ABSTRACT
This chapter focuses on the complex mechanisms of the pathogenesis of the fibrotic lung disorders. It considers the linkage between inflammation and fibrosis and the dynamics of the abnormal accumulation of collagens in interstitium. Regardless of the etiology, the interstitial lung diseases (ILD) commonly present a sequence of steps which lead to the development of pulmonary fibrosis. These are: initial lung damage; alveolitis Linkage between inflammation and fibrosis; and abnormal accumulation of collagen until the end-stage lung. Pulmonary fibrosis is a general term used to describe diseases with histological evidence of diffuse thickening of alveolar walls, where the main protein stained is collagen. BAL is a widely used procedure which serves different purposes such as the study of the lung disease activity for therapeutic decisions and follow-up, research into pathogenic mechanisms, and occasionally for diagnosis. Gallium lung scanning has been used to detect a variety of pulmonary diseases including lung cancer, infectious diseases, and more recently ILD.
