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.