Bacterial Meningitis Diagnostic Tool

Age Cerebrospinal Fluid Glucose CSF Glucose mg per dL Cerebrospinal Fluid Protein CSF Protein mg per dL Cerebrospinal Fluid White Blood Cell Count CSF WBC cells per mm3 Blood Glucose mg per dL Bacterial Meningitis Diagnostic Tool Explanation and Clinical Context This tool assists clinicians by providing a structured evaluation of the probability of bacterial meningitis using variables derived from cerebrospinal fluid studies and basic laboratory measurements. Bacterial meningitis typically produces a distinct biochemical pattern that reflects increased inflammatory activity and altered glucose transport into the cerebrospinal space. Age younger than sixty years may increase susceptibility and is included based on evidence demonstrating epidemiologic relevance.

A marked reduction in cerebrospinal glucose reflects heightened metabolic activity by bacteria and inflammatory cells which consume glucose rapidly. Elevation of cerebrospinal protein indicates increased permeability of the blood brain barrier. Very high cerebrospinal white cell counts reflect intense neutrophilic inflammation which is characteristic of bacterial infection.

The cerebrospinal fluid to serum glucose ratio is a key discriminator because ratios below zero point two three strongly correlate with bacterial etiologies. Combined scoring synthesizes these biomarkers into a practical guide. Interpretation is not definitive and must be integrated with clinical findings, imaging results, and microbiologic tests.

This tool does not replace lumbar puncture findings or culture results but supports early decision making when timely treatment is essential to prevent neurologic complications and mortality. Reference Nigrovic LE et al. Clinical prediction rule for identifying children with cerebrospinal fluid pleocytosis at very low risk of bacterial meningitis.

JAMA. 2007.298.575 to 579. Brouwer MC et al.

Bacterial meningitis. Lancet. 2010.380.1703 to 1717.