[From exclusion to uncertainty: the route to diagnosing idiopathic pulmonary fibrosis]

Idiopathic pulmonary fibrosis (IPF) is a differentiated disease within the idiophatic interstitial pneumonias. IPF is progressive and fibrosing and is limited to the lungs. This entity generally affects persons older than 50 years old and is associated with the radiological and/or histological pattern of usual interstitial pneumonia (UIP). Clinically, IPF causes progressive exertional dyspnea and nonproductive cough. In most patients, physical examination reveals fine bibasilar inspiratory crackles and 50% of patients have digital clubbing. There are no specific laboratory alterations. Bronchoalveolar lavage and transbronchial biopsy will not establish the diagnosis of IPF but are useful to exclude other entities. Definitive diagnosis requires: a) exclusion of other, defined clinical entities or diffuse pulmonary diseases of known cause, and b) the presence of a histological pattern of UIP on analysis of pulmonary tissue from surgical biopsy, radiological evidence of the defined pattern of UIP on high-resolution computed tomography, or both.