Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Corticosteroid responsiveness in patients with acute exacerbation of interstitial lung disease admitted to the emergency department

Interstitial lung disease (ILD), particularly idiopathic pulmonary fibrosis (IPF), has a poor prognosis. Corticosteroids are widely used in the treatment of acute exacerbation of ILD (AE-ILD). This study aimed to clarify the causes of AE-ILD, determine the efficacy of corticosteroids for treating AE-ILD, and detect differences in the mortality rate among subgroups of ILD. This was an observational retrospective single-center study. Patients with ILD who presented to the emergency department with acute respiratory symptoms from January 1, 2016, to December 31, 2018, were included. Patients with AE-ILD were classified into two groups depending on the prednisolone dose: low dose (0 to 1.0 mg/kg) or high dose (> 1.0 mg/kg). Mortality rates between patients with and without IPF were compared. This study included 182 patients with AE-ILD, including IPF (n = 117) and non-IPF (n = 65). Multivariate Cox regression analysis showed that corticosteroid dose (HR: 0.221, CI: 0.102–0.408, P < 0.001), initial P/F ratio (HR:0.995, CI:0.992–0.999, P = 0.006), and mechanical ventilation within 3 days of hospitalization (HR:4.205, CI:2.059–8.589, P < 0.001) were independent risk factors for mortality in patients with AE-ILD. This study showed that outcomes improve with higher doses of corticosteroids (> 1 mg/kg prednisolone) in patients with AE-non-IPF-ILD. However, this was not the case in patients with AE-IPF.

Acute exacerbation of interstitial lung disease after procedures

Interstitial lung disease (ILD) is a category of diffuse parenchymal lung diseases characterized by inflammation and/or fibrosis. The best characterized ILD is idiopathic pulmonary fibrosis (IPF). Acute exacerbation of IPF is a dreaded occurrence with grim prognosis and suboptimal treatment options. There have been recent reports that acute exacerbation can occur in other ILDs (AE-ILD). Of note, some of these acute exacerbations follow lung procedures. This review summarizes the available information on AE-ILD and discusses the procedures reported to cause AE-ILD. We also discuss proposed mechanisms, risk factors, treatment and prognosis. This review should help to inform decision-making about risks versus benefits of procedures that are commonly recommended to diagnose ILD.