Handler: Stroke Flashcards
the sudden or rapid onset of a neurologic deficit in distribution of a vascular territory lasting > 24 hours
Stroke
“Brain attack”
the sudden or rapid onset of a neurologic deficit in the distributionof a vascular territory lasting < 24 houts.
Most last <30 mins
TIA
Reversible ischemicinsult to brain cells that recover but increases risk of subsequent stroke
TIA
Worsening signs or symtpoms over time
Stroke-in-evolution
(progressive stroke)
Ischemia/infart __%
hemorrhage __%
85%
15%
3rd leading cause of death in the US
>200,000 deaths/year
Perception of elderly
Men 1.3x > Women
Blacks 1.3x > whites
Stroke
Most common cause of death in patients with cerebrovascular disease is _________?
Myocardial infarction
What is the most powerful risk factor for a stroke?
HTN
goal <140/90
Smoking (2-4x)
Atherosclerosis eslewhere (CHD, PAD)
Diabetes Mellitus (3x)
A fib (cardaic emboli)
Male gender, OCP, ETOH in excess, hyperlipidemia
Risk factors for?
Stroke
Large vessels (atheroscleorsis) often involved in ___% of all ischemic strokes (infarcts)
50%
Atherosclerosis: ______ vessels often involved
Large
___% of strokes are in anterior circulation of brain
80%
Why has incidence of stroke declined?
Development and treatment of HTN
Pathological outcomes depend on:
Adequacy of collateral circulation
Development of Circle of Willis
Duration of insult/restoration of blood flow
Stroke
Carotid bifurcation, origin of internal carotid
Base of aorta, external carotid, vertebral/basilar arteries
Effected in _____ strokes?
Ischemic
Small vessel disease
deep penetrating arterioles occlude/thrombose
Lacunar infarcts
20% of ischemic strokes are ____?
Lacunar infarcts
Major risk factor for lacunar infarcts is ____
lipids, DM contribute
HTN
Fibrous cap can erode and lead to an ______ placque?
ulcerative
Very small strokes or TIA’s defect < ____ cm (most are 5mm) on CT or MRI
1.5
May be without sx
detected by CT scan as incidental finding (small, punched out lesion)
lacunar infarcts
Embolism from heart or artery to brain
Important role in pathology of strokes and TIA’s
Cerebral Emboli
Blood clot breaks off, occludes more distant/distal vessel
Cerebral emboli
Often lodge in medium sized vessels (MCA,ACA)
If identified one, likely there are others
Cardiac emboli
20% of ischemic strokes are ____?
Cardioembolism
What is a very common cause of cardioelmbolism?
A fib
Abrupt onset of non-convulsive focal defect in a vascular territory
Stroke
___% of patients have no warning sx of stroke
___% have warning (TIA)
80-90%
10-20%
Contralateral hemiparesis or hemisensory loss
Hemianopsia (visual field defect)
If dominant hemisphere (left side of brain)-aphasia
If non-dominant- Speech and comprehension preserved; may develop anosognosia (denial/neglect of deficit) or a confusional state.
MCA
less common
Sx more pronounced in leg, associated language, gait disturbance.
ACA
least common
Vertebral artery (Branch of subclavian artery)
Crossed contralateral dysfunction (motor/sensory) plus ipsilateral bulbar/cerebellar signs: vertigo, dizziness, gait disturbance, diplopia, facial palsy, dysarthria, etc.
Posterior circulation
Clinical syndrome depending on where infarct is, may also present as TIA
Ex: contralateral motor/sensory deficit
Prognosis usually good
Lacunar strokes/infarcts
Carotid dx present
Transient monocular blindness
Embolism to opthalmic artery (off carotid)
Amaurosis fugax
What do you need to do to r/o hemorrhage associted with stroke?
MRI best in 1st 48 hours after intracranial hemorrhage
Detection of infarcts on CT is limited to what?
size and timing
__% of infarcts visible on CT in 1st 12 hours
>__% visible at one week
5%
90%
Changes of infarct may be seen as early as 1 hour
usually not available or needed emergently
Provides better detail than CT for small lesions and for imaging posterior fossa
MRI/MRA
Non-invasive with excellent resolution of large vessels
replaces need for arteriogramin some patients
May be difficult to differentiate complete vs. near complete occlusion
MRA
Screening tool for evaluating common carotid and origin of internal carotid artery
May be difficult to differeniate complete vs. near complete occlusions
Non-invasive but limited capacity
Carotid Doppler Ultrasound (Duplex)
MOST accurate
Invasive- “gold standard” for extra and intracranial disease
Arteriography
Complications: contrast reaction, kidney failiure, placque rupture, stroke
Use of non-ionic constrast has reduced complications
What type of imaging?
Arteriography
Risk factor modification: agressive control of BP, lipids, diabetes, smoking cessation, exercise, diet
Atrial fibrillation and emolization: full anticoagulation (Warfarin therapy long term)
Prevention for what?
CHD and stroke
Abrupt onset of sx with transient focal neuro deficit dependent on involved anatomy
Sx may vary during episodes
Exam between episodes normal
Warning for subsequent stroke
TIA’s
Embolic from carotid stenosis/placque or
Embolic from cardiac source
Severe carotid stenosis with transient HoTN
Small vessel occlusion: lacunar infarcts may minic
Etiology for ___?
