What is a pleural effusion?

The pleural space is a usually empty space formed by the pleura which is a double membrane surrounding your lungs.

Some diseases, such as cardiac failure, renal failure, liver failure, pneumonitis, tuberculosis, cancers, chronic inflammatory auto-immune diseases, and others can be responsible of an accumulation of fluid in that pleural space : it is called a « pleural effusion ».

When you have a pleural effusion, you usually feel difficulty to breathe on exertion, lateral chest pain increased while breathing deeply or changing position, and/or a dry cough.

Your doctor may suspect a pleural effusion while listening to your lungs and will prescribe a chest X-ray to confirm it. Although the chest X-rays shows a pleural effusion, it does not give you the cause of this pleural effusion.

To know the cause of your pleural effusion, your doctor will perform a pleural puncture,(also called a « thoracentesis ») to take a sample of the fluid and send it to the laboratory.

The laboratory will examine :

• the quantity of proteins and LDH: it helps to know if the pleural effusion is due to a disease of your pleura or to a lack of proteins in your blood;
• the amount and type of white blood cells: it indicates potential causes of the disease of the pleura;
• the presence of bacteria and their sensitivity to antibiotics.

Other tests can be performed, such as a pleural biopsy, depending on your particular case.

Thoracentesis allows also your doctor to remove all the fluid accumulated in your pleural space, in order to relieve your symptoms.

What is a thoracentesis?

A thoracentesis is a mini-invasive procedure, which allows your doctor to take a sample of fluid in the pleural space when you suffer from pleural effusion.

Your doctor introduces a fine needle under local anesthesia through your skin and chest wall, until reaching the pleural space. Then he aspirates the fluid coming in a syringe. The needle is removed at the end.

If the amount of fluid is low, this procedure can be performed after localization of the fluid with an ultrasound exam.

Afterwards, you don’t absolutely need to be hospitalized, but you should stay in observation during 4 hours and perform a chest X-ray before leaving hospital to be sure that everything went right.

What is a pleural biopsy?

A pleural biopsy is an invasive procedure which allows your doctor to take a sample of the pleura, a membrane surrounding your lungs.

There are two ways to perform a pleural biopsy:

• During a thoracentesis:
  • It is a mini-invasive procedure performed under local anesthesia by your respiratory physician.
  • Your doctor introduces a biopsy-needle through the same way than the thoracentesis and applies it against your chest wall to take samples of the pleura. The needle is removed at the end.
  • Afterwards, you don’t need absolutely to be hospitalized but you should stay in observation during 4 hours and perform a chest X-ray before leaving hospital to be sure that everything went right.
• During a thoracoscopy: it is an invasive procedure performed under general anesthesia by a thoracic surgeon. You need to be hospitalized for a few days after. This procedure is not described in this factsheet.

What are the risks of a throracentesis and of a pleural biopsy?

Thoracentesis and pleural biopsy are usually well tolerated procedures with few complications.

Some problems might occur:

• Pain during the procedure: usually avoided by the injection of local anesthesia. It disappear when the needle is removed.
• Bleeding: you may have a minimal bleeding when the needle is inserted trhough the skin, or when a pleural biopsy is performed, especially if you take blood thinner medications or if you have coagulation problems. That is why your doctor will check your medications and past medical history and prescribe you blood tests to check your coagulation ability if needed. Rarely the bleeding can be important after a pleural biopsy and need the insertion of a chest tube and an hospitalization.
• Pneumothorax: fluid may be replaced by air, either due to a puncture of your lung during the procedure or most often due to incomplete reexpansion of your lung. That is the reason why a chest X-ray should be performed after the procedure. In some cases, the air has to be removed by inserting a chest tube.
• Coughing up blood during the procedure: it is rare and often due to a puncture of your lung by the needle. It is usually benign and stops after few minutes.

When will you have the results?

The samples taken by your doctor are sent to the laboratory.

Analysis of cells, proteins and LDH are available in one day, however, results of microbiology, pathology and tuberculosis need more time.

After thoracentesis and pleural biopsy, your doctor will arrange you an appointment around 5 days to explain you the results and give you a treatment or propose you further tests if needed.