Idiopathic pulmonary fibrosis

Diagnostic criteria for idiopathic pulmonary fibrosis[1]Raghu G, Remy-Jardin M, Myers JL, et al; American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Latin American Thoracic Society. Diagnosis of idiopathic pulmonary fibrosis. An official ATS/ERS/JRS/ALAT clinical practice guideline. Am J Respir Crit Care Med. 2018 Sep 1;198(5):e44-68. https://www.atsjournals.org/doi/full/10.1164/rccm.201807-1255ST http://www.ncbi.nlm.nih.gov/pubmed/30168753?tool=bestpractice.com [5]Raghu G, Remy-Jardin M, Richeldi L, et al; American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Latin American Thoracic Society. Idiopathic pulmonary fibrosis (an update) and progressive pulmonary fibrosis in adults: an official ATS/ERS/JRS/ALAT clinical practice guideline. Am J Respir Crit Care Med. 2022 May 1;205(9):e18-e47. https://www.atsjournals.org/doi/10.1164/rccm.202202-0399ST http://www.ncbi.nlm.nih.gov/pubmed/35486072?tool=bestpractice.com ​​

Diagnostic criteria for idiopathic pulmonary fibrosis (IPF) have been proposed in joint guidance from the American Thoracic Society (ATS), European Respiratory Society (ERS), Japanese Respiratory Society (JRS), and Latin American Thoracic Association (ALAT).[1]Raghu G, Remy-Jardin M, Myers JL, et al; American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Latin American Thoracic Society. Diagnosis of idiopathic pulmonary fibrosis. An official ATS/ERS/JRS/ALAT clinical practice guideline. Am J Respir Crit Care Med. 2018 Sep 1;198(5):e44-68. https://www.atsjournals.org/doi/full/10.1164/rccm.201807-1255ST http://www.ncbi.nlm.nih.gov/pubmed/30168753?tool=bestpractice.com [5]Raghu G, Remy-Jardin M, Richeldi L, et al; American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Latin American Thoracic Society. Idiopathic pulmonary fibrosis (an update) and progressive pulmonary fibrosis in adults: an official ATS/ERS/JRS/ALAT clinical practice guideline. Am J Respir Crit Care Med. 2022 May 1;205(9):e18-e47. https://www.atsjournals.org/doi/10.1164/rccm.202202-0399ST http://www.ncbi.nlm.nih.gov/pubmed/35486072?tool=bestpractice.com ​​

IPF is clinically suspected in the presence of:

• Unexplained symptomatic or asymptomatic patterns of bilateral pulmonary fibrosis on a chest x-ray or high-resolution computed tomography (HRCT)

• Bi-basilar inspiratory crackles

• Age greater than 60 years (familial pulmonary fibrosis may rarely present from age 40 years)

The diagnosis of IPF is then based on high-resolution CT (HRCT) and biopsy patterns, in consideration of the following:

• Exclusion of other known causes of interstitial lung disease (e.g., domestic and occupational environmental exposures, connective tissue disease, and drug toxicity)

• And the presence of either of

  • A pattern consistent with usual interstitial pneumonia (UIP) on HRCT in patients not subjected to surgical lung biopsy

  • Specific combinations of HRCT and histopathology patterns in patients subjected to surgical lung biopsy

A multi-disciplinary approach to diagnosis, involving pulmonologists, radiologists, and pathologists, is of paramount importance to ensure an accurate diagnosis. IPF is the likely diagnosis when a multi-disciplinary team agrees to a confident diagnosis of IPF. This may be informed by several findings:

• Moderate-to-severe traction bronchiectasis/bronchiolectasis identified in men and women older than 50 and 60 years, respectively

• Extensive (>30%) reticulation present on HRCT in patients older than 70 years

• Increased neutrophils and/or absent lymphocytosis present in BAL fluid

Diagnostic criteria for acute exacerbation of idiopathic pulmonary fibrosis[15]Collard HR, Ryerson CJ, Corte TJ, et al. Acute exacerbation of idiopathic pulmonary fibrosis. an international working group report. Am J Respir Crit Care Med. 2016 Aug 1;194(3):265-75. https://www.atsjournals.org/doi/10.1164/rccm.201604-0801CI?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed http://www.ncbi.nlm.nih.gov/pubmed/27299520?tool=bestpractice.com

Proposed diagnostic criteria for acute exacerbation:

• Previous or concurrent diagnosis of IPF (Note: if not previously established, this criterion can be met by the presence of radiological and/or histopathological changes consistent with UIP at the current exam)

• Acute worsening or development of dyspnoea, typically <1 month duration

• HRCT with new bilateral ground-glass opacity and/or consolidation superimposed on a background pattern consistent with UIP (Note: the 'new' qualifier can be dropped if no previous computed tomography is available)

• Deterioration not fully explained by cardiac failure or fluid overload

Events that are clinically considered to meet the definition of an acute exacerbation, but where HRCT data are not available, are termed 'suspected acute exacerbations'.