Clinical decision rules for acute bacterial meningitis: current insights

Bacterial Meningitis Following Aneurysmal Subarachnoid Hemorrhage and Its Association with Cerebral Vasospasm

Aneurysmal subarachnoid hemorrhage (aSAH) is a critical condition with high in-hospital mortality rates. Delayed cerebral ischemia (DCI), a secondary complication associated with aSAH, can also contribute to morbidity and mortality. Although draining the hematoma from the subarachnoid space has been considered effective in preventing DCI, the placement of a drainage system could increase the risk of bacterial meningitis and ventriculitis. This study aimed to examine the association between meningitis following aSAH and the occurrence of DCI, focusing on the role of cerebral vasospasm. Patients who underwent endovascular coiling or surgical clipping for aSAH from April 2001 to March 2022 were included in this study, while those who did not undergo postoperative drainage were excluded. The patient's clinical characteristics, treatment modalities, and outcomes were then analyzed, after which logistic regression was used to assess the odds ratios (OR) for DCI. A total of 810 patients with aSAH were included in this study. Meningitis following aSAH was identified as an independent factor associated with DCI (odds ratio 5.0 [95% confidence intervals (CI) 2.3-11]). Other significant factors were female sex (odds ratio 1.5 [95% CI 0.89-2.5]) and surgical clipping (odds ratio 2.1 [95% CI 1.3-3.4]). This study demonstrated a significant association between meningitis following aSAH and the development of DCI, suggesting that the inflammatory environment associated with meningitis may contribute to cerebral vasospasm. Early recognition and treatment of meningitis in patients with aSAH could reduce the risk of DCI and improve patient outcomes.

The experience of using FilmArray Meningitis/Encephalitis Panel for the diagnosis of meningitis and encephalitis in pediatric patients

BACKGROUND/PURPOSE

Central nervous system infections can cause severe complications and even death in children. Early diagnosis of the causative pathogen can guide appropriate treatment and improve outcomes. The BioFire® FilmArray® Meningitis/Encephalitis Panel (FA-ME) is a multiplex polymerase chain reaction (PCR) assay targeting 14 pathogens. We aimed to examine FA-ME performance compared with conventional assays and its effect on antimicrobial usage.

METHODS

We prospectively enrolled 55 pediatric patients with suspected meningitis or encephalitis and simultaneously performed FA-ME and conventional assays. Sixty-three hospitalized patients with CNS infection before implementing FA-ME were considered controls. We compared the FA-ME results with conventional assays and the empiric antimicrobial usage and hospital stay between the two study groups.

RESULTS

Nine patients (16.4%) tested positive by FA-ME, four were bacterial, and five were viral. Three additional pathogens were detected by conventional assays: Enterococcus faecalis, Leptospira, and herpes simplex virus type 2. In the control group, two bacterial pathogens were detected by CSF culture and four viral pathogens by single PCRs. Compared with the control group, the FA-ME group had a shorter time for pathogen detection, but there were no significant differences in pathogen detection rate, duration of empiric antimicrobial therapy, and length of hospital stay.

CONCLUSION

Although no significant difference was found in empiric antimicrobial duration and length of stay between patients tested with FA-ME and conventional assays, FA-ME had the advantage of a shorter detection time and early exclusion of potential causative pathogens. The FA-ME results should be interpreted carefully based on the clinical presentation.

Population Pharmacokinetic Modeling and Probability of Target Attainment of Ceftaroline in Brain and Soft Tissues

