General Pathology USMLE Step 1 Practice Question
A 72-year-old man with ischemic cardiomyopathy presents with progressive dyspnea and bilateral lower extremity edema. Vital signs: BP 92/58, HR 104, RR 22, SpO2 88% on room air. Chest radiograph shows bilateral pleural effusions with elevated jugular venous pressure noted on exam. Thoracentesis yields clear, serous fluid with protein 2.2 g/dL, LDH 180 IU/L, and negative gram stain. No fever documented. Which of the following best explains this pleural fluid finding?
Answer choices
- AIncreased hydrostatic pressure producing a transudateCorrect answer
- BImmune complex deposition in pleural capillaries
- CIncreased vascular permeability due to histamine release
- DObstruction of lymphatics by metastatic carcinoma producing an exudate
- ENeutrophil mediated enzymatic digestion of tissue
- FDecreased plasma oncotic pressure due to hepatic cirrhosis producing a transudate
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