Cerebrovascular Dz Lecture Flashcards
Sudden or rapid onset of a neurologic deficit in the distribution of a vascular territory lasting over 24 hours
Stroke
The sudden onset of a neurologic deficit in the distribution of a vascular territory lasting less than 24 hours
**most last less than 30 mins
TIA
REVERSIBLE ischemic insult to brain cells that recover, but increases risk of subsequent stroke
TIA
**increase in frequency of TIAs is a bad sign!!!
worsening signs or symptoms over time ..describes what type of stroke?
Stroke-in-evolution (progressive stroke)
What percentage of strokes are ischemia/infarct?
What percentage are hemorrhagic?
Ischemic/infarct: 85%
Hemorrhagic: 15%
3rd leading cause of death in US
over 200,000 deaths per year
Men 1.3x more common
Blacks 1.3x more common
Strokes
MC cause of death in patients with cebrovascular disease
MI
Most powerful risk factor for developing a stroke?
HTN!
..esp systolic BP
What is the goal BP to keep under for preventing strokes?
under 140/90
Smoking increases risk of by 2-4x
Stroke
Diabetes Mellitus increases risk by 3x
Stroke
HTN
Smoking
Atherosclerosis
Diabetes Mellitus
Atrial fibrillation
others: male gender, OCPs, excess ETOH, hyperlipidemia
Risk factors for stroke
Atherosclerosis: large vessels often involved *involved in ____% of all ischemic strokes (infarct)
50%
- Adequacy of collateral circulation
- Development of Circle of Willis
- Duration of insult/restoration of blood flow.
Pathological outcomes depend on these
SMALL vessel disease- deep penetrating arterioles occlude/thrombose
Lacunar infarcts (aka lipohyalinosis)
Small vessel disease (Lacunar infarcts) account for ___% of ischemic strokes
20%
Major risk factor of Lacunar infarcts (small vessel disease)
HTN!
..lipids and DM also contribute
The defect on CT or MRI of a very small stroke or TIA (lacunar infarct) is less than…
1.5 cm (most are under 5 mm)
May be without symptoms..detected by CT scan as incidental finding
Lacunar (aka lopohyalinosis), or small vessel disease
Atherosclerosis of: base of aorta carotid bifurcation origin of internal carotid external carotid vertebral/basilar arteries
increase risk of ischemic stroke!!!
Embolism from heart or artery to brain
*blood clot breaks off, occludes more distant/distal vessel
Cerebral emboli
Why is a well developed Circle of Willis important?
This can be protective against stroke!
Cardiac emboli often lodge in _____ sized vessels (MCA, ACA)
MEDIUM
Artery to artery emboli often cause _____ or ___________
TIAs or small neuro deficits
*lodge, then break up
Frequent source:
Carotid bifurcation or internal carotid
*often small emboli: Platelets/fibrin/RBCs
Artery to artery emboli
~20% of ischemic strokes
*OFTEN CAUSED BY A FIB
Cardioembolism
MI with mural thrombus (35% incidence post large anterior wall MI) can lead to….
Cardioembolism
A fib***
MI with mural thrombus
Dilated cardiomyopathy
VHD
can all cause…
Cardioembolism
ABRUPT onset of non-convulsive focal defect in a vascular territory
Stroke
80-90% have NO warning symptoms
(10-20% have warning, TIA)
Stroke
- Contralateral hemiparesis or hemisensory loss
- Hemianopsia (visual field defect)
- If dominant hemisphere..Aphasia
- If non dominant..speech and comprehension preserved. may develop anosognosia (denial/neglect of deficit) or a confusional state
MIDDLE CEREBRAL ARTERY (MCA) involvement
Less common..
*Sx more pronounced in leg, associated language, gait disturbance
ANTERIOR CEREBRAL ARTERY (ACA) involvement
Least common..
Crossed contralateral dysfunction (motor/sensory) plus ipsilateral bulbar/cerebellar signs: vertigo, dizziness, gait disturbance, diplopia, facial palsy, dysarthria, etc
Posterior circulation (ie Vertebral artery off subclavian) involvement
HTN Deep penetrating arterioles
Small infarcts up to 1.5 cm on CT/MRI
*clinical syndrome depending on where infarct is; may also present as TIA
Lacunar strokes/infarcts
Transient monocular blindness
Embolism to ophthalmic artery (off carotid)
Amaurosis fugax (carotid disease present)
Image of choice for stroke within the first 48 hours?
CT scan!
(CTs are better than MRIs the first 48 hours after intracranial hemorrhage)
Detection of infarcts on CT limited to _____ and ______
SIZE and TIMING
only 5% of strokes are visible in 1st 12 hours, but more than ____% are visible at one week
90%
More readily available
Less expensive
No contrast required
Benefits of CT (over MRI)
Changes of infarct may be seen as early as one hour- usually not available or needed emergently
MRI/MRA
True or False…
MRI/MRA provide better detail than CT for small lesions and other pathology.
