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Pediatric asthma — USMLE Step 3 MCQ

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HardPediatrics (well-child, chronic management)Pediatric asthmaUSMLE Step 3

A 12-year-old with allergic rhinitis has episodic cough and wheeze, normal spirometry between episodes, and an inconclusive bronchodilator response. Fractional exhaled nitric oxide is 42 ppb. Which interpretation is most appropriate?

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Correct answer: D — Interpret elevated FeNO as adjunctive evidence of type 2 airway inflammation

The best answer is “Interpret elevated FeNO as adjunctive evidence of type 2 airway inflammation”. When the usual asthma evaluation remains uncertain, FeNO can support the presence of type 2 airway inflammation but cannot diagnose asthma by itself. Atopy can elevate FeNO, and one value neither proves nonadherence, excludes an alternative diagnosis, nor establishes severe-asthma biologic eligibility.

Reference: NHLBI 2020 Focused Updates to the Asthma Management Guidelines: https://www.nhlbi.nih.gov/health-topics/asthma-management-guidelines-2020-updates