Ceftaroline, approved to treat skin infections and pneumonia due to methicillin-resistant Staphylococcus aureus (MRSA), has been considered for the treatment of central nervous system (CNS) infections. A population pharmacokinetic (popPK) model was developed to describe ceftaroline soft tissue and cerebrospinal fluid (CSF) distributions and investigate the probability of target attainment (PTA) of the percentage of the dosing interval that the unbound drug concentration exceeded the MIC (%fT_>MIC) to treat MRSA infections. Healthy subjects' plasma and microdialysate concentrations from muscle and subcutaneous tissue following 600 mg every 12 h (q12h) and q8h and neurosurgical patients' plasma and CSF concentrations following single 600-mg dosing were used. Plasma concentrations were described by a two-compartment model, and tissue concentrations were incorporated as three independent compartments linked to the central compartment by bidirectional transport (clearance in [CL_in] and CL_out). Apparent volumes were fixed to physiological interstitial values. Healthy status and body weight were identified as covariates for the volume of the central compartment, and creatinine clearance was identified for clearance. The CSF glucose concentration (GLUC) was inversely correlated with CL_in,CSF. Simulations showed a PTA of >90% in plasma and soft tissues for both regimens assuming an MIC of 1 mg/L and a %fT_>MIC of 28.8%. Using the same target, patients with inflamed meninges (0.5 < GLUC ≤ 2 mmol/L) would reach PTAs of 99.8% and 97.2% for 600 mg q8h and q12h, respectively. For brain infection with mild inflammation (2 < GLUC ≤ 3.5 mmol/L), the PTAs would be reduced to 34.3% and 9.1%, respectively. Ceftaroline's penetration enhanced by meningeal inflammation suggests that the drug could be a candidate to treat MRSA CNS infections.

Navigating the ventricles: Novel insights into the pathogenesis of hydrocephalus

Congenital hydrocephalus occurs in one in 500-1000 babies born in the United States and acquired hydrocephalus may occur as the consequence of stroke, intraventricular and subarachnoid hemorrhage, traumatic brain injuries, brain tumors, craniectomy or may be idiopathic, as in the case of normal pressure hydrocephalus. Irrespective of its prevalence and significant impact on quality of life, neurosurgeons still rely on invasive cerebrospinal fluid shunt systems for the treatment of hydrocephalus that are exceptionally prone to failure and/or infection. Further understanding of this process at a molecular level, therefore, may have profound implications for improving treatment and quality of life for millions of individuals worldwide. The purpose of this article is to review the current research landscape on hydrocephalus with a focus on recent advances in our understanding of cerebrospinal fluid pathways from an evolutionary, genetics and molecular perspective.

Accuracy of Meningitis Bacterial Score (MBS) as an indicator in establishing the diagnosis of acute bacterial meningitis in adults

Bacterial meningitis persists as a worldwide threat contributing to high mortality and morbidity rate, where differentiating bacterial meningitis from aseptic meningitis is key for better management and outcomes. Hence, this study aimed to assess the Bacterial Meningeal Score (BMS) as a tool for early diagnosis of acute bacterial meningitis. This study employed a retrospective cross-sectional method using medical records of patients with meningitis and meningoencephalitis who were hospitalized at Dr. Soetomo Hospital, from January 2018 to September 2021. Data of demographics, clinical, laboratory and cerebrospinal fluid (CSF) profile and culture were collected. The diagnostic performance of the BMS in diagnosing acute bacterial meningitis was evaluated by its sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR +) and negative likelihood ratio (LR -). A total of 128 patients who had been diagnosed with meningitis and meningoencephalitis were included. Out of total patients, 53 samples were diagnosed with acute bacterial meningitis as confirmed by CSF culture. The sensitivity and specificity of BMS with cutoff >2.5 in diagnosing acute bacterial meningitis were 92.4% and 92.0%, respectively with PPV 89.1% and NPV 94.5%. The area under the curve (AUC) of BMS in diagnosing of acute bacterial meningitis was 95.6% (95%CI: 92.3%, 99%). A BMS score of greater than 2.5 indicates a high likelihood of acute bacterial meningitis, whereas a score less than 2.5 indicates a low likelihood.

