Acute exacerbation of idiopathic pulmonary fibrosis: a proposal

Acute exacerbation of idiopathic pulmonary fibrosis (IPF) occurs in approximately 10 % of IPF patients annually, and is a leading cause of morbidity and mortality in this disease. Although currently defined as idiopathic acute worsening, acute exacerbation of IPF may in fact have a variety of causes, in particular infection and aspiration. Central to the pathobiology of clinically meaningful events is a diffuse injury to the IPF lung, manifest histopathologically as diffuse alveolar damage, and biologically as accelerated alveolar epithelial cell injury or repair. On the basis of these recent observations, we propose a new conceptual framework for acute exacerbation of IPF that removes the idiopathic requirement and focuses on the pathophysiological mechanism involved.