Given the age of the patient and the diffuse involvement of all parts of the lung (especially the lower zones), which enzyme deficiency should be considered high on the differential diagnosis?
Alpha-1-antitrypsin deficiency.
Does smoking impact alpha-1-antitrypsin deficiency?
Yes, survival is substantially worse in smokers, who have a 15-20 year decrease in longevity relative to non-smokers.
What does the alpha-1-antitrypsin protein do and how is its absence responsible for emphysema?
The alpha-1-antitrypsin protein inhibits neutrophil elastase. In patients with severe deficiency, the neutrophil elastase acts unopposed resulting in damage to the lower respiratory tract. This damage is predominantly basal because of the gravitational distribution of pulmonary blood flow.
Diagram of the three types of emphysema.