Viral Infections USMLE Step 1 Practice Question
A 5-month-old boy presents to the emergency department in January with a 3-day history of cough and poor feeding. Vital signs show temperature 38.2°C, heart rate 148/min, respiratory rate 52/min, and oxygen saturation 89% on room air. Physical examination reveals nasal flaring, intercostal retractions, and diffuse wheezing. Chest radiograph demonstrates hyperinflation with peribronchial thickening. Notably, he has no fever-associated rash. Which organism is most likely responsible?
Answer choices
- AParainfluenza virus
- BInfluenza A virus
- CRespiratory syncytial virusCorrect answer
- DHuman herpesvirus 6
- EAdenovirus
- FRhinovirus
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