Cerebrospinal fluid tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and interleukin-8 as diagnostic markers of cerebrospinal fluid infection in neurosurgical patients

Development and Validation of a Predictive Model for Postoperative Intracranial Infections in Neurosurgery with Risk Factor Analysis

BACKGROUND

Currently, the diagnosis of postneurosurgical intracranial infection is mainly dependent on cerebrospinal fluid (CSF) bacterial culture, which has the disadvantages of being time-consuming, having a low detection rate, and being easily affected by other factors. These disadvantages bring some difficulties to early diagnosis. Therefore, it is very important to construct a nomogram model to predict the risk of infection and provide a basis for early diagnosis and treatment.

METHODS

This retrospective study analyzed postneurosurgical patient data from the Fourth Affiliated Hospital of Harbin Medical University between January 2019 and September 2023. The patients were randomly assigned in an 8:2 ratio into the training cohort and the internal validation cohort. In the training cohort, initial screening of relevant indices was conducted via univariate analysis. Subsequently, the least absolute shrinkage and selection operator logistic regression identified significant potential risk factors for inclusion in the nomogram model. The model's discriminative ability was assessed using the area under the receiver operating characteristic curve, and its calibration was evaluated through calibration plots. The clinical utility of the model was determined using decision curve analysis and further validated by the internal validation cohort.

RESULTS

Multivariate logistic regression analysis of the training cohort identified 7 independent risk factors for postoperative intracranial infection: duration of postoperative external drainage (odds ratio [OR] 1.19, P = 0.005), continued fever (OR 2.11, P = 0.036), CSF turbidity (OR 2.73, P = 0.014), CSF pressure (OR 1.01, P = 0.018), CSF total protein level (OR 1.26, P = 0.026), CSF glucose concentration (OR 0.74, P = 0.029), and postoperative serum albumin level (OR 0.84, P < 0.001). Using these variables to construct the final model. The area under the receiver operating characteristic curve value of the model was 0.868 in the training cohort and 0.900 in the internal validation cohort. Calibration and the decision curve analysis indicated high accuracy and clinical benefit of the nomogram, findings that were corroborated in the validation cohort.

CONCLUSIONS

This study successfully developed a novel nomogram for predicting postoperative intracranial infection, demonstrating excellent predictive performance. It offers a pragmatic tool for the early diagnosis of intracranial infection.

Diagnostic value of cerebrospinal fluid levels of D-lactate, tumour necrosis factor-alpha and interleukin-6, -8, and -17 in suspected nosocomial meningitis

INTRODUCTION

This study aimed to determine the diagnostic value of interleukin (IL)-6, IL-8, IL-17, tumour necrosis factor-alpha (TNF-α) and D-lactate levels in the cerebrospinal fluid (CSF) of nosocomial meningitis patients.

METHODS

The CSF levels of cytokines and D-lactate were compared across 29 episodes of nosocomial meningitis, 38 episodes of pleocytosis (without meningitis) and 54 control subjects.

RESULTS

The CSF levels of IL-6, IL-8, and D-lactate were higher in the group with nosocomial meningitis compared to the control group and the group with pleocytosis without meningitis ( P < 0.05). For IL-6 levels (threshold: >440 pg/mL), the sensitivity and specificity were 55.17% and 94.74%, respectively. For IL-8 levels (threshold: >1,249 pg/mL), the sensitivity and specificity were 44.83% and 84.21%, respectively. In patients with nosocomial meningitis, when the threshold of D-lactate levels was >1.05 μmol/mL, the sensitivity and specificity were 75.86% and 63.16%, respectively. In pleocytosis (without meningitis) CSF samples and in nosocomial meningitis CSF samples, the highest area under the receiver operating characteristic curve (AUC) was calculated for triple combination model of IL-6, IL-8 and D-lactate levels (AUC 0.801, P < 0.001) and double combination model of IL-6 and IL-8 (AUC 0.790, P < 0.001).

CONCLUSION

Our study findings suggest that IL-6, IL-8 and D-lactate levels could be diagnostic markers for nosocomial meningitis.

Heparin-binding protein as a marker of ventriculostomy related infection and central nervous system inflammation in neuro-intensive care

OBJECTIVE

Diagnosis of ventriculostomy related infections (VRI) in the neuro-intensive care unit remains challenging and current biomarkers lack adequate precision. The aim of this study was to explore the potential of Heparin-binding protein (HBP) in cerebrospinal fluid (CSF) as a diagnostic biomarker of VRI.

METHODS

All patients treated with an external ventricular drain (EVD) between January 2009 and March 2010 at Skåne university hospital in Lund, Sweden, were consecutively included. CSF samples obtained during routine care were analyzed for HBP. VRI was defined as a positive bacterial microbiology test result on a CSF sample with an erythrocyte-corrected leukocyte count of > 50 × 106/l. HBP levels at VRI diagnosis was compared to peak HBP levels in non-VRI controls.

RESULTS

In total, 394 CSF samples from 103 patients were analyzed for HBP. Seven patients (6.8%) fulfilled VRI criteria. Levels of HBP were significantly higher in VRI subjects (31.7 ng/mL [IQR 26.9-40.7 ng/mL]) compared to non-VRI controls (7.7 ng/mL [IQR 4.1-24.5 ng/mL]) (p = 0.024). The AUC of the receiver operating characteristic (ROC) curve was 0.76 (95% confidence interval [CI], 0.62-0.90). Among non-VRI patients, HBP was highest in patients with acute bacterial meningitis. Patients with subarachnoid hemorrhage displayed higher HBP levels than those with traumatic brain injury or shunt dysfunction.

CONCLUSIONS

HBP levels were higher in VRI subjects and varied between patients and different diagnoses. To validate the clinical usefulness and added value of HBP as a biomarker for VRI, the results need to be confirmed in larger studies with head-to-head comparisons to current biomarkers.

Inflammation and Oxidative Stress: Potential Targets for Improving Prognosis After Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) has a high mortality rate and causes long-term disability in many patients, often associated with cognitive impairment. However, the pathogenesis of delayed brain dysfunction after SAH is not fully understood. A growing body of evidence suggests that neuroinflammation and oxidative stress play a negative role in neurofunctional deficits. Red blood cells and hemoglobin, immune cells, proinflammatory cytokines, and peroxidases are directly or indirectly involved in the regulation of neuroinflammation and oxidative stress in the central nervous system after SAH. This review explores the role of various cellular and acellular components in secondary inflammation and oxidative stress after SAH, and aims to provide new ideas for clinical treatment to improve the prognosis of SAH.

