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### Course: Health and medicine>Unit 5

Lesson 9: Pleural Effusion

# Transudate vs exudate

In a pleural effusion, different fluids can enter the pleural cavity. Transudate is fluid pushed through the capillary due to high pressure within the capillary. Exudate is fluid that leaks around the cells of the capillaries caused by inflammation. Learn why transudative fluid does not contain proteins, why exudate does contain proteins, and how health professionals can differentiate between the two using Light’s criteria. Created by Jannah George.

## Want to join the conversation?

• what is the amount per ml that is the cutoff for differentiating between transudate and exudate? (protien, cholesterol, etc) thank!
• Good question, but I think Tom gave an incorrect answer to your question. First of all, there are about 2.2 POUNDS in a kilogram, so a measurement of 1.02 kg/L would be over 2 pounds of solute in a little over a quart of liquid. Good luck aspirating that through the thoracentesis needle. :>)

The correct answer to your question is that the difference between a transudate and an exudate is based on several factors. One of these is the SPECIFIC GRAVITY of the effusion fluid. If it is < 1.012 it is considered a transudate. If it is > 1.020 it is considered an exudate. The effusion is considered a transudate if the protein content is < 25 g/L and the cholesterol content is < 45 mg/dL, whereas an exudate has a protein content > 29 g/L and a cholesterol content > 45 mg/dL. For values in between the ones given, the results would be indeterminate, as it would not be clear whether the fluid was a transudate or an exudate. There are other factors that can be useful in differentiating the fluid as a transudate or an exudate. You might find the following link helpful: http://en.wikipedia.org/wiki/Template:Transudate_vs._exudate.
Hope this help clarify things for you. Good Luck.
• what are the causes of Exudate ?
• Exudate is the protein rich fluid migrating from capillaries as part of the inflammation response to fight infection. So you could say the cause is anything that triggers an inflammation response
• Is it possible to only have heart failure in just one chamber of the heart?If so, how?
• yes exactly .There may be any problem in left ventricle Of heat where from blood goes to body via aorta ..After blood comes from Right ventricle there may b no.prblm ..As it goes on into the left ventricle Any prblm in iT or if it does not work There the heart is called Left ventricular failure .
• Mrs. George says that a transudate effusion can be caused by left heart failure. A typical symptom of left heart failure is a pulmonary edema. The pathophysiology sounds very similar (fluid backup into the lung). My question is, when and why does the fluid back up into the pleural space and when into the lung itself? Or are pleural effusion and pulmonary edema the same thing? Thank you!
• Below there are links where you can search for the opposite term and read more about these conditions. The Merck manual has a general public version and a health professional version, I pasted one of each version and you can go back and forth between them.
Pleural effusion is the accumulation of fluid between the 2 pleural membranes surrounding the lungs. It can be a clear transudate fluid or a pus filled exudate fluid depending on the cause and length of time present. Pulmonary edema is the accumulation of fluid inside the lung tissue. These are different places. The reasons for the pulmonary edema and pleural effusion can overlap, such as inflammation. However, pulmonary edema is a predictable outcome due to left heart failure and high blood pressure causing back pressure to lung tissue. It is more life threatening then pleural effusion. Another cause for pulmonary edema is direct damage to the lungs due to inhaled toxic gases, for example. Pleural effusion maybe more difficult to predict and the causes are not so simple to understand. They could occur separately or together. Pleural effusion is free fluid ( think of it being like fluid in a plastic bag) that can be removed via a needle and tube. However, pulmonary edema is diffuse in the tissue ( think of it being like water in a sponge), it fills lung tissue, decreasing oxygen available to the patient and it is harder to treat as one waits for medications to manage the problem.
http://www.merckmanuals.com/home/lung-and-airway-disorders/pulmonary-hypertension/pulmonary-hypertension
http://www.merckmanuals.com/professional/pulmonary-disorders/mediastinal-and-pleural-disorders/pleural-effusion
https://www.medicalnewstoday.com/articles/167533.php
• A little mistake: Congestive cardiac failure is call when both ventricles are failing, Right HF is when right site is failing, and Left HF is when left ventricle is failing .
• Hello, I would ike to ask please what causes different types of exudate? Why does one case of tissue damade results in serous and another results in fibrinogen leaving the blood ? what is the mechanism which determins the type and amount of specific exudate?

Thank you