A pleural effusion is a buildup of fluid in the pleural space, an area between the layers of tissue that line the lungs and the chest cavity. It may also be referred to as effusion or pulmonary effusion.
The type of fluid that forms a pleural effusion may be categorized as either transudate or exudate. Transudate is usually composed of ultrafiltrates of plasma due to an imbalance in vascular hydrostatic and oncotic forces in the chest (heart failure, cirrhosis), while exudate is typically produced by inflammatory conditions (lung infection, malignancy).
Exudative pleural effusions are usually more serious and difficult to treat.
Your body produces pleural fluid in small amounts to lubricate the surfaces of the pleura. This is the thin tissue that lines the chest cavity and surrounds the lungs. Pleural effusion is an abnormal, excessive collection of this fluid.
There are two types:
Transudative pleural effusion is caused by fluid leaking into the pleural space. This is from increased pressure in the blood vessels or a low blood protein count. Congestive heart failure is the most common cause.
Exudative effusion is caused by blocked blood vessels or lymph vessels, inflammation, lung injury, and tumors.
Symptoms can include any of the following:
- Chest pain, usually a sharp pain that is worse with cough or deep breaths
- Rapid breathing
- Shortness of breath
- Sometimes there are no symptoms.
Exams and Tests
Your doctor will examine you and listen to your lungs with a stethoscope.
The following tests may help to confirm a diagnosis:
- Chest CT scan
- Chest x-ray
- Kidney and liver function blood tests
- Pleural fluid analysis (examining the fluid under a microscope to look for bacteria, cancer cells, and protein level)
- Thoracentesis (a sample of fluid is removed with a needle inserted between the ribs)
- Ultrasound of the chest and heart
What are the risk factors for pleural effusion?
Pleural effusions are caused by the underlying medical problems listed previously, therefore the presence of any of these medical problems are risk factors for the development of pleural effusions.
It is important to note, however, that not all individuals with these medical problems will develop pleural effusions.
Congestive heart failure is the most common cause of transudative pleural effusions, while infection (pneumonia) and malignancy are the most common causes of exudative pleural effusions.
The goal of treatment is to:
- Remove the fluid
- Prevent fluid from building up again
- Determine and treat the cause of the fluid buildup
- Removing the fluid (thoracentesis) may be done if there is a lot of fluid and it is causing chest pressure, shortness of breath, or other breathing problems, such as a low oxygen level. Removing the fluid allows the lung to expand, making breathing easier.
The cause of the fluid buildup must also be treated.
If it is due to congestive heart failure, you may receive diuretics (water pills) and other medications to treat heart failure.
Pleural effusion caused by infection is treated with antibiotics.
In people with cancer or infection, the effusion is often treated by using a chest tube for several days to drain the fluid.
Sometimes, small tubes can be left in the pleural cavity for a long time to drain the fluid. In some cases, the following may be done:
- Putting medication into the chest that prevents fluid from building up again after it is drained
- Radiation therapy
The outcome depends on the underlying disease.
Complications may include:
- Lung damage
- Infection that turns into an abscess, called an empyema, which will need to be drained with a chest tube
- Air in the chest cavity (pneumothorax) after thoracentesis
Can pleural effusion be prevented?
The development of pleural effusions may sometimes be prevented by the early treatment of the underlying causes listed above. However, in certain cases, the development of pleural effusions may not be preventable.
Some pleural effusions may be prevented from reoccurring by having individuals undergo pleurodesis, a procedure that seals up the pleural space.
When to Contact a Medical Professional
Call your doctor if you have symptoms of pleural effusion.
Call your doctor or go to the emergency room if shortness of breath or difficulty breathing occurs right after thoracentesis.