What Causes Emphysema?

Generally, lungs become damaged because of reactions to irritants entering the airways and alveoli. Researchers continue to investigate the factors that may make some people more susceptible to emphysema than others. But there are some clear causes for emphysema:

• Cigarette smoking

• Alpha-1 antitrypsin deficiency

Cigarette Smoking

Cigarette smoking is the major cause of emphysema. When exposed to cigarette smoke, the air sacs of the lungs produce defensive cells, called macrophages, which "eat" the inhaled particles. But macrophages are stimulated to release materials which can destroy the proteins that let the lungs expand and contract, called elastin and collagen.

Cigarette smoke also damages the cilia, tiny hair-like projections in the bronchi that "sweep" foreign bodies and bacteria out of the lungs.

Alpha-1 Antitrypsin Deficiency

People who a deficiency of a protein called alpha-1 antitrypsin (AAT) are at a higher risk of developing severe emphysema. Alpha-1 antitrypsin deficiency (AAT deficiency) is an inherited condition and occurs in varying degrees.

AAT is thought to protect against some of the damage caused by macrophages. In AAT deficiency-related emphysema, the walls of the bronchial tubes and the alveoli are both damaged, often leading to severe disease.