What are Chronic Bronchitis and Emphysema?

Dear Dr. Mahler: I was recently diagnosed as having COPD by my primary care doctor. She mentioned both chronic bronchitis and emphysema, but I didn’t quite understand what she meant by these terms. Can you explain? Jack from Tacoma, WA Dear Jack, I assume that you had breathing tests (called pulmonary function tests) in order for your doctor to diagnose COPD. COPD consists of two types: chronic bronchitis and emphysema. The figure below shows that the breathing tubes (airways) divide many times and end in air sacs (alveoli).
The breathing tubes (bronchus) divide many times and end in air sacs (alveoli).

The breathing tubes (bronchus) divide many times and end in air sacs (alveoli).

If inhaling cigarette smoke and other irritants mainly damages your breathing tubes, then the airways become red and swell (inflammation) and glands that line the inner lining of the tubes produce a thick substance called mucus. It is usually white or gray in color. Most people with this condition cough up mucus most days, especially in the morning. This is called chronic bronchitis. It is diagnosed if you report coughing up mucus most days for three months over a two year period. A cough productive of mucus is a common complaint or symptom.
Views of the inside of a normal breathing tube on left and of chronic bronchitis on the right. Note the white-yellow mucus lining the inside of the airway in chronic bronchitis.

Views of the inside of a normal breathing tube on left and of chronic bronchitis on the right. Note the white-yellow mucus lining the inside of the airway in chronic bronchitis.

If inhaling cigarette smoke and other irritants mainly damages your air sacs (alveoli), these areas are destroyed. This is called emphysema. It is usually diagnosed by a specific type of breathing test called diffusing capacity. In emphysema, the diffusing capacity is lower than normal. Emphysema can also be diagnosed if you have a CT scan of the chest that shows typical changes. Shortness of breath with activities is the most common complaint or symptom.
Microscopic view of the air sacs (alveoli) in the top right showing emphysema (destruction and enlargement).

Microscopic view of the air sacs (alveoli) in the top right showing emphysema (destruction and enlargement).

It is possible that you have a combination of both chronic bronchitis and emphysema which is quite common. At the present time, treatments for COPD are the same whether you have chronic bronchitis or emphysema. I suggest that you ask your doctor the same question that you asked me for more specific information about your condition. Sincerely, Donald A. Mahler, M.D.

Donald A. Mahler, M.D. is Emeritus Professor of Medicine at Geisel School of Medicine at Dartmouth in Hanover, New Hampshire. He works as a pulmonary physician at Valley Regional Hospital in Claremont, NH, where he is Director of Respiratory Services.