Pleural effusion overview
|
Pleural effusion Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Pleural effusion overview On the Web |
|
American Roentgen Ray Society Images of Pleural effusion overview |
|
Risk calculators and risk factors for Pleural effusion overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Template:GCC
Overview
Pleural effusion is the presence of excessive fluid in the pleural cavity resulting from transudation or exudation from the pleural surfaces.
In normal conditions, the pleural space contains a small amount of fluid (≈0.3 mL·kg-1) maintained by a complex interplay of hydrostatic pressures and lymphatic drainage, which allows for steady liquid and protein turnover.[1] Pathological processes may lead to the development of pleural effusions by causing disequilibrium between the rates of pleural fluid formation, pleural permeability and pleural fluid absorption.
Four types of fluids can accumulate in the pleural space:
- Serous fluid (hydrothorax)
- Blood (hemothorax)
- Chyle (chylothorax)
- Pus (pyothorax or empyema)
Pathophysiology
Healthy individuals have less than 15 ml of fluid in each pleural space. Normally, fluid enters the pleural space from the capillaries in the parietal pleura, from interstitial spaces of the lung via the visceral pleura, or from the peritoneal cavity through small holes in the diaphragm. This fluid is normally removed by lymphatics in the visceral pleura, which have the capacity to absorb 20 times more fluid than is normally formed. When this capacity is overwhelmed, either through excess formation or decreased lymphatic absorption, a pleural effusion develops.
Treatment
Physical Examination
When only 250 to 300ml of pleural fluid is present, physical examination may be unremarkable.
At a pleural fluid volume of approximately 500 ml, the typical physical findings are:[2]
- Dullness to percussion
- Decreased fremitus
- Normal vesicular breath sounds of decreased intensity compared with the contralateral side
At a pleural fluid volume exceeding 1000ml, there usually is:[2]
- Absence of inspiratory retraction and mild bulging of the intercostal spaces
- Decreased expansion of the ipsilateral chest wall
- Dullness to percussion up to the level of the scapula and axilla
- Decreased or absent fremitus posteriorly and laterally
- Bronchovesicular breath sounds, which may be of decreased intensity at the upper level of the effusion
- Egophony at the upper level of the effusion
When the effusion fills the entire hemithorax, physical examination will show:[2]
- Bulging of the intracostal spaces
- Minimal to no expansion of the ipsilateral chest wall
- A dull or flat percussion noted over the entire hemithorax
- Absent breath sounds over the majority of the chest with possible bronchovesicular bronchial breath sounds at the apex
- Egophony at the upper level of the pleural effusion
- Apalpable liver or spleen due to significant diaphragmatic depression