Intracranial hemorrhage

[Paramyxovirus]

I am kind of confused with the blood vessels involved in Subarachnoid haemorrhage vs Intraparenchymal haemorrhage.
A rupture of berry aneurysm (which is a part of Circle of willis) results in Subarachnoid haemorrhage. Does this mean that the major blood vessels supplying the brain parenchyma (ACA, MCA, PCA and their branches) lie in subarachnoid space?
If so, then how do we end up with Intraparenchymal haemorrhage? In what plane are the lenticulotriate vessels present? Deep to piamater?
FA says AV malformation can result in Subarachnoid haemorrhage, where as UWorld says AV malformation leads to intraparenchymal haemorrhage.
I am quite confused with the plane of blood vessels and what kind of hemorrhage they result in.

Would really appreciate if someone can elaborate me on this.

Thanks!

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[PowerDan]

I am kind of confused with the blood vessels involved in Subarachnoid haemorrhage vs Intracranial haemorrhage.

Sub-arachnoid hemorrhage is a sub-type of Intracranial hemorrhage.

 

[Paramyxovirus]

I am sorry, I meant to write "Intraparenchymal haemorrhage"

 

[PowerDan]

The blood vessels travel through all the layers to reach the brain matter; where oxygen, nutrients, etc are exchanged with the tissue through the BBB.

Whether an ICH will be a subarachnoid, epidural or intraparenchymal hemorrhage depends at what point of their path the blood vessels get damaged.

In case of damage to the small lenticulostriate vessels (usually secondary to uncontrolled hypertension) there is an intraparenchymal hemorrhage because those vessels have already traversed deeper past the subarachnoid space, whereas with injury to the larger vessels of the circle of Willis there is a subarachnoid hemorrhage as those vessels are ruptured more proximally.

 

[Paramyxovirus]

Thank you so much for the explanation! That makes sense!
To clarify, the lenticulostriate vessels traverse through piamater to supply the brain parenchyma?

 

[PowerDan]

Thank you so much for the explanation! That makes sense!
To clarify, the lenticulostriate vessels traverse through piamater to supply the brain parenchyma?

Yes, the blood vessels pass through the pia to nourish the brain.

 

[Paramyxovirus]

Got it, thanks a lot!!!