Differential diagnosis of usual interstitial pneumonia: when is it truly idiopathic?

Our plain-English summary of Differential diagnosis of usual interstitial pneumonia: when is it truly idiopathic?, by W.A. Wuyts, A. Cavazza, G. Rossi, et al (European Respiratory Review, 2014).

The study

• Authors: W.A. Wuyts, A. Cavazza, G. Rossi, F. Bonella, N. Sverzellati, P. Spagnolo
• Journal: European Respiratory Review
• Published: 2014;23(133):308-19
• Cited by: 84 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Idiopathic pulmonary fibrosis (IPF), the most common and lethal of the idiopathic interstitial pneumonias, is defined by a radiological and/or pathological pattern of usual interstitial pneumonia (UIP). However, UIP is not synonymous with IPF as other clinical conditions may be associated with UIP, including chronic hypersensitivity pneumonitis, collagen vascular disease, drug toxicity, asbestosis, familial IPF and Hermansky-Pudlak syndrome. Differentiating IPF ("idiopathic UIP") from conditions that mimic IPF ("secondary UIP") has substantial therapeutic and prognostic implications. A number of radiological and histological clues may help distinguish IPF from other conditions with a UIP pattern of fibrosis, but their appreciation requires extensive expertise in interstitial lung disease as well as an integrated multidisciplinary approach involving pulmonologists, radiologists and pathologists. In addition, multidisciplinary discussions may decrease the time to initial IPF diagnosis and, thus, enable more timely management. This concept was strongly emphasised by the 2011 ATS/ERS/JRS/ALAT guidelines. This article highlights, with the aid of a clinical case, the difficulties in making a diagnosis of IPF in clinical practice. Yet, an accurate diagnosis is critical, particularly given the availability of drugs that may reduce the pace of functional decline and disease progression in IPF.

©ERS 2014.

In plain English

This article was a review of how doctors tell idiopathic pulmonary fibrosis (IPF), lung scarring of unknown cause, apart from other conditions that produce the same scarring pattern, called usual interstitial pneumonia (UIP). It was built around one patient: a 62-year-old man, a current smoker who worked as a sales representative, seen in June 2012 with almost a year of breathlessness and dry cough. He denied significant occupational exposures but had taken the heart drug amiodarone and had been exposed to parrots. His forced vital capacity was 68% of predicted. After a surgical lung biopsy consistent with UIP, he was diagnosed with IPF, and the authors excluded drug-induced lung disease. Asbestos was not studied. The review listed asbestosis among conditions that can show a UIP pattern. Citing an American Thoracic Society statement, it noted that patients with extensive asbestos exposure, pleural plaques and typical CT abnormalities may be diagnosed with asbestosis without biopsy. The authors concluded that the key task is to separate idiopathic UIP from secondary UIP.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Narrative review illustrated by a single clinical case
• Who was studied: One patient: a 62-year-old man seen in June 2012 with slowly progressive shortness of breath and dry cough. He was a current smoker of 60 pack-years and worked as a sales representative. The review part discusses patients with IPF and conditions that mimic it in general.
• Exposure: No asbestos exposure was studied. The case patient denied significant occupational exposures. He had taken amiodarone, had been exposed to parrots for almost 5 years until 1995, and had a family history of rheumatoid arthritis.
• Main results:
  • In the case patient, lung function tests showed a restrictive defect: forced vital capacity was 68% predicted, with a moderately reduced diffusing capacity (42% predicted).
  • After clinical, radiological and pathological assessment, including a surgical lung biopsy consistent with a UIP pattern, the case patient was diagnosed with IPF.
  • Despite the patient's amiodarone exposure, the authors excluded drug-induced lung disease based on radiological, lavage and pathological findings.
  • The review listed asbestosis among the conditions that can be associated with a UIP pattern, so UIP is not the same as IPF (citing the 2011 guidelines).
  • Citing a 2004 American Thoracic Society statement, the review noted that patients with a history of extensive asbestos exposure, pleural plaques and typical CT abnormalities may be diagnosed with asbestosis without biopsy.
• The authors' conclusion: The authors concluded that the most important task with a patient with interstitial lung disease is to diagnose UIP and to separate idiopathic UIP (IPF) from secondary UIP, using integrated clinical, radiological and pathological data.

Topics

Medical terms in this study, explained in our Lexicon: Differential Diagnosis, Interstitial, Idiopathic, Pulmonary Fibrosis, Pneumonitis, Collagen, Fibrosis, Interstitial Lung Disease.

Related studies

• Usual interstitial pneumonia in asbestos-exposed cohorts - concurrent idiopathic pulmonary fibrosis or atypical asbestosis? — R.L. Attanoos, F.S. Alchami, et al. (2016)
• Comprehensive characterisation of individuals with fibrotic interstitial lung disease: baseline insights from the INJUSTIS study — F. Khan, I. Stewart, et al. (2026)
• Usual interstitial pneumonia: typical, possible, and "inconsistent" patterns — P.P.T.E.S. Torres, M.F. Rabahi, et al. (2017)
• Asbestosis and environmental causes of usual interstitial pneumonia — M. Gulati, C.A. Redlich (2015)
• Dyskeratosis congenita showing usual interstitial pneumonia — S. Imokawa, A. Sato, et al. (1994)
• Prognosis and causes of death of patients with acute exacerbation of fibrosing interstitial lung diseases — J. Salonen, M. Purokivi, et al. (2020)

Browse more research in European Respiratory Review, or return to medical research.