Intro to Stroke

Question 1

stroke

Answer 1

*sudden, focal brain injury due to blood-vessel problem
*brain attack (medical emergency)
*preventable and treatable

Question 2

epidemiology of stroke in the US

Answer 2

*affects > 800,000 persons per year
*causes 200,000 deaths per year
*5th leading cause of death in US
*leading cause of long-term disability
*costs > $70 billion per year

Question 3

the stroke belt

Answer 3

*area of US with highest death rate due to stroke
*southern (southeast) states and pacific northwest
*cause not known
*traditional risk factors do not explain it

Question 4

the stroke syndrome

Answer 4

*sudden acute neurological deficit
*vascular etiologies (hemorrhagic or ischemic)

Question 5

infarction - definition

Answer 5

death of neurons, glia, and endothelium due to ischemia

Question 6

hemorrhage - definition

Answer 6

occurs when there is bleeding into the brain parenchyma or potential intracranial space (from a blood vessel rupture)

Question 7

hemorrhagic infarction - definition

Answer 7

occurs when there is bleeding into an area of ischemic infarction

Question 8

3 stroke types

Answer 8

1) ischemic stroke (clot blocking artery)
2) intracranial hemorrhage (bleeding into brain)
3) subarachnoid hemorrhage (bleeding around brain)

Question 9

transient ischemic attack (TIA)

Answer 9

*ischemic (low-blood-flow) stroke without permanent damage
*usually 20-30 minutes, most < 1 hour
*important warning of impending stroke

Question 10

common stroke symptoms

Answer 10

*weakness or numbness, epc. 1 side of body
*difficulty speaking or understanding speech
*visual loss in one or both eyes
*severe, unusual headache
*dizziness, if associated with another symptom

Question 11

*hemorrhage vs. ischemic infarct

Answer 11

*both present with sudden, acute deficit
*supporting evidence for hemorrhage: severe H/A at onset, younger age with h/o HTN
*CANNOT MAKE DEFINITIVE DX BETWEEN THE 2 CLINICALLY (need imaging - non-contrast head CT looking for blood)

Question 12

stroke risk factors - non-modifiable

Answer 12

*age
*sex
*family history

Question 13

stroke risk factors - medical

Answer 13

*HYPERTENSION
*prior stroke/TIA
*heart disease, esp a-fib
*hyperlipidemia
*diabetes
*obesity
*sickle cell disease

Question 14

stroke risk factors - lifestyle

Answer 14

*smoking
*heavy alcohol use
*sympathomimetic drugs (legal & illegal)
*marijuana use
*sedentary lifestyle
*southern diet

Question 15

common causes of ischemic (low blood flow) strokes

Answer 15

*atherosclerosis!!
*small artery disease
*cardioembolism (a-fib)
*hypoperfusion
*hypercoagulable states
*dissections/vasculitis

Question 16

common causes of hemorrhagic (bleeding) strokes

Answer 16

*intracerebral: longstanding HTN and small artery rupture
*subarachnoid: trauma / ruptured berry aneurysm

Question 17

primary prevention of stroke

Answer 17

identify and control/treat risk factors (HTN, DM, hyperlipidemia, smoking, sickle cell, carotid stenosis, obesity)

Question 18

secondary prevention of stroke

Answer 18

1. identify cause of stroke
2. take appropriate action (meds, surgery) and initiate appropriate anti-thrombotic therapy
3. identify and treat all risk factors

Question 19

emergency stroke care

Answer 19

“the 7 D’s”:
-detection of onset of stroke signs and symptoms
-dispatch through activation of the EMS system and prompt EMS response
-delivery of the victim to the receiving hospital
-door (ED triage)
-data (ED evaluation, including CT scan)
-decision about potential therapies
-drug therapy

Question 20

t-PA for stroke treatment

Answer 20

*thrombolysis with t-PA available for patients with ischemic stroke
*tPA does NOT save lives - it decreases the RISK OF DISABILITY
*MUST be given with 4.5 hours of stroke onset (last known normal)
*can cause dangerous bleeding if given outside the time window

