What Is a Pleural Effusion?

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A pleural effusion is an accumulation of excess fluid in the pleural cavity. It is one of the symptoms that can severely affect your quality of life when dealing with mesothelioma.

The pleural cavity is an area between the two layers of the pleura — a thin, protective tissue that lines the outer surface of the lungs and the inside of the rib cage. A small amount of fluid fills the pleural cavity to help the lungs glide smoothly in the chest as we breathe in and out. When mesothelioma or another condition causes pleural effusion, excess fluid fills the pleural cavity and makes breathing difficult.

On their own, effusions are not life-threatening and will resolve completely after 3 or 4 months. However, they often recur periodically. They commonly arise before an asbestos-related disease called pleural thickening, and contribute toward its progression. Pleural thickening, characterized by the accumulation of fibrotic scar tissue on the pleura, can increase after each episode of effusion.

Symptoms and Causes

Patients may experience a variety of symptoms or no symptoms at all. They can include:
  • Dry cough
  • Shortness of breath
  • Sharp chest pain that worsens with cough or deep breaths
  • Fever
  • Malaise
  • Hiccups
  • Rapid breathing

If you don't seek immediate treatment, pleural fluid may become infected and cause a condition called empyema. Excess pleural fluid can also cause a lung to collapse.

Pleural effusions can develop for many reasons, but they commonly accompany asbestos-related illnesses like mesothelioma, lung cancer and asbestosis. After exposure to asbestos, inhaled asbestos fibers can reach the pleura, causing swelling and inflammation. In turn, this can make blood vessels leak, which may result in pleural effusion. The effusion can be malignant (caused by cancer) or nonmalignant (caused by a noncancerous condition).

In addition to asbestos-related causes, pleural effusion may arise from other conditions, including pneumonia, tuberculosis, pulmonary embolism, various cancers and congestive heart failure. Testing a fluid sample from the pleural space can help doctors determine why excess fluid is collecting. Treatment options will vary depending on the cause.

Diagnostic Process and Mesothelioma

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

Pleural effusion is a common symptom of mesothelioma and other asbestos-related diseases, especially as the diseases progress. In order to determine whether pleural effusion is present, doctors will order an imaging test, usually a simple chest X-ray. The fluid will show up on the X-ray once the accumulation has reached about 300 milliliters. Prior to that, it may be difficult to spot the fluid on a chest image.

There are additional signs of this condition that aid doctors in diagnosing it. Doctors may notice diminished breath sounds on the affected side of the chest, diminished chest movement on the affected side and decreased vocal resonance. Some of these symptoms can also indicate pneumonia and other diseases or disorders, so doctors typically order more tests to make an accurate diagnosis.

Diagnostic Thoracentesis

Once the doctor determines that there is indeed fluid in the pleural cavity, he or she 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 and draws out some or all of the fluid. The pleural fluid is then sent to a lab for testing.

Analysis of the fluid can help doctors determine if cancer or another condition caused the effusion. Statistics show that lung cancer, mesothelioma, breast cancer and lymphoma account for about 75 percent of all pleural effusions that contain cancer cells.

While the results of this test are not reliable enough to make a mesothelioma diagnosis, they can often reveal what caused the fluid buildup. If the cause appears to be mesothelioma, doctors will perform a biopsy to confirm the results.


There are several treatment options that doctors use to manage pleural effusion. Some aim to remove the fluid to alleviate symptoms, while others prevent future accumulations or treat the cause of the fluid buildup.

Palliative Thoracentesis

Most patients with asbestos-related pleural effusions receive a thoracentesis, which removes fluid to make breathing easier and relieve pressure on the lungs. The procedure is basically the same as the diagnostic thoracentesis doctors use to help make a diagnosis, but as a palliative treatment it aims to completely drain the fluid rather than take a small sample for testing.

Because thoracentesis does not address the cause of pleural effusion, the fluid continues to collect after the procedure. Most people need to have it repeated several times as necessary, usually when symptoms return.

Catheter Placement

Doctors may also 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 and collects the excess fluid. Once you have this procedure, your fluid will drain regularly and you won't have to keep returning to the doctor for a thoracentesis.


In some cases, doctors may recommend pleurodesis, a long-term solution for recurring fluid buildup. During pleurodesis, doctors permanently close the pleural cavity to prevent the accumulation of fluid. After the fluid is removed by thoracentesis, doctors insert a chest tube to deliver drugs like talc or bleomycin that cause inflammation and close the pleural space.

The procedure is not always effective and may have painful side effects. It should only be performed on people with good overall health and a prognosis of at least several months.

Shunt Placement

If pleurodesis is ineffective, 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 is more likely to 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, with the other end extending 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.

Although pleural effusion causes painful and uncomfortable symptoms, treatments are available to control fluid buildup that lead to symptom relief.

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  1. National Cancer Institute. (2013, March 25). Malignant Pleural Effusion. Retrieved from http://www.cancer.gov/cancertopics/pdq/supportivecare/cardiopulmonary/Patient/page3
  2. Myers, R. (2012, July). Asbestos-related Pleural Disease. Retrieved from http://www.eoncology.eu/site/wp-content/uploads/2013/01/Asbestos-related-pleural-disease.pdf
  3. Drexel University College of Medicine. (2008, August 29). Pleural Effusion. Retrieved from http://www.drexelmed.edu/Home/HealthEncyclopediaArticles/DiseasesandConditions/Pleuraleffusion.html
  4. Garrity, E. and Chandrasekhar, A.J. (n.d.). Pleural Effusion. Loyola University Medical Education Network. Retrieved from http://www.meddean.luc.edu/lumen/MedEd/elective/pulmonary/effusion/effusion_f.htm
  5. Agency for Toxic Substances and Diseases Registry. (2010, June 18.). Asbestos Toxicity
  6. What Respiratory Conditions Are Associated with Asbestos? Retrieved from http://www.atsdr.cdc.gov/
  7. National Heart, Lung and Blood Institute. (2011, May). How Are Asbestos-Related Lung Diseases Treated? Retrieved from http://www.nhlbi.nih.gov/health/health-topics/topics/asb/treatment.html
  8. Pass HI, Levin SM, Harbut MR, et al. (2012). Fibulin-3 as a blood and effusion biomarker for pleural mesothelioma. The New England Journal of Medicine, 367, 1417-1427
  9. The American Cancer Society. (2015, May 18). Palliative Procedures for Mesothelioma. Retrieved from http://www.cancer.org/cancer/malignantmesothelioma/detailedguide/malignant-mesothelioma-treating-palliative-procedures
  10. International Network for Cancer Treatment and Research. (2009, June 26). Pleural Effusion. Retrieved from http://inctr-palliative-care-handbook.wikidot.com/pleural-effusion

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