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Malignant pleural effusion — MCCQE Part 1 MCQ

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ModeratePleural EffusionMalignant pleural effusionMCCQE Part 1

72-year-old woman with prior breast cancer presents with progressive dyspnoea. CXR shows a large unilateral pleural effusion. Which of the following is the most appropriate next step?

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Correct answer: D — Arrange diagnostic thoracentesis with cytology unless contraindicated

Arrange diagnostic thoracentesis with cytology unless contraindicated is best because new unilateral effusion in a patient with cancer needs fluid diagnosis. Prescribe an antibiotic without assessing severity or likely cause is suboptimal because antibiotics are not the default for all respiratory presentations; Discharge without oxygen assessment or safety-netting is suboptimal because oxygenation and work of breathing guide urgency; Request elective pulmonary function testing as the immediate step is suboptimal because spirometry is rarely the first step in an unstable acute presentation; Treat as anxiety without excluding cardiorespiratory disease is suboptimal because anxiety is a diagnosis of exclusion when objective respiratory features are present. Pleural fluid analysis guides infection, malignancy and heart failure distinctions.

Reference: Canadian Thoracic Society pleural disease guidance