Interleukin 6 and Aneurysmal Subarachnoid Hemorrhage. A Narrative Review

Interleukin 6 (IL-6) is a prominent proinflammatory cytokine. Neuroinflammation in general, and IL-6 signaling in particular, appear to play a major role in the pathobiology and pathophysiology of aneurysm formation and aneurysmal subarachnoid hemorrhage (SAH). Most importantly, elevated IL-6 CSF (rather than serum) levels appear to correlate with delayed cerebral ischemia (DCI, “vasospasm”) and secondary (“vasospastic”) infarctions. IL-6 CSF levels may also reflect other forms of injury to the brain following SAH, i.e., early brain damage and septic complications of SAH and aneurysm treatment. This would explain why many researchers have found an association between IL-6 levels and patient outcomes. These findings clearly suggest CSF IL-6 as a candidate biomarker in SAH patients. However, at this point, discrepant findings in variable study settings, as well as timing and other issues, e.g., defining proper clinical endpoints (i.e., secondary clinical deterioration vs. angiographic vasospasm vs. secondary vasospastic infarct) do not allow for its routine use. It is also tempting to speculate about potential therapeutic measures targeting elevated IL-6 CSF levels and neuroinflammation in SAH patients. Corticosteroids and anti-platelet drugs are indeed used in many SAH cases (not necessarily with the intention to interfere with detrimental inflammatory signaling), however, no convincing benefit has been demonstrated yet. The lack of a robust clinical perspective against the background of a relatively large body of data linking IL-6 and neuroinflammation with the pathophysiology of SAH is somewhat disappointing. One underlying reason might be that most relevant studies only report correlative data. The specific molecular pathways behind elevated IL-6 levels in SAH patients and their various interactions still remain to be delineated. We are optimistic that future research in this field will result in a better understanding of the role of neuroinflammation in the pathophysiology of SAH, which in turn, will translate into the identification of suitable biomarkers and even potential therapeutic targets.

Plasma Levels of IL-6, IL-8, IL-10, ICAM-1, VCAM-1, IFNγ, and TNFα are not Associated with Delayed Cerebral Ischemia, Cerebral Vasospasm, or Clinical Outcome in Patients with Subarachnoid Hemorrhage

BACKGROUND

Delayed cerebral ischemia (DCI) is a serious and frequent complication following subarachnoid hemorrhage (SAH). The pathophysiology behind DCI remains poorly understood, but inflammation has been proposed to play a significant role. This study investigated the relationship between plasma levels of some of the most important inflammatory markers and DCI, cerebral vasospasm, and functional outcome in patients with SAH.

METHODS

In 90 patients with SAH, interleukin-6, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, high sensitivity C-reactive protein (HsCRP), interleukin-8, interleukin-10, interferon gamma, and tumor necrosis factor alpha were measured in peripheral blood day 3 and day 8 after SAH. Any occurrence of DCI or infection was recorded, and computed tomography angiography was performed on day 8. Clinical outcome was assessed after 3 months.

RESULTS

HsCRP on day 3 was higher in patients with angiographic vasospasm (P = 0.003), and HsCRP on day 8 was higher in patients with poor outcome (P = 0.014). No association with DCI, vasospasm, or outcome was found for any of the remaining analyzed substances.

CONCLUSIONS

High plasma levels of HsCRP were significantly associated with angiographic vasospasm and clinical outcome. Plasma levels of interleukin-6, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, interleukin-8, interleukin-10, interferon gamma, and tumor necrosis factor alpha were not associated with DCI, angiographic vasospasm, or clinical outcome at 3 months.

Neutrophil CD64 index in cerebrospinal fluid as a marker of bacterial ventriculitis in children with external ventricular drainage

Background

Bacterial ventriculitis is a common complication in children with temporary external ventricular drains (EVD) and the diagnosis is challenging. The present study compared the diagnostic accuracy of novel cerebrospinal fluid (CSF) marker - CD64 expression on neutrophils measured as neutrophil CD64 index (CD64in) to routine laboratory CSF and blood markers for bacterial ventriculitis in children with EVD.

Methods

We conducted a prospective, observational study, enrolling children with EVD. CD64in in CSF together with CSF markers (leukocyte count, percentage of neutrophils, glucose, and proteins) and blood markers (leukocyte and differential count, C-reactive protein (CRP), and procalcitonin (PCT)) were studied at the time of suspected bacterial ventriculitis. CD64in was measured by flow cytometry. Diagnostic accuracy determined by the area under the receiver–operating characteristic (ROC) curves (AUC) was defined for each marker.

Results

Thirty-three episodes of clinically suspected ventriculitis in twenty-one children were observed during a 26-month period. Episodes were classified into those with microbiologically proven ventriculitis (13 episodes) and into those with microbiologically negative CSF (20 episodes). CD64in and leukocyte count were the only CSF markers that could differentiate between groups with diagnostic accuracy of 0.875 and 0.694, respectively. Among blood markers only CRP and band neutrophils differentiated between groups with diagnostic accuracy of 0.792 and 0.721, respectively.

Conclusions

CD64in in CSF is a promising diagnostic marker of bacterial ventriculitis in children with EVD as it has higher diagnostic accuracy than routine blood and CSF markers for diagnosing bacterial ventriculitis at the time of clinical suspicion.

Tumor necrosis factor alpha and interleukin-1 beta levels in cerebrospinal fluid examination for the diagnosis of ventriculoperitoneal shunt-related ventriculitis

PURPOSE

Ventriculitis is known to develop after chronic inflammation and bacterial invasion of the ventricular surface with a recurrence of shunt infections. The aim of this study is to evaluate the diagnostic value of elevation in cerebrospinal fluid (CSF) interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) together with CSF culture and laboratory test results in the diagnosis of ventriculoperitoneal (VP) shunt-related ventriculitis, which is known to be more problematic than conventional shunt infection.

METHODS

The study included a total of 34 patients with a VP shunt due to hydrocephalus, who presented with a headache, fever, and shunt infection at the Emergency Department and had a pre-diagnosis of ventriculitis. Nineteen patients were diagnosed with shunt-related infection or ventriculitis using the CSF obtained from the shunt pump. The IL-1β and TNF-α levels from the CSF samples of all patients were measured using the Micro ELISA immunoassay method.

RESULTS

CSF direct microscopic observation revealed that the mean cell count, IL-1β level, CRP level, and blood leukocyte level were higher in patients with ventriculitis compared to those diagnosed with shunt infection (p = 0.02, p = 0.009, p = 0.004, and p = 0.009, respectively). The probability of predicting positive culture outcome was 92.7% with 90.9% sensitivity and 82.6% specificity when IL-1β values exceeded 4.0 pg/ml. TNF-α values did not show a significant, reliable pattern compared to IL-1β.

CONCLUSIONS

IL-1β is a reliable parameter which shall be used in the diagnosis of ventriculitis by predicting positive culture outcome with high sensitivity and specificity.

Clinical and Laboratory Characteristics for the Diagnosis of Bacterial Ventriculitis After Aneurysmal Subarachnoid Hemorrhage

Background

The diagnosis of nosocomial bacterial ventriculitis in patients with subarachnoid hemorrhage (SAH) can be challenging.

Methods

We performed a retrospective study on the diagnostic accuracy of clinical and laboratory characteristics for the diagnosis of bacterial ventriculitis in 209 consecutive patients with an aneurysmal SAH admitted in a tertiary referral center from 2008 to 2010. Diagnostic value of clinical characteristics and inflammatory indexes in CSF and blood were determined for three diagnostic categories: (1) no suspicion for bacterial ventriculitis; (2) clinical suspicion for bacterial ventriculitis, defined as initiation of empirical antibiotic treatment for ventriculitis, but negative CSF cultures; and (3) CSF culture-positive bacterial ventriculitis.

Results

Empirical antibiotics for suspected ventriculitis was initiated in 48 of 209 (23 %) patients. CSF cultures were positive in 11 (5 %) patients. Within the group of suspected ventriculitis, only longer duration of CSF drainage and lower CSF red blood cell counts predicted for culture positivity. None of the other clinical features or inflammatory indexes in CSF and blood were associated with culture-proven bacterial ventriculitis.