Healthcare-Associated Ventriculitis and Meningitis: A Retrospective Analysis

Background and objective Healthcare-associated ventriculitis and meningitis (HAVM) is frequent in neurocritical patients and associated with significant mortality. Surgery and intracranial devices are usually necessary and may lead to infection. Classical clinical signs and cerebral spinal fluid (CSF) analysis may be unreliable. The purpose of this study was to characterize the prevalence of HAVM, risk factors, and interventions in the neurocritical population admitted in the ICU. Methods This was a retrospective single-center analysis of all adult neurocritical patients admitted to an ICU during a three-year period. Results A total of 218 neurocritical patients were included. The prevalence of HAVM was 13% and it was found to be associated with mortality. When suspected, it was not possible to exclude HAVM in 30% of the patients. HAVM was significantly associated with surgery, surgical reintervention, and brain devices. Sustained fever was the most frequent clinical sign, and it was significantly associated with unexcluded HAVM. CSF cell count was significantly higher in HAVM, though without microbiological isolation in most of the cases. Conclusion Brain damage, interventions, and devices may significantly alter cerebral homeostasis. Sustained fever is very frequent and may be attributed to several conditions. CSF cell count is useful for the diagnosis of HAVM. HAVM is a clinical challenge in the management of neurocritical patients with important therapeutic and prognostic implications.

Frequency of etiological agents of acute bacterial meningitis using culture and polymerase chain reaction assay

Bacterial meningitis is one of the most severe infectious diseases with high rate of morbidity and mortality in developing countries. The current study aimed to investigate the frequency of etiological agents of bacterial meningitis among patients admitted to three hospitals in Zanjan, Iran. A total of 100 cerebrospinal fluid (CSF) samples were collected aseptically, and cytochemical analysis, Gram staining, culture, and PCR were performed. Forty-six percent of CSF samples had positive bacterial culture results. However, PCR showed a higher detection rate of bacterial meningitis causing pathogens when compared with culture (52% vs. 46%; p > 0.05). Fifty-two percent of patients with bacterial meningitis were aged <1 year. The most prevalent pathogen was Streptococcus pneumoniae (36.5%), followed by Neisseria meningitidis (28.8%) and Streptococcus agalactiae (15.4%). Listeria monocytogenes was not isolated from CSF culture. The frequency of Haemophilus influenzae, L. monocytogenes and Escherichia coli was 7.7%, 1.9% and 9.6%, respectively. Although in patients aged <1 year, S. pneumonia, N. meningitidis and group B streptococcus were the most common pathogens causing meningitis, and in patients aged between 1 and 10 years, Escherichia coli was the most common. According to the results, the culture was less effective for diagnosis of bacterial meningitis than PCR. Our findings indicate that the most common causative agents of bacterial meningitis in Iran may be vaccine-preventable pathogens. Therefore, the prevention and control measures should be considered to reduce the incidence of bacterial meningitis.

Toll-like receptor linked cytokine profiles in cerebrospinal fluid discriminate neurological infection from sterile inflammation

