Transudative Effusion — RACP Adult Medicine MCQ

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EasyRespiratoryTransudative EffusionRACP Adult Medicine

A 60-year-old man with heart failure has a right-sided pleural effusion. Pleural fluid: protein 18 g/L, LDH 110 U/L. Serum protein 65 g/L, serum LDH 250 U/L. Pleural:serum protein ratio 0.28, pleural:serum LDH ratio 0.44. What is the most likely type of effusion?

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Correct answer: E — Transudate

Light's criteria: pleural:serum protein ratio <0.5, pleural:serum LDH ratio <0.6, and pleural LDH <2/3 upper limit of serum normal. All three criteria indicate transudative effusion. Common causes: heart failure (bilateral), cirrhosis (hepatic hydrothorax), nephrotic syndrome. Treatment addresses the underlying cause. Diagnostic thoracentesis is needed only if atypical features (unilateral, febrile, failing to respond).

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