Publication:

Usual interstitial pneumonia - secondary vs idiopathic pulmonary fibrosis

Background Interstitial Lung Diseases is a group of disorders where the pulmonary interstitium, alveolar structures and the small airways are affected. Identification of a specific pattern on HRCT, with a thorough clinical evaluation can help a physician in narrowing down the differential diagnosis for the underlying cause. Usual Interstitial Pneumonia (UIP) is a frequently identified pattern. Differentiating patients with definite UIP pattern, into IPF and non-IPF spectrums is important. Aim of this study is to compare UIP patients with a secondary cause vs Idiopathic Pulmonary Fibrosis.

Methods Statistically 33 patients having UIP pattern on HRCT were evaluated based on the history of extrapulmonary symptoms, environmental exposure, drugs and subsequent serology testing. Patients were divided into two groups - IPF and UIP with a secondary cause. Both groups were compared on various clinical parameters. Inferences were drawn from the same.

Results Total 66.6% patients were identified to have Idiopathic Pulmonary Fibrosis, 33.3% had UIP with a secondary cause. Majority of patients with a secondary cause had Connective Tissue Disorder (90.9%) and one patient of Chronic Hypersensitivity Pneumonitis (HP).

Conclusions Absence of extrapulmonary symptoms in UIP patients need no further investigations and can be diagnosed as a case of IPF. However, presence of extrapulmonary symptoms needs further evaluation to diagnose the underlying disease and start treatment for the same.