33. Stroke Flashcards
Acute ischemic stroke can be caused by ___ or ____
thrombus (i.e. localized clot) that forms during a cerebral atherosclerotic infarction (similar to MI but in the brain); referred to as non-cardioembolic stroke (origin is in brain, not heart)
Embolus (i.e. a clot) that forms in the heart and travels to the brain. Referred to as cardioembolic stroke, common cause is Afib
A common cause of cardioembolic stroke is ___
Afib
What are the 2 types of strokes
Acute ischemic stroke (caused by thrombus or embolus)
Hemorrhagic stroke (bleeding in brain, often intracerebral hemorrhage (ICH) or subarachnoid hemorrhage (SAH)
____ is sometimes called a “mini-stroke”
It is caused by a temporary clot and blockage of blood flow in the brain, resolves within minutes to a few hrs with no permanent damage (often a warning sign for acute ischemic stroke and should be medically managed with the same risk reduction strategies)
Transient ichemic attack 9TIA)
What type of stroke is more common: ischemic or hemorrhagic?
Ischemic
Stroke risk factors
Modifiable:
HTN - most important
Afib
Dyslipidemia
DM
Physical inactivity
smoking
Non-modifiable risk factors:
Prior stroke or TIA
Advanced age (e.g. ≥80yo)
Race (higher risk in African American pts)
Genetic diseases (e.g. sickle cell)
S/sx of stroke (ACT F.A.S.T)
Face drooping
Arm weakness
Speech difficulty
Time to call 911 (immediately)
Brain imaging using ___ is ideally performed within 20 min of arrival to the ED to quickly identify whether stroke symptoms are d/t hemorrhage
computed tomography (CT) scan
In addition to cardiac and respiratory support, the immediate goal of treatment of ischemic stroke is to _____
restore blood flow to the ischemic area of the brain to obtain complete neurologic recovery
Restoring blood flow may require mechanical removal (e.g. with stent retrievers) or the clot can be dissolved with IV ____ if the pt arrives at the hospital in a timely manner after ischemic stroke symptom onset
fibrinolytic therapy
MOA alteplase
recombinant tissue plasminogen activator (tPA or rtPA)
Binds to fibrin in a clot and converts plasminogen to plasmin»_space; fibrinolysis
___ is the ONLY fibrinolytic drug FDA-approved to treat acute ischemic stroke
Alteplase
Note: Tenectplase, another fibrinolytic is occasionally used off-label
Pts are candidates for alteplase if no bleeding seen on CT scan, stroke symptom onset is ≤ _____, and alteplase can be administered within ___ of hospital arrival (door-to-needle time) + no contraindications
Symptom onset ≤ 4.5 hrs
Can be administered within 60min of hospital arrival
Contraindications to alteplase
Active internal bleed (e.g. ICH)
Risk of internal bleed d/t:
- severe HTN (BP >185/110) - lower with IV meds (e.g. labetalol, nicardipine) before proceeding with alteplase admin
- Other conditions (e.g. head trauma, hx of recent stroke (within 3 months))
- Labs (e.g. INR >1.7, platelet count <100,000, BG<50)
- DDIs (e.g. anticoag use - LMWH within previous 24 hrs, DOAC within 48hrs, warfarin with INR > 1.7)
Alteplase (Activase) dosing
0.9mg/kg
(max dose 90mg)
T/F: Alteplase contraindications and dosing differ when used for ACS vs stroke
True
Initiation of aspirin ___ PO daily is recommended within ___ after stroke onset to prevent early recurrent stroke.
Aspirin should NOT be given within ___ of fibrinolytic therapy
81-325mg
48 hrs
24 hrs
If alteplase is not administered, IV antihypertensives (e.g. labetalol, nicardipine) may not be required unless BP is severely elevated (≥____). In this case, a __% reduction in BP during the first 24 hrs after stroke onset is considered safe.
≥ 220/120
15%
After ischemic stroke, maintain BG levels in the range of ____ and closely monitor to prevent hypoglycemia (which can mimic stroke symptoms)
140-180
Which antihypertensives have best evidence for stroke risk reduction for secondary prevention? What is the BP goal for most pts?
Thiazides diuretics
ACEi/ARBs
<130/80
Weight reduction recommendation for treatment of modifiable risk factors (secondary ischemic stroke prevention)
BMI 18.5-24.9
Waist circumference <35 inches for women and <40 inches for men
for pts with non-cardioembolic ischemic stroke of TIA, antiplatelet therapy with ____ is recommended to reduce risk of recurrent stroke, MI, or death.
___ is contraindicated in anyone with hx of TIA or stroke d/t increased risk of intracranial bleed
aspirin, aspirin/ER dipyridamole, clopidogrel
Prasugrel contraindicated
Combination of clopidogrel and low-dose aspirin can be initiated within ___ of minor ischemic stroke (i.e. NIHSS score ≤3, did not receive alteplase) and continued for ___ days.
