An unusual cause of obstructive emphysema.

A 6-month-old child presented with a history, physical signs and radiographic findings suggestive of the presence of a foreign body in the tracheobronchial tree. However, further investigation revealed extrinsic compression of the left main bronchus by a grossly enlarged left atrium. Treatment of the patient's heart failure resulted in resolution of the signs. Anomalous origin of the left coronary artery was found to be the cause.