Left lung asthma.

The chest radiograph of a woman with acute asthma showed signs of obstructive emphysema of the left lung. Fiberoptic bronchoscopy excluded obstruction of a large bronchus. The signs disappeared after antiasthmatic treatment, suggesting that they were caused by airway closure. In usual asthma, airway closure affects both lungs; the reason for the unilateral predominance we observed is unknown.