Making a specific diagnosis of pulmonary hemorrhage based on radiographic findings is difficult. Lung consolidation visible radiographically in association with hemoptysis and anemia strongly suggests the diagnosis. However, chest radiographic and CT findings are often nonspecific (Fig. 19-1), and hemoptysis may be lacking even in patients with sufficient hemorrhage to result in anemia.

For the purposes of differential diagnosis, diffuse pulmonary hemorrhage should be distinguished from focal pulmonary hemorrhage occurring as a result of abnormalities such as bronchiectasis, chronic bronchitis, active infection (e.g., tuberculosis), chronic infection, neoplasm, pulmonary embolism, or other vascular abnormalities such as arteriovenous fistula.

Diffuse pulmonary hemorrhage can result from a variety of diseases (Table 19-1). The differential diagnosis of diffuse pulmonary hemorrhage includes (1) anti- glomerular basement membrane disease (Goodpasture’s syndrome), (2) idiopathic pulmonary hemosiderosis (IPH), (3) Large vessel vasculitis (including Behçet’s disease), (4) small vessel vasculitis associated with antineutrophilic cytoplasmic antibody or ANCA (Wegener’s granulomatosis, Churg-Strauss syndrome, microscopic polyangiitis), (5) immune complex-related vasculitis (collagen-vascular diseases, Henoch-Schönlein purpura, mixed cryoglobulinemia), (6) drug reactions, (7) anticoagulation, and (8) thrombocytopenia (see Fig. 19-1).

Goodpasture’s syndrome, vasculitis syndromes, and collagen-vascular diseases are often associated with the combination of pulmonary hemorrhage and renal abnormalities and may be termed pulmonary-renal syndromes.

Anti-glomerular basement membrane disease (Goodpasture’s syndrome) most typically occurs in patients aged 20 to 30; men are affected four times as commonly as women (Table 19-2). Hemoptysis, usually mild, and anemia are present in 90%.
Other symptoms include cough, dyspnea, and weakness. Findings of renal disease are usually but not always present, including hematuria, proteinuria, and renal failure. Anti-glomerular basement membrane antibodies are almost always (95%) present in the serum. These antibodies are directed against type IV collagen and cross-react with alveolar basement membrane. A pulmonary capillaritis is present. Renal biopsy shows glomerulonephritis with linear deposition of IgG in the glomeruli.

Although plain radiographs may be normal, they usually show diffuse air-space consolidation or ground-glass opacity, typically bilateral and symmetrical and often with a perihilar predominance (Figs. 19-6A and 19-7). HRCT usually shows consolidation or ground-glass opacity and may be abnormal in the face of subtle plain film findings or normal radiographs (see Fig. 19-6B).

After an acute episode of hemorrhage, the air-space opacities tend to resolve, being superseded by an interstitial abnormality or septal thickening.

IPH is a disease of unknown origin characterized by recurrent episodes of diffuse pulmonary hemorrhage without associated glomerulonephritis or a serologic abnormality (Table 19-3). Pathologic findings include alveolar hemorrhage, hemosiderin-laden macrophages, and a variable degree of interstitial fibrosis in longstanding cases. IPH most commonly occurs in children under the age of 10 or young adults. In adults, men are affected twice as often as women. IPH is sometimes associated with cow’s milk allergy, thyroid disease, or immunoglobulin A gammopathy. It has recently been reported in infants with exposure to toxic mold (Stachybotrys). Symptoms include cough, hemoptysis, dyspnea, and anemia. The diagnosis is usually made by exclusion. About a quarter of patients die as a result of respiratory insufficiency or cor pulmonale.