Spontaneous pneumomediastinum and subcutaneous emphysema in asthma exacerbation: The Macklin effect.

Objective: We describe the clinical features of a 17-year-old girl with severe asthma exacerbations. On admission to the intensive care unit, she manifested expiratory dyspnea, cyanosis, and an unproductive cough. Her chest x-rays showed extensive pneumomediastinum (PM), mild subcutaneous emphysema at the right anterior triangle of the neck, and right upper-lobe atelectasis.