Conclusions

Nosocomial bacterial ventriculitis in patients with aneurysmal SAH is often suspected but confirmed by culture in a minority of cases. Improvement of diagnostics for nosocomial bacterial ventriculitis in patients with aneurysmal SAH is needed.

Development of a prediction rule for diagnosing postoperative meningitis: a cross-sectional study

OBJECTIVE

Diagnosing nosocomial meningitis (NM) in neurosurgical patients is difficult. The standard CSF test is not optimal and when it is obtained, CSF cultures are negative in as many as 70% of cases. The goal of this study was to develop a diagnostic prediction rule for postoperative meningitis using a combination of clinical, laboratory, and CSF variables, as well as risk factors (RFs) for CNS infection.

METHODS

A cross-sectional study was performed in 4 intensive care units in Medellín, Colombia. Patients with a history of neurosurgical procedures were selected at the onset of febrile symptoms and/or after an increase in acute-phase reactants. Their CSF was studied for suspicion of infection and a bivariate analysis was performed between the dependent variable (confirmed/probable NM) and the identified independent variables. Those variables with a p value ≤ 0.2 were fitted in a multiple logistic regression analysis with the same dependent variable. After determining the best model according to its discrimination and calibration, the β coefficient for each selected dichotomized variable obtained from the logistic regression model was used to construct the score for the prediction rule.

RESULTS

Among 320 patients recruited for the study, 154 had confirmed or probable NM. Using bivariate analysis, 15 variables had statistical associations with the outcome: aneurysmal subarachnoid hemorrhage (aSAH), traumatic brain injury, CSF leak, positioning of external ventricular drains (EVDs), daily CSF draining via EVDs, intraventricular hemorrhage, neurological deterioration, age ≥ 50 years, surgical duration ≥ 220 minutes, blood loss during surgery ≥ 200 ml, C-reactive protein (CRP) ≥ 6 mg/dl, CSF/serum glucose ratio ≤ 0.4 mmol/L, CSF lactate ≥ 4 mmol/L, CSF leukocytes ≥ 250 cells, and CSF polymorphonuclear (PMN) neutrophils ≥ 50%. The multivariate analysis fitted a final model with 6 variables for the prediction rule (aSAH diagnosis: 1 point; CRP ≥ 6 mg/dl: 1 point; CSF/serum glucose ratio ≤ 0.4 mmol/L: 1 point; CSF leak: 1.5 points; CSF PMN neutrophils ≥ 50%: 1.5 points; and CSF lactate ≥ 4 mmol/L: 4 points) with good calibration (Hosmer-Lemeshow goodness of fit = 0.71) and discrimination (area under the receiver operating characteristic curve = 0.94).

CONCLUSIONS

The prediction rule for diagnosing NM improves the diagnostic accuracy in neurosurgical patients with suspicion of infection. A score ≥ 6 points suggests a high probability of neuroinfection, for which antibiotic treatment should be considered. An independent validation of the rule in a different group of patients is warranted.

Indicators of external ventricular drainage-related infections--a retrospective observational study

BACKGROUND

External ventricular drainage (EVD) is frequently used in different groups of patients in neurocritical care. Despite the frequent use of EVD, no consensus regarding the diagnosis of EVD-related infection currently exists, and diagnosis is commonly based on criteria for the diagnosis of non-EVD-related CNS infections. This study evaluates the diagnostic accuracy of clinical and laboratory parameters for the prediction of EVD-related infection in patients with proven EVD-related infection.

METHODS

In two tertiary care centers, data on EVD insertions were matched with a microbiologic database of cultured microorganisms and positive Gram stains of cerebrospinal fluid (CSF) to identify patients with EVD-related infections. Available clinical data and results of blood tests and CSF analysis were retrospectively collected. Predefined potential clinical and laboratory predictors of EVD-related infection were compared between three time points: at the time EVD insertion and 48 h before and at the time of occurrence of EVD-related infection.

RESULTS

Thirty-nine patients with EVD-associated infection defined by positive CSF culture or positive CSF Gram stains and concomitant clinical signs of infection were identified. At the time of infection, a significantly higher incidence of abnormal temperature, high respiratory rate, and a slightly but significantly higher incidence of decreased mental state were observed. The assessed blood and CSF parameters did not significantly differ between the different assessment time points.

CONCLUSIONS

Our analysis of 39 patients with culture positive EVD-related infection showed that commonly used clinical and laboratory parameters are not reliable infection predictors.

Applying the bacterial meningitis score in children with cerebrospinal fluid pleocytosis: a single center's experience

PURPOSE

The widespread introduction of bacterial conjugate vaccines has decreased the risk of cerebrospinal fluid (CSF) pleocytosis due to bacterial meningitis (BM) in children. However, most patients with CSF pleocytosis are hospitalized and treated with parenteral antibiotics for several days. The bacterial meningitis score (BMS) is a validated multivariate model derived from a pediatric population in the postconjugate vaccine era and has been evaluated in several studies. In the present study, we examined the usefulness of BMS in South Korean patients.

METHODS

This study included 1,063 patients with CSF pleocytosis aged between 2 months and 18 years. The BMS was calculated for all patients, and the sensitivity and negative predictive value (NPV) of the test were evaluated.

RESULTS

Of 1,063 patients, 1,059 (99.6%) had aseptic meningitis (AM). Only four patients (0.4%) had BM. The majority of patients (98%) had a BMS of ≤1, indicating a diagnosis of AM. The BMS was 0 in 635 patients (60%) and 1 in 405 patients (38%). All four BM patients had a BMS of ≥4.

CONCLUSION

To our knowledge, this is the first study to investigate the diagnostic strength of the BMS in South Korea. In our study, the BMS showed 100% sensitivity and 100% NPV. Therefore, we believe that the BMS is a good clinical prediction rule to identify children with CSF pleocytosis who are at a risk of BM.

Comparative proteomics of cerebrospinal fluid reveals a predictive model for differential diagnosis of pneumococcal, meningococcal, and enteroviral meningitis, and novel putative therapeutic targets

BACKGROUND

Meningitis is the inflammation of the meninges in response to infection or chemical agents. While aseptic meningitis, most frequently caused by enteroviruses, is usually benign with a self-limiting course, bacterial meningitis remains associated with high morbidity and mortality rates, despite advances in antimicrobial therapy and intensive care. Fast and accurate differential diagnosis is crucial for assertive choice of the appropriate therapeutic approach for each form of meningitis.

METHODS

We used 2D-PAGE and mass spectrometry to identify the cerebrospinal fluid proteome specifically related to the host response to pneumococcal, meningococcal, and enteroviral meningitis. The disease-specific proteome signatures were inspected by pathway analysis.

RESULTS

Unique cerebrospinal fluid proteome signatures were found to the three aetiological forms of meningitis investigated, and a qualitative predictive model with four protein markers was developed for the differential diagnosis of these diseases. Nevertheless, pathway analysis of the disease-specific proteomes unveiled that Kallikrein-kinin system may play a crucial role in the pathophysiological mechanisms leading to brain damage in bacterial meningitis. Proteins taking part in this cellular process are proposed as putative targets to novel adjunctive therapies.

