lung and airway disorders
Overview of Interstitial Lung Diseases
Introduction
Interstitial lung disease (also called diffuse parenchymal disease) is a term used to describe a number of different disorders that affect the interstitial space of the lungs. The interstitial space consists of the walls of the air sacs of the lungs (alveoli) and the spaces around blood vessels and small airways. Interstitial lung diseases result in abnormal accumulation of inflammatory cells in lung tissue, cause shortness of breath and cough, and have similarities in their appearance on imaging studies but are otherwise unrelated. Some of these diseases are very unusual. Early in the course of these diseases, White Blood Cells , macrophages, and protein-rich fluid accumulate in the interstitial space, causing inflammation. If the inflammation persists, scarring (fibrosis) may replace normal lung tissue. As alveoli are progressively destroyed, thick-walled cysts (called honeycombing because they resemble the cells of a beehive) are left in their place. The condition resulting from these changes is called pulmonary fibrosis. Although the various interstitial lung diseases are separate and have different causes, they have some similar features. All lead to a decreased ability to transfer oxygen to the blood, and all cause stiffening and shrinkage of the lungs, which makes breathing difficult and causes cough. However, being able to eliminate carbon dioxide from the blood is usually not a problem. 