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Bronchiolitis — USMLE Step 3 MCQ

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ModeratePediatrics (well-child, chronic management)BronchiolitisUSMLE Step 3

A 4-month-old boy has cough, rhinorrhea, and wheezing in winter. Oxygen saturation is 95%, and he is feeding adequately. Chest examination shows diffuse crackles and wheezes. Chest radiograph is not obtained. His older sibling has a cold. Which of the following is the most likely explanation for this patient's findings?

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Reveal the answer and explanation

Correct answer: D — Small airway inflammation from viral infection

Bronchiolitis in infants is usually viral, causing lower airway edema, mucus, and wheezing; supportive care is central.

Reference: AAP bronchiolitis guideline: https://www.aap.org/