COPD Conditions: Chronic Bronchitis & Emphysema

Reviewed by: HU Medical Review Board

People who have chronic obstructive pulmonary disease (COPD) may have symptoms of 2 different conditions: chronic bronchitis and emphysema. Those 2 conditions are usually classified under COPD because most people have symptoms of both.1

Everyone’s experience with COPD is different. You may have more symptoms of either chronic bronchitis or emphysema. Your symptoms may also change as the disease progresses. In the past, doctors used to diagnose each condition separately. It is still common to hear people refer to them separately.1

How does COPD damage the lungs?

COPD is typically caused by long-term exposure to inhaled irritants. Tobacco smoke is the most common irritant that causes COPD. About 3 out of every 4 COPD cases are in current or past smokers. COPD can also be caused by air pollution or workplace exposure to dust and fumes.2

Both chronic bronchitis and emphysema cause lung damage that cannot be reversed. The damage makes it harder for the lungs to properly function. This can make breathing tough and can cause symptoms that impact quality of life.2

Our lungs have 2 important jobs. First, they are responsible for moving oxygen from the air we breathe into our blood. Second, they remove carbon dioxide from our blood. We eventually exhale the carbon dioxide. For people with COPD, lung damage keeps both these processes from working as well as they should.2

What is chronic bronchitis?

Chronic bronchitis is the term for the chronic inflammation of the breathing tubes in the lungs. This includes the 2 main airways that lead to each lung and the smaller tubes that branch off from these main airways. The main breathing tubes are called bronchi, and the smaller tubes are called bronchioles.3

When people hear the term bronchitis, they may think of the more common short-term sickness. This sickness is called acute bronchitis. Acute bronchitis may have similar symptoms to chronic bronchitis, but it only lasts 1 to 2 weeks. Acute bronchitis is usually caused by a respiratory infection like a cold.3

What are the effects of chronic bronchitis?

Irritation in the airways causes 2 main problems in the lungs. First, the walls of the airways become thick and inflamed. Next, the airways overproduce mucus. Both effects make it difficult for air to freely move through the airways. Inflamed airways become narrower, and the overproduced mucus can clog them.2,3

Because the air cannot efficiently flow through the airways, people with chronic bronchitis will have trouble breathing and may feel out of breath. They also may develop a long-term cough as they try to clear mucus from their airways. People with chronic bronchitis are also more likely to develop respiratory infections. This is because the mucus can trap viruses or bacteria in their lungs.1,2

What is emphysema?

Emphysema is a condition that affects the millions of tiny air sacs in the lungs. These air sacs are called alveoli. The job of the alveoli is to transfer oxygen into the blood and carbon dioxide out of the blood. Healthy air sacs have flexible, elastic walls that allow them to expand and inflate with air. They require no energy to deflate and push out the air because their flexibility allows them to easily bounce back to their original smaller size.2

People with emphysema have damage to the walls of the alveoli. The damaged alveoli lose their natural elasticity. The walls between air sacs can also be destroyed. This results in fewer very big alveoli instead of many tiny ones.4

What are the effects of emphysema?

When alveoli lose their flexibility, they cannot easily deflate and bounce back to their original size. People with emphysema work harder to breathe because they must spend energy while breathing out to try to clear the alveoli. This makes people feel out of breath.2,4

If the alveoli combine into fewer big air sacs, they lose the surface area where the lungs can exchange oxygen and carbon dioxide. With each breath, there is then a smaller amount of oxygen that gets into the bloodstream. There is also a smaller amount of carbon dioxide that leaves the blood and the lungs.2,4

Damage from emphysema also causes problems fully emptying the lungs. The damaged air sacs trap old air. This makes it difficult for new, oxygen-rich air to enter the lungs or for carbon dioxide to exit.2,4

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