Pleural Effusion

What is a pleural effusion?

A pleural effusion is a gathering of fluid that builds up in the space between the lung and the chest wall. The pleura is a thin layer of membrane, which covers the lungs and the inner surface of the chest wall. Normally, there is a small amount of fluid between the pleura but if this builds up it can cause a pleural effusion.

What causes a pleural effusion?

A pleural effusion is caused by other health conditions, including:

• Pneumonia: pneumonia occurs when the lung tissue becomes inflamed as a result of infection.
• Tuberculosis.
• Lung cancer.
• Some types of arthritis, including rheumatoid arthritis: these conditions can cause the pleura to become inflamed.
• Heart failure: heart failure can cause back pressure in the veins, which can result in fluid flowing out of the vessels and into the pleura.
• Low protein levels: conditions such as liver cirrhosis and kidney disease can cause levels of protein in the blood to drop and this may cause fluid to seep from the blood vessels.

Diagnosing a pleural effusion

A chest X-ray can usually confirm a pleural effusion. However, if doctors know the reason for the pleural effusion they may not need to carry out any more tests. They may, however, order further tests, including lung function tests, pleura and fluid samples and blood tests, if the cause is not known.

Symptoms of pleural effusion

In many cases, pleural effusions do not cause any pain but as the effusion becomes larger it may start to become more difficult to breathe. This is because the fluid starts to press on the lung. You may also experience symptoms of the condition that actually caused the pleural effusion, which can be very varied as many different conditions can cause an effusion.

Treatment for pleural effusion

Usually the priority is to treat the underlying cause of the pleural effusion. As a result of this, treatment can vary greatly and will depend heavily on the nature of the underlying illness. If an individual has a pleural effusion caused by pneumonia, they will probably be given antibiotics to fight the infection. If the underlying condition can be treated effectively, it is likely that the pleural effusion will clear away for good. However, if the condition cannot be treated effectively, it may return again once it has been drained.

Small effusions that do not cause any pain or symptoms may not have to be treated, but doctors can adopt a policy of watchful waiting and intervene if the effusion does not clear. For larger pleural effusions it may be necessary to drain the effusion, which will ease breathlessness. Inserting a tube through the chest wall drains the effusion and local anaesthetic is injected prior to the procedure to ensure that the patient does not feel any pain.

In some cases, draining the pleural effusion may be sufficient treatment but if the underlying illness cannot be treated effectively, the effusion is likely to return and therefore other treatments may be recommended. Other treatment options include:

• Fitting a permanent drain.
• Pleurodesis: this treatment involves injecting a chemical known as a sclerosant into the pleural space. The chemical causes the pleural membranes to become swollen and stick together. This treatment is usually used when effusion is caused by cancer.
• Inserting a pleuroperitoneal shunt: a shunt acts as a drain inside the body and the shunt allows fluid to drain out of the chest and into the abdomen. This treatment is only used on an occasional basis.
• Pleurectomy: this is a surgical procedure, which involves removing the pleura. This procedure is usually only used for patients who have cancer and other treatments have failed.