Current management of patients with idiopathic pulmonary fibrosis (IPF) requires attention to the exclusion of other causes of interstitial lung disease and either a definitive pattern on high-resolution computed tomography (HRCT) or a suggestive HRCT plus surgical lung biopsy. The main differential considerations include chronic hypersensitivity pneumonitis and connective tissue disease-associated interstitial lung disease (CTILD). Treatment includes smoking cessation, anti-reflux therapy, and the therapeutic option of one of two recently approved drugs, pirfenidone or nintedanib. IPF remains a deadly disease despite these drugs; thus the greatest emphasis should be on exclusion of alternative, potentially favorable diagnoses, continued option for enrollment in ongoing clinical trials, and, for eligible patients, early lung transplant evaluation.
Fibrosis, idiopathic, interstitial, IPF, nintedanib, pirfenidone
Randall S Schwartz, MD, has nothing to disclose in relation to this article. Marilyn Glassberg, MD, FACP, FCCP, serves as a consultant/advisory board member for Boehringer Ingelheim, Genentech, and Mesoblast. This article is a short opinion piece and has not been submitted to external peer reviewers. No funding was received in the publication of this article.
This article is published under the Creative Commons Attribution Noncommercial License, which permits any noncommercial use, distribution, adaptation, and reproduction provided the original author(s) and source are given appropriate credit.
October 16, 2015 Accepted:
December 01, 2015
Marilyn Glassberg, MD, FACP, FCCP, Jackson Memorial Hospital, University of Miami, Miami, Florida, US. E: MGlassbe@med.miami.edu
Diagnosis Idiopathic pulmonary fibrosis (IPF) is the most common of the idiopathic interstitial pneumonias1 and accounts for about 20 % of all interstitial lung diseases (ILD).2 IPF should be considered in all adult patients with unexplained chronic exertional dyspnea,3 though it is rare in patients less than 50 years of age.4,5 The latest guidelines for diagnosis require exclusion of other known causes of ILD and presence of either a characteristic pattern on high-resolution computed tomography (HRCT) or specific combinations of HRCT and surgical lung biopsy with the pattern of usual interstitial pneumonia (UIP).3 Other disease processes that may cause UIP include collagen vascular disease (CT-ILD), drug toxicity, chronic hypersensitivity pneumonitis (cHP), asbestosis, and Hermansky–Pudlak syndrome.6 Diagnosis of an underlying cause, if known, is of great significance in terms of treatment and survival. For instance, in one study, patients with UIP secondary to CT-ILD lived 63 % longer than those with idiopathic UIP.7
Classic HRCT patterns seen in IPF include a basilar and subpleural predominant distribution of reticulation and honeycombing, commonly with, though not requiring, traction bronchiectasis.8 Presence of ground glass does not exclude UIP so long as there is a greater degree of reticulation.8 Emphysematous changes may complicate HRCT interpretation and has been shown to result in mistaking UIP for chronic pulmonary emphysema with fibrosis (CPEF) as well as nonspecific interstitial pneumonia (NSIP).9 Appearance of the UIP distribution may be asymmetrical in up to 25 % of cases.10
The most common differential diagnoses for IPF are cHP, CT-ILD, and pneumoconiosis with particular emphasis on asbestosis.3 Concomitant features such as centrilobular nodules, air trapping, and relative sparing of the bases may be suggestive of hypersensitivity pneumonitis; pleural plaques suggest asbestosis; and septal or bronchovascular nodules may be present in sarcoidosis.11 CT-ILD should be considered in the presence of pleural effusion and/or pleural thickening, as well as esophageal dilation.11
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