Cerebral Aneurysms B&B

Question 1

2 types of cerebral aneurysms - which is more common?

Answer 1

1. saccular/ berry - more common, occur in Circle of Willis
2. Charcot-Bouchard - micro-aneurysms, often occur in branches of lenticulo-striate arteries, cause of hemorrhagic stroke in severe HTN (analogous to lacunar stroke)

Question 2

what conditions/factors are associated with increased risk of berry aneurysms? (7)

Answer 2

1. ADPKD
2. Ehlers-Danlos
3. aortic coarctation
4. older age
5. HTN
6. smoking
7. African Americans

Question 3

what kind of brain bleed occurs from aneurysm rupture? differentiate for berry aneurysm vs micro-aneurysm

Answer 3

berry —> subarachnoid hemorrhage: bleeding into CSF space, neuro symptoms rare (mostly headache)

micro —> hemorrhagic stroke: symptoms based on site of bleeding

Question 4

where exactly do subarachnoid hemorrhages occur?

Answer 4

bleeding into space between arachnoid and pia mater

occur from rupture/aneurysm of cerebral arteries

Question 5

how do subarachnoid hemorrhages present?

Answer 5

SUDDEN ONSET of
1. “worst headache of my life”
2. fever
3. nuchal rigidity
4. xanthochromia (yellow discoloration of CSF) on spinal tap

CT scan usually diagnostic, NO focal deficits

Question 6

Pt presents to the ED complaining of the worst headache of their life that came on very suddenly and feeling very warm. What are you most worried about, and what diagnostic testing can you use? (2)

Answer 6

subarachnoid hemorrhage

1. CT scan usually diagnostic
2. spinal tap will also show xanthochromia (yellow discoloration of CSF)

Question 7

how is subarachnoid hemorrhage treated? (3) what is the risk thereafter?

Answer 7

tx: clipping or endovascular coiling

may also give nimodipine (Ca2+ channel blocker) to prevent vasospasms (unclear mechanism)

risks: re-bleeding is common, vasospasms causing worsening neuro symptoms days later

Question 8

where is the most common and 2nd most common location for berry aneurysms to occur?

Answer 8

1. anterior communicating artery
2. posterior communicating artery

berry aneurysms commonly occur at branch points!

Question 9

with what symptoms will anterior communicating artery berry aneurysms present?

Answer 9

most common site of berry aneurysm

headache + bitemporal hemianopsia (compression of optic chiasm)

Question 10

with what symptoms will posterior communicating artery berry aneurysms present? (3)

Answer 10

2nd most common site of berry aneurysms

unilateral headache + eye pain + CN III palsy (eye down/out, ptosis, dilation)

[if pupil is spared, cause is NOT an aneurysm!]

Question 11

what is the “rule of the pupil” regarding CN III with/without pupil sparing?

Answer 11

if CN III palsy + dilated pupil —> posterior communicating artery aneurysm, because pupillary constrictors are easily compressed in subarachnoid space

if pupil is normal (spared) —> CN III palsy is caused by ischemic neuropathy (often due to diabetes mellitus), sometimes painful, spontaneously resolves

Question 12

where do Charcot-Bouchard aneurysms occur?

Answer 12

micro-aneurysms occurring in small branches of lenticulo-striate arteries, which are derived from middle cerebral artery

causing bleeding into the basal ganglia and thalamus

rupture is believed to be origin of “hypertensive intra-cerebral hemorrhage (ICH)”