CONCLUSIONS

Comparative proteomics of cerebrospinal fluid disclosed candidate biomarkers, which were combined in a qualitative and sequential predictive model with potential to improve the differential diagnosis of pneumococcal, meningococcal and enteroviral meningitis. Moreover, we present the first evidence of the possible implication of Kallikrein-kinin system in the pathophysiology of bacterial meningitis.

Multicenter testing of the rapid quantification of radical oxygen species in cerebrospinal fluid to diagnose bacterial meningitis

Purpose

Meningitis is a serious concern after traumatic brain injury (TBI) or neurosurgery. This study tested the level of reactive oxygen species (ROS) in cerebrospinal fluid (CSF) to diagnose meningitis in febrile patients several days after trauma or surgery.

Methods

Febrile patients (temperature > 38°C) after TBI or neurosurgery were included prospectively. ROS were measured in CSF within 4 hours after sampling using luminescence in the basal state and after cell stimulation with phorbol 12-myristate 13-acetate (PMA). The study was conducted in a single-center cohort 1 (n = 54, training cohort) and then in a multicenter cohort 2 (n = 136, testing cohort) in the Intensive Care and Neurosurgery departments of two teaching hospitals. The performance of the ROS test was compared with classical CSF criteria, and a diagnostic decision for meningitis was made by two blinded experts.

Results

The production of ROS was higher in the CSF of meningitis patients than in non-infected CSF, both in the basal state and after PMA stimulation. In cohort 1, ROS production was associated with a diagnosis of meningitis with an AUC of 0.814 (95% confidence interval (CI) [0.684–0.820]) for steady-state and 0.818 (95% CI [0.655–0.821]) for PMA-activated conditions. The best threshold value obtained in cohort 1 was tested in cohort 2 and showed high negative predictive values and low negative likelihood ratios of 0.94 and 0.36 in the basal state, respectively, and 0.96 and 0.24 after PMA stimulation, respectively.

Conclusion

The ROS test in CSF appeared suitable for eliminating a diagnosis of bacterial meningitis.

Intracisternal administration of SB203580, a p38 mitogen-activated protein kinase inhibitor, attenuates cerebral vasospasm via inhibition of tumor-necrosis factor-α

Tumor-necrosis factor-α (TNF-α) is critical to the development of cerebral vasospasm after subarachnoid hemorrhage (SAH). Hence, therapeutic strategies targeting TNF-α can attenuate cerebral vasospasm. This study investigated the effects of SB203580, a p38 mitogen-activated protein kinase (MAPK) inhibitor, on TNF-α concentration in the cerebral arteries and the cerebrospinal fluid (CSF) after SAH and on subsequent cerebral vasospasm. Twenty-three rabbits were divided into four groups: (i) control (without SAH), (ii) SAH (SAH only), (iii) dimethylsulfoxide (DMSO, vehicle), and (iv) SB203580. The severity of vasospasm and the immunoreactivities of TNF-α and phosphorylated p38 MAPK in the brain vessels were determined in all animals, and the concentrations of TNF-α in the CSF were also assessed. Severe vasospasm was observed in the rabbits from the SAH and DMSO groups. SB203580 reversed vasospasm after SAH. Lower immunoreactivities of TNF-α and phosphorylated p38 MAPK were found in the basilar artery in the SB203580 group than in the DMSO group. The concentration of TNF-α in the CSF increased after SAH, but treatment with SB203080 after SAH suppressed this increase. Our data show that SB203580 reversed cerebral vasospasm by inhibiting the phosphorylation of p38 MAPK in the basilar artery and by suppressing the increase in TNF-α in the basilar artery and CSF after SAH. SB203580 could therefore potentially be used for the treatment of cerebral vasospasm after SAH.

Cerebrospinal fluid and plasma cytokines after subarachnoid haemorrhage: CSF interleukin-6 may be an early marker of infection

BACKGROUND

Cytokines and cytokine receptor concentrations increase in plasma and cerebrospinal fluid (CSF) of patients following subarachnoid haemorrhage (SAH). The relationship between plasma and CSF cytokines, and factors affecting this, are not clear.

METHODS

To help define the relationship, paired plasma and cerebrospinal fluid (CSF) samples were collected from patients subject to ventriculostomy. Concentrations of key inflammatory cytokines, interleukin (IL)-1ß, IL-1 receptor antagonist (IL-1Ra), IL-1 receptor 2, IL-6, IL-8, IL-10, tumour necrosis factor (TNF)-α, and TNF receptors (TNF-R) 1 and 2 were determined by immunoassay of CSF and plasma from 21 patients, where samples were available at three or more time points.

RESULTS

Plasma concentrations of IL-1ß, IL-1Ra, IL-10, TNF-α and TNF-R1 were similar to those in CSF. Plasma TNF-R2 and IL-1R2 concentrations were higher than in CSF. Concentrations of IL-8 and IL-6 in CSF were approximately10 to 1,000-fold higher than in plasma. There was a weak correlation between CSF and plasma IL-8 concentrations (r = 0.26), but no correlation for IL-6. Differences between the central and peripheral pattern of IL-6 were associated with episodes of ventriculostomy-related infection (VRI). A VRI was associated with CSF IL-6 >10,000 pg/mL (P = 0.0002), although peripheral infection was not significantly associated with plasma IL-6.

CONCLUSIONS

These data suggest that plasma cytokine concentrations cannot be used to identify relative changes in the CSF, but that measurement of CSF IL-6 could provide a useful marker of VRI.

The diagnostic value of cytokine and nitric oxide concentrations in cerebrospinal fluid for the differential diagnosis of meningitis

PURPOSE

In several cases of meningitis routinely used diagnostic procedures are unable to identify the cause of this disease. The objective of the present study was to determine whether proinflammatory cytokine (tumour necrosis factor (TNF-α), interleukin-1β (IL-1β), interleukin-8 (IL-8)) and nitric oxide (NO) concentrations in the CSF are useful markers for the differential diagnosis of meningitis.

MATERIAL AND METHODS

Sixty-seven patients (42 patients with bacterial meningitis and 25 patients with viral meningitis) were included in the present study. In the investigated group, the TNF-α, IL-1β and IL-8 concentrations in the CSF samples collected on the day of admission were assessed. Furthermore, the NO concentrations were assessed in 23 patients.

RESULTS

The results revealed that the measurement of proinflammatory cytokines in CSF can aid in a differential diagnosis. In particular, a high concentration of TNF-α may be a sensitive and specific marker of a bacterial aetiology of the neuroinfection. In the present study, TNF-α concentrations greater than 75.8 pg/ml differentiated between bacterial and viral meningitis with 100% sensitivity and specificity. The NO concentration in the CSF was also significantly greater in patients with bacterial meningitis than in those with viral meningitis.

CONCLUSIONS

The assessment of TNF-α, IL-1β and IL-8 concentrations in the CSF is useful in the differential diagnosis of neuroinfection. Because many factors may influence NO production in the central nervous system (CNS), it is not clear whether NO values can be used for the differential diagnosis of meningitis, and further studies are required.