*Better for imaging of POSTERIOR FOSSA
TRUE
Non invasive with excellent resolution of large vessels
*Replaces need for arteriogram in some patients
*May be difficult to differentiate complete vs near complete occlusions.
Magnetic resource angiogram (MRA)
3 to 4.5 hours is the window for…
giving tPA!!
DO NOT CORRECT ISCHEMIC STROKE PATIENT’S HYPERTENSION UNTIL IT REACHES…
over 200 systolic over 100 diastolic
*body regulates itself! so don’t mess with it
When do you start to correct an ischemic stroke patient’s HTN?
2 weeks after they come to the ER
What type of stroke patient is it OK to lower BP in?
(but must do cautiously)
Hemorrhagic stroke
Screening tool for evaluating COMMON CAROTID and ORIGIN OF INTERNAL CAROTID ARTERY
limitations: may be difficult to differentiate between complete vs near complete occlusions
Carotid doppler ultrasound (duplex)
**non invasive but limited capability
MOST ACCURATE
**GOLD STANDARD** for extra and intracranial disease
Arteriography
*also most invasive!
Gold standard for strokes!! most accurate (but invasive)
Complications: contrast reaction, kidney failure, plaque rupture, stroke
(*non ionic contrast has reduced complications)
Arteriography
Risk factor modification:
Aggressive control of… BP, Lipids, Diabetes
*smoking cessation, exercise, diet
Prevention of Stroke
Full anticoagulation for A fib pts!
*Warfarin (Coumadin) therapy long term
..this is essential for?
Prevention of strokes
Abrubt onset of symptoms with transient focal neuro deficit dependent on involved anatomy (anterior, posterior circulation).
*Sx may vary during episodes.
*Exam between episodes is normal.
*Warning for subsequent stroke.
TIAs
- *-Embolic from carotid stenosis/plaque*****
- Embolic from cardiac source
- Severe carotid stenosis with transient hypotension
- Small vessel occlusion: Lacunar infarcts may mimic
TIA causes!
How can you possibly predict/pick up an emboli from carotid stenosis/plaque?
By listening for bruits in carotid arteries!
Surgical tx of a carotid TIA which removes plaque
Carotid endarterectomy
Best results if SYMPTOMATIC blockage and greater than 70% stenosis
*significantly reduces risk of subsequent ipsilateral stroke
Carotid endarterectomy
Can be done in select* pts with symptoms and 50-70% stenosis
Carotid endarterectomy
(this has MAJOR complications)
These drugs are indicated for all patients with:
less than 70% stenosis and TIA symptoms
diffuse cerebrovascular dz
pts who are poor surgical candidates
patients with asymptomatic carotid disease
Anti-platelet agents
These agents prevent platelet aggregation and release of vasoactive substances like thromboxane A2
Anti platelet agents
Inhibits cyclooxygenase Inhibits synthesis of thromboxane A2,
increasing both platelet aggregation and vasoconstriction
Aspirin
lasts permanently for life of platelet (about 8 days)
*325 mg/daily
Aspirin
(SE= GI side effects and bleeding)
Decreases frequency of TIA’s and risk of subsequent stroke
Also applies to patient with prior stroke- ↓incidence of recurrence.
Aspirin
75mg/day
Inhibits platelet aggregation and prevents activation of glycoprotein IIb/IIIa (a fibrinogen binder)
*Decreases atherosclerotic events
Clopidogrel (Plavix)
Slightly better outcomes compared to ASA alone but expensive!
*alternative to ASA in patients with recurrent TIA’s or ASA intolerance/allergy.
Clopidogrel (Plavix)
(SE= diarrhea, rash)
Usually good prognosis for recovery over ~4-6 weeks
Tx= supportive measures plus ASA or Clopidogrel.
*AGGRESSIVE LONG TERM TX OF BP AND LIPIDS!!*****
Lacunar infarct tx
What is essential to control long term in pts with lacunar infarct?
BP and Lipids!
True or false…
You should hospitalize ALL stroke patients and most TIA patients (esp if first TIA episode)
TRUE
Cerebral infarct= thrombotic or embolic occlusion of major vessel.
Treatment dependent on timing!
What image must you obtain first to rule out hemorrhage?
head CT scan!
If onset of cerebral infarct (NO HEMORRHAGE) is within 4.5 hours, what can you give?
thrombolytic therapy with tPA (bolus infusion up to 90 mgs) over 1 hour
If within 4.5 hours, can give bolus infusion up to 90 mgs over 1 hour
tPA (thrombolytic therapy)
Thrombolytic therapy increases the chances of a favorable outcome by about …..
50%
True or false..
Thrombolytics cause neurologic outcome improved at 3 mos and 1 yr with decrease in expected deficit and reduction of initial deficit.
True
Cerebral hemorrhage in 6 to 7% (half will die)
. ..risk of?
tPA
Recent bleeding
Prior stroke
BP over 185/110
Recent major stroke
Contraindications of tPA
Loose mesh stent placed in thrombus obstructing cerebral vessel
*removes thrombus and restores blood flow.
