Elevated Cerebrospinal Fluid Protein Is Associated with Unfavorable Functional Outcome in Spontaneous Subarachnoid Hemorrhage

Temporal Changes in CSF Cell Parameters After SAH: Comparison of Ventricular and Spinal Drain Samples

BACKGROUND

Forty percent of patients with aneurysmatic subarachnoid hemorrhage (aSAH) develop acute hydrocephalus requiring treatment with cerebrospinal fluid (CSF) drainage. CSF cell parameters are used in the diagnosis of nosocomial infections but also reflect sterile inflammation after aSAH. We aimed to study the temporal changes in CSF parameters and compare external ventricular drain (EVD)-derived and lumbar spinal drain-derived samples.

METHODS

We retrospectively identified consecutive patients with aSAH treated at our neurointensive care unit between January 2014 and May 2019. We mapped the temporal changes in CSF leucocyte count, erythrocyte count, cell ratio, and cell index during the first 19 days after aSAH separately for EVD-derived and spinal drain-derived samples. We compared the sample sources using a linear mixed model, controlling for repeated sampling.

RESULTS

We included 1360 CSF samples from 197 patients in the analyses. In EVD-derived samples, the CSF leucocyte count peaked at days 4-5 after aSAH, reaching a median of 225 × 106 (interquartile range [IQR] 64-618 × 106). The cell ratio and index peaked at 8-9 days (0.90% [IQR 0.35-1.98%] and 2.71 [IQR 1.25-6.73], respectively). In spinal drain-derived samples, the leucocyte count peaked at days 6-7, reaching a median of 238 × 106 (IQR 60-396 × 106). The cell ratio and index peaked at 14-15 days (4.12% [IQR 0.63-10.61%]) and 12-13 days after aSAH (8.84 [IQR 3.73-18.84]), respectively. Compared to EVD-derived samples, the leucocyte count was significantly higher in spinal drain-derived samples at days 6-17, and the cell ratio as well as the cell index was significantly higher in spinal drain-derived samples compared to EVD samples at days 10-15.

CONCLUSIONS

CSF cell parameters undergo dynamic temporal changes after aSAH. CSF samples from different CSF compartments are not comparable.

Risk Factors for Cerebral Vasospasm After Subarachnoid Hemorrhage: A Systematic Review of Observational Studies

Cerebral vasospasm (CV) following subarachnoid hemorrhage (SAH) remains one of the leading causes of high mortality and poor outcomes. Understanding the risk factors associated with CV is pivotal to improving patients' outcomes. We conducted an extensive search for analytical observational studies that analyzed the correlation between various variables and the likelihood of CV development among adult patients with SAH (age ≥ 18 years). Five scholar databases were used, namely, PubMed, EBSCO, Web of Science, Science Direct, and Google Scholar. Relevant studies published between January 1st, 2016, and August 9th, 2023, were included. The Newcastle-Ottawa Scale was adopted to assess the risk of bias among included observational studies. A total of 33 studies met the inclusion criteria. Of the 24,958 patients with SAH who were identified, 6,761 patients had a subsequent CV (27.1%). Several statistically significant risk factors were reported across the literature. Younger age, female sex, smoking, alcohol intake, modified Fisher grade 3-4, higher Hunt and Hess grading, and the presence of multiple comorbidities (diabetes, hypertension, congestive heart failure, and history of stroke) were among the well-established risk factors for CV. Additionally, leukocytosis was consistently reported to be a significant predictor in multiple studies, providing compelling evidence for its association with CV. Even though single studies reported an association between CV and certain variables, further research is necessary to investigate the implications of these findings. These include arterial tortuosity, hypokalemia, potassium to glucose gradient, hypoalbuminemia, anemia, von Willebrand factor and vascular endothelial growth factor, use of desflurane, and hemodynamic stability. Overall, this systemic review provides a comprehensive summary of the current data that evaluates the potential risk factors for the development of CV after SAH. However, because of data heterogeneity, certain factors require further validation in their correlation with CV development. Larger-scale observational and clinical trials are mandatory to extensively investigate the significant predictors of CV to lay the scientific foundation for improving outcomes in susceptible patients with SAH.

