Etiology of Meningitis Based on Cerebrospinal Fluid (CSF) Parameters

Introduction

Meningitis is an inflammatory condition affecting the meninges, often diagnosed using cerebrospinal fluid (CSF) analysis. Understanding CSF parameters aids in identifying the causative organism and guiding appropriate treatment.

Key CSF Parameters for Diagnosing Meningitis

1. CSF Protein Levels

Elevated protein levels indicate increased permeability of the blood-brain barrier, common in bacterial meningitis.

2. CSF Glucose Levels

Reduced CSF glucose suggests bacterial or fungal infection, as pathogens consume glucose for metabolism.

3. White Blood Cell (WBC) Count

High WBC count with neutrophil predominance points to bacterial meningitis, while lymphocytic dominance suggests viral or tuberculous meningitis.

4. Gram Stain

Gram staining aids in rapid identification of bacterial pathogens, influencing early treatment decisions.

Etiological Classification of Meningitis

• Bacterial Meningitis: High protein, low glucose, neutrophilic predominance, positive gram stain.
• Viral Meningitis: Normal or slightly elevated protein, normal glucose, lymphocytic predominance, negative gram stain.
• Fungal Meningitis: High protein, low glucose, lymphocytic predominance, negative gram stain.
• Tuberculous Meningitis: Elevated protein, low glucose, lymphocytic predominance, possible acid-fast bacilli on staining.

Conclusion

CSF analysis is crucial for diagnosing meningitis, determining its etiology, and guiding appropriate treatment strategies.