Ch. 9 - Subarachnoid hemorrhage Flashcards Preview

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

Most common cause of SAH over age 20 years

A

Berry aneurysm rupture

2
Q

Most common cause of SAH under age 20 years

A

AVM rupture

3
Q

Cause of saccular (berry) vs. fusiform aneurysm

A

Saccular - congenital deficiency in muscle coat at vessel junctions

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

4
Q

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

A

7x increased risk = 2-5% lifetime risk

5
Q

Risk of rebleeding following SAH? Mortality associated with rebleed?

A

50% risk of rebleeding

50% will die from rebleed

6
Q

Timeline of vasospasm after SAH

A

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

7
Q

Surgical procedures available for tx of cerebral aneurysm

A
  • Occlusion of neck of aneurysm
  • Reinforcement of aneurysmal sac
  • Proximal ligation of feeding vessel
8
Q

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

A
  1. Hemorrhage (SAH or intracerebral)
  2. Epilepsy
9
Q

Chance of hemorrhage from ruptured or unruptured AVM

A

3% per year

10
Q

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

A

Subarachnoid hemorrhage

11
Q

What is a ‘sentinel’ HA?

A

Small leak from an aneurysm resulting in minor HA

12
Q

Presenting features of SAH

A

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

13
Q

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

A

Temporal lobe - hemiparesis and aphasia if dominant hemisphere is involved

14
Q

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

A

Frontal lobes - akinetic mutism

15
Q

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

A

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

16
Q

DDx of an apparently isolated CN3 palsy?

A

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

17
Q

Why does a transient communicating hydrocephalus often occur after SAH?

A

Blood blocks the arachnoid villi

18
Q

What are the 2 major classification systems for SAH?

A

Hunt and Hess - based on symptoms

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

19
Q

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

A

CT; if any doubt then lumbar puncture looking for xanthochromia

20
Q

What is the most common location for cerebral aneurysms?

A

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

21
Q

How common are multiple aneurysms?

A

15% of cases have aneurysms at more than one position

22
Q

Why are cerebral arteries more susceptible to weakening/degeneration?

A

Elastic layer of these arteries is limited to internal lamina

23
Q

What hereditary syndromes are associated with cerebral aneurysm?

A

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

24
Q

How common is angiographic vasospasm following SAH?

A

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

25
Q

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

A

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

26
Q

Tx of vasospasm after SAH

A

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

27
Q

Vein of Galen malformation

A

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

28
Q

How often is the cause of SAH unknown?

A

15% of cases

29
Q

Identify the lesion

A

Diffuse SAH in bilateral Sylvian fissures and basal cisterns

30
Q

Identify the lesion

A

Diffuse SAH (including basal cisterns)

31
Q

Identify the lesion

A

Anterior communicating artery aneurysm