26 terms

Neurovascular

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define the following aspects of aneurysms
1. epidemiology
2. types
3. source
4. risk factors
5. location
1. prevalence up to 5% in the general population
incidence increases w/age
F > M
15-30% have multiple aneurysms
yearly risk of SAH ~1-2%/yr in incidentally discovered aneurysm

2. saccular, fusiform, dissecting

3. embolic (infectious), traumatic, inflammatory, neoplastic, radiation-induced, congenital predisposition, atherosclerotic, flow related (AVM) or HTN
- saccular aneurysms are acquired lesions from degeneration of the internal elastic lamina, defects in the muscularis media

4. bacterial endocarditis (streptococcal), coarctation of the aorta, osler-weber-rendu, fibromuscular dysplasia, ADPKD, AVM, Ehlers-Danlos, pseudoxanthoma elasticum, familial intracranial aneurysm syndrome

5. branch points of major cerebral a's likely for saccular aneurysm. saccular 85-95% ant circulation, ACoA, 5-15% posterior circulation
- distal aneurysms more likely from traumatic or mycotic source
- mycotic aneurysms commonly in MCA distribution
- traumatic aneurysms occur on the distal ACA d/t shearing injury against the falx
- fusiform aneurysms are more likely in the vertebrobasilar system
location may determine symptoms

ie posterior communicating aneurysm -> 3rd nerve palsy
what are symptoms of SAH
"worst headache of my life"
HA, N/V, meningismus, photophobia, confusion, LoC, coma
may have a "sentinel bleed" resulting in HA, dizziness, up to a week before major SAH
what are the potential localizing signs in intracerebral hemorrhage of an aneurysm at:
1. Acom
1. BLE weakness, numbness
what are the potential localizing signs in intracerebral hemorrhage of an aneurysm at:
1. MCA bifurcation
1. contralateral weakness, aphasia (left), or hemi-neglect (right)
what are the potential localizing signs in intracerebral hemorrhage of an aneurysm at:
1. Basilar tip
1. vertical ophthalmoplegia
what are the potential localizing signs in intracerebral hemorrhage of an aneurysm at:
1. Vertebral-PICA junction
1. Wallenberg's, vertigo, Horner's, sensory deficits
what are the potential localizing signs in intracerebral hemorrhage of an aneurysm at:
1. ICA-Pcom junction
1. ipsilateral CN III palsy (pupil involving)
describe the Fisher Grading system
correlates the location & thickness of Subarachnoid blood on CT w/clinical outcome and likelihood of developing vasospasm.
1 - none
2 - diffuse, thin layer < 1mm
3 - localized clot or thick layer > 1mm
4 - thin or no SAH along w/ICH or IVH
describe the Hunt-Hess SAH grading system
1 - asymptomatic or mild HA & slight nuchal rigidity
2 - moderate to severe HA, nuchal rigidity, or CN palsy (II, VI)
3 - lethargy, confusion or mild focal deficit
4 - stupor, mod to severe hemiparesis or early decerebrate rigidity
5 - coma, decerebrate rigidity, moribund appearance
what is the treatment for SAH & outcomes
medical management (BP control, stool softeners, Ca channel blockers & bed rest), surgical clipping of the aneurysm vs endovascular coils placed to thrombose the aneurysmal sac
coiling is helpful if the lesion is surgically inaccessible or if the pt is elderly > 75 w/decreased morbidity w/coiling or w/multiple co-morbidities; good neck-dome ratio

- risk of repeat hemorrhage after aneurysmal SAH highest in first 2 weeks
- 50% of untreated, ruptured aneurysms hemorrhage w/in first 6 months, then drops to 3%/year
- mortality much higher in repeat SAH than 1st hemorrhage
describe the following for cerebral vasospasm
1. incidence
2. symptoms
3. DDx
4. Diagnostic studies
5. Rx
6. Prognosis
generally occurs following SAH from ruptured aneurysm (very rare in trauma)
- may be clinical (symptomatic neurologic deficit) or radiographic

