaborations.

Viral meningitis: an overview

Meningitis is a serious condition that affects the central nervous system. It is an inflammation of the meninges, which is the membrane that surrounds both the brain and the spinal cord. Meningitis can be caused by bacterial, viral, or fungal infections. Many viruses, such as enteroviruses, herpesviruses, and influenza viruses, can cause this neurological disorder. However, enteroviruses have been found to be the underlying cause of most viral meningitis cases worldwide. With few exceptions, the clinical manifestations and symptoms associated with viral meningitis are similar for the different causative agents, which makes it difficult to diagnose the disease at early stages. The pathogenesis of viral meningitis is not clearly defined, and more studies are needed to improve the health care of patients in terms of early diagnosis and management. This review article discusses the most common causative agents, epidemiology, clinical features, diagnosis, and pathogenesis of viral meningitis.

Diagnostic accuracy of cerebrospinal fluid lactate in confirmed cases of acute bacterial meningitis in children

Objective:

To determine the diagnostic accuracy of cerebrospinal fluid lactate level in confirmed cases of acute bacterial meningitis in children

Methods:

This cross sectional study was conducted in the Department of Paediatrics, King Edward Medical University/ Mayo Hospital, Lahore from January to December 2018. A total of 250 children, between two months - 12 years of age, of both the genders, with suspected acute bacterial meningitis were included by non-probability consecutive sampling. Each child was subjected to lumbar puncture for biochemistry, cytology, culture, and lactate level. CSF lactate level of 1.1-2.4 mmol/L was taken as normal, and >2.4 mmol/L was taken as cut off for acute bacterial meningitis. All collected data was entered and analyzed in SPSS version 22. A 2 x 2 table was made to calculate diagnostic accuracy, sensitivity, specificity, positive and negative predictive value for CSF Lactate.

Results:

The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of CSF lactate taking CSF culture as gold standard was 100%, 60.61%, 17.27%, 100% and 63.6% respectively, with kappa of 0.19 and p value of 0.000.

Conclusion:

At a cut off value of 2.4 mmol/L, cerebrospinal fluid lactate level has a high diagnostic accuracy for acute bacterial meningitis.

CSF lactate

Lactate is produced from anaerobic glycolysis, which occurs in most tissues in the human body. Blood lactate is tested in most physiologically unwell patients in the Emergency Department and helps to guide treatment and prognosis. Cerebrospinal fluid (CSF) lactate, however, is not often measured. Various central nervous system (CNS) conditions lead to a rise in CSF lactate, including acute neurological infection, stroke, seizures and mitochondrial pathologies. This article discusses the utility and limitations of CSF lactate, highlighting specific clinical situations where it can help in the diagnosis of CNS infections and unexplained encephalopathy.

Predictors of infectious meningitis or encephalitis: the yield of cerebrospinal fluid in a cross-sectional study

Background

Cerebrospinal fluid (CSF) analyses are recommended in patients with meningitis and/or encephalitis, but evidence regarding its diagnostic yield is low. We aimed to determine predictors of infectious pathogens in the CSF of adult patients presenting with meningitis, and/or encephalitis.

Methods

Consecutive patients with meningitis and/or encephalitis form 2011–17 at a Swiss academic medical care center were included in this cross-sectional study. Clinical, neuroradiologic, and laboratory data were collected as exposure variables. Infectious meningitis and/or encephalitis were defined as the composite outcome.

For diagnosis of bacterial meningitis the recommendations of the European Society of Clinical Microbiology and Infectious Diseases were followed. Viral meningitis was diagnosed by detection of viral ribonucleic or deoxyribonucleic acid in the CSF. Infectious encephalitis was defined according to the International Encephalitis Consortium (IEC). Meningoencephalitis was diagnosed if the criteria for meningitis and encephalitis were fulfilled. Multinomial logistic regression was performed to identify predictors of the composite outcome. To quantify discriminative power, the c statistic analogous the area under the receiver-operating curve (AUROC) was calculated. An AUROC between 0.7–0.8 was defined as “good”, 08–0.9 as “excellent”, and > 0.9 as “outstanding”. Calibration was defined as “good” if the goodness of fit tests revealed insignificant p-values.

Results

Among 372 patients, infections were diagnosed in 42.7% presenting as meningitis (51%), encephalitis (32%), and meningoencephalitis (17%). Most frequent infectious pathogens were Streptococcus pneumoniae, Varicella zoster, and Herpes simplex 1&2. While in multivariable analysis lactate concentrations and decreased glucose ratios were the only independent predictors of bacterial infection (AUROCs 0.780, 0.870, and 0.834 respectively), increased CSF mononuclear cells were the only predictors of viral infections (AUROC 0.669). All predictors revealed good calibration.

Conclusions

Prior to microbiologic workup, CSF data may guide clinicians when infection is suspected while other laboratory and neuroradiologic characteristics seem less useful. While increased CSF lactate and decreased glucose ratio are is the most reliable predictors of bacterial infections in patients with meningitis and/or encephalitis, only mononuclear cell counts predicted viral infections.

Trial registration

ClinicalTrials.gov identifier NCT03856528. Registered on February 26th 2019.

Methods for rapid diagnosis of meningitis etiology in adults

Infectious meningitis can be caused by viral, bacterial or fungal pathogens. Despite widely available treatments, many types of infectious meningitis are still associated with significant morbidity and mortality. Delay in diagnosis contributes to poor outcomes. Cerebrospinal fluid cultures have been used traditionally but are time intensive and sensitivity is decreased by empiric treatment prior to culture. More rapid techniques such as the cryptococcal lateral flow assay (IMMY), GeneXpert MTB/Rif Ultra (Cepheid) and FilmArray multiplex-PCR (Biofire) are three examples that have drastically changed meningitis diagnostics. This review will discuss a holistic approach to diagnosing bacterial, mycobacterial, viral and fungal meningitis.

