Causes of Pleural Effusion

Pleural effusions are very common in the United States of America, with almost a 100,000 cases diagnosed every year. There are a lot of causes of pleural effusions, with both transudative and exudative pleural effusions having different causes. In case of transudative pleural effusions there is a watery fluid in the lungs and the most common causes include:

  • Heart failure
  • Liver cirrhosis
  • Pulmonary embolism and
  • Complication of open heart surgeries
In case of exudative pleural effusions, the fluids are thicker and are rich in proteins. In such cases, the effusions are most likely to be caused due to:

  • Pneumonia
  • Kidney disease
  • Cancer
  • Internal inflammation
  • Pulmonary embolism
There are some other causes of pleural effusions as well, though these are likely to be very rare. These include:

  • Infectious diseases such as tuberculosis
  • Autoimmune diseases such as Addison’s disease
  • Benign ovarian tumors that cause Meig’s syndrome
  • Chylothorax induced due to trauma
  • Infections in the chest or the abdominal cavity
  • Over exposure to asbestos
  • Chest trauma which may cause internal bleeding and
  • Ovarian hyperstimulation syndrome
In addition to these, pleural effusion may develop as complications of abdominal surgery as well as treatment of cancer. Radiation therapy, especially when performed around the chest area and the abdomen, may also cause pleural effusion. The condition is also often a symptom of some other diseases such as lung cancer, lymphomas and breast cancer. Though rare, the fluid may sometimes be cancerous itself, but at most times it is a side effect of chemotherapy or radiation therapy. 
Frequently asked questions
  1. R.W. Light, Y.C.G. Lee, PLEURAL EFFUSIONS | Overview, In:   Geoffrey J. Laurent and Steven D. Shapiro, Editor(s)-in-Chief, Encyclopedia of Respiratory Medicine, Academic Press, Oxford, 2006, Pages 353-358, ISBN 9780123708793, 10.1016/B0-12-370879-6/00299-4.
  2. Jeffrey S. Pollak, Catherine M. Burdge, Melvin Rosenblatt, Jeffrey P. Houston, Wen-Jen Hwu, John Murren, Treatment of Malignant Pleural Effusions with Tunneled Long-term Drainage Catheters, Journal of Vascular and Interventional Radiology, Volume 12, Issue 2, February 2001, Pages 201-208, ISSN 1051-0443, 10.1016/S1051-0443(07)61826-0.