Spontaneous pneumomediastinum in a patient with facial rash

A 38-year-old male nonsmoker presented with constitutional symptoms, polyarthritis, facial rash, and progressive dyspnea of more than 1-year duration. Chest radiology revealed bilateral reticular and ground glass infiltrates. Connective tissue disease investigation was unrevealing. Pulmonary function test was consistent with restrictive lung disease and decreased diffusion capacity. The patient was treated with corticosteroids for amyopathic dermatomyositis with no improvement of dyspnea. Flexible bronchoscopy was noncontributory. Four and 6 months after initial presentation, he developed spontaneous pneumomediastinum and extensive subcutaneous emphysema that resolved with conservative therapy. Surgical lung biopsy revealed cellular-fibrotic nonspecific interstitial pneumonia for which he was started on cytotoxic medication, with no improvement in respiratory symptoms. The frequency of interstitial lung disease (ILD)-related polymyositis/dermatomyositis (DM) has been reported to range between 5% and 30% and nonspecific interstitial pneumonia is seen in up to 80% of DM-related ILD and in almost all the reported patients with amyopathic DM. On account of the increased morbidity and mortality of ILD-related DM, investigations for the early detection of ILD should be performed during initial evaluation and during follow-up of patients with polymyositis/DM. Serum levels of anti-Jo-1 antibodies, chest roentgenogram, high-resolution computed tomography of the lungs, and pulmonary function tests, including diffusing capacity of the lung for carbon monoxide, should be routinely included. In those patients with evidence of DM-related ILD, a lung tissue biopsy should be considered for better prognostic stratification. Conversely, the presence of spontaneous pneumomediastinum, pneumothorax, and subcutaneous emphysema should prompt a search for underlying connective tissue diseases.