Viral Infections USMLE Step 1 Practice Question
A 2-year-old boy presents to the emergency department at night with a barking cough and inspiratory stridor. He has had rhinorrhea and low-grade fever for 2 days. Vital signs show temperature 38.2°C, heart rate 112/min, respiratory rate 28/min, and blood pressure 95/60 mmHg. Neck radiograph demonstrates characteristic subglottic narrowing. Chest examination reveals no focal consolidation. He has received no recent antibiotics. Which organism is the most likely cause?
Answer choices
- ARespiratory syncytial virus
- BMeasles virus
- CParainfluenza virusCorrect answer
- DAdenovirus
- EInfluenza A virus
- FRhinovirus
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