The key difference between exudative and transudative pleural effusion is that exudative pleural effusion results in a cloudy filtrate rich in protein and cells, while transudative pleural effusion results in a clear filtrate with a low protein and cell content.
Pleural effusion is a condition that results in the building up of excess fluid in the pleural cavity. Generally, the pleural cavity is filled with fluid between the visceral and parietal pleura. Fluid helps in lubrication and facilitating breathing. Accumulation of excess fluid affects breathing by limiting lung expansion. Usually, patients do not show signs or symptoms during pleural effusion conditions. However, common signs include ascites, peripheral edema, lymphedema, unilateral lower extremity swelling, and yellowing of nails. In addition, it also causes chest pain, fever, dry cough, shortness of breath, orthopnoea, weight loss, and hemoptysis. There are two types of pleural effusions: exudative and transudative pleural effusion.
CONTENTS
1. Overview and Key Difference
2. What is Exudative Pleural Effusion
3. What is Transudative Pleural Effusion
4. Similarities – Exudative and Transudative Pleural Effusion
5. Exudative vs Transudative Pleural Effusion in Tabular Form
6. Summary – Exudative vs Transudative Pleural Effusion
What is Exudative Pleural Effusion?
Exudative pleural effusion is caused due to increase in capillary permeability. This leads to the leakage of proteins, cells, and other serum constituents. The most common causes of exudative pleural effusion are pneumonia, pulmonary embolism, cancer, and tuberculosis. This condition is characterized by the exudation or escaping of fluid into the pleural cavity through lesions in lymph vessels and blood vessels caused by inflammation and tumors. These lesions enable the passing of large molecules with solid matter into the pleural cavity.
Exudative pleural effusion results in a filtrate that is cloudy or bloody and contains high protein and cell content. In exudative pleural effusion, the protein/serum protein ratio is greater than 0.5, the LDH (Lactate dehydrogenase)/ serum LDH ratio is greater than 0.6, and the cholesterol content is greater than 1.2 mmol/L.
What is Transudative Pleural Effusion?
Transudative pleural effusion is caused due to the combination of increased hydrostatic pressure and a decrease in plasma oncotic pressure. The most common causes are heart failure, hypoalbuminemia, and cirrhosis. It is characterized by the transudation of the permeation of fluid into the pleural cavity through the walls of intact pulmonary vessels.
The two main conditions that result in transudative pleural effusion are increased hydrostatic pressure causing scenarios such as heart failure and decreased oncotic pressure causing cirrhosis or nephrotic syndrome. This condition also results in pale yellowish or clear fluid with a low protein and cell content. In transudative pleural effusion, the protein/serum protein ratio is less than 0.5, the LDH/ serum LDH ratio is less than 0.6, and the cholesterol content is less than 1.2 mmol/L.
What are the Similarities Between Exudative and Transudative Pleural Effusion?
- Exudative and transudative pleural effusion are pathophysiological conditions of pleural effusion.
- They both result in the accumulation of fluid or filtrate in the pleural cavity.
- They arise due to various pathological conditions.
- Moreover, they result in impaired breathing
- Both conditions are diagnosed by chest x-rays, chest CT scans, and lung ultrasounds.
What is the Difference Between Exudative and Transudative Pleural Effusion?
Exudative pleural effusion results in a cloudy filtrate rich in protein and cells, while transudative pleural effusion results in a clear filtrate with a low protein and cell content. Thus, this is the key difference between exudative and transudative pleural effusion. Moreover, exudative pleural effusion value is>2.9 g/dL while transudative pleural effusion value is<2.5g/dL. Besides, exudative pleural effusion results in high LDH whereas transudative pleural effusion results in low LDH.
The below infographic presents the differences between exudative and transudative pleural effusion in tabular form for side-by-side comparison.
Summary – Exudative vs Transudative Pleural Effusion
Pleural effusion is a condition of the lungs that causes the building up of excess fluid in the pleural cavity. It occurs in two ways as exudative and transudative pleural effusion. Exudative pleural effusion results in a cloudy filtrate rich in protein and cells, while transudative pleural effusion results in a clear filtrate with a low protein and cell content. Exudative pleural effusion is caused due to increase in capillary permeability due to inflammatory responses. The most common causes of exudative pleural effusion are pneumonia, pulmonary embolism, cancer, and tuberculosis. Transudative pleural effusion, on the other hand, is caused due to the combination of increased hydrostatic pressure and a decrease in plasma oncotic pressure. The most common causes are heart failure, hypoalbuminemia, and cirrhosis. So, this summarizes the difference between exudative and transudative pleural effusion.
Reference:
1. “Pleural Effusion: Symptoms, Causes, Treatments.” Cleveland Clinic.
2. Walker, Christopher M. “Pleural Effusion.” Chest Imaging, 2019, pp. 165–170.
Image Courtesy:
1. “2313 The Lung Pleurea” By OpenStax College – Anatomy & Physiology, Connexions Web site, Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia
2. “Diagram showing a build up of fluid in the lining of the lungs (pleural effusion) CRUK 054” By Cancer Research UK – Original email from CRUK (CC BY-SA 4.0) via Commons Wikimedia