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

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. Her PM resulted from the "Macklin effect," which involves a three-step process: overly distended alveolar rupture, air dissection along the bronchovascular sheaths, and air spreading into the mediastinum.

Treatment consisted of oxygen therapy, parenteral corticosteroids, and nebulized bronchodilators.

She made a good recovery, and was discharged from the intensive care unit after 2 days.

This case illustrates that conservative management strategies in this severe and unusual complication of asthma exacerbation can result in rapid and complete recovery. Nonetheless, every asthma exacerbation should be considered potentially life-threatening, and must be treated promptly and adequately.