Functional effects of haemoglobin can be rescued by haptoglobin in an in vitro model of subarachnoid haemorrhage

During subarachnoid haemorrhage, a blood clot forms in the subarachnoid space releasing extracellular haemoglobin (Hb), which causes oxidative damage and cell death in surrounding tissues. High rates of disability and cognitive decline in SAH survivors are attributed to loss of neurons and functional connections during secondary brain injury. Haptoglobin sequesters Hb for clearance, but this scavenging system is overwhelmed after a haemorrhage. Whilst exogenous haptoglobin application can attenuate cytotoxicity of Hb in vitro and in vivo, the functional effects of sub-lethal Hb concentrations on surviving neurons and whether cellular function can be protected with haptoglobin treatment remain unclear. Here we use cultured neurons to investigate neuronal health and function across a range of Hb concentrations to establish the thresholds for cellular damage and investigate synaptic function. Hb impairs ATP concentrations and cytoskeletal structure. At clinically relevant but sub-lethal Hb concentrations, we find that synaptic AMPAR-driven currents are reduced, accompanied by a reduction in GluA1 subunit expression. Haptoglobin co-application can prevent these deficits by scavenging free Hb to reduce it to sub-threshold concentrations and does not need to be present at stoichiometric amounts to achieve efficacy. Haptoglobin itself does not impair measures of neuronal health and function at any concentration tested. Our data highlight a role for Hb in modifying synaptic function in surviving neurons, which may link to impaired cognition or plasticity after SAH and support the development of haptoglobin as a therapy for subarachnoid haemorrhage.

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.

Update on intrathecal management of cerebral vasospasm: a systematic review and meta-analysis

OBJECTIVE

Aneurysmal subarachnoid hemorrhage (aSAH) accounts for a relatively small portion of strokes but has the potential to cause permanent neurological deficits. Vasospasm with delayed ischemic neurological deficit is thought to be responsible for much of the morbidity associated with aSAH. This has illuminated some treatment options that have the potential to target specific components of the vasospasm cascade. Intrathecal management via lumbar drain (LD) or external ventricular drain (EVD) offers unique advantages in this patient population. The aim of this review was to provide an update on intrathecal vasospasm treatments, emphasizing the need for larger-scale trials and updated protocols using data-driven evidence.

METHODS

A search of PubMed, Ovid MEDLINE, and Cochrane databases included the search terms (subarachnoid hemorrhage) AND (vasospasm OR delayed cerebral ischemia) AND (intrathecal OR intraventricular OR lumbar drain OR lumbar catheter) for 2010 to the present. Next, a meta-analysis was performed of select therapeutic regimens. The primary endpoints of analysis were vasospasm, delayed cerebral ischemia (DCI), cerebral infarction, and functional outcome.

RESULTS

Twenty-nine studies were included in the analysis. There were 10 studies in which CSF drainage was the primary experimental group. Calcium channel antagonists were the focus of 7 studies. Fibrinolytics and other vasodilators were each examined in 6 studies. The meta-analysis included studies examining CSF drainage via LD (n = 4), tissue plasminogen activator in addition to EVD (n = 3), intraventricular nimodipine (n = 2), and cisternal magnesium (n = 2). Results showed that intraventricular nimodipine decreased vasospasm (OR 0.59, 95% CI 0.37-0.94; p = 0.03). Therapies that significantly reduced DCI were CSF drainage via LD (OR 0.47, 95% CI 0.25-0.88; p = 0.02) and cisternal magnesium (OR 0.27, 95% CI 0.07-1.02; p = 0.05). CSF drainage via LD was also found to significantly reduce the incidence of cerebral infarction (OR 0.35, 95% 0.24-0.51; p < 0.001). Lastly, functional outcome was significantly better in patients who received CSF drainage via LD (OR 2.42, 95% CI 1.39-4.21; p = 0.002).

CONCLUSIONS

The authors' results showed that intrathecal therapy is a safe and feasible option following aSAH. It has been shown to attenuate cerebral vasospasm, reduce the incidence of DCI, and improve clinical outcome. The authors support the use of intrathecal management in the prevention and rescue management of cerebral vasospasm. More randomized controlled trials are warranted to determine the best combination of pharmaceutical agents and administration route in order to formulate a standardized treatment approach.