The Molecular Mechanisms that Promote Edema After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a devastating type of stroke with no effective therapies. Clinical advances in ICH treatment are limited by an incomplete understanding of the molecular mechanisms responsible for secondary injury and poor outcome. Increasing evidence suggests that cerebral edema is a major contributor to secondary injury and poor outcome in ICH. ICH activates specific signaling pathways that promote edema and damage neuronal tissue. By increasing our understanding of these pathways, we may be able to target them pharmaceutically to reduce edema in ICH patients. In this review, we focus on three major signaling pathways that promote edema after ICH: (1) the coagulation cascade and thrombin, (2) the inflammatory response and matrix metalloproteinases, and (3) the complement cascade and hemoglobin toxicity. We will describe the experimental evidence that confirms these pathways promote edema in ICH, discuss potential targets for new therapies, and comment on important directions for future research.

Automated detection of external ventricular and lumbar drain-related meningitis using laboratory and microbiology results and medication data

Objective

Monitoring of healthcare-associated infection rates is important for infection control and hospital benchmarking. However, manual surveillance is time-consuming and susceptible to error. The aim was, therefore, to develop a prediction model to retrospectively detect drain-related meningitis (DRM), a frequently occurring nosocomial infection, using routinely collected data from a clinical data warehouse.

Methods

As part of the hospital infection control program, all patients receiving an external ventricular (EVD) or lumbar drain (ELD) (2004 to 2009; n = 742) had been evaluated for the development of DRM through chart review and standardized diagnostic criteria by infection control staff; this was the reference standard. Children, patients dying <24 hours after drain insertion or with <1 day follow-up and patients with infection at the time of insertion or multiple simultaneous drains were excluded. Logistic regression was used to develop a model predicting the occurrence of DRM. Missing data were imputed using multiple imputation. Bootstrapping was applied to increase generalizability.

Results

537 patients remained after application of exclusion criteria, of which 82 developed DRM (13.5/1000 days at risk). The automated model to detect DRM included the number of drains placed, drain type, blood leukocyte count, C-reactive protein, cerebrospinal fluid leukocyte count and culture result, number of antibiotics started during admission, and empiric antibiotic therapy. Discriminatory power of this model was excellent (area under the ROC curve 0.97). The model achieved 98.8% sensitivity (95% CI 88.0% to 99.9%) and specificity of 87.9% (84.6% to 90.8%). Positive and negative predictive values were 56.9% (50.8% to 67.9%) and 99.9% (98.6% to 99.9%), respectively. Predicted yearly infection rates concurred with observed infection rates.

Conclusion

A prediction model based on multi-source data stored in a clinical data warehouse could accurately quantify rates of DRM. Automated detection using this statistical approach is feasible and could be applied to other nosocomial infections.

Heparin-binding protein: a diagnostic marker of acute bacterial meningitis

BACKGROUND

The early detection of bacterial meningitis is crucial for successful outcome. Heparin-binding protein, a potent inducer of increased vascular permeability, is released from activated neutrophils in severe sepsis.

OBJECTIVE

In this study we investigated whether heparin-binding protein levels in cerebrospinal fluid could be used as a diagnostic marker for acute bacterial meningitis.

DESIGN

One prospective and one retrospective patient cohort from two university hospitals in Sweden were analyzed.

SETTING AND PATIENTS

Cerebrospinal fluid samples were collected from 174 patients with suspected central nervous system infection. Thirty-seven patients with acute community-acquired bacterial meningitis, four patients with neurosurgical bacterial meningitis, 29 patients with viral meningitis or encephalitis, seven patients with neuroborreliosis, and 97 control patients were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Cerebrospinal fluid samples were analyzed for the concentrations of heparin-binding protein, lactate, protein, glucose, neutrophils, and mononuclear cells. Heparin-binding protein levels were significantly higher (p < .01) in patients with acute bacterial meningitis (median 376 ng/mL, range 12-858 ng/mL) than in patients with viral central nervous system infection (median 4.7 ng/mL, range 3.0-41 ng/mL) or neuroborreliosis (median 3.6 ng/mL, range 3.2-10 ng/mL) or in control patients with a normal cerebrospinal fluid cell count (median 3.5 ng/mL, range 2.4-8.7 ng/mL). In the prospectively studied group, a heparin-binding protein concentration exceeding 20 ng/mL gave a sensitivity of 100%, a specificity of 99.2%, and positive and negative predictive values of 96.2% and 100%, respectively, in diagnosing acute bacterial meningitis. The area under the receiver-operating characteristic curve for heparin-binding protein was 0.994, which was higher than for the other investigated parameters.

CONCLUSION

Elevated cerebrospinal fluid levels of heparin-binding protein distinguish between patients with acute bacterial meningitis and patients with other central nervous system infections.

Cerebrospinal fluid levels of interleukin-6 and interleukin-12 in children with meningitis

PURPOSE

Certain cytokines play important roles in the pathophysiology of meningitis. The main purpose of this study was to investigate if the levels of interleukin-6 (IL-6) and interleukin-12 (IL-12) in cerebrospinal fluid (CSF) could be diagnostic predictors of bacterial meningitis in children.

METHODS

CSF was obtained from 95 patients suspected with meningitis. These cases were classified to the bacterial meningitis (n = 12), aseptic meningitis (n = 41), and nonmeningitis (n = 42) groups. The levels of IL-6 and IL-12 in CSF were measured using the enzyme-linked immmunosorbent assays test.

RESULTS

The CSF IL-6 levels in the bacterial meningitis group (45.2 +/- 50.0 pg/ml) were significantly higher than those in the aseptic meningitis group (12.9 +/- 10.2 pg/ml) and the nonmeningitis group (6.5 +/- 7.8 pg/ml; p < 0.05). The CSF IL-12 levels in the bacterial meningitis group (69.8 +/- 67.1 pg/ml) were significantly higher than those in the aseptic meningitis group (22.9 +/- 10.8 pg/ml) and the nonmeningitis group (15.3 +/- 11.2 pg/ml; p < 0.05). With regard to diagnosis, the measurement of CSF IL-6 and IL-12 levels showed sensitivities of 96% and 96%, respectively, and specificities of 51% and 75%, respectively.

CONCLUSION

It is suggested that the CSF IL-6 and IL-12 levels are useful markers for distinguishing bacterial meningitis from aseptic meningitis.

Cerebrospinal fluid pleocytosis in children in the era of bacterial conjugate vaccines: distinguishing the child with bacterial and aseptic meningitis

Although bacterial meningitis remains an important cause of childhood morbidity and mortality, the incidence of bacterial meningitis has greatly decreased with the advent of polysaccharide-protein conjugate vaccines in the past 2 decades. Most children with cerebrospinal fluid pleocytosis have aseptic rather than bacterial meningitis, raising the possibility that some patients may be managed as outpatients. In this article, we review the changing epidemiology of bacterial meningitis as well as the available clinical decision rules that may assist the clinician in distinguishing aseptic from bacterial meningitis in patients with cerebrospinal fluid pleocytosis.

A pilot study to detect high mobility group box 1 and heat shock protein 72 in cerebrospinal fluid of pediatric patients with meningitis

OBJECTIVE

To determine whether cerebrospinal fluid (CSF) levels of high mobility group box 1 (HMGB1) or heat shock protein 72 (Hsp72) are elevated in patients with meningitis.

DESIGN

Prospective study of four cohorts of patients.

SETTING

Intensive care unit and infectious disease clinic of pediatrics at the Xiangya Hospital.

