Reviewed by Dr. Clement J. Cheng
Emphysema is a potentially fatal lung condition characterized by over-inflation of the alveoli, or air sacs, and loss of elasticity in the lungs. Several factors can lead to the development of emphysema, such as heredity, pollution, and pre-existing lung disease. However, heavy, long-term smoking most often causes emphysema.
Emphysema is the leading cause of respiratory death in the United States. Currently, 1.8 million Americans in the United States have emphysema. It ranks 15th among chronic conditions that contribute to activity limitation.
No cure exists, and no treatment can reverse its effects. However, the earlier emphysema is treated, the better chance the patient has of slowing the advancement of the disease.
Alveoli are small, thin-walled air sacs located in clusters at the ends of the airways, deep within the lungs. Their functions are delivering oxygen into the bloodstream and drawing out carbon dioxide waste. Emphysema occurs when the alveoli become damaged or enlarged.
When the lungs become damaged, usually due to smoking, breathing becomes labored. Long periods of difficult breathing put a strain on the alveoli and stretch them beyond their limits. Over time, they lose their elasticity and may burst. When this happens, the lungs cannot function properly and the surface area of the lungs shrinks. The airways narrow and collapse, and you become short of breath and can develop a wheeze. Even the slightest form of exercise can trigger breathlessness.
Any lung disease that causes the respiratory airways to narrow may contribute to the development of emphysema. The resulting pressure on the lungs from conditions such as bronchitis or asthma can exhaust and damage the alveoli. Less often, emphysema can be caused by the lack of a cellular enzyme that maintains the elasticity of the fibers in the walls of the alveoli.
Emphysema is found most commonly in men between the ages of 50 and 70 who have smoked heavily over a period of years. However, the disease is becoming more common in women as they make up a larger percentage of smokers.
Researchers believe that cigarette smoke breaks down the elastic fibers in the walls of the alveoli, causing the air sacs to be more susceptible to rupture. Smoking also weakens the walks of the branching airways, causing them to collapse on exhalation and trap stale air.