Acute exacerbation of idiopathic pulmonary fibrosis as the initial presentation of the disease.

The clinical course of patients with idiopathic pulmonary fibrosis (IPF) is generally marked by a decline in pulmonary function over time, although recently there is increasing recognition that fatal deterioration from acute exacerbation can occur at any stage. The patient described in the present case study was a 65-yr-old male who presented with exertional dyspnoea and fever of 2 weeks' duration. He had no history of chronic lung disease or physiological or radiological hallmarks of pre-existing disease. He underwent surgical lung biopsy and the histological examination showed a background pattern of usual interstitial pneumonia (UIP) with a pattern of focal acute diffuse alveolar damage (DAD) in the area where normal lung architecture was preserved. It is notable that the pathological diagnosis of this rapidly progressive interstitial pneumonia was DAD on UIP, which is typically seen in acute exacerbations of IPF. Unusual findings on high-resolution computed tomography scan were also noted. We presume that in this case acute exacerbation developed in the very early course of IPF. Given the possibility that similar cases may have arisen among patients diagnosed with acute interstitial pneumonia or acute respiratory distress syndrome, the histopathology of rapidly progressive interstitial pneumonia may need to be revisited.