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Predictive performance of cerebrospinal fluid parameters for diagnosis of meningitis in infants: a cohort study
Christine O'Leary1, Laure F Pittet2,3,4, Rachael Beaumont1
1Department of General Medicine, Royal Children's Hospital, Parkville, Victoria, Australia.
Background:
The gold standard for diagnosis of meningitis is the isolation of a pathogen from cerebrospinal fluid (CSF) by culture or PCR. However, treatment is routinely commenced based on CSF findings prior to microbiological results. This study determined the predictive value of CSF parameters for diagnosing bacterial and viral meningitis in young infants.
Methods:
Multicentre retrospective (2010-2020) cohort study of 1088 CSF results from infants aged 0-90 days. The predictive value of CSF parameters (white blood cell count (WCC), neutrophil, protein, glucose) was evaluated in 538 meningitis cases (39 bacterial, 499 viral) compared with controls with negative CSF microbiological testing and no prior antibiotics.
Results:
For bacterial meningitis, the sensitivity of the commonly used CSF WCC cut-off of 20×106/L for neonates, 15×106/L for infants 1-2 months old and 5×106/L for infants 2-3 months old was 89%, 91% and 86% and the specificity was 78%, 77% and 61%, respectively. CSF protein levels ≥1 g/L in neonates and ≥0.8 g/L in infants aged 1-3 month, or CSF neutrophils ≥2×106/L, independently increased the likelihood of bacterial meningitis (positive likelihood ratios ≥5 and ≥3, respectively). 3 of 39 cases of bacterial meningitis would have been missed using the commonly used WCC cut-offs alone. However, two would have been identified using CSF protein and neutrophil thresholds. All CSF parameters were poor at identifying viral meningitis.
Conclusion:
A single CSF parameter cannot reliably diagnose bacterial meningitis. For identification of bacterial meningitis, elevation of CSF WCC, neutrophil count or protein levels above threshold values improves accuracy of diagnosis.
Insights
Cerebrospinal fluid (CSF) white blood cell count alone is insufficient for diagnosing bacterial meningitis in infants. Combining CSF white blood cell count, neutrophil, and protein levels improves diagnostic accuracy for bacterial meningitis.
Area of Science:
- Pediatric infectious diseases
- Clinical microbiology
- Diagnostic accuracy studies
Background:
- Meningitis diagnosis in infants relies on cerebrospinal fluid (CSF) analysis, often before definitive pathogen identification.
- Current diagnostic methods include CSF culture and PCR, but treatment initiation precedes these results.
Purpose of the Study:
- To evaluate the predictive value of CSF parameters for diagnosing bacterial and viral meningitis in young infants.
- To assess the accuracy of CSF white blood cell count (WCC), neutrophil, protein, and glucose levels in differentiating meningitis types.
Main Methods:
- A multicentre retrospective cohort study analyzed 1088 CSF results from infants aged 0-90 days between 2010-2020.
- Evaluated CSF parameters in 538 meningitis cases (39 bacterial, 499 viral) against controls with negative CSF microbiology and no prior antibiotics.
Main Results:
- CSF white blood cell count cut-offs showed varying sensitivity and specificity for bacterial meningitis across age groups.
- CSF protein levels (≥1 g/L in neonates, ≥0.8 g/L in 1-3 month olds) and neutrophil counts (≥2×10^6/L) independently increased bacterial meningitis likelihood.
- Common WCC cut-offs alone missed 3 bacterial meningitis cases, whereas protein and neutrophil thresholds identified two of these.
Conclusions:
- No single CSF parameter reliably diagnoses bacterial meningitis in infants.
- Elevated CSF white blood cell count, neutrophil, or protein levels above specific thresholds enhance the accuracy of bacterial meningitis diagnosis.
- CSF parameters were found to be poor indicators for diagnosing viral meningitis.
