Pleural Effusion: Fluid Around the Lung

What a pleural effusion is

A pleural effusion is fluid that builds up between the lung and the chest wall, causing breathlessness and sometimes chest discomfort. It is not a diagnosis in itself, but a sign of another problem such as heart failure, infection, liver or kidney disease, or cancer.

How it shows up

A small amount of fluid in the pleural space may cause little or no symptoms. When fluid accumulates slowly over time, as in cancer or TB, breathlessness and chest pain may appear only once a very large amount has built up. Pleural fluid can be detected on a chest X-ray or CT scan, but ultrasound remains the most sensitive way to detect even small amounts.

What causes it

The main causes are infection, cancer and fluid accumulation due to organ failure, whether of the heart, the kidneys or the liver. We can often determine the cause from the characteristics of the fluid.

Draining and testing the fluid

Ultrasound allows us to drain the fluid safely, and testing the fluid often points to the cause. The fluid is removed either with a needle and syringe or through a chest tube. A small volume for diagnosis is taken with a needle; when larger amounts have to be removed, a chest tube is inserted between the ribs. Both procedures are done under ultrasound guidance for safety and under local anaesthetic, so pain is usually minimal and well controlled.

When the cause is unclear, a small camera examination of the chest, called thoracoscopy, can help. This is a keyhole procedure in which a scope is passed into the chest, usually under local anaesthetic with moderate sedation. It is mainly used to evaluate cancers on the outer surface of the lung.

When the fluid keeps coming back

For fluid that keeps coming back, particularly from cancer, talc pleurodesis, in which sterile talc is introduced into the pleural space to seal it and stop fluid re-accumulating, or an indwelling pleural catheter, a small tube that stays in place to drain it at home, can restore comfort and independence. An indwelling pleural catheter is placed through the chest wall for a longer period, usually for lung cancers in which large amounts of fluid keep accumulating. With adequate training, patients can go home with the catheter and drain the fluid periodically to relieve their symptoms.

When the fluid is infected (empyema)

When the fluid is infected and becomes thick and loculated, as in empyema, antibiotics and a chest drain are often combined with intrapleural fibrinolytics, namely tPA (tissue plasminogen activator) and DNase, placed through the drain to break down the thick fluid and help it drain, which can avoid the need for surgery. An empyema is a serious infection in the pleural space, and in almost all cases antibiotics alone are not enough: the fluid has to be drained as soon as possible. Some patients need medicines instilled into the pleural space, and some need surgery (VATS decortication, keyhole surgery to clear the infected space) to drain it adequately.

Treat the cause

The key is to find out why the fluid is there and to treat the cause.

Lung and Respiratory Conditions: A Patient Guide · Pneumothorax: Where Do We Go From Here? · The Aeden Physicians

Frequently Asked Questions

What is a pleural effusion?

A pleural effusion is fluid that builds up between the lung and the chest wall, causing breathlessness and sometimes chest discomfort.

What causes fluid to build up around the lungs?

It is not a diagnosis in itself, but a sign of another problem. The main causes are infection, cancer and fluid accumulation from heart, kidney or liver failure, and the characteristics of the fluid often point to the cause.

How is a pleural effusion treated?

Ultrasound allows us to drain the fluid safely, with a needle for small volumes or a chest tube for larger amounts, both under local anaesthetic. The key is to find out why the fluid is there and to treat the cause.