Pulmonary manifestations of the idiopathic inflammatory myopathies.

Pulmonary involvement in myositis includes interstitial lung disease (ILD), respiratory muscle weakness, aspiration, infections, and drug-induced disease. ILD may precede myositis, and results in increased morbidity and mortality rates. Initial evaluation should include pulmonary function tests and high-resolution computed tomography. Nonspecific interstitial pneumonia (NSIP) is the most common histologic pattern on lung biopsy. Treatment usually consists of a combination of steroids and other immunosuppressive agents, and the response depends on the clinical presentation and underlying histology.