Diffuse pulmonary hemorrhage: a review and classification.

Diffuse pulmonary hemorrhage is an uncommon condition that is difficult to differentiate radiographically from diffuse pneumonia or pulmonary edema. The diagnosis should be suspected when a patient has even mild hemoptysis or has one of the diseases known to be associated with diffuse pulmonary hemorrhage. This paper reviews the clinical and radiographic features of diffuse pulmonary hemorrhage and presents a classification scheme depicted as a Venn diagram formed by four overlapping circles representing pulmonary hemorrhage, renal disease, immune complex disease, and antiglomerular basement membrane (anti-GBM) disease. This scheme results in six categories of pulmonary hemorrhage: associated with glomerulonephritis and anti-GBM antibody; associated with renal disease without demonstrable immunologic abnormalities; associated with glomerulonephritis and immune complex disease; associated with immune complex disease without renal disease; associated with anti-GBM antibodies without renal disease; without associated immunologic or renal abnormality. Examples of these disorders are illustrated. Improved clinical-radiographic correlation may lead to earlier diagnosis and treatment of diffuse pulmonary hemorrhage and its causes.