Stroke Flashcards
What is the pathophysiology of a stroke?
- abrupt onset focal neurologic deficit that lasts >24 hours and is of presumed vascular origin
What is an ischemic stroke?
an interruption of blood flow to the brain due to a clot
- occlusion of the cerebral artery causing abrupt development of a focal neurological deficit due to inadequate blood supply to an area of the brain
What is a hemorrahgic stroke?
caused by uncontrolled bleeding in the brain
What are ischemic strokes sometimes caused by?
caused by a thrombus formation inside an artery in the brain (i.e. atherosclerosis of cerebral vasculature)
What are the kinds of embolisms that can cause an ischemic stroke?
- carotid stenosis: atherosclerotic plaque rupture -> thrombus formation -> local occlusion or dislodge as emboli and causes downstream cerebral vessel occlusion
- cardiogenic embolism:
secondary to valvular heart disease, or nonvalvular atrial fibrillation
atrial blood stasis ->emboli -> occlusion of cerebral circulation
Describe a TIA
- temporary focal neurologic deficit lasting less than 24 hours (typically <30 minutes) as a result of diminished or absent blood flow
- results from small clots breaking away from larger, distant blood clots
- blood flow is reestablished as the emboli are dissolved by the fibrinolytic system
- no residual neurological deficit
- absence of acute infarction on imaging
- at high risk for an infarction or recurrent TIA
Describe the pathophysiology go the hemorrhagic stroke?
- escape of blood from cerebral vasculature into surrounding brain structure
- initial neurologic deficit attributable to direct irritant effects of blood in contact with brain tissue
- subsequent dysfunction due to anoxia (similar to ischemic stroke)
What are some causes of hemorrhagic stroke?
- subarachnoid hemorrhage, intracranial hemorrhage
What are some of the main causes of cerebral hemorrhage?
- cerebral artery aneurysm, hypertensive hemorrhage, trauma, drugs
What are some predictors for worsened outcomes with hemorrhagic stroke?
- higher clot volume
- early and late edema
What are some of the main modifiable risk factors associated with a stroke?
- hypertension
- smoking
- dyslipidemia
- diabetes
- heart disorders (atrial fibrillation, infective endocarditis)
- hypercoagulability
- obesity, physical inactivity
- psychosocial stress
- intracranial aneurysms
- alcohol use, carotid stenosis
- drugs
What are some go the main non-modifiable risk factors associated with a stroke?
- age (risk doubles for each decade older than 55)
- male sex
- family history
- prior stroke
- race (african american, asian-pacific islanders, hispanics)
What are the main clinical presentations associated with stroke?
- one sided weakness (sudden loss of strength or suffer numbness)
- trouble speaking/confusion
- vision problems/photophobia
- headache
- dizziness/ N/V
- altered level of consciousness
What timeline is acute phase treatment?
0-7 days
What timeline is hyper acute phase treatment?
0-24 hours
What are the goals of therapy associated with stroke therapy?
- stabilization
- reperfusion
- supportive measures
- prevent complications
- prevent stroke recurrence
What are the main acute phase treatments associated with ischemic strokes?
- ABCs
- BPs
- HTN common and transient in acute phase post stroke
- treat only is the SBP is >220/120 mmHg, have evidence of aortic dissection, acute MI, pulmonary edema or hypertensive encephalopathy
- aim for a moderate reduction only (15-25%) - fluid, electrolytes, temperature
- glucose management
- neurological assessment
What is typically used as reperfusion strategy after a stroke?
r-tPA
What is the inclusion criteria to use tPA?
- age 18 years or older
- ischemic stroke causing measurable neurologic deficit
- r-tPA can be given within 4.5 hours before symptom onset
What would exclude tPA from being used to treat a stroke?
- only minot or rapidly improving stroke symptoms
- any source of active hemorrhage or any condition that could increase risk of major hemorrhage after r-tPA
- any hemorrhage on brain imaging
- recent major surgery
- SBP >185 or DBP >110 refractory to antihypertensives
What should be avoided for 24 hours after r-tPA?
- anticoagulants and antiplatelets
What is the purpose of anti platelets after a stroke?
- reduces the risk of early recurrent stroke
ASA 160-325 mg po daily should be given within 24-48 hours of stroke onset - ASA should be given 24 hours AFTER tPA
_________ combination reduces the risk of recurrent stroke without increasing the risk of hemorrhagic stroke
Clopridogrel/ASA
Combination antiplatelets (ASA/Clopridogrel) combination is not indicated in most cases due to what?
due to a concern of increased bleeding risk/hemorrhagic transformation (especially not after the 90 days after a stroke- there is a lack of long term benefit)
What is used for DVT prophylaxis?
LMWH and UFH
these are used for hospitalized patents with limited mobility
When should heparin be administered after a stoke?
should be initiated within 24-48 hours (avoid within 24 hours of thrombolytic)
What are the main symptoms associated with ischemic stroke?
- neurologic symptoms (speech, extremity strength, facial symmetry, worsening symptoms indicate recurrence or extension)
- blood pressure
- electrolytes
- complications (DVT/PE- calf and chest pain, infections )
- adverse effects such as bleeding
What kind of surgical intervention can be used as secondary prevention for ischemic stokes?
- carotid endarterectomy (CEA) for secondary prevention of ischemic stroke (indicated for carotid artery stenosis of >70% on the side of the neurologic deficit)
- only performed in experienced stroke centre - Carotid artery angioplasty and stenting (CAS)
- restricted to patients refractory to medical therapy and not surgical candidates
- higher 30 day stroke/death rate vs CEA
For patients with nonardioembolic ischemic stroke or TIA, the use of what drug is preferred to reduce the risk of recurrent stroke or other cardiovascular event?
- antiplatelets over oral anticoagulants (ASA 50-325 or clopridogrel 75 mg when ASA is contraindicated)
What can be used as an addition to ASA for the secondary prevention of a noncardioembolic ischemic stroke?
- dipyridamole can be added
- ASA 25 mg + ERDP 200 mg BID is superior to ASA alone in secondary stroke prevention
What are the most common AE associated with ASA and dipyramidole combination?
- headache
- dyspepsia, nausea, diarrhea
- increased risk of bleeding with combination vs ASA alone
Is there a difference in stroke rate when using clopridogrel vs ASA?
no, there is not
What are the most common SE associated with clopridogrel?
- diarrhea, rash
- less GI bleeding than ASA alone
What about ticagrelor? Is it superior to ASA?
NO
What is the dose of ticagrelor?
180 mg loading dose and a 90 mg po bid dose after
Is warfarin superior to ASA?
no! warfarin is not superior to ASA 325 mg, but does give an increased bleeding risk
- not recommended for noncardioembolic ischemic stroke
What are the major risks associated with using a direct oral anticoagulant?
- there is no measure of the anticoagulation state
- no reversible agent in cases of severe, life threatening bleed
- not approved for patients with valvular AF
- safety post-thrombolytic is unknown
What are things that should be done as secondary prevention to a stroke?
- blood pressure lowering
- statin therapy
- diabetes management
- lifestyle changes
- depression screening
What should the target blood pressure therapy be for those that are in the acute stroke phase?
SBP 141-150
How long after a stroke should a person wait to restart antihypertenstives?
24 hours after the stroke
