SAH Flashcards
Subarachnoid hemorrhage’s (SAH) are caused by
A ruptured aneurysm
Where does the blood go in a SAH?
Same place as CSF flows…subarachnoid space
Blood is in between brain tissue not in the brain tissue.
What can happen with a SAH
Increased CFS pressure
Hematoma expansion
Vasospasm
Statistics for hematoma expansion after a SAH
26% will have hematoma enlargement within 1 hr.
72% have some hematoma expansion over the first 24 hrs
What can happen in days to weeks following a SAH?
Cerebral vasospasm
What are aneurysms?
Weakened bulging section of a cerebral artery
What is a saccular aneurysm
Looks like a sack or berry with a narrow neck and a widened dome
What are the most common types of aneurysms?
Saccular
Where do saccular aneurysms commonly form?
At the junction of vessels, particularly at the junction points in the circle of Willis.
How would you describe a fusiform aneurysm?
A cylindrical, longer length outpouching of the vessel.
Where do fusiform aneurysms form?
Generally located in the vertbrobasilar vascular system
What happened at the moment of aneurysm rupture?
Mechanical injury occurs from blood rushing into the subarachnoid space and sudden increase in ICP which results in a mass effect at the clinical signs of SAH.
Early brain injury after a ruptured brain aneurysm is caused by
Localized and generalized edema.
An increase of Excitatory neurotransmitter levels.
Severe reduction in cerebral blood flow in the microcirculation of the brain.
Cortical spreading depression.
Spreading ischemia.
Microvasoconstriction
Cerebral vasospasm is also known as
Delayed cerebral injury
When is cerebral vasospasm likely to occur?
Large vessel vasospasm generally begins on day 4 after the hemorrhage and May continue as long as 21 days.
What is the most common cause of spontaneous SAH not caused by trauma?
80% are due to intracranial saccular aneurysms
What percentage of strokes and deaths are attributed to SAH?
3% of strokes and 5% of deaths
What is the incidence of SAH?
Higher in females Poly cystic kidney disease Marfans syndrome Ehlers-Danlos syndromes Coartication of the aorta Fibromuscular dysplasia
Locations of SAH
30% ACA 25% PCA 20% MCA 10% basilar 5% vertebral 25% multiple
Symptoms of SAH
Worst HA of my life
Thunder-clap headache
HA associated with focal neurologic symptoms
If the CT is negative and there is a high suspicion of SAH, what procedure must you do and why?
Lumbar puncture
CT can miss small or subtle SAH
What is the the gold standard test to diagnose Intracranial aneurysms
Digital subtraction angiography.
When is rebleeding likely to occur with SAH and what percentage
24 hrs 4% will rebleed with high mortality
What is the MAP goal to prevent rebleeding?
70-100 mm Hg
What is the best way to prevent re-bleeding with an aneurysm
Craniotomy and Clipping
What are some common complications to SAH?
Hydrocephalus
Sz
Cerebral vasospasm
Delayed ischemic deficits
What percent of pts with SAH have hydrocephalus?
20%
What are the clinical and diagnostic signs of hydrocephalus
Decreased LOC
HTN
Bradycardia
CT shows enlargement of ventricles
What is the percentage of SAH pts that experience cerebral vasospasm, when does it occur, and what percentage of pts have resulting ischemic strokes?
30%
3-5 days, maximum 5-10 days
15-20% have resulting ischemic strokes
Which calcium channel blocker is used to prevent cerebral vasospasm in SAH?
Nimodipine 60 mg PO every 4 hrs X 3 weeks
What tests are used to evaluate for cerebral vasospasm?
TCD
CTA
Angiography
Clinical signs and symptoms
What is HHH for treatment of cerebral vasospasm in SAH
HTN
Hypervolemia
Hemodilution
What is the mortality associated with SAH?
3% die before reaching hospital
1/3 died in the first month
What is the breakdown of mechanism of death related to SAH
1/4 are due to initial bleed
1/4 are due to vasospasm
1/4 are due to re-bleeding
For an u secured/unsecured aneurysm in SAH THE BP should be
> 160/<160
