Double aortic arch presenting as severe bronchiolitis in a 2-week-old infant.

A 2-week-old female infant was transferred from a regional hospital for mechanical ventilation after developing severe respiratory distress. Stridor had been present since the age of 1 week and was complicated by coryzal illness. Mechanical ventilation was difficult with marked inspiratory and expiratory flow obstruction recorded by the ventilator. Echocardiogram showed a normal heart. Flexible bronchoscopy revealed mid-tracheal extrinsic compression (unchanged with positive end-expiratory pressure) and advancement of the endotracheal tube by 2 cm completely corrected the flow obstruction. Repeat echocardiogram showed a double aortic arch. This case report emphasizes the importance of clinical history, examination findings and interpretation of the ventilator waveforms in the differential diagnosis of a difficult-to-ventilate infant with bronchiolitis.