Diagnosing interstitial lung disease: A practical approach to a difficult problem

Interstitial lung disease has a variety of causes: environmental, infectiou s, autoimmune, and drug-related. Accurate diagnosis is essential because th e prognosis and treatment of the disease varies widely depending on the cau se. However, the respiratory symptoms and pulmonary radiographic picture of these various causes of interstitial lung disease are often similar, makin g the diagnosis of its cause confusing and frustrating. The practical, algo rithmic approach to diagnosis outlined here identifies key diagnostic clues in the patient's history, physical exam, and radiographic findings.