1. (following SAH) clinical up to 30%, radiographic up to 70%
- onset between days 4-14 post-SAH, most frequently during days 6-8
risk of clinical vasospasm increases w/Hunt-Hess grade from 1 - 5

2. depend on distribution of vasospasm (ie ACA has frontal lobe findings, leg weakness)

3. infection, hydrocephalus, seizure, cerebral edema, rehemorrhage, e- disturbance, hypoxia

4. r/o other causes of neurologic deterioration (head CT to r/o hydrocephalus, CSF studies to r/o infection, EEG to r/o seizure)
- transcranial dopplers may have increased mean middle cerebral artery MCA velocity w/an increased MCA:ICA (Lindegaard) ratio; levels > 120cm/s (ratio > 3) or daily increases of > 50 suggest vasospasm; Lindegaard ratio distinguishes vasospasm from hyperemia
- angiogram for diagnosis & rx

5. Ca channel blocker, hyperdynamic aka "triple H" therapy of Hemodilution, HTN, Hypervolemia; for secured aneurysm, balloon angioplasty, intra-arterial injection of antispasmodics, intravascular stent

6. most signif cause of morbidity (7%) & mortality (7%) from ischemic infarct in pts who survive initial SAH
describe the modified Fisher grading scheme for risk of vasospasm after SAH
1 - thin SAH on CT (10%)
2 - b/l intraventricular hemorrhage (20%)
3 - thick cisternal clot (20%)
4 - b/l IVH + cisternal clot (40%)
describe AVM in terms of:
1. pathology
2. epidemiology
3. radiology
4. treatment
5. outcome
1. congenital dilated communication between the arterial system & venous system w/o capillaries
- AVMs are mid-high pressure systems w/high flow rates
- progressive neuro deficit may result from "steal" phenomenon where blood flow is diverted to AVM from normal brain parenchyma

2. average age of dx is 33
-risk of bleeding 2-4%/yr
-usual presentation is hemorrhage
-increased risk of hemorrhage in pregnancy

3. can be diagnosed via CT, MRI or angiography
-10% ass'd w/flow dependent, intranidal aneurysm

4. endovascular embolization followed by surgical excision
- stereotactic radiosurgery (indicated for deep lesions < 2.5cm; requires 1-3yrs for ablation during which hemorrhage rate is 2-3%/yr)
- general rule: Grade 1-3 AVMs can be operated on with an acceptable risk of complications (compared to the natural history of untreated AVM)
- pt's w/a score of > 3 have a high risk of complication & many surgeons recommend nonsurgical management
- postop complication of normal perfusion pressure breakthrough necessitates tight BP control (usually MAP 60-80 overnight) to avoid hemorrhage & edema

5. 10% mortality & 30-50% morbidity w/each hemorrhage
Describe the Spetzler-Martin AVM Grading System:
1. Size
2. Eloquence of nearby brain tissue
3. Venous drainage pattern
1. small < 3cm - 1
medium 3-6cm - 2
large > 6cm - 3

2. noneloquent - 0
eloquent - 1

3. superficial only - 0
deep - 1

Grade = size, eloquence, & drainage score totals

Grade 1 = 100% no deficit
Grade 2 = 95% no deficit, 5% minor
Grade 3 = 84% no , 12% minor, 4% major
Grade 4 = 73% no deficit, 20% minor, 7% major
Grade 5 = 69% no deficit, 19% minor, 12% major

Patients w/a score of > 3 have high risk of complications & most surgeons recommend nonsurgical management

Postop complication of normal perfusion pressure breathrough necessitates tight BP control (MAPs 60-80) to avoid hemorrhage & edema
Describe Dural AV Fistula in terms of:
1. pathology
2. epidemiology
3. location
4. treatment
5. outcome
1. anomalous connection between the pial/dural arteries & dural venous sinus

2. 10-15% of all AVMs
- 2/3 females 40-50Yo
- may result from trauma
- commonly present with tinnitus
- increased risk of hemorrhage with retrograde cortical venous drainage

3. most commonly seen at the lateral (transverse) sinus (L > R) at the junction of the lateral sinus with the sigmoid sinus

