Distension and damage of the respiratory bronchioles selectively occur. Opening develops in the walls of the bronchioles. and they become enlarged and confluent and tend to from a single space as the walls enlarge. Distribution is uneven but more severe in upper portions in centrilobular emphysema (CLE). In panlobular Emphysema (PLE) more uniform enlargement and destruction of alveoli, more diffuse and more severe in lower lung.
Signs and Symptoms
Increased lung compliance, loss of elastic recoil resulting firm destruction of elastin in lung parenchyma causes the lungs to become permanently distended. Increased airway resistance. Distribution of elastic lung tissue causes the small airway to either collapse or narrow particularly during expiration. Thus, air becomes trapped in the distal airspaces. More pressure on diaphragm from distended lungs, so more use of accessory muscles to force the trapped air out of lungs leading to intra pleural pressure that increases the airway collapse. Altered 02/C02 exchange.