Deciphering the Language of COPD (Emphysema and Chronic Bronchitis)

The Terminology of COPD

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Although many patients know that the letters COPD stand for “chronic obstructive pulmonary disease,” it comes as a surprise to many that while the term ‘emphysema’ is commonly used interchangeably with ‘COPD’, not all patients with COPD have emphysema. It may be even more surprising to learn that ‘chronic bronchitis’ is a form of COPD that is distinct from emphysema. Deciphering the lingo of COPD can be challenging and confusion for patients.

Compounding the problem is that the media, online articles and even clinicians often (incorrectly) use these terms interchangeably.

Below we’ve described some of the most commonly used and misused terminology of COPD.

COPD (Chronic Obstructive Pulmonary Disease). COPD is a disease that occurs when air in the lung cannot be effectively exhaled, and remains ‘trapped’ inside the lung. This phenomenon can cause shortness of breath and increased work of breathing.

For example, take a deep breath in and then slowly exhale until all the air is comfortably out of your lungs. Now, take another breath in, but this time, instead of exhaling all the air out take another breath halfway through your exhalation. Notice how uncomfortable that sensation is! If you repeat this over and over, your chest will fill up with air until you feel short of breath. This is an exaggerated demonstration of how COPD affects the lungs.

Types of COPD

Patients with COPD can develop this problem through one of two mechanisms, and those two mechanisms are named “emphysema” and “chronic bronchitis”. The underlying problem in both mechanisms of COPD is the same: the air deep in the tiny sacs that make up the lungs is not completely emptied with each breath (causing ‘obstruction’), and this causes shortness of breath.

  • Emphysema. Emphysema is a specific type of COPD. Patients with emphysema are unable to empty all the air out of their lungs because there is destruction of the lung tissue that composes the lung. This results in ‘holes’ in the lung tissue, much like a sponge or Swiss cheese. Air gets trapped in those holes and the lungs cannot empty with each breath, which causes air to be obstructed (as described above). Patients with emphysema may have low levels of oxygen as a result of the destroyed lung tissue and many patients will require oxygen therapy.

  • Chronic Bronchitis. Chronic bronchitis is another type of COPD. Like patients with emphysema, patients with chronic bronchitis do not completely empty the lungs of all the air after each breath. However, unlike patients with emphysema, this problem is not due to lung tissue destruction. Instead, patients with chronic bronchitis have increased mucus production and swelling of the airways, and this is what limits the ability of air to flow out of the airways. As a result, patients with chronic bronchitis tend to have a productive cough with frequent bacterial infections.

    Overlap of the Two Kinds of COPD

    It’s important to understand that many patients may have elements of both of kinds of COPD (emphysema and chronic bronchitis). That is, not everyone has just one type or the other.

    Why Does This Matter?

    Although the medications used to treat COPD are (for the most part) the same for both emphysema and chronic bronchitis, patients with emphysema may have slightly different needs and problems than those with chronic bronchitis. For example, patients with emphysema often require supplemental oxygen, while patients with chronic bronchitis may have more problems with cough, mucus, and frequent infections.

    The Bottom Line

    COPD is a disease that reduces the ability of air to be fully exhaled from the lungs and results in shortness of breath. Patients with COPD may have emphysema, chronic bronchitis or a combination of both. Although the treatment is very similar, it is important to be aware that the label “COPD” is a general term that encompasses both of these disease entities.

    For more information about COPD terminology (including emphysema and chronic bronchitis) visit the ​American Thoracic Society Patient Information website

    Other Resources

    COPD Foundation

    National Heart Lung & Blood Institute

    American Lung Association

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