Viral Infections USMLE Step 1 Practice Question
A 62-year-old man with a 15-year history of COPD presents to the emergency department with a 3-day history of fever (39.2°C), productive cough with purulent sputum, dyspnea, and myalgias. He received the seasonal influenza vaccine 10 days ago. Vital signs include BP 128/82 mmHg, HR 102 bpm, RR 24/min, and SpO2 91% on room air. Physical examination reveals crackles in the right lower lobe. Chest X-ray shows right lower lobe consolidation with no evidence of acute exacerbation pattern. Laboratory results: WBC 13,200/μL with left shift, sputum Gram stain shows gram-positive cocci in pairs. Blood cultures and sputum cultures are pending. Nasopharyngeal swab for influenza is positive for influenza A. Which of the following best explains this patient's clinical presentation?
Answer choices
- APrimary influenza A viral pneumonia with acute COPD exacerbation
- BCommunity-acquired bacterial pneumonia caused by environmental exposure unrelated to recent viral infection
- CHypersensitivity pneumonitis triggered by vaccine adjuvant components
- DSecondary bacterial pneumonia superimposed on acute influenza A infectionCorrect answer
- EAcute exacerbation of COPD from environmental allergen exposure with incidental influenza colonization
- FVaccine-strain influenza pneumonia with inadequate immune response in COPD
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