Aetiologies and outcomes of diffuse alveolar haemorrhage presenting as acute respiratory failure of uncertain cause

Connective tissue diseases are the most common disorders causing diffuse alveolar haemorrhage (DAH) confirmed by open lung biopsy. However, it is not known whether these diseases are also the most common causes of DAH in patients presenting with the features of ARDS/acute lung injury (ALI). This study evaluated the frequency of concomitant disease in patients with ARDS/ALI and DAH.The sampling frame comprised all patients in a tertiary referral hospital diagnosed with ARDS/ALI and who underwent BAL between January 2000 and July 2006. The medical records of those patients who had BAL fluid findings compatible with DAH were reviewed.Of the 97 patients diagnosed with ARDS/ALI and who underwent BAL, 27 had BAL fluid findings compatible with DAH. Sixteen of the 27 patients did not have connective tissue diseases (59%); of these 12 patients had concomitant haematological malignancies or solid tumours. Of the seven patients who presented with DAH and no known underlying disease, only two were subsequently diagnosed with a connective tissue disorder. The in-hospital mortality rate was 55% and 63% for patients with DAH with and without connective tissue diseases, respectively (P = 0.710).The majority of patients with DAH presenting with the features of ARDS/ALI did not have underlying connective tissue diseases. Concomitant malignancies were found frequently in these patients. The outcome did not differ between patients with DAH with or without connective tissue diseases.