Bronchiolar complications of connective tissue diseases.

Inflammatory and fibrotic processes can involve the small airways (i.e., respiratory and terminal bronchioles) in several connective tissue disorders (CTDs). Obliterative (constrictive) bronchiolitis (OB) as well cryptogenic organizing pneumonia (COP), previously termed bronchiolitis obliterans with organizing pneumonia (BOOP), are well-recognized, albeit rare, complications of rheumatoid arthritis and other CTDs. Bronchiectasis has also been described in patients with CTDs. Among the various pathologic conditions, clinical, radiographic, and histologic features and prognosis differ markedly. Clinical features are often nonspecific, and sometimes patients may be asymptomatic. Diagnosing these disorders may be difficult. High-resolution computed tomography (HRCT) is useful in detecting bronchiolar pathology, even when symptoms are minimal or absent. Surgical (open or thoracoscopic) lung biopsies can substantiate the diagnosis, but in some cases, the diagnosis can be affirmed less aggressively by appropriate imaging studies (e.g., HRCT) and transbronchial lung biopsies. Corticosteroids are highly efficacious for COP, but therapeutic options for OB are disappointing. Prophylactic antibiotics and good pulmonary hygiene remain the mainstay of therapy for patients with bronchiectasis.