Cerebrospinal fluid predictors of shunt-dependent hydrocephalus after hemorrhagic stroke: a systematic review and meta-analysis

Hydrocephalus is a common complication of hemorrhagic stroke and has been reported to contribute to poor neurological outcomes. Herein, we aimed to investigate the validity of cerebrospinal fluid (CSF) data in predicting shunt-dependent hydrocephalus (SDHC) in patients with hemorrhagic stroke. PubMed, CENTRAL, and Embase databases were searched for relevant studies published through July 31, 2021. The 16 studies with 1505 patient included those in which CSF data predicted risk for SDHC and reports on CSF parameters in patients in whom SDHC or hydrocephalus that was not shunt-dependent developed following hemorrhagic stroke. We appraised the study quality using Newcastle-Ottawa Scale and conducted a meta-analysis of the pooled estimates of the CSF predictors. The meta-analysis revealed three significant CSF predictors for shunt dependency, i.e., higher protein levels (mean difference [MD] = 32.09 mg/dL, 95% confidence interval [CI] = 25.48-38.70, I² = 0%), higher levels of transforming growth factor β1 (TGF-β1; MD = 0.52 ng/mL, 95% CI = 0.42-0.62, I² = 0%), and higher ferritin levels (MD = 108.87 µg/dL, 95% CI = 56.68-161.16, I² = 36%). The red blood cell count, lactate level, and glucose level in CSF were not significant in predicting SDHC in patients with hemorrhagic stroke. Therefore, higher protein, TGF-β1, and ferritin levels in CSF are significant predictors for SDHC in patients with hemorrhagic stroke. Measuring these CSF parameters would help in the early recognition of SDHC risk in clinical care.

Prognostic molecular markers for motor recovery in acute hemorrhagic stroke: A systematic review

BACKGROUND AND AIMS

Molecular biomarkers are associated with poor prognosis in ischemic stroke individuals. However, it might not be generalizable to post-acute hemorrhagic stroke since the underlying mechanisms of this brain damage differ from those found in ischemic stroke. The main purpose of this review was to synthesize the potential predictive molecular biomarkers for motor recovery following acute hemorrhagic stroke.

MATERIALS AND METHODS

An electronic search was conducted by 2 independent reviewers in the following databases: PubMed (Medline), EMBASE, Web of Science, and CINAHL. We included studies that addressed the following: collected blood, urine, or cerebrospinal fluid samples within 72 h after hemorrhagic stroke and that reported the prognostic association with functional motor recovery for each molecular biomarker. Screening of titles, abstracts, and full texts and data extraction were undertaken independently by pairs of reviewers.

RESULTS

Twelve thousand, five hundred and sixty-four studies were identified and 218 were considered eligible. Finally, we included 70 studies, with 96 biomarkers analyzed, of which 61 were considered as independent prognostic biomarkers, and 10 presented controversial results.

CONCLUSION

This systematic review shows that motor functional recovery can be predicted by 61 independent prognostic molecular biomarkers assessed in the acute phase after a hemorrhagic stroke.

Inflammasome Caspase-1 Activity is Elevated in Cerebrospinal Fluid After Aneurysmal Subarachnoid Hemorrhage and Predicts Functional Outcome

BACKGROUND/OBJECTIVE

Subarachnoid hemorrhage (SAH) is a devastating neurological injury, further complicated by few available methods to objectively predict outcomes. With the recent shift in focus to neuroinflammation as a potential cause of adverse outcomes following SAH, we investigated the inflammasome-derived enzyme, caspase-1, as a potential biomarker for poor functional outcome.

METHODS

SAH patients were recruited from a regional stroke referral center. Cerebrospinal fluid (CSF) samples from 18 SAH subjects were collected via an external ventricular drain and obtained as close as possible to admission (within 72 h). For control subjects, we collected CSF from 9 patients undergoing lumbar puncture with normal CSF. Caspase-1 activity was measured using commercially available luminescence assays. SAH subjects were categorized at hospital discharge into those with good outcomes (Glasgow Outcome Scale, GOS, of 4-5) and poor outcomes (GOS of 1-3).

RESULTS

CSF analysis demonstrated a nearly seven-fold increase in caspase-1 activity in SAH patients compared to controls (p < 0.0001). Within the SAH group, 10 patients (55.6%) had good outcomes and 8 patients (44.4%) had poor outcomes. Mean caspase-1 activity in the poor outcome group was approximately three-times higher than the good outcome group (p = 0.001). Caspase-1 activity was significantly correlated with GOS score (r = - 0.705, p = 0.001). Receiver operating characteristic curve analysis showed that caspase-1 activity can accurately differentiate between patients with good versus poor functional outcome (area under the curve 0.944, p = 0.002).

CONCLUSIONS

Inflammasome-derived caspase-1 activity is elevated in the CSF of SAH patients compared to controls and higher levels correlate with worse functional outcome.