Virtual Medical Centre

Pleural effusion

• What is Pleural effusion?
• Who gets Pleural effusion?
• Predisposing Factors
• Progression
• Probable Outcomes
• How is Pleural effusion Diagnosed?
• How is Pleural effusion treated?
• Pleural effusion References

What is Pleural effusion?

A pleural effusion is a disease of the lung.

The pleura are thin films of connective tissue, which line both the outer surface of the lungs, and the inside of the chest cavity. The relationship of the pleura to the lungs and chest can be imagined as if the pleura were a balloon blown up inside the chest, into which the lungs have been pushed. Thus, there are in fact two layers of pleura between the outer surface of the lung and the chest wall. One is adherent to the lung, whereas the other layer follows the outline of the chest wall. The two layers press up against one another, and in the healthy chest, there is no air or significant fluid between them. In a pleural effusion, fluid is present in this potential space between the two layers of pleura.


This does not include pus in the pleural space (empyema) or blood (haemothorax).

Who gets Pleural effusion?

Pleural effusions are a very common phenomena, since they can be caused by any of a number of lung and heart disorders. A small pleural effusion is often present on a chest x-ray when somebody has a significant heart or lung problem.

Predisposing Factors

The following diseases may cause pleural effusion:

• Heart failure
• Bacterial pneumonia
• lung cancer and other tumours with lung metastases
• Pulmonary embolism
• Radiation therapy to the chest
• Nephrotic syndrome
• Hypothyroidism
• Ovarian tumours
• Tuberculosis
• Connective tissue disease (for example, rheumatoid arthritis, lupus)
• Rarely: heart attack, acute pancreatitis, mesothelioma, sarcoidosis, yellow-nail syndrome, familial Mediterranean fever.

Progression

The natural history of pleural effusions is largely determined by the cause. Pleural effusions as a result of a transient cause (e.g. pneumonia, infarction, exacerbation of heart failure) will reasorb. However if the cause is progressive (eg. mesothelioma or pulmonary metastases), then the effusion, even if drained will re-accumulate.

Large effusions will cause shortness of breath since they preclude the lung on that side from expanding adequately - they are often accompanied by a degree of collapse.