PATIENTS

A total of 104 children (13 with bacterial meningitis, 38 with aseptic meningitis, 7 with tuberculous meningitis, and 46 without meningitis).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

At the time of admission, CSF samples were obtained from 104 patients with suspected meningitis and examined for the presence of invading pathogens, changes in CSF white blood cell counts, and protein and/or glucose concentrations. Based on CSF parameters, 13, 38, and 7 patients were diagnosed as having bacterial, aseptic, and tuberculous meningitis, respectively. All CSF samples were assayed for HMGB1 or Hsp72 using semiquantitative Western blot analysis. CSF levels of HMGB1 were elevated in patients with bacterial meningitis or aseptic meningitis but were four times higher in patients with bacterial meningitis vs. aseptic meningitis. There was a significant correlation between CSF HMGB1 levels and CSF white blood cell counts and glucose levels in patients with bacterial meningitis. Similarly, CSF levels of Hsp72 were significantly elevated in patients with bacterial meningitis or tuberculous meningitis and correlated well with CSF white blood cell counts in patients with bacterial meningitis or tuberculous meningitis.

CONCLUSIONS

CSF levels of HMGB1 and Hsp72 were significantly higher in patients with bacterial meningitis than those with aseptic meningitis and correlated well with CSF white blood cell counts in patients with bacterial (but not aseptic) meningitis.

Cytocompatibility of a tissue conditioner containing vinyl ester as a plasticizer

In the current study, we examined the cytocompatibility of eight vinyl esters as candidate plasticizers for producing phthalate- and ethanol-free tissue conditioners. We measured the estrogenic activity and cytotoxicity of vinyl esters in human fibroblasts and keratinocytes using an E-screen assay and a mitochondrial dye conversion assay, respectively. We also assessed the cytotoxicity of three prototype materials and commercially available tissue conditioners on human fibroblasts grown in collagen gels. Finally, we measured the effects of these materials on the expression of cytokines in three-dimensional cultures by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assays. None of the tested vinyl esters had estrogenic activity. Vinyl octanoate and vinyl pivalate were the least cytotoxic of the eight tested vinyl esters. In the same vein, a prototype tissue conditioner containing vinyl octanoate had equivalent or weaker cytotoxicity and induction of cytokine expression than conventional materials.

CSF markers for diagnosis of bacterial meningitis in neurosurgical postoperative patients

OBJECTIVE: To evaluate the diagnostic usefulness of cerebral spinal fluid (CSF) cellularity, protein, neutrophils, glucose and lactate for detection of postoperative bacterial meningitis. METHOD: This prospective study was conducted in 28 postoperative neurosurgical patients from 2002 to 2005 at University of São Paulo. The CSF markers were plotted in a receiver operating characteristic (ROC) curve to evaluate their accuracy. RESULTS: Based on the area under ROC curve CSF glucose, cellularity, and lactate were considered good tests. Polymorphonuclear and protein did not achieve enough accuracy to be used clinically. CONCLUSION: The CSF glucose, lactate, and cellularity can be used for the diagnosis of bacterial meningitis. Moreover, it can be helpful to differentiate bacterial from aseptic meningitis.

Intrathecal cytokines in spinal cord schistosomiasis

We investigate the cytokine profile in the cerebrospinal fluid (CSF) and serum of patients with spinal cord schistosomiasis (SCS). Increased levels of IL-1beta, IL-4, IL-6 and IL-10 and low concentrations of TNF-alpha and IFN-gamma were observed in both CSF and serum. CSF showed higher levels of IL-4 and IL-6 when compared to the paired serum samples. A negative correlation between the concentrations of IL-10 and IFN-gamma was observed in the CSF. These findings suggest an inflammatory as well as a skewed type-2 immune response that probably occur both locally and systemically and may be involved in the pathogenesis of SCS.

Postoperative fever after hemispherectomy: The role of non-infectious factors

Postoperative fever is a usual source of concern among caregivers and patients' family given that it may reflect a wide range of complications. The objective of this paper was to outline the expected postoperative temperature variation after hemispherectomies, and to establish factors that affect this curve. From 1987 to 2003, 30 patients were hemispherectomized in our institution. Among them, 24 patients without clinical diagnosis of infection were selected for this study. Postoperative axillary temperature from each patient was recorded over 10 days. Data was initially analyzed for all 24 patients and, later, for subgroups by (1) surgical technique (functional hemispherectomy, anatomical hemispherectomy, and hemispherotomy) and (2) hemispheric volume of the causative pathology (groups with large, moderately atrophic, and severely atrophic hemispheres). There was a trend of temperature elevation (p=0.06) over the first 4 days in all patients where 14 subjects recorded values over 38.5 degrees C, and 3 over 39.0 degrees C. Temperature curves from subgroups undergoing different techniques presented no statistical differences. However, the group including causative pathologies with larger hemispheres had a higher temperature curve when compared to patients with severely atrophic hemispheres (p<0.05). Our findings support the view that fever is an predictable event after hemispherectomies and causative pathologies with larger hemispheres present higher postoperative temperatures.

TNF-alpha and IL-6 in the diagnosis of bacterial and aseptic meningitis in children

The objective of this study was to analyze the usefulness of tumor necrosis factor-alpha and interleukin-6 cerebrospinal fluid concentrations for the differential diagnosis between bacterial and aseptic meningitis in children and in the prognostic evaluation. A cross-sectional study was performed on 35 children between 1 month and 12 years of age with suspected meningitis. Cytokines determination was performed by enzyme-linked immunosorbent assay technique. The Mann-Whitney test and Spearman's correlation coefficients were used for statistical analysis. Six children presented bacterial meningitis, 13 aseptic, and 16 had no meningitis. The tumor necrosis factor-alpha concentrations were significantly higher in the bacterial meningitis group as compared with the aseptic group (P = 0.001) and among groups with and without meningitis (P = 0.000). There was correlation between tumor necrosis factor-alpha and cerebrospinal fluid leukocytes (P = 0.019), protein (P = 0.000), and glucose (P = 0.038). There was no association between cytokines and complications of the meningitis. The tumor necrosis factor-alpha concentrations in the cerebrospinal fluid were useful markers for distinguishing bacterial from aseptic meningitis and were demonstrated to be useful in evaluating the intensity of the inflammatory process in the central nervous system.

Lack of value of routine analysis of cerebrospinal fluid for prediction and diagnosis of external drainage–related bacterial meningitis

Object

Routine microbiological and chemical analysis of cerebrospinal fluid (CSF) is often performed to diagnose external drainage–related bacterial meningitis (ED-BM) at an early stage. A cohort study was performed to investigate the value of several commonly used CSF parameters for the prediction and diagnosis of ED-BM.

Methods

In a cohort of 230 consecutive patients in whom external drains had been placed, CSF samples were collected daily, prospectively evaluated for the presence of bacteria using Gram stain and microbiological culture, and analyzed for leukocyte count, protein concentration, glucose concentration, and ratio of CSF glucose to blood glucose. In addition, the CSF concentration of interleukin-6 (IL-6) was determined. The definition of ED-BM was based on positive culture results in combination with clinical symptoms. A matched case–control study was performed to evaluate the cohort longitudinally and to control for biasing factors such as duration of external drainage.

