Diffuse alveolar hemorrhage (DAH) is rare but often fatal. To determine the clinical manifestations of DAH, its etiology, clinical course and prognosis were studied.

A retrospective analysis was performed in 21 patients that were diagnosed as DAH. Diagnosis of DAH was based on the presence of the "classical triad" of hemoptysis, anemia, and rapidly progressive infiltrates on chest X-ray and a finding of bronchoalveloar lavage or lung biopsy.

Thirteen patients (61.9%) had collagen vascular diseases (CVDs) as underlying disease and 10 patients had systemic lupus erythematosus. Females were more prevalent in CVD than in non-collagen vascular disease (NCVD). Otherwise, there were no significant differences between the two groups in terms of clinical manifestations. Dyspnea (95.2%), cough (76.2%), hemoptysis (61.9%), and fever (33.0%) were frequent symptoms. The initial creatinine level was higher in CVD than in NCVD (3.27±3.15 mg/dl vs. 1.19±0.94 md/dl, p=0.030). The corresponding drop in hemoglobin level was 2.69±1.26 g/dl. Maximal drop in hemoglobin preceded the progression of infiltrates on the chest radiograph by 1.38±4.22 days. The mortality rate was higher in the patients with NCVD than in those with CVD (50.0% vs. 23.1%).

The DAH can occur not only in patients with CVD but also in those with NCVD. Higher creatinine level CVD in patients is associated with renal involvement in conjunction with DAH. The maximal drop in hemoglobin preceeding the progression of infiltrates on the chest radiograph suggests that the drop in hemoglobin is important for diagnosing DAH.