Emphysema. Light micrograph of a section through a lung with emphysema. Emphysema is a disease in which the tiny air sacs (alveoli, white spaces) of the lung become enlarged and the walls separating them are damaged. Surface area for gaseous exchange is reduced, restricting oxygen uptake. This may cause breathlessness, bluish skin, and heart or respiratory failure. Occurrence of emphysema is strongly associated with smoking. Treatment is with drugs and the cessation of smoking.