TIA’s
Important to listen for ___ with stethoscope with TIA’s?
bruit
Carotid Endarterectomy and carotid angioplasty/stenting are surgical rx for?
Carotid TIA/Incomplete Stroke
Surgical rx to remove placque
Best results if symptomatic blockage and >70% stenosis
Significantly recuces risk of subsequent ipsilateral stroke
For selected patients with sx and 50-70% stenosis
Risks: stroke and complications of surgery
Carotid endarterectomy
Promising alternative to carotid endarterectomy but long term data is lacking
option in POOR surgical candidates
Carotid angioplasty/stenting
For patients with poor operative risk
<70% stenosis or asymptomatic carotid disease
Risk factor modification: HTN, smoking, lipids, DM
Medical rx for carotid TIA’s
Indicated for ALL patients with <70% stenosis and TIA sx, diffuse cerebrovascular dx, poor operative candidates, and asx carotid dx
Prevent platelet aggregation and release of vasoactive substances like thromboxane A2
Anti-platelet agents
Inhibits cyclooxygenase
Inhibits synthesis of thromboxane A2, decreasing both platelet aggregation and vasoconstriction
Decreases frequency of TIA’s and risk of subsequent stroke and decreased recurrence of stroke
325mg daily: GI side effects and bleeding
Aspirin
Inhibits platelet aggregation and prevents activation of glycoprotein ||b/|||a (a fibrinogen binder)
Decreases atherosclerotic events
Alternative to ASA for patients with recurrent TIA’s or ASA intolerance/allergy
75 mg/day: Diarrhea, rash
Clopidogrel (Plavix)
Supportive measures plus ASA or Clopidogrel
Aggressive long term tx of BP and lipids
Usually good prognosis for recovery over 4-6 weeks
Lacunar infarct tx
Hospitalize all patients (most TIA-1st episode)
Supportive (IV fluids)
Consider thrombolytic therapy
Tx for what?
Stroke
What do you want to avoid when treating a stroke?
Rapid BP reduction
decreases perfusion and brain will autoregular perfusion
Only tx if <200/100 –> wait 2 weeks for oral meds if possible
Dependent on timing
1st obtain head CT to r/o hemorrhage
if onset of sx <4.5 hours –> thrombolytic therapy with t-PA (bolus/infusion up to 90 mgs) over 1 hour
Tx for?
Cerebral infarct
Requires team approach- best done in large tx centers
neurologic outcome improved at 3 mon and 1 year with decrease in expected deficit and reduction of intial deficit
increases chances of favorable outcome by ~50%
What type of stroke therapy?
Thrombolytic therapy
Risks: Cerebral hemorrhage (6-7% incidence adn half will die)
Contraindications: recent bleeding, prior stroke, BP >185/110, recent major surgery
For what type of stroke therapy?
thrombolytic therapy (t-PA)
loose mesh stent placed in thrombus obstructing cerebral vessels
removes thrombus and restores blood flow
Not yet FDA approved for all stroke patients
Solitare FR Revascularization Device
Indications:
Embolus from heart (stroke or TIA)
A fib > 72 hours
Risk is cerebral hemorrhage
What type if tx?
FULL anticoagulation
What must you do before starting full anticoagulation?
CT to r/o hemmorrhage
Used for immediate and short term anticoagulation
Inhibit action of clotting factors
Heparin
Long term oral anticoagulation
Inhibits production of clotting factors in liver
Stroke or TIA from cardiac embolism (decrease subsequent stroke risk)
Chronic A fib (decrease stroke risk)
Monitored by INR and frequent follow up for dosing
Warfarin
Physical therapy, occupation therapy, speech therapy
Avoid prolonged best rest (UTI’s, skin infection/ulcers, PE)
Post stroke management
What are the two types of Hemorrhagic stroke?
Intracerebral (HTN, AVM, Trauma)
Subarachnoid space (Aneurysm, AVM)
________ is diagnositic for hemorrhagic stroke
CT
What should you do if CT is negative for to rule out SAH?
Spinal tap
Rupture of small arteries or microaneurysms of perforating vessels
Risks: HTN, hematologic and bleeding disorders (leukemia, thrombocytopenia, hemophilia), trauma, anticoagulant therapy, liver dx
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 HA are common
Intracerebral hemorrhage
Cautious BP reduction where applicable
Conservative and supportive tx - some benefit from surgical evacuation of hematoma
Surgery: decompression (limited usefulness)–> best in cerebellar bleeds and bleeding in AVM
Tx for?
Hemorrhagic stroke
Most due to bleeding from saccular aneurysms
In 3-4% of population, usually w/o sx
2-3% risk of bleed per year
Highest risk if >6mm
Subarachnoid bleeds
Sudden onset of severe HA followed by N and V, impaired or loss of consciousness +/- neuro deficits
Meningeal signs often present
Subarachnoid bleeds
What are the two meningeal signs?
Kernigs and Brudzinski signs
What imaging is used to identify blood in subarachnoid space?
CT
If subarachnoid hemorrhage is suspected and CT is negative do _______ to look for blood or xanthochromia
CSF tap
If patient conscious: bed rest, sx and supportive care with cautious reduction of BP
Once patient stable: angiography
Surgery or coil placement to precent re-bleed when applicable
Tx for?
Subarachnoid hemorrhage
most common vascular malformation of CNS often involving MCA and branches
