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Pneumococcal Meningitis — RACP Adult Medicine MCQ

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EasyInfectious DiseasesPneumococcal MeningitisRACP Adult Medicine

A 25-year-old man presents with fever (39°C), headache, neck stiffness, and photophobia. CSF: Opening pressure 28 cmH₂O, WCC 1500 cells/μL (95% polymorphs), protein 2.5 g/L, glucose 1.0 mmol/L (serum glucose 6.5 mmol/L). Gram stain shows gram-positive diplococci. What is the most likely CSF diagnosis?

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Correct answer: A — Bacterial meningitis

High WCC with neutrophilic predominance, very elevated protein, very low glucose (CSF:serum ratio <0.4), elevated opening pressure, and gram-positive diplococci (S. pneumoniae) is classic bacterial meningitis. Empirical therapy is ceftriaxone IV plus dexamethasone IV (started before or with first antibiotic dose) per eTG.

Reference: eTG Antibiotic – 2025 – Bacterial Meningitis