Diagnosing external ventricular drain-related ventriculitis by means of local inflammatory response: soluble triggering receptor expressed on myeloid cells-1

Clinical characteristics of unvaccinated or incompletely vaccinated children with neurological manifestations due to SARS-CoV-2 Omicron infection

Omicron generally causes milder disease than previous strains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), especially in fully vaccinated individuals. However, incompletely vaccinated children may develop Omicron-related complications such as those affecting the central nervous system. To characterize the spectrum of clinical manifestations of neuro-COVID and to identify potential biomarkers associated with clinical outcomes, we recruited 15 children hospitalized for Omicron-related neurological manifestations in three hospitals in Hong Kong (9 boys and 6 girls aged 1-13 years). All were unvaccinated or incompletely vaccinated. Fourteen (93.3%) were admitted for convulsion, including benign febrile seizure (n = 7), complex febrile seizure (n = 2), seizure with fever (n = 3), and recurrent breakthrough seizure (n = 2), and the remaining nonconvulsive patient developed encephalopathic state with impaired consciousness. None of the seven children with benign febrile seizure and six of eight children with other neurological manifestations had residual deficits at 9-month follow-up. SARS-CoV-2 RNA was undetectable in the cerebrospinal fluid (CSF) specimens of seven patients who underwent lumbar puncture. Spike-and-wave/sharp waves affecting the frontal lobes were detected in four of seven (57.1%) patients who underwent electroencephalogram. Children with Omicron-related neurological manifestations had significantly higher blood levels of IL-6 (p < 0.001) and CHI3L1 (p = 0.022) than healthy controls, and higher CSF levels of IL-6 (p = 0.002) than children with non-COVID-19-related febrile illnesses. Higher CSF-to-blood ratios of IL-8 and CHI3L1 were associated with longer length of stay, whereas higher ratios of IL-6 and IL-8 were associated with higher blood tau level. The role of CSF:blood ratio of IL-6, IL-8, and CHI3L1 as prognostic markers for neuro-COVID should be further evaluated.

Postprocedural Complications of External Ventricular Drains: A Meta-Analysis Evaluating the Absolute Risk of Hemorrhages, Infections, and Revisions

BACKGROUND

External ventricular drain (EVD) insertion is often a lifesaving procedure frequently used in neurosurgical emergencies. It is routinely done at the bedside in the neurocritical care unit or in the emergency room. However, there are infectious and noninfectious complications associated with this procedure. This meta-analysis sought to evaluate the absolute risk associated with EVD hemorrhages, infections, and revisions. The secondary purpose was to identify and characterize risk factors for EVD complications.

METHODS

We searched the MEDLINE (PubMed) database for "external ventricular drain," "external ventricular drain" + "complications" or "Hemorrhage" or "Infection" or "Revision" irrespective of publication year. Estimates from individual studies were combined using a random effects model, and 95% confidence intervals (CIs) were calculated with maximum likelihood specification. To investigate heterogeneity, the t2 and I2 tests were utilized. To evaluate for publication bias, a funnel plot was developed.

RESULTS

There were 260 total studies screened from our PubMed literature database search, with 176 studies selected for full-text review, and all of these 176 studies were included in the meta-analysis as they met the inclusion criteria. A total of 132,128 EVD insertions were reported, with a total of 130,609 participants having at least one EVD inserted. The pooled absolute risk (risk difference) and percentage of the total variability due to true heterogeneity (I2) for hemorrhagic complication was 1236/10,203 (risk difference: -0.63; 95% CI: -0.66 to -0.60; I2: 97.8%), infectious complication was 7278/125,909 (risk difference: -0.65; 95% CI: -0.67 to -0.64; I2: 99.7%), and EVD revision was 674/4416 (risk difference: -0.58; 95% CI: -0.65 to -0.51; I2: 98.5%). On funnel plot analysis, we had a variety of symmetrical plots, and asymmetrical plots, suggesting no bias in larger studies, and the lack of positive effects/methodological quality in smaller studies.

CONCLUSIONS

In conclusion, these findings provide valuable information regarding the safety of one of the most important and most common neurosurgical procedures, EVD insertion. Implementing best-practice standards is recommended in order to reduce EVD-related complications. There is a need for more in-depth research into the independent risk factors associated with these complications, as well as confirmation of these findings by well-structured prospective studies.

Longitudinal ventricular cerebrospinal fluid profile in patients with spontaneous subarachnoid hemorrhage

Background

Spontaneous subarachnoid hemorrhage (SAH) is a severe neurological disease that frequently requires placement of external ventricular drainage (EVD). Cerebrospinal fluid (CSF) obtained via the drain is used to detect potential complications of SAH.

Objective

This study aimed to describe the longitudinal profile of routine CSF parameters in patients with SAH and to identify associations with neurological complications.

Methods

A total of thirty-three patients with spontaneous SAH who required an EVD and had at least three consecutive CSF samples collected over a period of more than 7 days were included in this study.

