Interstitial lung disease, or ILD, is a group of disorders that affect the lungs with scarring, also called fibrosis or inflammation, or both. In order to understand how this affects the lungs, I think it's important to understand the normal anatomy and function of the lungs. The lungs are like an upside down tree. The trunk of the tree is the windpipe or the trachea. The branches of the tree are airways or bronchi, and the leaves of the tree are alveoli. Normal alveoli are thin and delicate. This allows for easy transfer of oxygen from the airspace into the circulation, and for offloading of carbon dioxide. The normal lung is also very elastic or spongy, and this translates into very easy breathing with minimal effort to expand our lungs when we take a deep breath. When a patient has ILD, scarring or inflammation is deposited in the walls of those alveoli, it also results in a stiffer lung. Now, a patient has to exert more work to draw a breath into their lungs, and a patient notices more shortness of breath or difficulty breathing. Left untreated, the lungs are often irreversibly damaged. We have available effective treatments now that in some cases can improve lung function, and in most patients can slow or temporarily halt the progression of this disease.
