Interstitial lung disease (ILD) is a broad category of lung diseases that includes more than 130 disorders characterized by scarring (i.e. "fibrosis") and / or inflammation of the lungs. ILD accounts for 15 percent of the cases seen by pulmonologists (lung specialists).
In ILD, the tissue in the lungs becomes inflamed and / or scarred. The interstitium of the lung includes the area in and around the small blood vessels and alveoli (air sacs) where the exchange of oxygen and carbon dioxide takes place. Inflammation and scarring of the interstitium disrupts this tissue and leads to a decrease in the ability of the lungs to extract oxygen from the air.
The progression of ILD varies from disease to disease and from person to person. It is important to determine the specific form of ILD in patients because what happens over time and the treatment may differ depending on the cause. Importantly, each person responds differently to treatment, so close monitoring during treatment is important.