Written By: Karen Selby, RN,
Last modified: February 26, 2021

What Is a Pleural Effusion?

Pleural effusion is buildup of fluid between the chest wall and the lung. A small amount of fluid normally fills the pleural cavity and helps the lungs glide smoothly in the chest as we breathe. When mesothelioma or another condition causes excess fluids to accumulate, the result is a pleural effusion.

The extra fluid around the lungs takes up space and fills the pleural cavity. This compresses the lungs and limits their ability to move freely, making breathing more difficult. When the lung is compressed by fluid or tumor it is referred to as nonexpandable lung.

A 2019 study of 229 patients with mesothelioma found 83% had a pleural effusion at presentation, and nonexpandable lung was observed in 33% of this group.

Pleural effusions may signal a developing asbestos-related disease, such as pleural thickening, and contribute to its progression.

Pleural thickening is characterized by the accumulation of scar tissue on the pleura, and it can increase and spread to additional pleural areas after each effusion episode.

On their own, uncomplicated pleural effusions are not life-threatening. They can resolve in a few months without medical intervention. However, once a person has one pleural effusion, they are more likely to experience this condition again.

Symptoms of Pleural Effusions

The most common pleural effusion symptoms in patients with nonexpandable lung were breathlessness and cough, while chest pain was more common among mesothelioma patients without effusions.

Symptoms of pleural effusion can vary from mild to severe. Some patients experience no symptoms at all. The type and severity of symptoms often correlates with the amount of fluid and any underlying breathing conditions or infections.

Common Pleural Effusion Symptoms

  • Dry cough
  • Shortness of breath
  • Sharp chest pain that worsens with cough or deep breathing
  • Malaise (general feeling of discomfort)
  • Fatigue
  • Hiccups
  • Rapid, shallow breathing
  • Fever if fluid becomes infected

Although pleural effusions can resolve on their own, it is best to seek treatment if you have breathing changes or new onset of shortness of breath. The pressure from excess pleural fluid can cause a lung to collapse.

If you don’t seek immediate treatment, pleural fluid may become infected. An infection of the pleural fluid is called empyema.

What Causes Pleural Effusions?

Pleural effusions are caused by many reasons, but they commonly accompany asbestos-related illnesses such as mesothelioma, lung cancer and asbestosis.

After exposure to asbestos, inhaled asbestos fibers can reach the pleura, causing swelling and inflammation. This increases the risk of blood vessels in the area leaking fluids, leading to the development of pleural effusions.

Effusions can be malignant, which means they are caused by cancer. Nonmalignant effusions are due to benign, noncancerous conditions.

In addition to asbestos-related causes, pleural effusion may arise from other conditions.

Nonmalignant causes of the condition include pneumonia, tuberculosis, pulmonary embolism and congestive heart failure. Other cancers may cause pleural effusions, too.

To identify a cause, your doctor can extract fluid from the pleural effusion and run tests on it. The best treatment option will vary depending on what is causing fluid to accumulate.

Diagnosing Mesothelioma and Pleural Effusion

Pleural effusion is a common symptom of mesothelioma and other asbestos-related diseases, especially as these diseases progress.

An X-ray can be used to diagnose pleural effusion once accumulation reaches approximately 300 milliliters, or 1.25 cups of fluid. If there is less than this, the effusion may not be visible on chest X-ray.

There are other signs your doctor can look for to help diagnose this condition. Diminished breath sounds and decreased chest movement, especially one side of the body, can signal pleural effusion. Your doctor also may notice a decrease in vocal resonance.

Because these symptoms may signal less serious conditions, such as pneumonia, your doctor will order additional tests to make an accurate diagnosis. Looking for mesothelioma cells in pleural fluid can help doctors identify this asbestos-related cancer as a possible cause of pleural effusion.

Dr. Snehal Smart video on mesothelioma

Watch: Dr. Snehal Smart of Asbestos.com explains how pleural effusions can lead to a mesothelioma diagnosis.

Diagnostic Thoracentesis

Once the doctor determines there is fluid in the pleural cavity, they may collect a sample for evaluation using a technique called thoracentesis. During the procedure, a doctor inserts a thin needle or plastic tube into the space where the fluid is collecting.

They draw out some or all of the fluid and send it to the lab for further testing. In about 75% of cases where cancer cells are present in pleural fluid, the tumor is lung cancer, mesothelioma, breast cancer or lymphoma.

Results of this test usually are not reliable enough to make a definitive mesothelioma diagnosis. However, they often reveal the underlying cause of fluid buildup. If the cause is mesothelioma or another cancer, doctors will perform a biopsy to confirm the results.

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Pleural Effusion Treatment

Pleural effusion can be treated with several options that ease painful and uncomfortable symptoms.

Palliative Thoracentesis

Most patients with asbestos-related pleural effusions receive a thoracentesis, which removes fluid to relieve pressure on the lungs and ease breathing.

The procedure is similar to diagnostic thoracentesis. However, for palliative treatment, the fluid is completely drained rather than the doctor collecting a small sample for further testing.

Palliative thoracentesis does not address the cause of pleural effusion, and the fluid will collect again after the procedure. Most people need to have it repeated several times, typically when enough fluid accumulates to cause return of symptoms.

Catheter Placement

Doctors can place a thin tube called a catheter into the pleural space, leaving one end outside the body. The catheter is then connected to a device that drains the excess fluid. Once you have this procedure, your fluid will drain regularly.

Unlike regular thoracentesis, with a catheter, you won’t have to return to the doctor over and over as fluid keeps reaccumulating.


In some cases, doctors may recommend pleurodesis, a longer-term solution for recurring fluid buildup.

During pleurodesis, doctors remove excess pleural fluid by thoracentesis, then attempt to permanently close the pleural cavity to prevent further fluid accumulation.

The surgeon inserts a chest tube to deliver drugs like talc or bleomycin, which cause inflammation that closes off the pleural space.

The procedure can have painful side effects and isn’t 100% effective. It should only be performed on people with good overall health and a life expectancy of at least several months.

Video Assisted Thoracoscopic Surgery

Video Assisted Thoracoscopic Surgery (VATS) is a minimally invasive surgical procedure that allows doctors to see the pleural lining and surface of the lungs. VATS can be used to look for signs of mesothelioma and identify pleural plaques and pleural thickening.

One step of thoracoscopic surgery is a thoracotomy, which is a cut made between the ribs to allow access to the lungs and other organs in the chest. A thoracotomy allows doctors to visualize and remove tissue for a biopsy as part of the diagnostic process.

During VATS, the surgeon will insert a small, flexible tube containing a fiber optic camera called a thoracoscope into the chest cavity. The surgeon can view your lungs and pleura on a video monitor and look for signs of disease.

The advantage of this procedure is that it can help guide a biopsy. It ensures enough tissue from the right areas is collected to secure an accurate diagnosis.

Thoracoscopic surgery is sometimes called pleuroscopy when the purpose is to examine only the pleura. As with pleurodesis, your doctor can take steps during the procedure to look for, diagnose and possibly address the cause of pleural effusions.

Shunt Placement

Another way of treating pleural effusion is placing a device called a shunt, which can be used to move the fluid from the pleural space to another part of the body. A pleuro-peritoneal shunt transfers excess chest fluid to the abdomen, where it can be absorbed by the body.

For this procedure, the doctor inserts one end of a long, thin tube with a small pump in the middle into the pleural space. The other end of the tube extends into the abdominal cavity. The pump is placed over the ribs, just under the skin.

Once the shunt is in place, you can press on the pump to drain chest fluid into the abdomen. Pumping can be repeated several times each day to help with symptoms.

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