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What Is Empyema? - Definition, Causes & Treatment

Instructor: Emily Smathers
Infections affect the body in many different ways. In this lesson, we will define empyema and discuss its causes and treatment. Like many infections, treatment options must be addressed.


Have you ever had a cold that caused you to have nasal discharge? Colds are fairly common, and can be caused by germs in the air we breathe. Empyema is similar in that it has a germy fluid, but it is created by an infection in an internal cavity.

What Is Empyema?

Empyema is a condition that causes pus to collect in a body cavity, usually in the lung cavity. While it is possible for pus to build up in other body cavities, it is not common. Pus, or fluid created from an infection, increases as the body fights and is stored in the body cavity, or in this case the pleural cavity. The pleural cavity is the space between the outside of the lungs and the chest wall. Lung infections are common due to how easy germs can enter the lungs. When pus builds up around the lung, it becomes difficult for the lung to expand when you inhale.

The difficulty in lung expansion can cause pain when you inhale and can lead to shortness of breath as you try to avoid breathing as deeply. This pain is known as pleurisy and should lead to a doctor's care. Other symptoms that can help determine if you have lung empyema include dry cough, excessive sweating, fever, general discomfort and unintentional weight loss. Lung empyema is generally referred to as pleural empyema, as it occurs in the pleural space or cavity.


Empyema is caused by other factors occurring in the body. Most often, it starts in the lung through infections or chest surgery. Less common reasons for pleural empyema is lung abscess or injury to the chest. Infections that are not thoroughly cured or that are difficult to cure can cause empyema as a complication of the infection. Difficult infections come from many sources, such as bacterial pneumonia or cancer. Cancer can cause empyema through the body's lack of natural immunity after various cancer therapies, which allow bacteria to grow easier. While the body is fighting the infection, pus can form around the lung. Since cancer is not the only time the body is immunocompromised, empyema can also occur whenever a person has a weakened or compromised immune system.

In the case of chest trauma or lung abscess, the body is attempting to heal itself from an external blow to the body, and fluid builds up in the pleural space. This fluid either has infection or becomes infected, resulting in empyema.


While medical care is needed for the fluid build up, treatment needs to be balanced and must address the associated chest trauma. In a chest injury, it is likely that broken bones exist and require stabilization and potential surgery. Once the bones are stable, infections can be addressed with appropriate antibiotics and fluid can naturally be removed from the pleural cavity.

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