Rapid determination of an infective aetiology causing neurological inflammation in the cerebrospinal fluid can be challenging in clinical practice. Post-surgical nosocomial infection is difficult to diagnose accurately, as it occurs on a background of altered cerebrospinal fluid composition due to the underlying pathologies and surgical procedures involved. There is additional diagnostic difficulty after external ventricular drain or ventriculoperitoneal shunt surgery, as infection is often caused by pathogens growing as biofilms, which may fail to elicit a significant inflammatory response and are challenging to identify by microbiological culture. Despite much research effort, a single sensitive and specific cerebrospinal fluid biomarker has yet to be defined which reliably distinguishes infective from non-infective inflammation. As a result, many patients with suspected infection are treated empirically with broad-spectrum antibiotics in the absence of definitive diagnostic criteria. To begin to address these issues, we examined cerebrospinal fluid taken at the point of clinical equipoise to diagnose cerebrospinal fluid infection in 14 consecutive neurosurgical patients showing signs of inflammatory complications. Using the guidelines of the Infectious Diseases Society of America, six cases were subsequently characterized as infected and eight as sterile inflammation. Twenty-four contemporaneous patients with idiopathic intracranial hypertension or normal pressure hydrocephalus were included as non-inflamed controls. We measured 182 immune and neurological biomarkers in each sample and used pathway analysis to elucidate the biological underpinnings of any biomarker changes. Increased levels of the inflammatory cytokine interleukin-6 and interleukin-6-related mediators such as oncostatin M were excellent indicators of inflammation. However, interleukin-6 levels alone could not distinguish between bacterially infected and uninfected patients. Within the patient cohort with neurological inflammation, a pattern of raised interleukin-17, interleukin-12p40/p70 and interleukin-23 levels delineated nosocomial bacteriological infection from background neuroinflammation. Pathway analysis showed that the observed immune signatures could be explained through a common generic inflammatory response marked by interleukin-6 in both nosocomial and non-infectious inflammation, overlaid with a toll-like receptor-associated and bacterial peptidoglycan-triggered interleukin-17 pathway response that occurred exclusively during infection. This is the first demonstration of a pathway dependent cerebrospinal fluid biomarker differentiation distinguishing nosocomial infection from background neuroinflammation. It is especially relevant to the commonly encountered pathologies in clinical practice, such as subarachnoid haemorrhage and post-cranial neurosurgery. While requiring confirmation in a larger cohort, the current data indicate the potential utility of cerebrospinal fluid biomarker strategies to identify differential initiation of a common downstream interleukin-6 pathway to diagnose nosocomial infection in this challenging clinical cohort.

High-mobility group box-1 protein as a novel biomarker to diagnose healthcare-associated ventriculitis and meningitis: a pilot study

BACKGROUND

The diagnosis of healthcare-associated ventriculitis and meningitis (HAVM) is challenging in the ICU setting. Traditional cerebrospinal fluid (CSF) markers and clinical signs of infection fail to diagnose HAVM in the critically ill setting. We sought to determine the diagnostic accuracy of measuring levels of high-mobility group box 1 (HMGB1) protein in cerebrospinal fluid (CSF) for the diagnosis of HAVM.

METHODS

In this prospective observational cohort study, we enrolled 29 patients with an implanted external ventricular drainage (EVD). We tested the accuracy of CSF-HMGB1 as a diagnostic test for HAVM when compared to standard CSF parameters.

RESULTS

HAVM was diagnosed in 11/29 (37.9%) patients. These patients had significantly higher CSF-HMGB1 levels compared to patients without HAVM (median [IQR] 43.39 [83.51] ng/mL vs 6.46 ng/mL [10.94]; P<0.001). CSF-HMGB1 and CSF-glucose were independently related to HAVM, with OR's (95% CI) of 15.43 (15.37 to 15.48, P<0.0001) and 0.31 (0.30 to 0.32, P<0.0001), respectively. The AUC [CI] of CSF-HMGB1 to predict HAVM was 0.83 [0.72 to 0.94].

CONCLUSIONS

HMGB1 is an accurate marker of HAVM and it adds incremental diagnostic value when paired with CSF-glucose measurements. Future larger and multicenter studies should assess the incremental diagnostic value of HMGB1 data when used alongside other established CSF markers of infection, and the external validity of these preliminary results.

Infectious Complications of Expanded Endoscopic Transsphenoidal Surgery: A Retrospective Cohort Analysis of 100 Cases

