Introduction: What Is IPF?

Clinical Course of IPF Graph, Small

Reprinted with permission of the American Thoracic Society. Copyright © 2014 American Thoracic Society. Raghu G, Collard HR, Egan JJ, et al. An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management. Am J Respir Crit Care Med. 2011;183:788-824. Official Journal of the American Thoracic Society. Note: this document was published in 2011 and is currently in revision. Certain aspects of this document may be out of date and caution should be used when applying these in clinical practice or other usages.


IPF is a severe, debilitating, progressive form of fibrotic lung disease,1 and is the most common of the idiopathic interstitial pneumonias (IIPs).2 The cause of IPF is not yet fully understood. IPF typically occurs in older adults, and is associated with characteristic histopathologic and radiographic pattern known as usual interstitial pneumonia (UIP).1

At present, IPF is a diagnosis of exclusion; to establish a diagnosis of IPF, other forms of interstitial lung disease including other IIPs and interstitial lung diseases associated with certain environmental exposures, medications, or systemic disease must be adequately evaluated for and excluded.1

The 2013 American Thoracic Society and the European Respiratory Society Classification of IIPs recognizes 6 major IIPs, each with specific radiographic and/or pathologic-morphologic patterns (Table 1).3 Achieving an accurate diagnosis requires a multidisciplinary approach with close communication between the clinician, radiologist and pathologist.1

Table 1.
Major idiopathic interstitial pneumonias and associated radiologic and/or pathologic-morphologic patterns. Adapted from Travis WD, et al. Am J Respir Crit Care Med. 2013;188:733-748.3

Classification Associated Radiologic and/or
Pathologic-Morphologic Patterns
Idiopathic pulmonary fibrosis Usual interstitial pneumonia
Idiopathic nonspecific interstitial pneumonia Nonspecific interstitial pneumonia
Respiratory bronchiolitis interstitial lung disease Respiratory bronchiolitis
Desquamative interstitial pneumonia Desquamative interstitial pneumonia
Cryptogenic organizing pneumonia Organizing pneumonia
Acute interstitial pneumonia Diffuse alveolar damage

Clinical Presentation

IPF should be considered in any adult patient with the gradual onset of chronic dyspnea (with exertion or at rest) or non-productive cough that cannot be attributed to other causes.1 Bibasilar inspiratory crackles (known as “Velcro crackles”) are commonly seen at presentation,12 and finger clubbing is present in 25% to 50% of patients.12

Content contributed by:
Jonathan A. Kropski, MD
Vanderbilt University