Early lumbar puncture in adult bacterial meningitis-rationale for revised guidelines

Current international guidelines recommend cerebral computerized tomography (CT) before lumbar puncture (LP) in many adults with suspected acute bacterial meningitis (ABM), due to concern about LP-induced cerebral herniation. Despite guideline emphasis on early treatment based on symptoms, performing CT prior to LP implies a risk of delayed ABM treatment, which may be associated with a fatal outcome. Firm evidence for LP-induced herniation in adult ABM is absent and brain CT cannot discard herniation. Thus, the recommendation to perform CT before LP may contribute to an avoidable delay of LP and ABM treatment. The inappropriate use of the diagnostic treatment sequence of brain CT scan, followed by LP, followed by antibiotics and corticosteroids should be avoided in adults with suspected ABM by omitting needless contraindications for LP, thus eliminating an unnecessary fear of immediate LP. Revised Swedish guidelines regarding early LP are presented, and the background documentation and reasons for omitting impaired consciousness, new onset seizures, and immunocompromised state as contraindications to LP are discussed

Neuron-Specific Enolase Is Correlated to Compromised Cerebral Metabolism in Patients Suffering from Acute Bacterial Meningitis; An Observational Cohort Study

<div><p>Introduction</p><p>Patients suffering from acute bacterial meningitis (ABM) with a decreased level of consciousness have been shown to have an improved clinical outcome if treated with an intracranial pressure (ICP) guided therapy. By using intracranial microdialysis (MD) to monitor cerebral metabolism in combination with serum samples of biomarkers indicating brain tissue injury, S100B and Neuron Specific Enolase (NSE), additional information might be provided. The aim of this study was to evaluate biomarkers in serum and MD parameters in patients with ABM.</p><p>Methods</p><p>From a prior study on patients (n = 52) with a confirmed ABM and impaired consciousness (GCS ≤ 9, or GCS = 10 combined with lumbar spinal opening pressure > 400 mmH₂O), a subgroup of patients (n = 21) monitored with intracerebral MD and biomarkers was included in the present study. All patients were treated in the NICU with intracranial pressure (ICP) guided therapy. Serum biomarkers were obtained at admission and every 12 hours. The MD parameters glucose, lactate, pyruvate and glycerol were analyzed. Outcome was assessed at 12–55 months after discharge from hospital. Mann-Whitney U-Test and Wilcoxon matched-pairs signed rank test were applied.</p><p>Results</p><p>The included patients had a mean GCS of 8 (range, 3–10) on admission and increased ICP (>20 mmHg) was observed in 62% (n = 13/21) of the patients. Patients with a lactate:pyruvate ratio (LPR) >40 (n = 9/21, 43%) had significantly higher peak levels of serum NSE (p = 0.03), with similar, although non-significant observations made in patients with high levels of glycerol (>500 μmol/L, p = 0.11) and those with a metabolic crisis (Glucose <0.8 mmol/L, LPR >25, p = 0.09). No associations between serum S100B and MD parameters were found. Furthermore, median MD glucose levels decreased significantly between day 1 (0–24h) and day 3 (48–72h) after admission to the NICU (p = 0.0001). No correlation between MD parameters or biomarkers and outcome was found.</p><p>Conclusion</p><p>In this observational cohort study, we were able to show that cerebral metabolism is frequently affected in patients with ABM. Furthermore, patients with high LPR (LPR>40) had significantly higher levels of NSE, suggesting ongoing deterioration in compromised cerebral tissue. However, the potential clinical impact of MD and biomarker monitoring in ABM patients will need to be further elaborated in larger clinical trials.</p></div

Outcome.

<p>Outcome.</p

Outcome.

<p>Outcome.</p

Demographics.

<p>Demographics.</p

Biomarkers vs MD parameters.

<p>Illustrates NSE (A-C) and S100B (D-F) levels in patients (n = 21) with either increased LPR (>40), metabolic crisis (LPR >25, MD-glucose <0.8 mmol/L) and increased glycerol (>500 μmol/L). In general, increased NSE levels were correlated to worse metabolic conditions.</p

MD parameters, fever and serum glucose over time.

<p>Illustrating parameter change over time (median 0–24h, Day 1, vs median 48–72h, Day 3) from insertion of microdialysis (MD) catheters. MD-glucose (2A) and serum-glucose (2B) levels were significantly lower on Day 3 compared to Day 1 (p<0.01 respectively, Wilcoxon matched-pairs signed rank test). No other parameter presented any significant difference over time. For all parameters n = 15 patients are compared except pyrexia (n = 13).</p