COPD, or chronic obstructive pulmonary disease, is a progressive disease that makes it difficult to breathe.
COPD can cause coughing that produces large amounts of mucus , wheezing, shortness of breath, chest tightness, and other symptoms.
Cigarette smoking is the leading cause of COPD. Most people who have COPD smoke or used to smoke. Long-term exposure to other lung irritants, such as air pollution, chemical fumes, or dust, also may contribute to COPD.
Healthy Alveoli and Damaged Alveoli
The illustration shows the respiratory system and images of healthy alveoli and alveoli damaged by COPD.
In the United States, the term "COPD" includes two main conditions—emphysema and chronic obstructive bronchitis.
In emphysema, the walls between many of the air sacs are damaged, causing them to lose their shape and become floppy. This damage also can destroy the walls of the air sacs, leading to fewer and larger air sacs instead of many tiny ones.
In chronic obstructive bronchitis, the lining of the airways is constantly irritated and inflamed. This causes the lining to thicken. Lots of thick mucus forms in the airways, making it hard to breathe.
Most people who have COPD have both emphysema and chronic obstructive bronchitis. Thus, the general term "COPD" is more accurate.