Emphysema is a lung disease involving damage to the air sacs (alveoli). There is progressive destruction of alveoli and the surrounding tissue that supports the alveoli. With more advanced disease, large air cysts develop where normal lung tissue used to be. Air is trapped in the lungs due to lack of supportive tissue. This decreases oxygenation.
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.