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Malignant Effusion — RACP Adult Medicine MCQ

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EasyRespiratoryMalignant EffusionRACP Adult Medicine

A 50-year-old woman with lung cancer has a left-sided effusion. Pleural fluid: protein 45 g/L, LDH 350 U/L, glucose 2.5 mmol/L. Cytology shows adenocarcinoma cells. Pleural:serum protein ratio 0.65, pleural:serum LDH ratio 0.82. What is the most likely type of effusion?

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Correct answer: C — Malignant effusion

All three Light's criteria met (exudate). Positive cytology confirms malignant effusion. Malignant effusions are exudative with variable glucose (low glucose suggests high tumour burden). Lung and breast cancer are the commonest causes. Management: therapeutic thoracentesis for symptom relief, indwelling pleural catheter for recurrent effusions, talc pleurodesis if lung re-expands.

Reference: BTS – 2023 – Malignant Pleural Effusion; eTG Respiratory 2024