Objective  To identify perioperative factors that may predict postoperative cerebrospinal fluid (CSF) leak and meningitis following expanded endoscopic transsphenoidal surgery (EETS). Study Design  This is a retrospective study. This study was set at the Cedars-Sinai Medical Center, Los Angeles. A total of 78 patients who underwent EETS between January 2007 and November 2018 were participated. The main outcome measures were CSF leak and meningitis. Results  A total of 78 patients underwent a total of 100 EETS procedures; 17.9 and 10.3% of patients developed postoperative CSF leaks and meningitis, respectively. Out of eight, three patients with meningitis did not develop an observable CSF leak. The risk of developing meningitis in patients with a CSF leak was significantly higher than those without a leak, with an odds ratio (OR) of 11.48 (95% confidence interval, 2.33-56.47; p  = 0.004). Pituicytomas were significantly associated with meningitis compared with other pathologies. No other patient-specific factors were identified as risks for leak or meningitis, including method of skull base repair, sex, tumor volume, or body mass index, although there was a strong trend toward reduced CSF leak rates in patient with nasoseptal flaps used for skull base repair, compared with those without (9.5 vs. 25%). CSF protein was consistently elevated on the first CSF values obtained when meningitis was suspected. Conclusion  CSF leak and meningitis are common complications of expanded endonasal surgery No statistically significant risk factors for developing a postoperative leak other than the pathology of pituicytoma were identified, including method of skull base repair, although the use of a vascularized nasoseptal flap did trend toward a reduced CSF leak rate. CSF protein is the most sensitive marker for the presumptive diagnosis and timely treatment of meningitis.

Diagnostic Value of Procalcitonin for Bacterial Meningitis in Children: A Comparison Analysis Between Serum and Cerebrospinal Fluid Procalcitonin Levels

The aim of this study was to analyze and compare procalcitonin (PCT) levels in serum and cerebrospinal fluid (CSF) as tools for detecting bacterial meningitis (BM) in children. Serum and CSF PCT levels as well as albumin index (AI = CSF albumin/serum albumin × 1000) were measured from 29 BM, 25 viral meningitis (VM), and 47 non-meningitis patients. Differences between groups only for CSF PCT were significant. A stronger positive correlation between CSF PCT level and AI was observed in the BM patients ( R = 0.68, P < .001). As a predictor of BM, the area under the receiver operating characteristics curve for CSF PCT was greater than that of serum PCT (0.76 vs 0.67, P < .05) and a cutoff of ⩾0.085 ng/mL achieved 55.17% sensitivity and 95.83% specificity. High levels of CSF PCT may indicate loss of integrity of the blood-brain barrier; only CSF PCT has a diagnostic value for BM in children suspected meningitis.

Diagnostic Approach to Health Care- and Device-Associated Central Nervous System Infections

Health care- and device-associated central nervous system (CNS) infections have a distinct epidemiology, pathophysiology, and microbiology that require a unique diagnostic approach. Most clinical signs, symptoms, and tests used to diagnose community-acquired CNS infections are insensitive and nonspecific in neurosurgical patients due to postsurgical changes, invasive devices, prior antimicrobial exposure, and underlying CNS disease. The lack of a standardized definition of infection or diagnostic pathway has added to this challenge. In this review, we summarize the epidemiology, microbiology, and clinical presentation of these infections, discuss the issues with existing microbiologic tests, and give an overview of the current diagnostic approach.

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.

Cerebrospinal fluid monocytes in bacterial meningitis, viral meningitis, and neuroborreliosis

OBJECTIVE

Cerebrospinal fluid (CSF) leukocytes analysis is commonly used to diagnose meningitis and to differentiate bacterial from viral meningitis. Interpreting CSF monocytes can be difficult for physicians, especially in France where lymphocytes and monocytes results are sometimes pooled.

PATIENTS AND METHODS

We assessed SF monocytes in patients presenting with microbiologically confirmed meningitis (CSF leukocyte count>10/mm³ for adults or >30/mm³ for children<2 months), i.e. bacterial meningitis (BM), viral meningitis (VM), and neuroborreliosis (NB).

RESULTS

Two-hundred patients (82 BM, 86 VM, and 32 NB) were included. The proportions of monocytes were higher in VM (median 8%; range 0-57%) than in BM (median 5%; range 0-60%, P=0.03) or NB (median 5%; range 0-53%, P=0.46), with a high value overlap between conditions.

CONCLUSION

CSF monocytes should not be used to discriminate BM from VM and NB because of value overlaps.

