The patient was a 51/2-week-old male who was hospitalized with a 10-day history of choking spells. The child’s spells began with repetitive coughing and progressed to his turning red and gasping for breath. In the prior 2 days, he also had three episodes of vomiting in association with his choking spells. His physical examination was significant for a pulse rate of 160 beats/min and a respiratory rate of 72/min (both highly elevated). The child’s chest radiograph was clear. There was no evidence of tracheal abnormalities. His white cell count was 15,500/microliter with 70% lymphocytes. The culture from the nasopharyngeal swab revealed “mercury-like” colonies and a gram stain revealed gram negative coccobacilli.