Chronic Obstructive Pulmonary Disease (COPD)
Chronic obstructive pulmonary disease (COPD) is a progressive lung disease that makes it difficult to breathe. “Progressive” means that the disease gets worse over time.
Approximately 12 million people in the United States have been diagnosed with COPD. Many more may be affected and not know they have it. According to the Centers for Disease Control and Prevention (CDC), COPD is the fourth leading cause of death in the United States. Its prevalence increases with age. Men are more likely to have the disease, but the death rate for men and women is about the same.
The most common cause of COPD is smoking. The two main forms of COPD are chronic bronchitis and emphysema. Many people have a combination of both.
To better understand COPD, it will help to understand how the lungs work. Every time you breathe in, air passes through your windpipe and into your bronchial tubes. In your lungs, these bronchial tubes branch off into thousands of smaller tubes called bronchioles. At the ends of the bronchioles are air sacs called alveoli. These air sacs are like little balloons. When you breathe in, they stretch and fill with air. When you breathe out, they shrink back down.
In the walls of the air sacs are tiny blood vessels called capillaries. When the air sacs fill with air, oxygen goes into the capillaries to be carried through your blood stream to all parts of your body. At the same time, carbon dioxide (a waste material) passes out of the capillaries into the air sacs. Then you breathe it out.
COPD causes the following changes in your lungs and airways:
- air sacs and airways lose their ability to stretch
- the walls of the air sacs are destroyed
- the walls of the airways become thickened and inflamed
- airways become clogged with mucus
If you have COPD, you may have one or more of these changes in your lungs. These changes reduce the flow of air in and out of your lungs. This deprives your body of much-needed oxygen.
There are two main forms of COPD.
Chronic bronchitis: This is chronic inflammation of the air passages with airflow obstruction. It involves a long-term cough with mucus. Long term means most days of the week for at least three months in two successive years.
Emphysema involves destruction of the lung tissue, specifically the alveoli.
Both forms of COPD cause damage to your airways and interfere with the absorption of oxygen and the release of carbon dioxide.
There is no cure for COPD, and doctors are not able to reverse the damage it causes. Over time, ordinary tasks may become more difficult. However, with treatment and lifestyle changes, you can slow the progress of the disease so that you can feel better and stay more active.
Written by: David Heitz
Published on Jul 30, 2014
Medically reviewed on Jul 30, 2014 by George Krucik, MD, MBA