Fluid buildup on the lungs (pleural effusion)
Canadian Cancer Society Société canadienne du cancer
Some cancers can cause pleural effusion, which is a buildup of fluid in the space between the lungs and the chest wall.
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Canadian Cancer Society
Fluid buildup on the lungs is called pleural effusion. It's when too much fluid builds up in the pleural cavity, which is the space between the lungs and the chest wall. The pleural cavity is surrounded by 2 thin layers of tissue called the pleura that cover the lungs and line the chest wall. Normally there is a small amount of fluid between the layers of the pleura that keeps the tissues moist and helps the lungs breathe without any friction. The fluid is made by cells in the pleura, and it is constantly drained through the lymphatic system and replaced again.

If pleural effusion is a side effect of cancer or there are cancer cells in the fluid, it may be called malignant pleural effusion.

Pleural effusion can be in just one lung or in both lungs.

Several diseases or medical conditions can cause fluid to build up around the lungs. These include:

heart failure

a blood clot in the lung (called a pulmonary embolism)

liver disease

a lung infection (pneumonia)

kidney disease

A malignant pleural effusion is caused by cancer cells spreading to the space between the pleural layers. Cancer cells cause the body to make too much pleural fluid, and they stop the fluid from draining properly. They can also block or change the flow of lymph fluid in the pleural cavity.

The following cancers are more likely to cause pleural effusion:

lung cancer

breast cancer

mesothelioma

non-Hodgkin lymphoma

stomach cancer

kidney cancer

ovarian cancer

colon cancer

cancer of unknown primary

Pleural effusion may not cause any symptoms at first, or the symptoms may be mild. Symptoms of pleural effusion depend on how much fluid there is and how quickly it is collecting in the pleural cavity.

Symptoms of pleural effusion may include:

shortness of breath

a cough

chest pain or a feeling of heaviness in the chest

anxiety

a fever (if the fluid becomes infected)

malaise

Shortness of breath can get worse when you lie down, which can make it hard for you to sleep. You may get very tired and breathless when you try to exercise.

When you can't breathe very well, you may also be anxious and feel like you are being suffocated.

A thoracentesis is a procedure that drains extra fluid from around the lung. A hollow needle is inserted between the ribs into the pleural cavity. The needle is used to remove the fluid.

The fluid removed from the pleural cavity during a thoracentesis is examined in a lab. This fluid can help your healthcare team identify the cause of the pleural effusion. There are 2 types of fluid.

Transudate fluid is watery and light coloured. It has little or no protein and low levels of an enzyme called lactate dehydrogenase (LDH), which is found in most of our body's tissues. Transudate fluid is caused by organ failure, most often heart, liver or kidney failure, or a pulmonary embolism.

Exudate fluid is thick and cloudy. It has high levels of protein and LDH. Exudate fluid is most often caused by a lung infection, a pulmonary embolism or cancer. Cancer cells may be found in the fluid. Looking at these cancer cells can help identify the type of cancer causing pleural effusion in people who don't have a history of cancer.

Blood and pus may also be found in the fluid that is removed. If there is blood in the fluid, it is most likely caused by cancer. If there is pus in the fluid, it is caused by a lung infection.

Cell and tissue tests may also be done on the fluid to look for any genetic changes that may help identify the type of cancer or help with treatment decisions.

Find out more about a thoracentesis.

If fluid keeps building up in the lungs, your healthcare team may offer to place a tunnel catheter so that you can have treatment at home. This procedure is usually done in an outpatient clinic.

A thin, soft silicone tube is placed inside the chest cavity through a small cut (incision) between the ribs under local anesthesia. The tube is then tunnelled underneath the skin to come out through another small incision. The pleural fluid drains into a bottle at the end of the tube. When the fluid has stopped draining, a cap is placed on the end of the catheter and sterile waterproof tape is placed on top.

Fluid is drained 2 or 3 times a week by a nurse at home or at a local health unit. When the pleural fluid dries up, the tube is removed.

In the hospital, the doctor or surgeon may place a tube through an incision in the chest between the ribs and into the pleural cavity. The tube is left in place to drain the extra fluid that is causing the pleural effusion.

A chest tube may be placed at the end of a video-assisted thoracoscopic surgery (VATS). VATS is a type of chest surgery done with a flexible tube (called a thoracoscope) that has a camera attached to the end. The thoracoscope is placed inside the chest cavity through an incision in the ribs. The surgeon uses the camera as a guide to look at the pleural cavity. Then the chest tube is put through the incision and into the pleural cavity where the fluid is collecting. The pleural fluid drains into a bottle at the end of the tube.

A pleurodesis is done to stop a pleural effusion from coming back after it has been drained. A pleurodesis seals up the space between the 2 layers of the pleural lining surrounding the lungs. It uses a chemical called a sclerosing agent to irritate and scar the lining so that it sticks to the lung. The most commonly used sclerosing agent is talc.

A pleurodesis is done using a VATS surgery for placing a chest tube after the surgeon has found and drained the pleural effusion. After the fluid has drained, a sclerosing agent is put into the tube, which is closed to keep the agent in the area where the fluid was removed. Once the pleural membrane is sealed, the tube is opened and drained.

You may have to have the procedure done again to completely seal the layers of the pleura to stop the fluid from building up.