4. embolization (transarterial or transvenous), surgery or stereotactic radiosurgery
- indicated if neurological dysfunction, hemorrhage, or refractory symptoms or if retrograde cortical venous drainage discovered

5. Hemorrhage - morbidity/mortality of 30%
Describe a Carotid cavernous fistula
may lead to increased intraorbital pressure (from optic congestion) & resulting blindness
- transvenous embolization treatment via inferior petrosal sinus can be curative

10-15% of all AVMs
- 2/3 in females age 40-50 Yo
- may result from trauma
- common signs/symptoms present w/tinnitus, bruit, headache, visual impairment, papilledema
- increased risk of hemorrhage with retrograde cortical venous drainage
Describe Venous Malformations (developmental venous anomalies) in terms of:
1. epidemiology
2. presentation
3. pathophysiology
4. location
5. treatment
6. radiology
7. outcome
1. up to 2% of the population
-may be associated with cavernous malformation (30%), sinus pericranii, cortical dysplasias
-multiple in blue rubber bleb nevous syndrome
- rarely if ever bleed (usually d/t ass'd AVM or cavernous hemangioma)

2. incidental
- rarely result in seizures or hemorrhages

3. benign, developmental venous drainage of normal brain (deep white matter)
- dilated anomalous veins or dilation of normal veins, which drain to transcortical vein
low flow, low pressure systems

4. anywhere
-supratentorial hemispheric white matter more common?

5. rarely required

6. seen as a starburt or caput medusae patterns on aniography

7. generally do no cause symptoms or require treatment
- thrombosis may lead to a venous infarct b/c these anomalous veins drain normal brain tissue
Describe cerebral venous sinus thrombosis
1. etiology
2. signs/symptoms
3. diagnosis
4. treatment
1. dehydration (esp in infants from N/V), DM (DKA), local infection (mastoiditis), pregnancy & puerperium (greatest risk <2weeks postpartum), OCP, homocystinuria, Behcets syndrome, cardiac dz, UC, sickle cell, CHI, iatrogenic (radical neck surgery, transvenous pacer, postcraniotomy), periarteritis nodosa, malignancy, hypercoagulable state

2. HA, N/V, seizures, hemiparesis, CN dysfunction, papilledema, blurred vision, AMS

3. CT 'delta' sign - looking at sagittal sinus, MRI w/MRV, angiography

4. aggressive heparine anticoagulation to recover ischemic tissue, +/- thrombolytics, correct underlying disorder, avoid steroids, BP control, monitor ICP (lower ICP increases coagulability), intravascular stenting
Describe Vertebral Artery dissection
1. presentation
2. etiology
3. treatment
1. acute onset of neurological deficit
- occipital neck pain, severe HA, AMS, SAH, TIA/stroke (usually lateral medullary syndrome), cerebellar infarction, neck hematoma, embolic stroke

2. Spontaneous
due to oral contraceptives, fibromuscular dysplasia, marfan's syndrome, moyamoya, cystic medial necrosis, ehlers-danlos, takayasu's dz, migraine
-commonly in young males
-commonly on the dominant vertebral
-36% w/other dissections present, 21% b/l

Traumatic
2/2 minor neck/posterior head trauma (chiropractor, MVA, sudden head turning or sports)
-C1-2 subluxation
-may lead to pseudoaneurysm development

3. anticoagulation or antiplatelet therapy for 6 mo
- if SAH, symptoms despite medical therapy, progressing dissections or intradural dissection, surgery or interventional treatment (angioplasty &/or stent) may be indicated
Describe Internal Carotid artery stenosis
1. pathophysiology
2. presentation
3. radiology
4. treatment
1. atherosclerosis of the common carotid artery

2. TIA or acute neurological deficit
- amaurosis fugax, blindness, MCA symptoms (ie contralateral arm/face motor/sensory deficits w/hyperreflexia) &language deficits

3. duplex US (not above mandible)
CT angio
angiography
MRA (can overestimate degree of stenosis

