This website is for informational use only and does not provide any medical advice.

What is pleural effusion?

Pleural effusion is extra fluid around the lung. This often causes shortness of breath as the lung gets compressed from the fluid. The reasons for effusion are many, and the specific diagnosis is often based upon tap or drainage of the fluid.


Symptoms of pleural effusion include:

  • Chest pain
  • Cough
  • Fever
  • Shortness of breath


The pleura is a thin membrane that lines the surface of the lungs and the chest wall outside the lungs. With pleural effusion, fluid collects in the space between the layers of pleura. Usually a teaspoon amount of fluid is found in the pleural space, which lets the lungs expand and contract during the breathing process. There are a number of conditions that can cause pleural effusion, including:

  • Cancer
  • Congestive heart failure
  • End-stage renal disease
  • Liver disease
  • Lupus and other autoimmune conditions
  • Nephrotic syndrome
  • Pneumonia
  • Pulmonary embolism

Excess fluids may collect because the body cannot handle the fluid properly. It may also be caused by inflammation, such as in pneumonia, autoimmune disease, and many other conditions.