Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Figure 1: Baseline chest radiograph of a patient with known idiopathic pulmonary fibrosis (IPF) shows bibasilar coarse reticular opacities, traction bronchiectasis and subpleural opacities.
Figure 2: Chest radiograph performed 3 months later when the patient developed acute dyspnea and hypoxemia shows new groundglass opacities superimposed on areas of pre-existing IPF.

Facts: IPF

• Most common form of idiopathic interstitial pneumonias
• Gradually progressive disease with steady worsening of symptoms, lung function and gas exchange
• Median survival 3 years, no current treatment proven effective

Facts: Acute Exacerbation of IPF

• Some patients with IPF develops acute respiratory deterioration, which is an unusual natural course of diseases
• Idiopathic, no identifiable cause (infection, heart failure or pulmonary embolism)
• This can occur at anytime during the disease course, and can be a presenting symptom of IPF
• More common in men
• Acute to subacute worsening of dyspnea, generally within 30 days, fever, cough, flulike symptoms, severe hypoxemia, respiratory failure requiring mechanical ventilation, low PaO2/FiO2 ratio

Imaging Features

• Bilateral groundglass opacities with or without consolidation, superimposed on pre-existing IPF
• Groundglass opacities can be peripheral, multifocal or diffuse (pathology from surgical lung biopsy usually shows diffuse alveolar damage)
• Differential diagnosis on imaging: pulmonary edema, pneumonia superimposed on IPF

Diagnostic Criteria

• Previous or concurrent diagnosis of IPF
• Unexplained worsening or development of dyspnea within 30 days
• HRCT with new bilateral groundglass abnormality and/or consolidation superimposed on a background reticular or honeycomb patter consistent with IPF
• No evidence of pulmonary infection by endotracheal aspirate or bronchoalveolar lavage
• Exclusion of alternative causes, including the following: left heart failure, PE, identifiable cause of acute lung injury

Reference

Collard HR, Moore BB, Flaherty KR, et al. Acute exacerbations of idiopathic pulmonary fibrosis. Am J Respir Crit Care Med 2007;176:636-643.