Question 21

penumbra

Answer 21

*zone of reversible ischemia around core of irreversible infarction
*salvageable within the first few hours after ischemic stroke onset
*damaged by: hypoperfusion, hyperglycemia, fever, seizure

Question 22

mechanism of thrombolytic therapy (ex. tPA)

Answer 22

*disruption of an acute thrombus may allow restoration of blood flow into penumbra cells (revascularization and reperfusion)
*reperfusion cannot help the patient if the brain downstream is already dead

Question 23

thrombus formation - overview

Answer 23

*fibrinogen -> fibrin (red cells and platelets adhere to fibrin strands; activated factor XIII stabilizes the clot)
*plasminogen -> plasmin (plasminogen activators, like tPA, are upregulated by binding to fibrin, making their activity “clot-specific”; plasmin degrades fibrin)

Question 24

tPA criteria

Answer 24

*time < 4.5 hours (from last known normal)
*pressure < 185/110
*any other contraindications (already anticoagulated; bleeding contraindications; seizure or trauma; blood sugar low; recent surgery or arterial stick in non-compressible site)

Question 25

endovascular therapy for stroke

Answer 25

*example = thrombectomy
*clot retrieval or mechanical disruption with stent retriever devices work best
*used for proximal, large artery occlusions
*within 24 hours, IF perfusion imaging demonstrates salvageable penumbra

Question 26

acute stroke treatment - overview

Answer 26

*only ACUTE stroke treatments are tPA and endovascular therapy (heparin is not an acute stroke treatment, it is an anticoagulant; does NOT dissolve a clot that is already there)

Question 27

general principles of stroke evaluation

Answer 27

*do NOT ASSUME etiology
*identify cause based upon stroke syndrome and lab confirmation (clinical stroke syndrome, imaging characteristics, risk factors, and lab correlates)

Question 28

imaging for stroke

Answer 28

*brain imaging (CT head, MRI)
*arterial imaging (CTA, MRA, ultrasound)
*cardiac imaging (TEE, EEE)

Question 29

antiplatelet agents

Answer 29

MOA: inhibition of platelet activation and aggregation
*aspirin (inhibits COX)
*clopidogrel & ticagrelor (block P2Y12 ADP receptors)
*dipyridamole & cilostazole (increases plasma adenosine & inhibits platelet phosphodiesterase)

Question 30

anticoagulant agents

Answer 30

*warfarin (depletes Vit K dependent clotting factors - II, VII, IX, and X and protein C)
*dabigatran (direct thrombin inhibitor)
*apixaban, ribaroxaban (oral factor Xa inhibitors)

Question 31

mechanism of action of warfarin

Answer 31

depletes Vit K dependent clotting factors - II, VII, IX, and X and protein C

Question 32

when to use anticoagulants

Answer 32

**cardioembolic sources (A-FIB; mechanical valves; severe cardiomyopathy; patent foramen ovale)
*hypercoagulable states (such as protein S deficiency)
*venous infarction (sagittal sinus thrombosis)

Question 33

when to use anti-platelet agents

Answer 33

*atherosclerotic disease
*small artery disease
*any ischemic stroke patient without an identified need for anticoagulation

Question 34

algorithm for stroke treatment

Answer 34

1. pt presents with acute ischemic stroke
2. determine eligibility for treatment with tPA and/or endovascular therapy and treat if eligible
3. acutely, all stroke patients need some form of antithrombotic therapy with at least aspirin (note: NO antithrombotics for 24 hrs if patient receives tPA)
4. early statin therapy
5. DVT prophylaxis

Question 35

facial droop - forehead spared

Answer 35

UMN problem (brain)

Question 36

facial droop - forehead included in paralysis

Answer 36

LMN problem (facial nerve)

Question 37

Bell’s Palsy

Answer 37

facial paralysis; forehead included in the paralysis; LMN lesion of CN VII (facial nerve)