A previously healthy 3-year-old boy is brought to the ED one hour after acute onset fever and difficulty breathing. His father says he has had noisy breathing that seemed to improve a little when he was brought outside. Immunizations are up to date. Temperature is 38 C. Examination shows use of accessory muscles with respiration. Inspiratory stridor is heard. Which of the following is the most likely explanation for these findings?
Bronchiolar inflammation
Edema and enlargement of the epiglottis
Narrowing of small- and moderate-sized airways
Pulmonary parenchymal inflammation
Subglottic edema
