Lung, Usual interstitial pneumonia

The incidence of usual interstitial pneumonia (UIP) increases with age. The patients are often between 50-70 years of age. Approximately 66% are over the age of 60 years at the time of presentation. The cause is unknown. The typical patient presents with an insidious onset of breathlessness with exertion and nonproductive cough. The lung function tests show restriction and impairment in gas exchange. Routine laboratory studies are usually not helpful. Chest radiographs typically show bilateral symmetric irregular linear opacities causing a reticular pattern. Common additional findings include ground glass opacities honeycombing and decreased lung volumes. The abnormalities may be diffuse but involve mainly the lower lung zones in about 80% of cases. The pleural surface of the lungs has a cobblestone appearance. There is patchy lung involvement with frequent subpleural, paraseptal and/or peribronchiolar distribution. There is dense fibrosis causing remodeling of the lung architecture with frequent honeycomb fibrosis. Fibroblast foci are scattered at the edges of dense scars. There is mild to moderate interstitial inflammation.