vicinihil

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Anyone know where I can find this? I looked and it refers me back to a thread created on SDN in 2008. Are there any updated Errata available?

Question: In her book she says that Histamine dilates arterioles and constricts veins thereby causing edema via increased capillary filtration.

I thought edema 2nd to histamine was due to contraction of the endothelial cells in the veins making them more permeable to fluid. :confused:
 

username456789

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I don't have Goljan by my side at the moment, but I seem to remember from the audio that histamine dilates arterioles and contracts the endothelial cells of veins (or was it venules?) so that fluid can escape.

But I'm picturing Costanzo's explanation more like glomerular flow where the afferent arteriole dilates and the efferent arteriole constricts, causing more or less a "build up" of pressure, causing the fluid to exit. No idea which is more "correct", unfortunately.
 

rem6775

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Anyone know where I can find this? I looked and it refers me back to a thread created on SDN in 2008. Are there any updated Errata available?

Question: In her book she says that Histamine dilates arterioles and constricts veins thereby causing edema via increased capillary filtration.

I thought edema 2nd to histamine was due to contraction of the endothelial cells in the veins making them more permeable to fluid. :confused:
I think the way she worded that is somewhat misleading. Histamine causes arteriole dilation and increases venule permeability. Histamine binds to H1 receptors on vascular endothelial cells to cause these effects. The edema due to inflammation is mediated by: 1. contraction of endothelial cells (as you said) which causes larger interendothelial cell spaces (caused by histamine as well as bradykinin, leukotrienes and substance P); 2. endothelial injury and necrosis; 3. increased transcytosis.

I wouldn't say "constrict veins" is a proper way to say it, and I think that's the problem. It's the endothelial cell contraction leading to bigger gaps and extravasation of fluid/protein due to increased venule permeability.