Acute exacerbations, of IPF

Acute exacerbations of IPF are characterized by rapid development of cough, dyspnea, hypoxemia, and worsening pulmonary infiltrates in patients with known IPF (29,148-151). Presentation is similar to acute respiratory distress syndrome (ARDS) (29,148,149,151,152). The cardinal histological feature is DAD superimposed on a background of UIP (149,151). Idiopathic acute interstitial pneumonia (AIP) (28,152) exhibits similar clinical and histological features as acute exacerbations of IPF, but lacks the requisite features of UIP. High-dose intravenous (IV) pulse methylprednisolone has been used to treat acute exacerbations of IPF, but data on treatment are limited to anecdotal cases and small series (29,148,149,151). This entity is reviewed in chapter 15 and will not be further discussed here. 

Despite the relative safety of VATS-SLB, a decision to pursue SLB should take into account the patient s age, comorbidities, and potential to alter disease course given biopsy result and subsequent therapeutic trial. Previous literature suggested that clinical deterioration associated with an acute exacerbation of IPF occurred in 2.1% of patients undergoing SLB for evaluation of UIP (64). Recently, SLB has been noted to exacerbate idiopathic NSIP with associated rapid deterioration in respiratory status (32). These findings warrant further investigation. 

Episodes of rapid deterioration have been described in idiopathic NSIP and more recently in CTDs-ILD, resembling acute exacerbations of IPF and featuring DAD superimposed UIP or fibrotic NSIP (21). In a recent study, acute exacerbations occmred in 4 of 93 patients with histologically proven CTDs-ILD including 3 with RA-UIP and 1 with SSc-NSIP (21). The estimated one-year frequency was 5.6% among aU patients with CTDs-UIP, but was higher in those with RA-UIP. As in IIPs, the outcome was poor. 

Fig. 26.4a,b. Axial CT image in a 63-year-old man with usual interstitial pneumonia (UIP)/idiopathic pulmonary fibrosis (IPF) shows bilateral reticular opacities, honeycombing (black arrowheads), and traction bronchiectasis (arrow). In addition, patchy, ground-glass opacities are present (white arrowhead) (a). Acute exacerbation in the same patient shows marked progression of ground-glass opacities (arrowheads) (b)... 

UIP may carry a poorer prognosis than NSIP (13), in ctmtrast with other CTDs-ILD. In a recent study, the mortality of RA-UIP was similar to that of IPF and higher than in other CTDs-UIP on univariate but not multivariate analysis (4). RA-ILD can be complicated by acute exacerbations with a fatal outcome in aU cases (21,166,170). The one-year frequency of acute exacerbation has been estimated at 11.1% in patioits with RA-UIP, which is higher than in other CTDs-ILD (21). 

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