Solitaire device
What did the SWIFT-PRIME trial show?
that tPA plus Solitare device works better than tPA alone!
3 months later.. tPA alone, 35% functioning
tPA+solitare, 60% functioning
Which study showed…
tPA alone, 3 months later 35% of pts function independently
tPA plus Solitare, 3 months later 60% of pts function independently
SWIFT-PRIME
True or False..
Heparin preparations are used for immediate and short term anticoagulation (days)
TRUE
Is Warfarin used for short or long term oral anticoagulation?
LONG! (works by inhibiting production of clotting factors in liver)
Best diagnostic for detecting or ruling out a hemorrhage?
CT scan!!
If CT scan is negative, what can you do to rule out a subarachnoid hemorrhage?
Spinal tap
Major risk factor of intracerebral hemorrhage?
HTN
HTN
Heme and bleeding disorders
Trauma
Anticoagulant therapy
Liver dz
..all risk factors of?
Intracerebral hemorrhage
Rapid evolution of neuro deficit often progressing to hemiparesis, hemiplegia or hemisensory loss; 50% mortality *Loss of or impaired consciousness develops in 50%. *Vomiting and headache are common.
Intracerebral hemorrhage
Most due to bleeding from saccular aneurysms
*highest risk if greater than 6 mm
Subarachnoid bleed
Sudden onset of severe headache followed by:
N/V
impaired or loss of consciousness
+/- neuro deficit.
*Meningeal signs often present: Kernigs and Brudzinski signs
Subarachnoid bleed
If suspected and CT is negative…
do CSF tap and look for blood or xanthochromia
Subarachnoid bleed
Treatment: If patient is conscious.. bed rest, symptomatic and supportive care with cautious reduction of B.P.
*Angiography once patient stable
*Surgery or coil placement to prevent re-bleeding where applicable.
Subarachnoid bleed
Most common vascular malformation of CNS often involving MCA and branches.
*Tangled web of arteries connected directly to veins- congenital
up to 70% bleed
often by age 40
Males>Females
some familial trends
2-3% risk bleed per year
Arterial Venous Malformations (AVM)
S/S: hemorrhage (30-60%), headache (5-25%), recurrent seizure (20-40%), focal deficits
CT may confirm hemorrhage;
angiography necessary for diagnosis.
Treatment: surgery if lesion is accessible.
Arterial Venous Malformations (AVM)
Carotid bifurcation
Internal carotid
..common sources of?
Artery to artery emboli
Strokes involving anterior circulation (ie anterior choroidal, anterior cerebral, middle cerebral arteries)
are associated with what type of symptoms?
Hemispheric:
aphasia
apraxia (difficulty with skilled movements)
hemiparesis
hemisensory losses
visual field defects
Strokes involving posterior circulation (vertebral and basilar arteries)
are associated with what symptoms?
Brainstem dysfunction:
Coma
Drop attacks
Vertigo
N/V
Ataxia
______ strokes are often preceded by TIAs
______ strokes occur abruptly without warning
(choices: embolic, thrombotic)
Thrombotic strokes usually preceded by TIAs (Thrombotic have TIAs)
Embolic strokes usually abrupt without warning
(thrombotic strokes are when a clot forms in one of the arteries that supplies the brain)
Usually caused by embolus from carotid or left ventricle
Sxs:
Contralateral hemiplegia (arm/face > legs)
Hemianesthesia
dominant hemisphere: global aphasia (receptive and motor)
non-dominant hemisphere: anosognosia (denial/neglect of deficit), contructional apraxia
Middle cerebral artery (MCA)
What happens if there is an occlusion in the anterior cerebral artery (ACA) proximal to anterior communicating artery and the circle of willis is intact?
NO symptoms!
If distal occlusion….
Paralysis of opposite foot/leg
Sensory loss to toes, foot and leg
Urinary incontinence
Grap reflex
Suck reflex
Abulia (slowness to respond)
Impaired gait/stance
Behavioral changes
Memory disturbances
Anterior cerebral arery (ACA)
Contralateral hemiparesis or hemisensory loss
Hemianopsia (visual field defect)
dominant hemisphere: aphasia
non dominant hemisphere: anosognosia (denial) or a confused state
Middle cerebral artery (MCA)
Less common
Sx more pronounced in leg, associated language, gait disturbance
Anterior cerbral artery (ACA)
HTN, deep penetrating arterioles
small infarcts up to 1.5 cm on MRI/CT
clinical syndrome depends on location
may present as TIA
Lacunar infarct
AKA multi-infarct dementia
Classically hypertensive patients
+/- history of TIA or stroke
Usually manifests as forgetfulness in absence of depression and inattentiveness
*typically occurs in stepwise fashion, related to area of CNA affected
Vascular dementias
DO NOT CONFUSE THIS WITH A STROKE
Classic triad:
Cannot close 1 eye
Cannot raise eyebrow
Periauricular pain
Bell’s Palsy
What nerve is involved in Bell’s Palsy?
Facial nerve