Cerebrospinal Fluid Presepsin As a Marker of Nosocomial Infections of the Central Nervous System: A Prospective Observational Study

Background

Nosocomial CNS infection (NI-CNS) is a common and serious complication in neurocritical care patients. Timely, accurate diagnosis of NI-CNS is crucial, yet current infection markers lack specificity and/or sensitivity. Presepsin (PSP) is a novel biomarker of macrophage activation. Its utility in NI-CNS has not been explored. We first determined the normal range of cerebrospinal fluid (CSF) PSP in a control group without brain injury before collecting data on CSF PSP levels in neurocritical care patients. Samples were analyzed in four groups defined by systemic and neurological infection status.

Results

CSF PSP levels in 15 control patients without neurological injury were 50–100 pg/ml. Ninety-seven CSF samples were collected from 21 neurocritical care patients. In patients without NI-CNS or systemic infection, CSF PSP was 340.4 ± 201.1 pg/ml. Isolated NI-CNS was associated with CSF PSP levels of 640.8 ± 235.5 pg/ml, while levels in systemic infection without NI-CNS were 580.1 ± 329.7 pg/ml. Patients with both NI-CNS and systemic infection had CSF PSP levels of 1,047.7 ± 166.2 pg/ml. In neurocritical care patients without systemic infection, a cut-off value of 321 pg/ml gives sensitivity and specificity for NI-CNS of 100 and 58.3%, respectively.

Conclusion

CSF PSP may prove useful in diagnosing NI-CNS, but its current utility is as an additional marker only.

Overview of cerebrospinal fluid cytology

Cerebrospinal fluid (CSF) cytology, i.e., the cytologic evaluation of its cellular composition, forms an integral part of the neurologist's armamentarium. Total and differential cell counts provide important first information across a spectrum of pathologic conditions involving the central nervous system and its coverings. CSF samples require immediate processing, ideally within 1 hour from collection. Upon centrifugation cytology is commonly assessed on May-Grunwald-Giemsa stains. Several additional stains are available for the identification of infectious agents such as bacteria or fungi, or the further specification of neoplastic cells by immunocytochemistry. The evaluation warrants familiarity with cytologic characteristics of cells across normal and diseased states. In normal CSF, lymphocytes and monocytes are encountered. A predominance of neutrophil granulocytes suggests bacterial meningitis and prompts search for intracellular bacteria. In contrast, in viral and chronic infections lymphocytes and monocytes prevail. Upon activation lymphocytes typically enlarge and eventually differentiate into plasma cells. Similarly, monocytes differentiate into macrophages that clear cellular debris. Macrophages that contain fragments of erythrocytes or hemoglobin degradation products are referred to as erythro- or siderophages, both of which indicate prior subarachnoid hemorrhage. Likewise, the detection of tumor cells is specific for neoplastic meningitis, although false-negative CSF cytologies are frequent. In summary, detailed morphologic workup of CSF samples provides valuable diagnostic information and is mandated in all cases with elevated cell count, computed tomography-negative suspected subarachnoid hemorrhage, and neoplastic meningitis. In all cases it needs to be interpreted in the clinical context and complements other clinical and laboratory findings.

Chemical meningitis related to intra-CSF liposomal cytarabine

Therapeutic options of leptomeningeal metastases include intra-cerebrospinal fluid (CSF) chemotherapy. Among intra-CSF agents, liposomal cytarabine has advantages but can induce specific toxicities. A BRAF-V600E-mutated melanoma leptomeningeal metastases patient, treated by dabrafenib and liposomal cytarabine, presented after the first injection of liposomal cytarabine with hyperthermia and headaches. Despite sterile CSF/blood analyses, extended intravenous antibiotics were given and the second injection was delayed. The diagnosis of chemical meningitis was finally made. Dose reduction and appropriate symptomatic treatment permitted the administration of 15 injections of liposomal cytarabine combined with dabrafenib. A confirmation of the diagnosis of chemical meningitis is essential in order (1) not to delay intra-CSF or systemic chemotherapy or (2) to limit the administration of unnecessary but potentially toxic antibiotics.