What is COPD (Chronic Obstructive Pulmonary Disease)?

Chronic obstructive pulmonary disease (COPD) results from progressive destruction of or decreased functionality of lung tissue. Cough, shortness of breath and low oxygen levels become more prominent as time goes on.

COPD is actually a collective term for two separate, but often overlapping, lung conditions:

• Emphysema: The lining of the air sacs in the lungs are weakened and destroyed over time. Emphysema is usually the main component of COPD.
• Chronic Bronchitis: Inflammation narrows the airways. Mucous builds up and a wet cough may be prominent.

These conditions both result in the decreased ability to transfer oxygen into and carbon dioxide out of the blood. This is a crucial function of lung tissue and all other organ systems depend on it.

Smoking is by far the most common cause of COPD.

The phrase "chronic obstructive pulmonary disease" gives some clues as to the nature of the disorder. Chronic means this is an ongoing problem that does not have a real cure. Obstructive provides insight that the disorder relates to blockage of air. Indeed, air trapping and inability to fully exhale the air from the lungs becomes part of the pathology. Pulmonary disease tell us that this is affecting the pulmonary system- the lungs and exchange of oxygen and waste gases.

Alveoli are the air sacs at the end of the air tubes in the lungs. The alveoli are the sites of actual air exchange. The video below provides a good visual demonstration of gas exchange in the lungs.

Oxygen that is inhaled in the air passes down the lung tubes which branch out through the lung tissue until they end at a cluster of alveoli. The thin walls of the alveoli sacs touch the walls of tiny blood vessels. Oxygen is transferred across the alveolar walls and into the blood stream. It can then be distributed to the rest of the body.

Likewise, carbon dioxide and other waste gases are gathered up throughout the body into the blood stream. When that blood reaches the lungs, it is eventually passed to the small vessels that are paired with alveoli. The waste gas transfers across blood vessel walls and into the alveoli and is then exhaled out.

This component of COPD is characterized by inflammation of the airways. The inflammation crowds the inside of the tiny airway tubes through which air must pass. Mucous also can build up in the airways. All of this results in the uncomfortable symptoms of

• wheezing
• cough (wet cough with mucous may occur)
• shortness of breath
• Pain or tightness of the chest

The symptoms and complications of emphysema result from pathology at the level of the alveoli.

As the disease progresses, the thin walls of the alveoli weaken and eventually are destroyed. Gas exchange cannot occur normally. Because the walls between adjoining alveoli disintegrate, the air sacs become fewer but abnormally large pockets. The elasticity of the sacs decreases causing air to become trapped since with lower alveolar elasticity, it cannot be exhaled out normally.

Signs and Symptoms of Emphysema

• shortness of breath- gradual onset, then progressive
• fatigue- and easy fatigue with activity
• cyanosis (blue lips or fingertips)
• cough
• wheeze
• 'barrel chest'

SMOKING is far and away the most common risk factor for COPD. Not all smokers will develop COPD, but a great majority of COPD patients are smokers of former smokers.

Once COPD starts to develop, the damage is irreversible. Quitting smoking will, however, keep the disease from progressing.

There are a few other known causes of COPD:

• A genetic disorder called alpha-1-antitrypsin deficiency
• Exposure to certain fumes or chemicals

Treatment for COPD targets control of symptoms and halting progression of the disease.

Quitting smoking is the single most important measure to achieve both of these goals.

Often, medicines given via inhalers or nebulizers to decrease inflammation, relax the airways and reduce wheezing will be used.

Other medications such as steroids (inhaled or oral) may become necessary.

As the disease worsens, oxygen may be needed on a progressive basis.