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What Is COPD?
Chronic obstructive pulmonary disease (COPD) is a lung disease
in which the lungs are damaged, making it hard to breathe.
In COPD, the airways—the tubes that carry air in and
out of your lungs—are partly obstructed, making it
difficult to get air in and out.
Cigarette smoking is the most common cause of COPD. Most
people with COPD are smokers or former smokers. Breathing
in other kinds of lung irritants, like pollution, dust, or
chemicals, over a long period of time may also cause or contribute
to COPD.
The airways branch out like an upside-down tree, and at
the end of each branch are many small, balloon-like air sacs.
In healthy people, each airway is clear and open. The air
sacs are small and dainty, and both the airways and air sacs
are elastic and springy. When you breathe in, each air sac
fills up with air like a small balloon; when you breathe
out, the balloon deflates and the air goes out. In COPD,
the airways and air sacs lose their shape and become floppy.
Less air gets in and less air goes out because:
- The airways and air sacs lose their elasticity (like
an old rubber band).
- The walls between many of the air sacs are destroyed.
- The walls of the airways become thick and inflamed (swollen).
- Cells in the airways make more mucus (sputum) than usual,
which tends to clog the airways.
COPD develops slowly, and it may be many years before you
notice symptoms like feeling short of breath. Most of the
time, COPD is diagnosed in middle-aged or older people.
COPD is a major cause of death and illness, and it is the
fourth leading cause of death in the United States and throughout
the world.
There is no cure for COPD. The damage to your airways and
lungs cannot be reversed, but there are things you can do
to feel better and slow the damage.
COPD is not contagious—you cannot catch it from someone
else.
Other Names for COPD
- Chronic obstructive airway disease
- Chronic obstructive lung disease
In the United States, chronic obstructive pulmonary disease
(COPD) includes:
- Emphysema
- Chronic bronchitis
In the emphysema type of COPD, the walls between many of
the air sacs are destroyed, leading to a few large air sacs
instead of many tiny ones (see the How
the Lungs Work section). Consequently, the lung looks
like a sponge with many large bubbles or holes in it, instead
of a sponge with very tiny holes. The large air sacs have
less surface area for the exchange of oxygen and carbon dioxide
than healthy air sacs. Poor exchange of the oxygen and carbon
dioxide causes shortness of breath.
In chronic bronchitis, the airways have become inflamed
and thickened, and there is an increase in the number and
size of mucus-producing cells. This results in excessive
mucus production, which in turn contributes to cough and
difficulty getting air in and out of the lungs.
Most people with COPD have both chronic bronchitis and emphysema.
What Causes COPD?
Smoking Is the Most Common Cause of COPD
Most cases of chronic obstructive pulmonary disease (COPD)
develop after repeatedly breathing in fumes and other things
that irritate and damage the lungs and airways. Cigarette
smoking is the most common irritant that causes COPD. Pipe,
cigar, and other types of tobacco smoke can also cause COPD,
especially if the smoke is inhaled. Breathing in other fumes
and dusts over a long period of time may also cause COPD.
The lungs and airways are highly sensitive to these irritants.
They cause the airways to become inflamed and narrowed, and
they destroy the elastic fibers that allow the lung to stretch
and then return to its resting shape. This makes breathing
air in and out of the lungs more difficult.
Other things that may irritate the lungs and contribute
to COPD include:
- Working around certain kinds of chemicals and breathing
in the fumes for many years
- Working in a dusty area over many years
- Heavy exposure to air pollution
Being around secondhand smoke (smoke in the air from other
people smoking cigarettes) also plays a role in an individual
developing COPD.
Genes—tiny bits of information in your body cells
passed on by your parents—may play a role in developing
COPD. In rare cases, COPD is caused by a gene-related disorder
called alpha
1 antitrypsin deficiency. Alpha 1 antitrypsin (an-te-TRIP-sin)
is a protein in your blood that inactivates destructive proteins.
People with antitrypsin deficiency have low levels of alpha
1 antitrypsin; the imbalance of proteins leads to the destruction
of the lungs and COPD. If people with this condition smoke,
the disease progresses more rapidly.
Who Is At Risk for COPD?
Most people with chronic obstructive pulmonary disease (COPD)
are smokers or were smokers in the past. People with a family
history of COPD are more likely to get the disease if they
smoke. The chance of developing COPD is also greater in people
who have spent many years in contact with lung irritants,
such as:
- Air pollution
- Chemical fumes, vapors, and dusts usually linked to certain
jobs
A person who has had frequent and severe lung infections,
especially during childhood, may have a greater chance of
developing lung damage that can lead to COPD. Fortunately,
this is much less common today with antibiotic treatments.
Most people with COPD are at least 40 years old or around
middle age when symptoms start. It is unusual, but possible,
for people younger than 40 years of age to have COPD.
To read the rest of this article from the National Heart, Lung
and Blood Institute, please click here: http://www.nhlbi.nih.gov/health/dci/Diseases/Copd/Copd_WhoIsAtRisk.html
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