4. antiplatelet therapy, BP, & lipid control
- intraarterial stenting
- carotid endarterectomy is helpful for stenosis 60-80% depending upon surgical risk & symptoms
- complications of CEA include stroke, hemorrhage, vocal cord paralysis, hypoglossal n injury, mandibular n injury, bleeding, infection, seizures & recurrent stenosis
Describe Cavernous Hemangioma (aka Cavernous malformation, Cavernoma)
1. epidemiology
2. presentation
3. location
4. radiology
5. pathology
6. Treatment
7. Outcome
low flow, low pressure vascular malformation
1. majority are sporadic
- familial inheritance, autosomal dominant (AD) often in latinos on ch 7

2. seizures (60%), progressive neurological deficit (50%), & hemorrhage (20%) or hydrocephalus
- asymptomatic

3. most supratentorial, 10-23% in posterior fossa around the pons

4. not easily seen on angiography but can be seen on MRI
(flow void/previous hemorrhage) & CT (calcification or lucency)
-GRE is most sensitive for hemorrhage
-many have multiple lesions
-well circumscribed
-may have ass'd AVM or venous malformation
-enhances w/contrast
-T2 may have a dark rim from hemosiderin deposition

5. irregular vasulature w/no intervening brain
- popcorn or mulberry appearance

6. controversial
observation, surgery for symptomatic/assessable lesions & radiosurgery might be helpful to reduce risk of rebleeding w/inaccessible malformations
-brainstem cavernous malformations should only be surgically resected if they have recurrent hemorrhage, reach a pial surface & are symptomatic

7. .25-.75%/yr untreated hemorrhage
-hemorrhagic infratentorial lesions have increased risk of
Moyamoya disease
1. epidemiology
2. signs/symptoms
3. pathophys
4. radiology
5. Rx
1. higher incidence in Japan > US
0.9/100,000

2. seizures, hemorrhage, TIAs, stroke, progressive neuro deficit, cognitive decline

3. progressive occlusion of one or both supraclinoid ICAs, M1, A1 (rarely P1) resulting in "puff of smoke" appearance of dilated capillary lenticulostriate collateral vessels
- ass'd w/intracranial aneurysms

4. angiography or flow voids seen on MRA

5. urgent decompression can be used if a patient presents w/mass effect from hemorrhage
- revascularization for those presenting w/signs of ischemia, previous hemorrhage, or progressive neuro deficits can be performed on a nonemergent basis
- no medical or surgical rx to date reduces rate of hemorrhage in moyamoya dz
-nevertheless, treating the pt for moyamoya decreases 5yr rate of stroke or death from 65% -> 5.5%
-antiplatelet therapy, ASA
Amyloid Angiopathy
1. epidemiology
2. location
3. radiology
4. pathology
5. Rx
6. Outcome
1. presents as lobar intraparenchymal hemorrhage (15% of ICH) in normotension, dementia
- elderly

2. frontoparietal, corticomedullary junction

3. GRE may reveal a higher # of hemosiderin depositions or "microbleeds"

4. deposition of beta amyloid in the media & adventitia of small & mid-sized arteries

primary vs secondary (DM, beta microglobulinemia)

5. surgical evacuation in intermediate-sized hematomas (20-60cc) w/progressive deterioration in LoC

6. hemorrhage recurrence rate of 38%, mortality 44%
Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu disease)
1. genetics
2. si/sx
arteriovenous malformation of liver, lungs, brain & spine
1. AD
-mutation in TGF-beta receptor gene
2. in addition to AVMs, pt's develop telangiectasias of skin, mucosa -> epistaxis
- nail bed telangiectasias, pulmonary shunt (high risk of brain abscess), cerebral aneurysms
Wyburn-Mason syndrome (aka Bonnet-Dechaume-Blanc)
1. si/sx
multiple intracranial AVMs along the visual pathways (including optic tracts, midbrain, retina) & facial cutaneous vascular nevi
1. optic nerve atrophy, seizures, strokes & SAH
Blue rubber bleb nevus syndrome
1. si/sx
vascular malformations of skin, GI tract, CNS (hemangiomas, venous angiomas, sinus pericranii)
1. anemia from GI bleeds, nevi on arms/trunk/palms, fractures (from bone hemangiomas)