External drainage–related bacterial meningitis developed in 22 patients (9.6%). Results from analyses of 1516 CSF samples showed no significant differences between the patients in whom ED-BM developed and a control group without ED-BM during the first 3 days of infection or during the 3 days preceding the infection with regard to leukocyte count, protein concentration, glucose concentration, and CSF/blood glucose ratio. No significant difference between groups was found for the CSF IL-6 concentration during the 3 days preceding the infection. In the matched case–control study, none of the parameters had significant predictive or diagnostic value for ED-BM in analyses using absolute values, ratios, and differences between the current and previous day’s values. A comparison of the results from Gram stains and CSF cultures showed that the Gram staining had a very high specificity (99.9%) but a low sensitivity (18% [four of 22 patients] on the 1st day of infection and 60% [nine of 15 patients] on the 2nd day).

Conclusions

Severe disturbances in the CSF of patients with external drains limit the value of routine CSF analysis for prediction or diagnosis of ED-BM. Routine Gram stain of CSF has also limited predictive or diagnostic value due to its low sensitivity in screening for ED-BM.

Role of Tumor Necrosis Factor-α in Sensorineural Hearing Loss after Bacterial Meningitis

HYPOTHESIS

Blockade of tumor necrosis factor-alpha with tumor necrosis factor-alpha antibody will reduce the extent of cochlear injury and hearing loss associated with Streptococcus pneumoniae meningitis.

BACKGROUND

Inflammatory mediators play a significant role in the morbidity associated with bacterial meningitis, including hearing loss and labyrinthitis ossificans. Previous studies have shown the attenuation of hearing loss by the nonspecific blockade of such pathways.

METHODS

Fifty Mongolian gerbils were divided into four groups. Auditory brainstem response testing was conducted to measure hearing thresholds. Streptococcus pneumoniae meningitis was induced in Groups 1 and 2. Group 2 was then given a single intraperitoneal injection of tumor necrosis factor-alpha antibody, whereas Group 1 received phosphate-buffered saline. Uninfected animals in Groups 3 and 4 were implanted with osmotic pumps that delivered a continuous 8-day intrathecal flow of either tumor necrosis factor-alpha (Group 4) or phosphate-buffered saline (Group 3). After 6 weeks, auditory brainstem response testing was repeated. The cochleas were harvested and analyzed histomorphometrically.

RESULTS

Group 2 animals with Streptococcus pneumoniae meningitis that also received tumor necrosis factor-alpha antibody developed significantly less hearing loss than Group 1 animals with meningitis alone. The decrease in the average threshold at 4, 8, 16, and 32 kHz was 31, 30, 25, and 28 dB sound pressure level, respectively (p < 0.0092 for each). Furthermore, histomorphometric analysis showed significantly less damage to the organ of Corti, spiral ganglion, spiral ligament, and stria vascularis in Group 2. Conversely, tumor necrosis factor-alpha induced meningitis animals (Group 3) showed increased hearing loss compared with phosphate-buffered saline controls (Group 4), with p < 0.0001 at all frequencies.

CONCLUSION

Tumor necrosis factor-alpha plays an important role in cochlear injury after bacterial meningitis. Blockade of tumor necrosis factor-alpha reduces postmeningitic hearing loss and cochlear injury. Induction of meningitis with intrathecal tumor necrosis factor-alpha also resulted in hearing loss and cochlear injury similar to bacterial meningitis.

Tumor necrosis factor-alpha, interleukin-1beta and interleukin-6 in the cerebrospinal fluid of newborn with meningitis

OBJECTIVE

To analyze the usefulness of determining the cerebrospinal fluid (CSF) levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) for the early diagnosis and evaluation of the prognosis of neonatal meningitis.

METHOD

We studied 54 newborn that underwent lumbar puncture. Thirty patients had meningitis and 24 were the control group. CSF and sera were obtained at the moment of suspicion of meningitis and stored at -70 degrees C. Cytokines were performed by enzyme-linked immunosorbent assay method.

RESULTS

CSF cytokines were detected in all the newborn with meningitis. TNF-alpha was detected in the CSF in 63.3% of the neonates, IL-1beta in 73.3% and IL-6 in 96.6%. The CSF levels were significantly higher than serum in neonates with meningitis. There was no correlation between the CSF levels of cytokines and neurologic complications.

CONCLUSION

The detection of TNF-alpha, IL-1beta and IL-6 in the CSF is of great value in order to achieve a early diagnosis of neonatal meningitis. Among the three cytokines analyzed, IL-6 was the best indicator of meningeal inflammation.

Leflunomide-induced aseptic meningitis

Drug-induced aseptic meningitis is uncommon and occurs primarily in patients with autoimmune disease. We report the first known case of leflunomide-induced aseptic meningitis, in a patient with rheumatoid arthritis.

Cerebrospinal fluid interleukin 8 concentrations and the subsequent development of postherpetic neuralgia

PURPOSE

Other than age, the risk factors for postherpetic neuralgia are not well established. We studied whether the concentration of interleukin 8 in the cerebrospinal fluid is associated with the risk of postherpetic neuralgia.

METHODS

We enrolled 170 patients more than 50 years old who had a typical painful and nontrigeminal herpetic rash. Patients were treated with acyclovir; no corticosteroids were given. Cerebrospinal fluid was taken for analysis of interleukin 8 during and at full crusting of the herpetic rash. Age, sex, comorbid conditions, prodromal pain, localization and severity of herpetic rash, number of skin lesions, and degree of pain were recorded. We used multivariate logistic regression modeling to identify significant predictive factors. Receiver operating characteristic (ROC) curves were evaluated to determine the contribution of each factor.

RESULTS

Six months after healing, 31 patients (18%) had postherpetic neuralgia; 27 patients still had it after 1 year. Only three variables-age (odds ratio [OR] = 2.7 per 10-year increase; 95% confidence interval [CI]: 1.2 to 6.2), acute pain (OR = 1.8 per unit increase in visual analog scale; 95% CI: 1.2 to 2.8), and interleukin 8 concentration in the cerebrospinal fluid at full crusting of the herpetic rash (OR = 1.6 per 20-microg/L increase; 95% CI: 1.3 to 2.0)-were significant predictors of postherpetic neuralgia at 1 year. Interleukin 8 concentration also had the highest area under the ROC curve at these evaluation points (P <0.001).

CONCLUSION

Our results suggest that interleukin 8 concentration in the cerebrospinal fluid at full crusting of herpetic rash may be useful for identifying patients who are likely to develop intractable postherpetic neuralgia.

Interleukin-1β and adverse effects on cerebral blood flow during long-term global hypoperfusion

Object. The effects of interleukin (IL)-1β on the cerebral vasculature are complex and incompletely understood. Many pathophysiological states in which inflammatory cascades have been implicated also have varying degrees of cerebral hypoperfusion. The purpose of this investigation was to examine the long-term effects of this proinflammatory cytokine and its antagonist on cerebral blood flow (CBF) following global cerebral hypoperfusion.

Methods. Sprague—Dawley rats were randomly assigned to 12 groups and given continuous intracerebroventricular (ICV) infusions of IL-1β, the IL-1 receptor antagonist (IL-1ra), or saline vehicle (control). Global cerebral hypoperfusion was produced by occlusion of both carotid arteries and one vertebral artery. Cerebral blood flow was measured at baseline and again after initiation of the infusions by performing a 133Xe clearance study.

