October 01, 2018

What — besides smoking — can cause emphysema?

Q: A family friend was recently diagnosed with emphysema, but he never smoked. Are there other causes of emphysema?

A: Emphysema involves long-term, permanent damage to the tiny clusters of air sacs (alveoli) in the lungs, where oxygen is absorbed into the bloodstream and carbon dioxide is released to be exhaled.

Alveoli tissues are normally elastic, but emphysema causes them to become stiffer. This makes it harder to move air and ultimately results in shortness of breath that gets progressively worse over time.

Emphysema is one of a group of lung diseases, including chronic bronchitis, that make up chronic obstructive pulmonary disease (COPD).

Tobacco smoking tops the list of emphysema risk factors. Less common risk factors include long-term exposure to dust or fumes.

There also are rare inherited risk factors. One is alpha-1 antitrypsin deficiency, which is diagnosed with a simple blood test. Normally, large amounts of the alpha-1 antitrypsin protein are made in the liver, released into the bloodstream and distributed to the body. This protein helps protect the lungs from damage and preserves the elasticity of lung tissues.

In those who have alpha-1 antitrypsin deficiency, an abnormal protein is made and it isn't fully released by the liver into the bloodstream. Thus, the lungs lose a major protective element and become susceptible to emphysema even in people who never smoked and had only limited exposure to other lung irritants. Smoking can greatly accelerate the damage that leads to emphysema in those with alpha-1 antitrypsin deficiency. Moreover, buildup of the abnormal alpha-1 antitrypsin protein in the liver can also lead to permanent liver damage (cirrhosis).

Breathing tests or chest imaging may...