A recent international working group has suggested redefining AE of IPF (AE-IPF) as an acute, clinically significant respiratory deterioration characterised by evidence of new widespread alveolar abnormality. These revised diagnostic criteria consist of: 1) previous or concurrent diagnosis of IPF, 2) acute worsening or development of dyspnoea typically of <1 month duration, 3) CT with new bilateral ground-glass opacity and/or consolidation superimposed on a background pattern consistent with a usual interstitial pneumonia pattern and 4) deterioration not fully explained by cardiac failure or fluid overload. This represents a major change from the previous definition and diagnostic criteria, most significantly in no longer requiring AEs to be idiopathic. Historically, the annual incidence of AE-IPF ranges between 1% and 20%, and AEs have an in-hospital mortality of 27–65%. Multicentre registries and networks are necessary to revisit the epidemiology of AE using the revised definition, further define the risk factors for AE, and develop both preventative and therapeutic management approaches.

Cite as: Tanizawa K, Collard HR, Ryerson CJ. IPF: definition, severity and impact of pulmonary exacerbations. In: Burgel P-R, Contoli M, López-Campos JL, eds. Acute Exacerbations of Pulmonary Diseases (ERS Monograph). Sheffield, European Respiratory Society, 2017; pp. 58–65 [https://doi.org/10.1183/2312508X.10015916].