We have prbably all seen a chest Xray of pulmonary edema due to left ventricular failure, there is something confusing in this situation which is:

IN the CXR u see the characteristic perihilar shadows which are areas of alveolar edema, these shadows are absent peripherally, the confusing part is, if the shadows are located perihilar, then why would the crepitations due to pulmonary edema would be basal?

Gravity.

first i miss u man.
second:
Dude, if it is gravity why wouldnt the edema be in the bases, patients with LVF never show basal edema on Xrays.

You're thinking X-Ray and I'm thinking crepitations.
Fair enough, think of Kerley B then, it's peripheral.

To link crepitations and x-ray findings, u need to remind yourself (coz I'm 10000% sure that u already know) that the crepitations are caused by air opening and closing the small alveoli which are filled with liquid (due to edema) + the air flow through the liquid.
Now, think of the perihilar region, it doesn't have the small alveoli, and it doesn't have liquid (or as much liquid as the basal areas) due to the gravity, so it's impossible to have crepitations there eventhough they would be swollen, right?

That's my personal conclusion and I may be wrong and would love to someone to correct me.

Otherwise, I think I answered your question dude.

p.s: I miss u too wallah


Take Care

Kadum, the Kerly B lines are dilated lymphatic channes, they are not the edema itself but they are a manifestation of it, the perihilar opacities are due to the pulmonary edema mainly and partly due to the dilated pulmonary veins and their divisions. U dont usually hear the crepitations in the perihilar regions but rather peripherally.

my question is simply y does the edema appear perihilar while the crepitations are heard at the periphy?

u r near, but u need to go deeper.
think and induce, do not deduce.

Hi Samer, How R U ?
I wish U R doing fine ..

For UR question ....

The Edema appears perihilary on CXR, & this is due the Interstitial Edema ..
The Criptations are heared on the periphery, & this due to the Alveolar Edema ..

& in Pulmonary Edema due to Left Ventricular Failure there will Mixed type of Pulmonary Edema ( Interstitial + Alveolar ), so the edema will appear perihilar & the crepitations are heared on the periphery ..

& I think U all know what is the Interstitial & Alveolar Edema, so I will not illustrate them ..

I hope that is the correct answer ..
Miss U sooooooo much Samer ..

Salam to all friends ..

Hello Hamoodi, mushtakeeen hub.

U have figured the parts of the answer

The perihilar opacity is due to the alveolar edema and the crepitations peripherally heard are due to the interstitial edema.

in the alveolar edema, the alveoli are filled with fluids which forms a consolidated area that no air can enter and therefore it is unlikely to hear crepitations there. This type of edema is visible on plain films at the perihilar regioin which forms the characteristic bat wings or butterfly appearance.

in the interstitial edema peripherally the fluid accumulates between the walls of the alveoli [the interstitium] and normally follows the gravity causing the alveoli to open against resistance which gives the basal crepitations. This type of edema is recognized by the presence of Kerly B lines [dilated lymphatic channels at the septal lines] peripherally and Kerly A lines at the perihilar areas.

the edema as u said ahmed is mixed starting as interstial and progressing to alveolar. So there is edema peripherally but its not that easy to see

TY dear Samer for the great explanation .....

Nice discussion pals

It would have been nicer (I guess ) if I were allowed to reply! coz Samer personally asked me not to reply anymore

lol

Dude, I lead u to the answer after hours of discussion, u kept busting my humps until i practically answered u.

It was barely half an hour of chat discussion and I admit that I didnt quite get what you were aiming for
I did answer u eventually so I cant see y u said so... anyway if u thought I didnt answer then y u asked me not to reply on this topic or any other question topics of yours?

cheers mate