Calculators & Tools

Bacterial Meningitis Score

In a child with CSF pleocytosis, identifies very low risk of BACTERIAL (as opposed to aseptic) meningitis.

1 What is the Bacterial Meningitis Score?

The Bacterial Meningitis Score is a Neurology & trauma scoring tool used in paediatric practice. In a child with CSF pleocytosis, identifies very low risk of BACTERIAL (as opposed to aseptic) meningitis. It scores 5 criteria and interprets the total across 2 bands, so the number always arrives with the severity it implies rather than on its own. In PediAid each criterion is shown as a labelled option with the weight it carries, so the total can be checked rather than taken on trust.

2 When to use it

  • Grading severity at the bedside in Neurology & trauma
  • Recording an objective severity band in the case notes
  • Deciding when a total crosses the threshold for escalation
  • Re-scoring to track whether a child is improving or deteriorating
  • Checking the exact criteria of a score used infrequently

3 Formula & method

The score sums 5 criteria: Positive CSF Gram stain; CSF absolute neutrophil count ≥ 1 000 cells/µL; CSF protein ≥ 80 mg/dL; Peripheral blood absolute neutrophil count ≥ 10 000 cells/µL; Seizure at or before presentation. Totals are then banded: any score - Very low risk: no predictors - very low risk of bacterial meningitis (sensitivity ~99-100%, NPV ~99.9%). Many protocols allow observation off antibiotics with close follow-up; 1 predictor or more - Not low risk: one or more predictors - NOT low risk. Treat as bacterial meningitis: empirical antibiotics and admission pending cultures.
  • Applies to children aged 29 days-19 years with CSF pleocytosis who are not critically ill, not pre-treated with antibiotics, without purpura, immunosuppression, VP shunt or recent neurosurgery.
  • Source: Nigrovic LE et al. Clinical prediction rule for identifying children with CSF pleocytosis at very low risk of bacterial meningitis. JAMA 2007;297:52-60.

4 Frequently asked questions

How many criteria does the Bacterial Meningitis Score use?

5. They are Positive CSF Gram stain; CSF absolute neutrophil count ≥ 1 000 cells/µL; CSF protein ≥ 80 mg/dL; Peripheral blood absolute neutrophil count ≥ 10 000 cells/µL; Seizure at or before presentation.

What do the bands of the Bacterial Meningitis Score mean?

The total is interpreted as: any score - Very low risk: no predictors - very low risk of bacterial meningitis (sensitivity ~99-100%, NPV ~99.9%). Many protocols allow observation off antibiotics with close follow-up; 1 predictor or more - Not low risk: one or more predictors - NOT low risk. Treat as bacterial meningitis: empirical antibiotics and admission pending cultures.

Does the score replace clinical judgement?

No. It is a structured way to record and communicate severity. A clinician concerned about a child should act on that concern regardless of the total.

Where does this score come from?

Applies to children aged 29 days-19 years with CSF pleocytosis who are not critically ill, not pre-treated with antibiotics, without purpura, immunosuppression, VP shunt or recent neurosurgery.

Does it work offline?

Yes. Score definitions are bundled with the PediAid app, so the score computes without a connection.

For qualified clinicians. This page and the PediAid app are a clinical aid only. Calculations and reference data must be verified against the patient's clinical context, the source guideline and your local protocols before any treatment decision is made.