Aneurysms Flashcards
Where is the most common intracranial aneurysm?
ACOMM
What is the overall incidence of intracranial aneurysms? What is the risk of bleeding?
2-8%
1-2%
What is the most common cause of spontaneous SAH?
Ruptured aneurysm
What are the causes of convexity SAH in adults or kids?
Adults: amyloid, venous thrombosis
Younger: PRES, vasculitis
RARELY aneurysm
What is the critical size for aneurysm rupture?
5-7mm
Where does the blood occur in ruptured ACOMM?
Gyri recti, anterior interhemispheric fissue, septum pellucidum, frontal horns lateral ventricles
What is the association with ACOMM aneurysm?
Azygous or fenestrated ACA
What is the symptoms of PCOMM aneurysm?
Ipsilateral CN III palsy +/- SAH
What is the 30 day mortality of intracranial aneurysm?
50%
What is the major cause of intracranial aneurysms?
Hemodynamic stress
Where is the blood in MCA bifurcation aneurysm?
Sylvian fissue, frontal opercula, basilar cisterns
When is the greatest risk of rebleed in aneurysm rupture?
20-50% in first 2 weeks
What are the diseases assocaited with intracranial aneurysm rupture?
FMD, ADPKD, connective tissue disorder, aortic coarctation, AVM, hypervascular tumors
What is the size limit on MRA vs CTA
MRA detects 3mm
CTA 1mm
Where is the bleed in basilar tip rupture?
basilar cisterns, posterior third ventricle
Which area has increased risk of giant aneurysms?
Basilar tip
What is the percentage of intracranial aneurysms with aortic aneurysms?
10% have an associated aortci aneurysm
Where are infratentorial aneurysms most common? Where do they bleed?
PICA (origin, choroidal) > AICA/SCA
posterior fossa and 4th ventricle
What percentage of intracranial aneurysms are multiple? Who gets multiple?
What are the associated conditions?
Which aneurysm bleeds?
10-15%
Female, family history
AVM, tumors, infections, collagen vasular disorders, SCD, moyamoya, AIDS
LArgest, irregular, lobulated, surrounded most by SAH, adjacent vasospasm
What is a giant aneurysm? What are the types?
> 2.5cm
Thin wall - small ones that grew
Thick wall - bleeding into walls
Fusiform - postviral, collagen vascular
Serpentine - recanalized thrombosed aneurysm
Where are the common sites of giant aneurysms?
ICA bifurcation, intracavernous ICA, MCA bifurcation, basilar artery tip
What is the difference in rupture of thin vs thick walled aneurysms?
Thin will bleed into SAH
Thick will be intramural hematoma
What is a pseudoaneurysm?
Posttraumatic secondary to tear in parent artery wall
Irregular shape
Where are the common sites of pseudoaneurysm?
ICA bifurcation, ICA entrance into base of skull, cavernous sinus, supraclinoid segment
Vertebral artery as it enters foramen transversarium, C1 and C2, as it pierces dura and enters foramen magnum
Which type of SAH is more likely to have vasospasm?
Nontraumatic
What is the timeline for vasospasm after SAH?
Begins 3-5 days
Peaks 7-10 days
Lasts up to 3 weeks
What is the treatment of SAH vasospasm?
Hypertension, Hyperhydration, Hypervolemia (Triple H)
What velocity suggests vasospasm after SAH?
MCA velocity >120cm/s