24 hrs
21-90 days
Note: Should NOT be used long-term for secondary prevention of stroke or TIA d/t increase risk of hemorrhage). Use short-term DAPT and then antiplatelet monotherapy indefinitely - diff recs than DAPT in heart disease (
T/F: if pt is already taking aspirin, increasing aspirin dose will provide additional antiplatelet benefit for ischemic stroke or TIA
False - no added benefit to increasing aspirin dose in pts already taking aspirin who have an ischemic stroke or TIA
Aspirin MOA in secondary ischemic stroke prevention
Irreversibly inhibits COX-1 and 2, resulting in decreased prostaglandin and TXA2 production (potent vasoconstrictor and inducer of platelet aggregation)
Dipyridamole MOA
inhibits uptake or adenosine into platelets and increases cAMP levels, which inhibits platelet aggregation
Clopidogrel MOA
prodrug that irreversibly inhibits P2Y12 ADP-mediated platelet activation and aggregation
Which formulations of aspirin are Rx?
ER capsule (Durlaza)
DR tablet (Yosprala)
Contraindications of aspirin (Bayer, Bufferin, Ecotrin)
NSAID or salicylate allergy, children and teenagers with viral infection d/t risk of Reye’s syndrome
Warnings with aspirin (Bayer, Bufferin, Ecotrin)
bleeding
Tinnitus (salicylate overdose)
Side effects of aspirin (Bayer, Bufferin, Ecotrin)
Dyspepsia, heartburn, bleeding, nausea
Warnings with ER dipyridamole/aspirin (Aggrenox)
hypotension and chest pain (in pts iwth coronary artery disease) can occur d/t vasodilatory effects of dipyridamole
Side effects of ER dipyridamole/aspirin (Aggrenox)
Headache (From vasodilatory effects of dipyridamole)
T/F: ER dipyridamole/aspirin (Aggrenox) can be replaced wtih dipyridamole and aspirin separately
False - not interchangeable
Clopdiogrel (Plavix) dose
75mg daily
Clopdiogrel is a prodrug and requires conversion to active metabolite by ____
CYP2C19
Poor metabolizers exhibit higher CV events than normal CYP2C19 function
Test CYP2C19 genotype
Contraindications of clopidogrel (Plavix)
Active serious bleeding
Warnings clopidogrel (Plavix)
Bleeding risk: Stop 5 days prior to elective surgery, do not use with omeprazole or esomeprazole
Premature d/c (increased risk of thrombosis), thrombotic thrombocytopenic purpura (TTP)
____ is drug of choice in stroke/TIA if contraindication or allergy to aspirin
Clopidogrel (Plavix)
Avoid concurrent use of clopidogrel and PPIs __ and __ (other PPIs interact less) and use caution with other CYP2C19 inhibitors
Omeprazole, esomeprazole
For intracerebral hemorrhage (ICH), ___ should be d/c and reversal agents should be administered (if appropriate). If there is clinical evidence of seizures, they should be treated but ____ should NOT be used
anticoagulants d/c
ppx antiepileptic drugs should NOT be used
Increased intracranial pressure (ICP) is a medical emergency that can lead to brain death. What can be done to lower ICP?
Elevating head by at least 30 degrees
Administering IV osmotic therapy with either hypertonic saline (NaCl 3%, NaCl 23.4%) or mannitol»_space; draws water out of brain and into intravascular space where it can be renally excreted
Contraindications of mannitol (Osmitrol) injection
Severe renal disease (anuria)
Others: severe hypovolemia, pulmonary edema or congestion, active intracranial bleed (except during craniotomy)
Before administering mannitol(Osmitrol), what should be done?
inspect for crystals - if crystals present, warm the solution to redissolve
Use a filter for administration with mannitol conc ≥___%
≥20%
Subarachnoid hemorrhage (SAH) usually results from ___and results in a ___
cerebral aneurysm rupture
severe headache (usually described as “worst HA ever experienced”)
Cerebral artery vasospasm can occur ___ days after bleed, causing delayed cerebral ischemia; ____ has been show to improve outcomes a/w vasospasm-induced ischmia and should be initiated in pts with SAH
3-21 days
oral nimodipine (Nymalize)
Nimodipine MOA
DHP CCB that is more selective for cerebral arteries d/t increase lipophilicity
Only indicated for SAH and not used for HTN
Boxed warning for nimodipine (Nymalize)
Do not administer nimodipine IV or by other parenteral routes; death and serious life-threatening ADEs have occured when the contents of nimodipine caps have been inadvertently injected parenterally
Side effects of nimodipine (Nymalize)
hypotension
If nimodipine (Nymalize) capsules cannot be swallowed and oral solution is not available, what do you recommend?
Capsule contents may be withdrawn with parenteral syringe and then transferred to oral syringe that cannot accept a needle and only administer PO or via NG tube
What auxillary labels should be placed on nimodipine (Nymalize) oral syringes
“For Oral Use Only”
“Not for IV Use”
