What does “Interstitial” mean?


interstitium for website

The interstitium is the thin connective tissue between the surface of the alveoli and the blood vessels.


When a person breathes, air passes through the airways to the tiny air sacs called alveoli. These alveoli are the sites where oxygen passes into the blood and carbon dioxide exits the blood to be exhaled. In between the surface of the alveoli and the small blood vessels is a very thin connective tissue. This tissue is known as the interstitium. Changes to the interstitium, like swelling or scarring, can reduce the lungs ability to absorb oxygen and/or release carbon dioxide.

When the doctors first began defining chILD, most believed Children’s Interstitial Lung Disease was due to changes in this tissue. As we learned more, we have discovered that several chILD disorders like NEHI have normal interstitial tissue. As a result, we now consider chILD to include forms of Children’s Interstitial and Diffuse Lung Disease.