What Is a Pleural Effusion?

Fact Checked

Pleural effusion is excess fluid around the lungs and may be a sign of mesothelioma. These fluids, also called “water on the lungs,” accumulate between the layers of the pleura, a thin membrane lining the chest cavity and surrounding the lungs. Pleural effusions cause shortness of breath.

Find a Mesothelioma Doctor Near You
Dr. Snehal Smart of Asbestos.com explains how pleural effusions can lead to a mesothelioma diagnosis.
Dr. Snehal Smart of Asbestos.com explains how pleural effusions can lead to a mesothelioma diagnosis.

Pleural Effusions and Mesothelioma

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 in 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. This is sometimes 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.

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.

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.

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.

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

Also of concern is lung collapse. The pressure from excess pleural fluid can cause a lung to collapse.

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.

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.

Asbestos.com Mesothelioma Guide

Learn About Pleural Effusions with Our Free Guide

Free information, books, wristbands and more for patients and caregivers.

Get Your Free Guide

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 an endoscope into the chest cavity. The surgeon can view your lungs 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. 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

If pleurodesis doesn’t work, a device called a shunt 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. This can be repeated several times each day to help with symptoms.

Free VA Claims Assistance

File a Claim Now

Free Mesothelioma Nutrition Guide

Get Recipes

Need Financial Help for Your Mesothelioma?

Find Out How

Registered Nurse and Patient Advocate

Karen Selby joined Asbestos.com in 2009. She is a registered nurse with a background in oncology and thoracic surgery and was the regional director of a tissue bank before becoming a Patient Advocate at The Mesothelioma Center. Karen has assisted surgeons with thoracic surgeries such as lung resections, lung transplants, pneumonectomies, pleurectomies and wedge resections. She is also a member of the Academy of Oncology Nurse & Patient Navigators.

Walter Pacheco, Managing Editor at Asbestos.com
Edited by
Reviewed by placeholder
Medical Review By

8 Cited Article Sources

  1. Bibby, A.C. et al. (2019, June 12). The Prevalence and Clinical Relevance of Non-expandable Lung in Malignant Pleural Mesothelioma: A Prospective, Single-Center Cohort Study of 229 Patients.
    Retrieved from: https://www.atsjournals.org/doi/abs/10.1513/AnnalsATS.201811-786OC
  2. National Cancer Institute. (2019, April 26). Malignant Pleural Effusion.
    Retrieved from: http://www.cancer.gov/cancertopics/pdq/supportivecare/cardiopulmonary/Patient/page3
  3. The American Cancer Society. (2018, November 16). Palliative Procedures for Mesothelioma.
    Retrieved from: http://www.cancer.org/cancer/malignantmesothelioma/detailedguide/malignant-mesothelioma-treating-palliative-procedures
  4. American Lung Association. (2018, March 13). Thoracotomy.
    Retrieved from: https://www.lung.org/lung-health-and-diseases/lung-procedures-and-tests/thoracotomy.html
  5. Agency for Toxic Substances and Disease Registry. (2018, January 29). Asbestos Toxicity: How Are People Exposed to Asbestos?
    Retrieved from: https://www.atsdr.cdc.gov/csem/csem.asp?csem=29&po=6
  6. Myers, R. (2012, July). Asbestos-related Pleural Disease.
    Retrieved from: http://journals.lww.com/co-pulmonarymedicine/Abstract/2012/07000/Asbestos_related_pleural_disease.15.aspx
  7. International Network for Cancer Treatment and Research. (2009, June 26). Pleural Effusion.
    Retrieved from: http://inctr-palliative-care-handbook.wikidot.com/pleural-effusion
  8. National Heart, Lung and Blood Institute. (n.d.). Asbestos-Related Lung Diseases. Retrieved from: https://www.nhlbi.nih.gov/health/health-topics/topics/asb/treatment

Did this article help you?

Did this article help you?

Thank you for your feedback. Would you like to speak with a Patient Advocate?

On This Page

Back to Top

Share this article

Last Modified July 17, 2019

Chat live with a patient advocate now