Causes
of Emphysema
It is known from scientific research that the normal lung
has a remarkable balance between two classes of chemicals
with opposing action. The lung also has a system of elastic
fibers. The fibers allow the lungs to expand and contract.
When the chemical balance is altered, the lungs lose the ability
to protect themselves against the destruction of these elastic
fibers. This is what happens in emphysema.
There are a number of reasons this chemical imbalance occurs.
Smoking is responsible for 82% of chronic lung disease, including
emphysema. Exposure to air pollution is one suspected cause.
Irritating fumes and dusts on the job also are thought to
be a factor.
A small number of people with emphysema have a rare inherited
form of the disease called alpha I-antitrypsin (AAT) deficiency-related
emphysema, or early onset emphysema. This form of disease
is caused by an inherited lack of a protective protein called
alpha I-antitrypsin (AAT).
How Does Emphysema Develop?
Emphysema begins with the destruction of air sacs (alveoli)
in the lungs where oxygen from the air is exchanged for carbon
dioxide in the blood. The walls of the air sacs are thin and
fragile. Damage to the air sacs is irreversible and results
in permanent "holes" in the tissues of the lower
lungs. As air sacs are destroyed, the lungs are able to transfer
less and less oxygen to the bloodstream, causing shortness
of breath. The lungs also lose their elasticity. The patient
experiences great difficulty exhaling.
Emphysema doesn't develop suddenly, it comes on very slowly.
Years of exposure to the irritation of cigarette smoke usually
precede the development of emphysema. A person may initially
visit the doctor because they start to feel short of breath
during activity or exercise. As the disease progresses, a
short walk can be enough to bring on breathing difficulty.
Some people may have chronic bronchitis before developing
emphysema.
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