Results

A median of 6 longitudinally collected CSF samples per patient were available within 1–22 days after SAH onset. Overall, red blood cells (RBC) steadily decreased over time, whereas white blood cells (WBC) and total protein (TP) increased until days 6 and 13, respectively, and decreased thereafter. The estimated decay rates of RBC, WBC, and TP were 28, 22, and 6% per day. Distinct CSF patterns over time were linked to known complications after SAH. Patients with rebleeding showed increased RBC, TP, and phagocytosing cells compared to patients without re-bleeding. For ventriculitis, an elevated cell index with a higher proportion of granulocytes was characteristic. CSF of patients with delayed cerebral ischemia showed increased RBC and WBC compared to patients without DCI. Early CSF WBC and cell index were predictive for the occurrence of DCI and ventriculitis later during the disease course. The amount of daily CSF drainage via EVD had no impact on routine CSF parameters.

Conclusion

Longitudinal CSF characteristics are associated with SAH-related complications.

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.

Utility of the Cell Index in Predicting External Ventricular Drain-Related Ventriculo-Meningitis

BACKGROUND/OBJECTIVE

Ventriculo-meningitis (VM) is an important complication of external ventricular drains (EVDs) in neurosurgical patients. Consequences include increased morbidity, mortality, and duration of hospital stay. Early diagnosis of EVD-associated VM allows earlier treatment intervention. The cell index (CI) may provide a simple measure that overcomes the limitations of isolated cerebrospinal fluid (CSF) parameters and other diagnostic tests, allowing earlier prediction of VM.

METHODS

All patients admitted to a tertiary hospital and requiring EVD insertion during 2015 and 2016 were assessed for inclusion in this retrospective case-control study. Patients with a known or suspected intracranial infection were excluded. Of the 186 patients who underwent EVD insertion, 95 patients were included in the final cohort. Data pertaining to patient characteristics and laboratory indices were extracted from health records and the microbiology laboratory database. The CI was calculated as the ratio of temporally related CSF leukocytes/erythrocytes to peripheral blood leukocytes/erythrocytes. Data from patients with microbiologically confirmed VM were analyzed in comparison with those not developing VM during the course of their stay. Categorical and continuous variables with skewed distributions were analyzed by Chi square and Mann-Whitney tests, respectively.

RESULTS

EVD-associated VM developed in 7.4% of patients. The highest CSF CI (within 3 days prior to diagnosis of VM or at any time for those not developing VM) differed significantly between the two groups (16; IQR 10.8-48.5 vs. 3.3; IQR 1.0-12.8, respectively; p = .046). The area under the receiver operating characteristic curve (AUROC) for the highest CI was 0.727 (95% confidence interval [CI] 0.526-0.929; p = .027). A CI of 10.4 provided a sensitivity and specificity of 80.5% and 70.5%, respectively, for the early diagnosis of VM.

CONCLUSIONS

In neurosurgical patients with an EVD, the CSF CI significantly predicted the development of VM.

Significance of cerebrospinal fluid inflammatory markers for diagnosing external ventricular drain–associated ventriculitis in patients with severe traumatic brain injury

Objective

The aim of this study was to investigate the diagnostic potential of the inflammatory markers interleukin-6 (IL-6), total leukocyte count (TLC), and protein in the CSF and IL-6, C-reactive protein, and white blood cell count in the serum for the early diagnosis of ventriculitis in patients with traumatic brain injury (TBI) and an external ventricular drain compared with patients without ventriculitis.

Methods

Retrospective data from 40 consecutive patients with TBI and an external ventricular drain treated in the authors’ intensive care unit between 2013 and 2017 were analyzed. For all markers, arithmetical means and standard deviations, area under the curve (AUC), cutoff values, sensitivity, specificity, positive likelihood ratio (LR), and negative LR were calculated and correlated with presence or absence of ventriculitis.

Results

There were 35 patients without ventriculitis and 5 patients with ventriculitis. The mean ± SD IL-6 concentration in CSF was significantly increased, with 6519 ± 4268 pg/mL at onset of ventriculitis compared with 1065 ± 1705 pg/mL in patients without ventriculitis (p = 0.04). Regarding inflammatory markers in CSF, IL-6 showed the highest diagnostic potential for differentiation between the presence and absence of ventriculitis (AUC 0.938, cutoff 4064 pg/mL, sensitivity 100%, specificity 92.3%, positive LR 13, and negative LR 0), followed by TLC (AUC 0.900, cutoff 64.5 /µL, sensitivity 100%, specificity 80%, positive LR 5.0, and negative LR 0) and protein (AUC 0.876, cutoff 31.5 mg/dL, sensitivity 100%, specificity 62.5%, positive LR 2.7, and negative LR 0).

Conclusions

The level of IL-6 in CSF has the highest diagnostic value of all investigated inflammatory markers for detecting ventriculitis in TBI patients at an early stage. In particular, CSF IL-6 levels higher than the threshold of 4064 pg/mL were significantly associated with the probability of ventriculitis.

