Marfan, Ehler-Danlos, Cystic medial degeneration & Berry aneurysms??

[dr_awaheed]

Hello everyone,
So I always held this belief that both Marfan & EDS cause aortic dissection or aneurysm by cystic medial degeneration & perhaps it was also the same mechanism by which they (Marfan & EDS) cause berry aneurysms.

However, after doing the UWorld vascular pathology questions, it clearly states the following:
- Marfan causes cystic medial degeneration but Ehler-Danlos doesn't
- Cystic medial degeneration is the mechanism by which Marfan leads to aortic aneurysm & dissection
- Ehler-Danlos causes berry aneurysms but Marfan doesn't!!
- Cystic medial degeneration (myxomatous changes) isn't seen in berry aneurysms
- It didn't say clearly whether Ehler-Danlos causes aortic dissection & aneurysm or not

This actually made me very confused. If anyone could help me with that, I'd be very grateful. It gave me a hard time

[dr_awaheed]

Anyone? .

[crossroad]

Marfan's is a defect in fibrllin which forms a scaffold around elastin whereas ED is a collagen defect. So, marfan affects elastic arteries where elastin predominates especially in the media, hence aorta. ED affects collagen which is predominant in smaller arteries therefore causes berry aneurysms and affects elastic arteries to a minimal extent. Others plz correct me if I'm wrong

[dr_awaheed]

Originally Posted by crossroad

Marfan's is a defect in fibrllin which forms a scaffold around elastin whereas ED is a collagen defect. So, marfan affects elastic arteries where elastin predominates especially in the media, hence aorta. ED affects collagen which is predominant in smaller arteries therefore causes berry aneurysms and affects elastic arteries to a minimal extent. Others plz correct me if I'm wrong

Thanks for your help, but do you mean that Marfan do not cause berry aneurysms ?

[crossroad]

In first aid they also mentioned Marfan's in the causes of berry aneurysms

[acff]

You are misunderstanding UW.

UW does NOT explicitly say Berry aneurysms are not associated with Marfan. The question you are thinking is asking about cystic medial degeneration. Aortic aneurysm, yes. Berry aneurysm, no.

Berry aneurysms occur at bifurcations at the Circle of Willis. At these branching points, the media is undeveloped which makes it naturally weaker. Certainly, without a media layer, there can be no cystic medial degeneration. Cheers.