Idiopathic interstitial pneumonias: a re-appraisal of idiopathic pulmonary fibrosis.

Over the last 30 years the clinical and histopathological definitions of the diffuse lung diseases have evolved considerably. Initially pathological entities were defined in parallel with clinico-radiological diagnoses, but these have more recently become consolidated into a more meaningful combined classification. These refinements have impacted on the diffuse lung diseases in particular, and have defined individual diseases more precisely than in previous classifications in which a number of distinct entities had been grouped together and mistaken for idiopathic pulmonary fibrosis, resulting in much confusion. The American Thoracic and European Respiratory Societies' committees, charged with the task of defining the idiopathic interstitial pneumonias, have recently published a statement on idiopathic pulmonary fibrosis, and a statement on the other idiopathic interstitial pneumonias should follow this year. Of these diseases, idiopathic pulmonary fibrosis is the most lethal, and this review deals with the impact that the changes in the nomenclature will have on our understanding of this and the other diseases with which idiopathic pulmonary fibrosis was previously confused and explores the implications of our new understanding on clinical practice. It also attempts to highlight areas of previous dogma in the literature that now need to be re-considered in the context of these more recent statements.