Diffuse alveolar hemorrhage in coumarin users: a fibrosing interstitial pneumonia trigger?

BACKGROUND: Fibrosing interstitial pneumonias (IPs) include idiopathic pulmonary fibrosis (IPF) and nonspecific interstitial pneumonia (NSIP). It has been suggested that oxidative damage plays a role in the pathophysiology of idiopathic interstitial pneumonias. Diffuse alveolar hemorrhage (DAH) can cause oxidative stress. Accordingly, we hypothesized that episodes of DAH might trigger fibrosing IP development. METHODS: Patients using coumarins with confirmed DAH were retrospectively gathered during a 9 year period and reviewed for the development of IPF or fibrosing NSIP. RESULTS: A total of 65 patients with DAH could finally be included, 31 (48 %) of whom subsequently developed a fibrosing IP. The majority of these 31 patients developed the fibrosing IP within 3 years after DAH confirmation. A total of 41 (63 %) patients died within 3.0 +/- 0.9 (range 1.3-4.7) years after the DAH diagnosis had been confirmed. Twenty-two of the deceased (54 %) had finally developed fibrosing IP. CONCLUSIONS: Almost half of the patients with established episodes of DAH developed fibrosing IP; therefore it seems that DAH might be a trigger for the development of fibrosing IP. This observation warrants prospective studies to further evaluate the clinical impact of these findings.