Ch. 9 - Subarachnoid hemorrhage Flashcards Preview

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Flashcards in Ch. 9 - Subarachnoid hemorrhage Deck (31)
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1

Most common cause of SAH over age 20 years

Berry aneurysm rupture

2

Most common cause of SAH under age 20 years

AVM rupture

3

Cause of saccular (berry) vs. fusiform aneurysm

Saccular - congenital deficiency in muscle coat at vessel junctions

Fusiform - diffuse atheromatous degeneration of arterial wall often a/w HTN

4

Risk of hemorrhage in patients who have first-degree relatives with aneurysmal SAH

7x increased risk = 2-5% lifetime risk

5

Risk of rebleeding following SAH? Mortality associated with rebleed?

50% risk of rebleeding

50% will die from rebleed

6

Timeline of vasospasm after SAH

Typically occurs within 2-3 days, rarely after 14 days

7

Surgical procedures available for tx of cerebral aneurysm

- Occlusion of neck of aneurysm

- Reinforcement of aneurysmal sac

- Proximal ligation of feeding vessel

8

What is the most frequent sign of an AVM? Second most common sign?

1. Hemorrhage (SAH or intracerebral)

2. Epilepsy

9

Chance of hemorrhage from ruptured or unruptured AVM

3% per year

10

Sudden onset of severe HA should be regarded as what, until proven otherwise?

Subarachnoid hemorrhage

11

What is a 'sentinel' HA?

Small leak from an aneurysm resulting in minor HA

12

Presenting features of SAH

HA, diminished conscious state, meningism (neck stiffness, vomiting, photophobia, fever), focal neurologic signs, fundal changes (e.g. retinal hemorrhage)

13

What lobe does a middle cerebral artery aneurysm frequently rupture into? What symptoms would you expect?

Temporal lobe - hemiparesis and aphasia if dominant hemisphere is involved

14

What lobe does an anterior communicating artery aneurysm frequently rupture into? What symptoms would you expect?

Frontal lobes - akinetic mutism

15

What neurological signs would you expect from a posterior communicating artery aneurysm?

Pressure on CN3 causing ptosis, mydriasis, and extraocular muscle palsy

16

DDx of an apparently isolated CN3 palsy?

Posterior communicating artery aneurysm OR ischemic lesion from DM or atherosclerosis - if there is ANY doubt then obtain angiography

17

Why does a transient communicating hydrocephalus often occur after SAH?

Blood blocks the arachnoid villi

18

What are the 2 major classification systems for SAH?

Hunt and Hess - based on symptoms

WFNS (World Federation of Neurological Surgeons) - based on GCS score and motor deficits

19

Best initial investigation in suspected SAH? If there is any doubt, what do you obtain next?

CT; if any doubt then lumbar puncture looking for xanthochromia

20

What is the most common location for cerebral aneurysms?

Equal frequency at internal carotid (posterior communicating), anterior communicating, and middle cerebral arteries

21

How common are multiple aneurysms?

15% of cases have aneurysms at more than one position

22

Why are cerebral arteries more susceptible to weakening/degeneration?

Elastic layer of these arteries is limited to internal lamina

23

What hereditary syndromes are associated with cerebral aneurysm?

Marfans, Ehlers-Danlos syndrome, coarctation of aorta, polycystic kidney disease

24

How common is angiographic vasospasm following SAH?

50% of cases but only 25% result in serious neurological complications

25

Blood in the basal cisterns after SAH is correlated with what?

Risk of developing vasospasms; amount of blood is DIRECTLY correlated with risk and severity

26

Tx of vasospasm after SAH

No good tx; if aneurysm was surgically occluded then hypertensive therapy + hypervolemia; can consider CCB (e.g. nifedipine)

27

Vein of Galen malformation

Arteries feed directly into vein of Galen (drains into sinuses of posterior cerebral fossa); most frequent AVM in infants

28

How often is the cause of SAH unknown?

15% of cases

29

Identify the lesion

Diffuse SAH in bilateral Sylvian fissures and basal cisterns

30

Identify the lesion

Diffuse SAH (including basal cisterns)