Chronic pneumomediastinum and subcutaneous emphysema: association with dermatomyositis.

We describe a 41-year-old patient with adult-onset dermatomyositis who developed persistent pneumomediastinum and severe subcutaneous emphysema due to end-stage interstitial lung disease. The diagnosis of dermatomyositis was based on proximal muscle weakness, electromyographic findings of inflammatory myopathy, and positive findings on muscle biopsy. Low levels of creatine kinase elevation were found at the time of diagnosis (a form of dermatomyositis which has been associated with a poor prognosis). The patient had no signs of cutaneous vasculitis. Despite treatment with prednisone and azathioprine, she died of intercurrent gram-negative sepsis 15 months after the diagnosis of dermatomyositis.