Emphysema

Emphysema

Definition

 - Abnormal permanent increase in the size of air spaces beyond the terminal bronchioles

 - With destruction of their walls
 - Without fibrosis

Pathogenesis
Imbalance between protease & anti-protease activity

... leads to...

Neutrophils & macrophages = released proteases

Alpha-1-antitrypsin most common protease inhibitor
h/e...
Neutrophils = also release O2 free radicals

+ oxidants from cigarette smoke
Leads to inhibition of alpha-1-antitrypsin

Classification

Centriacinar emphysema
 - assoc with cig smoking & CB
 - increased protease activity
 - affects upper zone of lungs
 - 2ry to airway inflammation

Panacinar emphysema
 - assoc with alpha-1-antitrypsin deficiency

 - decreased anti-protease activity
 - affects lower zones of lungs
 - homozygotes (PiZZ) = emphysema <40
 - heterozygotes = emphysema if they smoke

Pathology
Macro
Cystic alveolar spaces (end-stage emphysema)
Micro
Destruction & dilatation of alveolar walls

Effects
Functional obstruction
 - loss of elastic recoil
 - premature closure of small airways