Cardiac tamponade — ABEM Board MCQ

Correct answer: A — Mild bronchiolitis

The most likely diagnosis is mild bronchiolitis. In US exam practice, bronchiolitis is a clinical diagnosis in children 1–23 months with a viral upper respiratory prodrome followed by lower airway findings such as cough, wheeze, tachypnea, and mild increased work of breathing. This 9-month-old has rhinorrhea, cough, wheeze, RR 48, SpO2 93%, mild retractions, adequate feeding, and normal hydration, which fits mild bronchiolitis. An SpO2 above 90% and preserved feeding support mild disease and observation/supportive care rather than an alternative diagnosis. Bacterial pneumonia is less likely without fever, toxic appearance, focal crackles, or focal decreased breath sounds. Foreign-body aspiration is typically abrupt in onset, often after choking, with unilateral wheeze or asymmetric breath sounds. Epiglottitis causes high fever, drooling, dysphagia, tripod positioning, and stridor, not a wheezing viral syndrome. Congestive heart failure would suggest poor feeding, diaphoresis, hepatomegaly, edema, cardiomegaly, or chronic respiratory distress rather than acute rhinorrhea with wheeze.

Reference: American Academy of Pediatrics. Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis. Pediatrics. 2014;134(5):e1474-e1502; endorsed/reaffirmed by AAFP in 2019. https://publications.aap.org/pediatrics/article/134/5/e1474/75848/Clinical-Practice-Guideline-The-Diagnosis