Thoracentesis Purpose & Causes


Thoracentesis is a procedure which is used to clear excessive pleural fluid from pleural space. Pleural space lies between lungs and chest wall. Normally small amount of pleural fluid is present in pleural space but due to any cause volume of pleural fluid increases and leads towards further complications. Thoracentesis procedure is used for two main purposes i.e. for diagnostic purpose and for treatment purpose. In case of diagnostic purpose, a fine needle is used to inject in pleural space from back side right through chest wall. Only syringe is filled with pleural fluid and sample is collected. Then this sample is passed on to lab for further testing. But in case of treatment, a two way plastic catheter or a syringe is used to eject pleural fluid from pleural space. If a needle is used, then a vacuum container is attached with it to collect excessive pleural fluid. If thoracentesis is used for treatment purpose, then it will take longer than sample collection.

This procedure may be used in many pathological conditions. Most commonly this procedure is used to diagnose leading cause behind accumulation of pleural fluid over the limit. There may be many reasons behind accumulation of pleural fluid some of them are discussed below.


  • Congestive heart failure CHF is considered a most common cause behind accumulation of excessive pleural fluid.
  • Any kind of infection like viral, fungal or bacterial infection can cause pleural effusion.
  • (Pleural effusion is defined as accumulation of pleural fluid ) 
  • Lung cancer leads to decrease in lung cells functionality which may cause pleural effusion and necessarily require thoracentesis.  
  • Some autoimmune diseases like systemic lupus erythematosus SLE is another main cause of pleural effusion and ultimately thoracentesis.  
  • Pancreatitis which is inflammation of pancreas  
  • Pulmonary embolism may cause accumulation of pleural fluid and need thoracentesis. Pulmonary embolism is defined as condition in which a blood clot is formed in lung.  
  • Other than congestive heart failure, empyema is also considered as main cause behind pleural effusion.  
  • Rarely problem in liver cause pleural effusion.  
  • It may occur secondary to medicines used as treatment for another pathological condition.  
  • Tuberculosis infection also requires thoracentesis. 
  • Last but not least pleural effusion occurs due to pneumonia.  


There are many other pathological conditions other than these mentioned above which need thoracentesis. In all above mentioned conditions, thoracentesis is performed for diagnostic purpose. And sample is collected for further testing. These tests show reason behind these pathological conditions. Pleural effusion is the only reason in which thoracentesis is performed for treatment purpose. It is a safest procedure, but still care is required during and after thoracentesis. A consent form have to be signed by patient before starting this procedure. And special precautions are given to patient as a care chart to help him. In this chart, patient is advised to take medications prescribed by doctor and avoid some things. When thoracentesis is performed, some tests like ultrasonography is performed to check success of thoracentesis and complications occurring after it.
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