What is a Pleural Effusion?
Two membranes called pleurae surround the lungs. One pleurae covers the lung itself and a second membrane is attached to the chest wall. The pleural cavity is the space between the two membranes. Although fluid is normally in the pleural cavity, if too much is present it is called a pleural effusion. There are various causes of pleural effusions. The most common causes are pneumonia and certain types of cancer, such as lung cancer. Other causes include heart failure and a pulmonary embolism, which is a blood clot in the lung. A pleural effusion can cause a variety of symptoms depending on the amount of excess fluid in the pleural cavity. If the effusion is small, such as less than 300 ml, there may not be any symptoms. Larger effusions may cause symptoms, such as shortness of breath, a dry cough and chest pain. In addition to symptoms, there are physical findings during a physical exam. A physician will hear a decrease in lung sounds over the area of the lung affected. A pleural rub is
