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Can someone explain the difference between RHF and LHF in terms of which one has transudate and exudate?

Goljan said RHF (pitting edema) is transudate and LHF (pulmonary edema) is exudate, but why? Couldn't you theoretically have protein leak out of the blood vessels in either one?
 
Jun 11, 2012
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Can someone explain the difference between RHF and LHF in terms of which one has transudate and exudate?

Goljan said RHF (pitting edema) is transudate and LHF (pulmonary edema) is exudate, but why? Couldn't you theoretically have protein leak out of the blood vessels in either one?
I will only answer this question via socratic method.

First. What is the definition of Exudate? Transudate? In other words what is the main cause of Exudate and transudate (ie what causes high protein fluid loss vs. low protein fluid loss).

Second- what happens during heart failure to the blood?

Third- Specifically, what happens to blood in LHF and RHF?

what is the essential differentiating factor found near the capillary-alveolar barrier that separates the prefusion of the lungs from perfusion of other organ tissues (in general). Is edema in systemic circulation an easier process than in pulmonary circulation?
 
Jun 11, 2012
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I will only answer this question via socratic method.

First. What is the definition of Exudate? Transudate? In other words what is the main cause of Exudate and transudate (ie what causes high protein fluid loss vs. low protein fluid loss).

Second- what happens during heart failure to the blood?

Third- Specifically, what happens to blood in LHF and RHF?

what is the essential differentiating factor found near the capillary-alveolar barrier that separates the prefusion of the lungs from perfusion of other organ tissues (in general). Is edema in systemic circulation an easier process than in pulmonary circulation?
Also- ARDS is associated with this. Explain why ARDS has exudative fluid.
 

CaliAtenza

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FA says transudate in cases of CHF; doesnt make a distinction between left heart failure and right heart failure. Wikipedia says left sided failure is a transudate. Pathoma doesnt even say which is which.
 
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FA says transudate in cases of CHF; doesnt make a distinction between left heart failure and right heart failure. Wikipedia says left sided failure is a transudate. Pathoma doesnt even say which is which.
I think trans/exu is beyond the scope of Step 1. Frankly either can happen but exudate happens more with Left heart due to its complexity and close proximity to alveoli. The smaller area with greater contact with capillaries enables macrophages and immune mediated systems to increase inflammation in the lung perfusion. This is less so in the systemic circulation due to the largeness of the system. If I had to venture a guess you would see more exudate in the pulmonary system.

After looking online based on what you said I would agree with you.
 

notbobtrustme

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ARDS is widespread inflammation of the alveoli, so with that in mind, you get opening of the post-capillary venule by the various inflammatory mediators (eg PGI/E/D, leukotrienes, etc etc). That causes fluid to fill the alveoli spaces and with that fluid comes inflammatory cells, namely neutrophils. Since plasma is being leaked into the space wholesale and neutrophils are coming into the space, the fluid that accumulates is high in protein and high in cells. That classifies it as an exudate.

In contrast, a transudate is basically plasma being filtered through tiny pores in the capillaries. Since cells are too large to fit through the pores, the fluid is low in cellular matter. Since proteins are either charged or too large to fit through the pores, the fluid is low in protein as well. That classifies it as a transudate. Typically, anything that pulls fluid preferentially or push fluid preferentially will lead to a transudate. In left CHF, blood is backed up in the left atrium, which backs blood up into the pulmonary circuit. That increases the pulmonary circuit pressure, causing fluid to be filtered against the capillary. The most common cause of RHF is LHF, so that's how a transudate will be associated with RHF. In cases of cor pulmonale, where the RH fails independently of the LH, then fluid is backed into the systemic circuit and this is where you get pitting edema. This occurs in the leg because you have gravity acting on the fluid as well as the excess fluid being backed up, causing a transudate to flow out of the circulation. Finally, if there is an imbalance between capillary and interstitial oncotic pressure, this will force fluid to leave the circulation and into the interstitum, which leaves behind enough oncotic pressure in the capillaries to balance out the disparity. Since protein and cell-free fluid is accumulating in the interstitium, this fluid is also a transudate.
 
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Transposony

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Medstudy says:
A transudative effusion is a secondary phenomenon, due to systemic changes influencing the formation and absorption of pleural fluid. The most common causes are LV failure, cirrhosis, and nephrotic syndrome
An exudative effusion is due to a local cause, and the 2 most common ones are bacterial pneumonia and cancer—but don’t forget pulmonary embolism, even though it is not as common.
 

Instatewaiter

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Can someone explain the difference between RHF and LHF in terms of which one has transudate and exudate?

Goljan said RHF (pitting edema) is transudate and LHF (pulmonary edema) is exudate, but why? Couldn't you theoretically have protein leak out of the blood vessels in either one?
Both care transudative. Neither caused a "leaky" state. Therefore the protein stays in the vessels and the fluid comes out.
 

Instatewaiter

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Both care transudative. Neither caused a "leaky" state. Therefore the protein stays in the vessels and the fluid comes out.
Contrast this with ARDS where there is breakdown of the intracellular junctions and you get loss of the endothelial barrier cuasing a leaky state and therefore an exudate.