What Is a Pleural Effusion?

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A pleural effusion occurs when an area between the two membranes (pleura) that line the lungs and chest cavity becomes filled with fluid. This cavity is called the pleural cavity.

Typically, the pleural cavity contains a small amount of fluid that functions as a lubricant. But disease processes, including heart problems or lung infections (pneumonia), can create the buildup of excess fluid associated with pleural effusion.

This article will discuss the various types, causes, symptoms, diagnoses, treatments, and prognoses for pleural effusion.

Woman sitting on couch feeling chest pain and difficulty breathing

Riska / Getty Images

Types of Pleural Effusion

The two types of pleural effusion are:

  • Transudative pleural effusion occurs when increased pressure in the blood vessels causes fluid to leak into the pleural space. The most common causes of transudative pleural effusion are heart failure (the heart does not pump enough blood to meet the body's needs) and hypoalbuminemia (low blood protein).
  • Exudative pleural effusion is directly related to lymphatic flow and high protein counts. Common causes include infection, malignancy, and inflammatory diseases.

Pleural Effusion Symptoms

The symptoms a person has with a pleural effusion are often due to the condition that led to the effusion developing rather than stemming from the pleural effusion itself.

Someone with pleural effusion may experience one or more of the following symptoms:

  • Chest pain
  • Difficulty breathing
  • Shortness of breath
  • Dry cough
  • Difficulty sleeping


The following conditions may lead to pleural effusion:


A healthcare provider may suspect pleural effusion based on your physical examination, medical history, and symptoms. They may also use the following tests to aid in diagnosis:

  • Chest X-ray
  • Computed tomography (CT) scan
  • Ultrasound
  • Thoracentesis (draining the pleural fluid) and analysis of pleural fluid
  • Video-assisted thoracoscopic surgery (VATS): This surgical procedure involves making small incisions in the chest wall and inserting a camera (thoracoscope) to visualize the area. Other surgical tools can be inserted through the incisions to take samples (biopsies), and the fluid can be drained.

Pleural fluid can be tested for pH, glucose, protein counts including albumin, cell counts, the presence of bacteria or other infections, and more. The content of pleural fluid can help determine a diagnosis and whether or not the pleural effusion is transudative or exudative.


The particular treatment for a pleural effusion is individual and based on the underlying cause as well as the amount of fluid and seriousness of symptoms. Large amounts of fluid or more distressing symptoms may require more aggressive treatment.


Pleural effusion caused by congestive heart failure is often treated with medication, including diuretics. Pleural effusions caused by infections such as pneumonia are often treated using antibiotics.

Therapeutic Thoracentesis

When the fluid volume in the pleural effusion is causing difficulty breathing, the fluid may be drained by thoracentesis so the lungs can expand. This can be done in a clinic or hospital. The healthcare provider inserts a needle between the ribs and drains the excess fluid.


Pleurodesis is used to treat recurrent malignant pleural effusions (effusions that contain cancer cells). It is a surgical procedure that essentially eliminates the pleural space.

Small incisions are made in the chest, and a tube is inserted to drain off the pleural fluid. A chemical called a sclerosing agent (talc, tetracycline, or doxycycline) is then used to create permanent scarring. Alternatively, mechanical pleurodesis is performed either through video-assisted thoracoscopic surgery (VATS) or thoracoscopy.

Chest Tube

A chest tube may be inserted through a small incision in the chest to drain air and fluid from the pleural space. The tube is usually attached to a drainage collection system, which may or may not be connected to suction. Chest tubes come in different sizes, they can be inserted under general or local anesthesia.


Video-assisted thoracoscopic surgery (VATS) can be used for both the diagnosis and treatment of pleural effusions. Through small half-inch incisions, pleurodesis can be performed (the insertion of antibiotics or talc into the pleural space), or fluid can be removed.


A thoracotomy is also called open thoracic surgery because it involves a large incision approximately 6–8 inches long (usually between the ribs). It is generally used for pleural effusions caused by severe infections. Through the incision, fibrous tissue and infectious material can be removed.

A chest tube is usually inserted during the procedure to drain any remaining excess fluid and to reinflate the lungs. The chest tube stays in place for a few days after the surgery.


The seriousness of pleural effusion depends on many factors, including your overall health, the underlying cause of your pleural effusion, and the severity of respiratory symptoms.

In many cases, pleural effusion can be cured. But in other cases, it may be recurring, or respiratory symptoms may lead to severe complications, including death. The prognosis is extremely variable. Early treatment before respiratory symptoms progress may increase your chance of curing a pleural effusion in many cases.


Pleural effusion is excess fluid in the space surrounding the lungs. Common causes of pleural effusions include congestive heart failure, cancer, pulmonary embolism, and lung infections.

Symptoms range in severity and include difficulty breathing. Pleural effusions are typically diagnosed based on symptoms, medical history, and medical imaging such as X-rays.

Treatments are tailored depending on the severity of symptoms and the underlying cause of the pleural effusion. Treatment may involve the use of medications, surgical intervention, or a combination of both. Some cases of pleural effusion can be cured, while other cases may be more complicated and quite serious.

A Word From Verywell

Even a mild pleural effusion is an indication of an underlying health problem that needs to be addressed. Consult a qualified healthcare professional for any symptoms of pleural effusion. For many causes of pleural effusion, early treatment can increase your chances of a cure or slow the progression of the underlying disease.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Kristin Hayes, RN
Kristin Hayes, RN, is a registered nurse specializing in ear, nose, and throat disorders for both adults and children.