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Pleural effusion — USMLE Step 2 CK MCQ

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HardInternal MedicinePleural effusionUSMLE Step 2 CK

A 52-year-old Middle Eastern woman comes to the hospital because of progressive symptoms. History and focused examination are notable for dullness to percussion and decreased breath sounds with unilateral meniscus sign. Temperature is 98.6°F (37.0°C), blood pressure is 126/78 mmHg, pulse is 84/min, respirations are 16/min, and oxygen saturation is 98% on room air. Physical examination confirms the key finding and shows no unrelated abnormality that would better explain the presentation. Chest imaging and arterial blood gas testing show abnormalities matching the respiratory findings; serum electrolytes are within reference range. Which of the following is the most appropriate initial diagnostic study?

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Correct answer: E — Diagnostic thoracentesis

The vignette describes Pleural effusion, supported by dullness to percussion and decreased breath sounds with unilateral meniscus sign. Diagnostic thoracentesis is the single best answer because it matches the diagnostic or management priority in this clinical setting. The other choices are plausible alternatives in related presentations, but they do not best fit the timing, findings, and guideline-directed approach described here.

Reference: https://www.ncbi.nlm.nih.gov/books/#stage-9-order-85