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Empyema — RACP Adult Medicine MCQ

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ModerateRespiratoryEmpyemaRACP Adult Medicine

A 45-year-old man with pneumonia has a loculated effusion. Pleural fluid: protein 42 g/L, LDH 3500 U/L, glucose 1.2 mmol/L, pH 6.9. Gram stain shows gram-positive cocci. The fluid is turbid and foul-smelling. What is the most likely type of effusion?

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Correct answer: C — Empyema

Frankly purulent or turbid fluid with very high LDH, very low glucose (<2.2 mmol/L), pH <7.2, and positive Gram stain/culture is empyema. Any ONE of: pus, positive Gram stain/culture, pH <7.2, or glucose <2.2 indicates complicated parapneumonic effusion/empyema requiring chest drain insertion. Intrapleural fibrinolytics (alteplase + DNase) may be needed for loculated collections.

Reference: BTS – 2023 – Pleural Infection; MIST-2 Trial