Factors and measures predicting external CSF drain-associated ventriculitis

Objective

To determine the diagnostic value of clinical factors and biochemical or microbiological measures for diagnosing a drain-associated ventriculitis, we summarized the available evidence.

Methods

We performed a systematic review and meta-analysis of studies of patients with external ventricular CSF drains who developed drain-associated ventriculitis by searching MEDLINE, EMBASE, and CENTRAL electronic database. We reported the occurrence of abnormal test results in patients with and without drain-associated ventriculitis. For continuous variables, we recalculated mean values presented in multiple studies.

Results

We identified 42 articles published between 1984 and 2018 including 3,035 patients with external CSF drains of whom 697 (23%) developed drain-associated bacterial ventriculitis. Indications for drain placement were subarachnoid, intraventricular or cerebral hemorrhage or hemorrhage not further specified (69%), traumatic brain injury (13%), and obstructive hydrocephalus secondary to a brain tumor (10%). Fever was present in 116 of 162 patients with ventriculitis (72%) compared with 80 of 275 (29%) patients without ventriculitis. The CSF cell count was increased for 74 of 80 patients (93%) with bacterial ventriculitis and 30 of 95 patients (32%) without ventriculitis. CSF culture was positive in 125 of 156 episodes classified as ventriculitis (80%), and CSF Gram stain was positive in 44 of 81 patients (54%). In patients with ventriculitis, PCR on ribosomal RNA was positive on 54 of 78 CSF samples (69%).

Conclusion

Clinical factors and biochemical and microbiological measures have limited diagnostic value in differentiating between ventriculitis and sterile inflammation in patients with external CSF drains. Prospective well-designed diagnostic accuracy studies in drain-associated ventriculitis are needed.

Molecular and biomarker-based diagnostics in early sepsis: current challenges and future perspectives

Introduction: Sepsis, defined as a life-threatening organ dysfunction resulting from dysregulated host response to infection, is still a major challenge for healthcare systems. Early diagnosis is highly needed, yet challenging, due to the non-specificity of clinical symptoms. Rapid and targeted application of therapy strategies is crucial for patient's outcome.Areas covered: Faster and better diagnostics with high accuracy is promised by novel host response biomarkers and a wide variety of direct pathogen identification technologies, which have emerged over the last years. This review will cover both - host response-guided diagnostics and methods for direct pathogen detection. Some of the markers and technologies are already market-ready, others are more likely aspirants. We will discuss them in terms of their performance and benefit for use in clinical diagnostics.Expert opinion: Latest technological advances enable the development of promising diagnostic tests, detecting the host response as well as identifying pathogens without the need of cultivation. However, the syndrome's heterogeneity makes it difficult to develop a universal test suitable for routine use. Moreover, the robustness of the biomarkers and technologies still has to be verified. Combining these technologies and clinical routine parameters with bioinformatic methods (e.g., machine-learning algorithms) may revolutionize sepsis diagnostics.

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.

Modalities and accuracy of diagnosis of external ventricular drainage-related infections: a prospective multicentre observational cohort study

BACKGROUND

Device infection is a major complication of placement external ventricular drains (EVD). Diagnostic features are often masked by underlying disease or cerebrospinal fluid (CSF) contamination by blood. We aim to assess which diagnostic modalities are applied for EVD-related infection (ERI) diagnosis and evaluate their accuracy.

METHODS

This observational prospective study included 187 adult patients with an EVD. Modalities of clinical diagnosis of ERI diagnosed by treating physicians on clinical grounds and blood and CSF analysis (clinically diagnosed ERI (CD-ERI)) were assessed prospectively. Additionally, the diagnostic accuracy of clinical and laboratory parameters for the diagnosis of culture proven ERI (CP-ERI) was evaluated, using data of the study patients and including a retrospective cohort of 39 patients with CP-ERI.

RESULTS

Thirty-one CD-ERIs were diagnosed in the prospective cohort. Most physicians used CSF analysis to establish the diagnosis. ROC analysis revealed an AUC of 0.575 (p = 0.0047) for the number of positive SIRS criteria and AUC of 0.5420 (p = 0.11) for the number of pathological neurological signs for diagnosis of CP-ERI. Diagnostic accuracy of laboratory values was AUC 0.596 (p = 0.0006) for serum white blood cell count (WBCC), AUC 0.550 (p = 0.2489) for serum C-reactive protein, AUC 0.644 (p < 0.0001) for CSF WBCC and AUC 0.690 for CSF WBC/red blood cell count ratio (both p < 0.0001). Neither a temporal trend in potential predictors of CP-ERI nor a correlation between clinical diagnosis and proven CSF infection was found.

CONCLUSIONS

Clinicians base their diagnosis of ERI mostly on CSF analysis and occurrence of fever, leading to over-diagnosis. The accuracy of the clinical diagnosis is low. Commonly used clinical and laboratory diagnostic criteria have a low sensitivity and specificity for ERI.

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.

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.