What is it?
A pleural effusion is excess fluid between the two membranes (pleura) that surround the lungs. There is normally a small amount of fluid between the pleura, which acts lie a lubricant for the membranes.
Fluid that can collect in the pleural space can be serous fluid, blood, chyle (lymphatic fluid) or pus.
The type of effusion is further classified into transudative or exudative fluid.
Transudative pleural effusions are caused by fluid leaking into the pleural cavity. This is caused by a low protein concentration in, or a high blood pressure within, the blood vessels. Common causes of transudative effusions are:
Left sided heart failure
Liver cirrhosis
Exudative pleural effusions are commonly a result of inflammation of the pleura. This causes the blood vessels to be more "leaky", leading to fluid to collect in the pleural space. Common causes of exudative effusions are:
Pneumonia
Lung cancer
Tuberculosis
How is it diagnosed?
The diagnosis of a pleural effusion is made from the patient's history, the examination findings and from test results. Chest X-rays are effective at confirming the presence of an effusion.
Thoracentesis, the procedure of obtaining a sample of pleural fluid, will be required to determine the nature of effusion and also for symptomatic relief.
What are the symptoms?
Common symptoms include:
Chest pain, especially on breathing in
Cough
Shortness of breath
Fever, if there is an inflammatory/infective process
What is the treatment?
The underlying cause of the pleural effusion will need to be treated. Some pleural fluid can be removed for symptom relief (therapeutic aspiration or chest drain insertion).
The pleural fluid will need to be sent for analysis when a sample is obtained to further investigate its nature, and the cause of the effusion.
Repeated effusions may require pleurodesis. This can be done either via drugs, or surgically. The chest tube that is inserted for pleurodesis will have to remain in place until fluid drainage stops.
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