Prolonged ICV administration of IL-1β resulted in a significant decrease in CBF compared with that in controls. Prolonged administration of the antagonist IL-1ra resulted in significant increases in CBF compared with that in both IL-1β—treated animals and controls.

Conclusions. This experiment demonstrates that long-term treatment with the proinflammatory cytokine IL-1β adversely affects CBF.

Approach to discriminate subgroups in multiple sclerosis with cerebrospinal fluid (CSF) basic inflammation indices and TNF-alpha, IL-1beta, IL-6, IL-8

Lumbar CSF and serum pairs of untreated multiple sclerosis patients (MS; n=47) were analyzed on admission. On average, higher CSF leukocyte (lymphocyte and monocyte) counts, IgG index, CSF IgG contents, but not of TNF-alpha, IL-1beta, IL-6, IL-8 in CSF and serum, were revealed in all MS or patients with long disease course (LO-MS) compared with controls. In primary progressive MS (PP-MS) cell counts were low, but IgG contents were high, when compared to relapsing-remitting MS (RR-MS). In clinically probable MS (CP-MS) both contents were low, in clinically definite MS (CD-MS) high. Spearman's correlation with the four monokines and the basic indices in CSF revealed activation patterns known for microglia/macrophages in the four MS subgroups, for astrocytes in CP-MS and RR-MS, for CSF lymphocytes in CP-MS and PP-MS, for cells of blood-brain barrier (BBB) in CP-MS, for intrathecal IgG synthesis in PP-MS and for lymphocyte transfer in CD-MS. Correlations between CSF and serum parameters indicated CNS disease processes to be associated with systemic processes of inflammation (acute, chronic) in CD-MS, RR-MS, and PP-MS in different ways. CSF IgG content, IgG index and systemic markers of inflammation correlated with overall disability scores in LO-MS; increasing levels may indicate a bad outcome.

Development and validation of a multivariable predictive model to distinguish bacterial from aseptic meningitis in children in the post-Haemophilus influenzae era

CONTEXT

Children with meningitis are routinely admitted to the hospital and administered broad-spectrum antibiotics pending culture results because distinguishing bacterial meningitis from aseptic meningitis is often difficult.

OBJECTIVE

To develop and validate a simple multivariable model to distinguish bacterial meningitis from aseptic meningitis in children using objective parameters available at the time of patient presentation.

DESIGN

Retrospective cohort study of all children with meningitis admitted to 1 urban children's hospital from July 1992 through June 2000, randomly divided into derivation (66%) and validation sets (34%).

PATIENTS

Six hundred ninety-six previously healthy children aged 29 days to 19 years, of whom 125 (18%) had bacterial meningitis and 571 (82%) had aseptic meningitis.

INTERVENTION

Multivariable logistic regression and recursive partitioning analyses identified the following predictors of bacterial meningitis from the derivation set: Gram stain of cerebrospinal fluid (CSF) showing bacteria, CSF protein > or =80 mg/dL, peripheral absolute neutrophil count > or =10 000 cells/mm3, seizure before or at time of presentation, and CSF absolute neutrophil count > or =1000 cells/mm3. A Bacterial Meningitis Score (BMS) was developed on the derivation set by attributing 2 points for a positive Gram stain and 1 point for each of the other variables.

MAIN OUTCOME MEASURE

The accuracy of the BMS when applied to the validation set.

RESULTS

A BMS of 0 accurately identified patients with aseptic meningitis without misclassifying any child with bacterial meningitis in the validation set. The negative predictive value of a score of 0 for bacterial meningitis was 100% (95% confidence interval: 97%-100%). A BMS > or =2 predicted bacterial meningitis with a sensitivity of 87% (95% confidence interval: 72%-96%).

CONCLUSIONS

The BMS accurately identifies children at low (BMS = 0) or high (BMS > or =2) risk of bacterial meningitis. Outpatient management may be considered for children in the low-risk group.

Infections in neurosurgery: using laboratory data to plan optimal treatment strategies

Laboratory services contribute to the management of patients with neurosurgical infections in a variety of ways and, in so doing, increase the likelihood of a favourable outcome. Microbiology laboratories and clinical microbiologists are able to confirm the diagnosis, identify the causative agents and facilitate optimal antimicrobial therapy. Other pathology specialties perform investigations which help neurosurgeons to differentiate between postoperative aseptic and bacterial meningitis, these disease processes being indistinguishable on clinical grounds. A broad range of variables have been evaluated to date, but only the lactate and interleukin-1beta concentrations in cerebrospinal fluid have been shown to have sufficiently high sensitivities and specificities to be useful for this purpose. In preliminary studies measurement of the serum C-reactive protein concentration has been shown to be an effective criterion for monitoring the response to antibacterial therapy in patients with spinal extradural abscesses, postoperative discitis, brain abscesses and subdural empyemas, thereby enabling patients to be treated successfully with courses of these drugs that are markedly shorter than those currently recommended.

Role of nitric oxide in the cerebrovascular and thermoregulatory response to interleukin-1 beta

Central administration of interleukin-1 beta (IL-1 beta) increases cerebral blood flow (CBF) and body temperature, in part, through the production of prostaglandins. In previous studies, the temporal relationship between these effects of IL-1 beta have not been measured. In this study, we hypothesized that the increase in CBF occurs before any change in brain or body temperature and that the cerebrovascular and thermoregulatory effects of IL-1 beta would be attenuated by inhibiting the production of nitric oxide (NO). Adult male rats received 100 ng intracerebroventricular (icv) injection of IL-1 beta, and cortical CBF (cCBF) was measured by laser-Doppler in the contralateral cerebral cortex. A central injection of IL-1 beta caused a rapid increase in cCBF to 133 +/- 12% of baseline within 15 min and to an average of 137 +/- 12% for the remainder of the 3-h experiment. Brain and rectal temperature increased by 0.4 +/- 0.2 and 0.5 +/- 0.2 degrees C, but not until 45 min after IL-1 beta administration. Pretreatment with N(omega)-nitro-L-arginine methyl ester (L-NAME; 5 mg/kg iv) completely prevented the changes in cCBF and brain and rectal temperature induced by IL-1 beta. L-Arginine (150 mg/kg iv) partially reversed the effects of L-NAME and resulted in increases in both cCBF and temperature. These findings suggest that the vasodilatory effects of IL-1 beta in the cerebral vasculature are independent of temperature and that NO plays a major role in both the cerebrovascular and thermoregulatory effects of centrally administered IL-1 beta.

New Advances in the Pathogenesis and Pathophysiology of Bacterial Meningitis

Acute bacterial meningitis continues to be a significant health concern, with a fatality rate of more than 30% in some studies. Although the face of bacterial meningitis has changed substantially over the past 15 years, this disease still causes significant mortality (particularly in underdeveloped countries) and neurological sequelae. Our understanding of the pathophysiology of bacterial meningitis continues to develop. Our understanding of the mechanisms of neuronal injury now includes the concept that many of the pathological changes are only secondary to the infection and that the human immune system contributes to the majority of the neuronal death. A complicated series of interactions among immune, vascular and central nervous system cells, cytokines and chemokines, matrix metalloproteinases and free radical molecules are ultimately responsible for many bacterial meningitis changes. We hope that a complete understanding of these processes will ultimately lead to better diagnostic techniques and improved treatments.