What is pleural effusion?

The lungs are covered by a lining (membrane) called the pleura. The pleura has an inner and outer layer. The inner layer covers the lungs. The outer layer lines the rib cage and diaphragm, which is the sheet of muscle that separates the chest from the tummy (abdomen).

The pleura makes a fluid that acts as a lubricant. This helps you to breathe easily, by allowing the lungs to move in and out smoothly. Sometimes too much of this fluid can build up between the two layers of the pleura. This is called a pleural effusion. 

 Illustration shows the lungs in the chest

Causes of a pleural effusion

Pleural effusions are common and are often due to:

  • lung infections, such as pneumonia
  • heart failure, which is when the heart is not pumping blood around the body as well as it should.

A pleural effusion can also be a symptom of several types of cancer. An effusion can develop if cancer cells have spread into the pleura. They can lead to irritation and cause fluid to build up. The types of cancer that are more likely to cause a pleural effusion are:

Signs and symptoms of a pleural effusion

Common symptoms of a pleural effusion include:

The build-up of fluid presses on the lung, making it difficult for the lung to expand fully. In some situations, part or all of the lung will collapse. This can make you more and more breathless, when you’re active and when you’re resting. You may also get some chest pain and a cough. If you are worried about any symptoms, speak to your healthcare team.

Diagnosing a pleural effusion

You may have a chest x-ray or an ultrasound scan, or both. Sometimes you may need other tests to confirm the diagnosis and the cause of the effusion.

Treating a pleural effusion

The first treatment of a pleural effusion involves draining it to relieve the symptoms.

Draining a small pleural effusion

If there is only a small amount of pleural fluid in the chest, the doctor may insert a small needle or thin tube (cannula) into the chest. They will use a syringe to draw off the fluid. The tube is removed immediately after the fluid has been drained off and the area is covered with a dressing. You may have an ultrasound scan before you have the fluid drained off.

Illustration shows the lungs in the chest with pleural effusion drainage

Draining a pleural effusion with a chest drain

A pleural effusion is usually drained by putting a tube into the chest. This is called a chest drain and is done by a doctor. You will be asked to sit either on a chair or on the edge of the bed. Someone will help you lean forward over a table with a pillow on it, so that your back is showing.

Your doctor will decide where to put in the tube. It is usually put in the side of the chest. The doctor will clean the skin over the area with an antiseptic solution to stop the area from becoming infected. They will then give you an injection of local anaesthetic to numb the area, so you won’t feel any pain during the procedure.

Your doctor will make a very small cut in the chest and insert the chest drain into the space where the fluid is collecting. Sometimes they will use an ultrasound scan to help guide the tube into the correct position. Once the tube is in position, they attach the chest drain to a bag or bottle for the fluid to drain into. The fluid that drains may be bloodstained.

Usually the fluid will be drained off fairly slowly, as a sudden release of pressure in the chest can cause your blood pressure to drop. A litre (about 2 pints) of fluid may be drained safely as soon as the drain has been put in. After this, drainage will be carried out more slowly. Your blood pressure will be checked during the procedure. You should let your doctor or nurse know if you feel dizzy, sick or light-headed.

In many hospitals, you usually have this done as a day patient (day-case procedure) by a specialist lung team. Occasionally, you may need to stay in hospital for a couple of days afterwards.

You may have some pain when the local anaesthetic wears off. Let your doctor or nurse know if this happens so that they can prescribe painkillers. The drainage tube will be held in place with a small stitch until all the fluid has drained. If your drainage tube is attached to a bottle or bag, you will be able to walk about with it. The chest drain may feel uncomfortable at times. Let your doctors or nurses know if it is very uncomfortable.

It's important to be careful with the bottle or bag. It shouldn't be raised above the level of the chest, as the fluid could go back into your lungs.

Once the drainage has slowed down and the doctors think that most of the fluid has drained, you will have a chest x-ray to see how well your lung has re-expanded. If it has, the drain will be removed.

Possible complications of chest drains

  • Blocked drain

    This is rare, and can sometimes be cleared by you changing your position or sitting up straight. Occasionally, the drain may need to be replaced.

  • Infected drain 

    The staff will check your temperature for any sign that you may be developing an infection.

  • Breathlessness and sharp pain in chest (pneumothorax)

    Sometimes when the fluid is drained from the chest, the lung cannot re-expand to fill the chest cavity. This leaves an air-filled space around the lung. This is called a pneumothorax. If it is a small pneumothorax, you may not need any treatment and it is likely to clear over a few days. You may need to have an x-ray to check that it is gone. If it is a larger pneumothorax, you may need to have another drainage tube put in to remove the air.

  • The fluid can collect again 

    If this happens, you may need to have the effusion drained more than once. To stop the fluid from building up again, your doctor may recommend other types of treatment. These may be chemotherapy or hormonal therapy depending on the type of cancer. Your doctor may also advise you to have a pleurodesis or a thoracoscopy.

Draining a pleural effusion at home

If fluid keeps building up, it is possible to have repeated chest drains put in. However, this can be uncomfortable and may mean making a number of trips to the hospital.

It may be possible for you to have a special catheter put in, called a tunnelled indwelling pleural catheter (TIPC). This is so you can have your pleural effusion drained easily while you are at home. When you have a build up of fluid on the lung, the TIPC allows you to drain the fluid into a bottle. This can be done by you, a family member or a nurse.

The catheter is inserted in hospital on a day ward. As long as there are no complications, you can usually go home on the same day.

Your doctor or specialist nurse will explain more about this method and tell you if it’s suitable for you.

If a pleural effusion comes back

Talc pleurodesis for a pleural effusion

If the lung re-inflates after the fluid has been drained, it may be possible to seal the two layers of the pleura together to stop the fluid from building up again. This is known as talc pleurodesis. Usually, sterile talcum powder is used to help stick the pleura together.

The doctor injects the talc through the drain and then leaves the drain clamped for about an hour. This allows time for the two linings to stick together. The doctor may attach the drain to a suction machine to apply a small amount of pressure. This can help the pleura to seal together. After a pleurodesis, you will usually have the drain in place for another 24 hours.

If there is a stitch that has been holding the drain in, a doctor or nurse will pull this together when the drain is removed. This closes the hole. They will cover it with a dressing. The stitch is usually removed about a week later. Sometimes just a dressing is used to cover the area where the drain has been.

After a pleurodesis, you may get chest pain for a day or so and you may need to take painkillers. Your doctor or nurse can give you more information about pleurodesis.

Thoracoscopy for a pleural effusion

It may be possible to drain a pleural effusion and to do a pleurodesis using a procedure called thoracoscopy.

You will be asked to lie on your side and given an injection of a sedative to make you feel drowsy. You will have a local anaesthetic to numb the area where the doctor will make one or two small cuts. They then put a flexible tube (thorascope) into the chest. The tube has a light and camera at the end, so the doctors can see into your chest.

Any fluid can be drained and the doctor can spray sterile talc through the tube. This helps the layers of the pleura stick together. The procedure takes about 40 to 60 minutes.

After the thoracoscopy, the doctors will put a plastic tube (chest drain) through the cut. They use this to drain any remaining fluid. The drain will be attached to a bottle or bag and secured in place with a stitch.

You will usually be able to go home 2 to 5 days after a thoracoscopy. Your hospital team will be able to give you more information about this procedure.