Delirium in Meningitis and Encephalitis: Emergence and Prediction in a 6-Year Cohort

BACKGROUND/OBJECTIVE

Data regarding delirium in patients presenting with infections of the central nervous system, such as meningitis and/or encephalitis (ME), are scarce. We aimed to determine the frequency and early predictors of delirium in the acute phase of ME.

METHODS

We assessed clinical, radiologic, and laboratory data of patients with ME at a Swiss academic medical center from 2011 to 2017. The highest Intensive Care Delirium Screening Checklist (ICDSC) score was assessed within 24 hours around lumbar puncture. Multivariable logistic regression was performed to identify predictors of delirium (ICDSC ≥4).

RESULTS

Among 330 patients with ME, infectious pathogens were identified in 41%. An ICDSC >1 was found in 28% with and 19% without identified infectious pathogens. Delirium was diagnosed in 18% with and 14% without infectious pathogens and significantly associated with prolonged in-hospital treatment and mechanical ventilation, more frequent administration of neuroleptics and anesthetics (in 96% with delirium vs 35% without), complications, and less recovery to premorbid functional baseline. Low serum albumin at presentation was the only independent predictor of delirium (area under the receiver-operating curve [AUROC] = 0.792) in patients with pathogens. In patients with infections, the AUROC was smallest for encephalitis (AUROC = 0.641) and larger for patients with meningeal infections (meningitis AUROC = 0.807; meningoencephalitis AUROC = 0.896).

CONCLUSIONS

Delirium in the context of ME is seen in almost every fifth patient and linked to prolonged treatment, complications, and incomplete recovery. Among clinical, radiologic, and laboratory parameters, the good calibration and discrimination of low albumin serum concentrations for the prediction of delirium in patients with ME seem promising, especially if meninges are affected.

Lyme neuroborreliosis in adults: A nationwide prospective cohort study

The goal of this paper is to characterize the clinical presentation, serological results, current antibiotic treatment practice, including compliance with current European guidelines, and outcome in adults with Lyme neuroborreliosis (LNB) diagnosed at departments of infectious diseases in Denmark. Using a nationwide prospective cohort of patients with central nervous system infections, we identified all adults (≥ 18 years of age) treated for LNB at departments of infectious diseases in Denmark from 2015 through 2017. The database contains information on baseline demographics, history of tick bite, erythema migrans, clinical presentation, laboratory results of blood samples, and cerebrospinal (CSF) biochemistry (e.g. specific Borrelia burgdorferi sensu lato (s.l.) antibodies in serum, B. burgdorferi s.l. intrathecal antibody index) as well as antibiotic therapy. Outcome was assessed by the Glasgow Outcome Scale (GOS) and the presence of residual symptoms at follow-up one month after discharge. We included 194 LNB patients with a median age of 59 years (range 18-85 years, interquartile range [IQR] 47-69 years). The female-to-male ratio was 0.8. A total of 177 of 191 (93 %) of patients had early (second stage) LNB. A history of tick bite or erythema migrans was registered in 75 (39 %) and 49 (25 %) patients, respectively. The median duration of neurological symptoms before first hospital contact was 21 days (range 0-600 days, IQR 10-42 days). Predominant symptoms consisted of radicular pain in 135 of 194 (70 %), cranial nerve paresis in 88 of 194 (45 %), headache in 71 of 185 (38 %), and extremity paresis in 33 of 194 (17 %) patients. Serum-B. burgdorferi s.l. IgM and/or IgG antibodies were detectable in 166 of 181 (92 %) patients at the time of first CSF investigation. Median duration of antibiotic treatment was 14 days (range 10-35 days, IQR 14-21 days) and 59 (39 %) of the patients received intravenous ceftriaxone and/or benzylpenicillin G throughout treatment. At the 1-month follow-up, GOS was unfavorable (< 5) in 54 of 193 (28 %) patients. An unfavorable GOS score was more often registered in patients with ≥ 45 days of symptom duration (20 of 45 (44 %) vs. 34 of 145 (23 %); P = 0.006). In conclusion, a European cohort of adult patients with LNB diagnosed between 2015-2017 presented with classic symptoms and CSF findings. However, a substantial diagnostic delay was still observed. In disagreement with current guidelines, a substantial part of LNB patients were treated with antibiotics longer than 14 days and/or intravenously as route of administration.

Performance of lactate in discriminating bacterial meningitis from enteroviral meningitis

The cytological and biochemical examination of cerebrospinal fluid (CSF) has been used for the presumed diagnosis of bacterial meningitis until the final microbiological results are achieved. We assessed the ability of CSF lactate in comparison with other CSF parameters to discriminate bacterial and enteroviral community acquired meningitis. We included 1,187 CSF samples of acute community-acquired meningitis, being 662 cases of bacterial and 525 of enteroviral meningitis. Lactate concentration (mg/dL), leukocyte count/mm³, protein (mg/dL), and glucose (mg/dL) were compared between bacterial and viral meningitis. Receiver operator characteristic (ROC) curves were used to assess diagnostic performance. CSF leukocytes, CSF protein and CSF lactate were significantly higher in bacterial meningitis cases (P<0.0001). CSF glucose was significantly lower in bacterial meningitis cases (P<0.0001). CSF lactate showed the best predictive ability with an area under the curve of 0.944 (95% CI 0.929 – 0.959). Considering a cut off of CSF lactate of 30 mg/dL, the sensitivity and specificity for bacterial meningitis were 84.1% and 99%, respectively. In the cytological and biochemical CSF analysis, CSF lactate was the most accurate marker for bacterial meningitis.

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.