Pneumonia USMLE Step 1 Practice Question
A 59-year-old woman with no prior lung disease presents with fever (38.9°C), productive cough, and dyspnea. Vital signs show BP 128/82, HR 102, RR 22, SpO2 92% on room air. Chest X-ray reveals left lower lobe consolidation with moderate pleural effusion. Thoracentesis yields fluid with protein 4.2 g/dL (serum 6.8), LDH 450 IU/L (serum 180), and negative cultures. She takes no regular medications. Which of the following best describes this pleural fluid process?
Answer choices
- AExudative parapneumonic effusionCorrect answer
- BPulmonary embolism
- CTransudative pleural effusion from congestive heart failure
- DPleural effusion
- EEmpyema
- FMalignant pleural effusion from primary lung adenocarcinoma
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.