Stroke and vascular neurology

Question 1

Epidemiology of stroke

Answer 1

• 800,000 strokes/yr
• 4th leading cause of death, 1st leading cause of long-term disability
• Every minute during a stroke the brain loses 1.9 million neurons (14 billion synapses)
• 1/3rd of patients w/ intracerebral hemorrhaging (ICH) will deteriorate btwn paramedic and ED imaging
• Brain receives 20% of blood but accounts for 2% of total body weight

Question 2

Warning signs of stroke (high yield)

Answer 2

• Sudden weakness of numbness
• Sudden change in vision
• Sudden difficulty speaking or understanding
• Sudden dizziness or loss of balance
• Sudden headache

Question 3

Types of stroke

Answer 3

• 80% are ischemic strokes (no bleeding just deprivation of blood)
• Ischemic strokes can be atherothrombotic (most common ischemic), lacunar, cardioembolic, or cryptogenic (no defined etiology)
• Hemorrhagic strokes represent 20% of all strokes
• These can be intracerebral hemorrhage (70%, bleed directly into brain tissue) or subarachnoid hemorrhage (30%, bleed into CSF outside of brain tissue)

Question 4

Pathology of stroke

Answer 4

• When an area of brain is infarcted due to ischemic stroke there are various levels of cell death
• The infarct core is the most severely affected as it is the tissue that was receiving blood directly from the infarcted artery
• Around the infarct core is the salvageable penumbra, which will infarct more slowly due collaterals
• These collaterals are usually not enough to completely supply the penumbra, thus it will infarct given enough time
• While the core infarct is not salvageable the penumbra is if the infarct is Rx’d fast enough

Question 5

Risk factors of stroke (modifiable)

Answer 5

• Modifiable and non-modifiable
• Age is a very important risk factor that is non-modifable; the older you are the higher your risk of stroke (esp. >65)
• Gender is another non-modifiable risk factor
• Across all ages the prevalence btwn men and women is about equal
• The death rate though is higher in women than it is for men

Question 6

Non-modifiable risk factors

Answer 6

• Cerebrovascular disease (atherosclerosis in the vasculature)
• Diabetes can increase risk of stroke
• Hypercoagulability/thrombosis increases risk
• Hypertension increases risk
• Lifestyle changes: smoking, alcohol, obesity all increase risk
• Exercise decreases risk

Question 7

Locations of strokes

Answer 7

• Strokes of MCA will lead to deficits depending on where in MCA it occurs
• Could lead to damage of FEF, broca’s and wernicke’s areas, sensory and motor to upper limbs and face, can also produce ischemia of internal capsule, basal ganglia, and pole of the lateral temporal lobe
• Infarct of ACA leads to loss of sensory and motor to the lower limbs

Question 8

-Timing of strokes

Answer 8

• Always sudden onset
• Maximal deficits at onset: ischemic stroke
• Builds to maximal deficit over minutes to hrs: hemorrhagic
• Always ask when was the last time you saw the pt acting normal (important for determining Rx)
• Must also know if it is ischemic or hemorrhagic (for Rx), can confirm by imaging

Question 9

Tests when suspecting stroke

Answer 9

• Labs (coagulation labs, metabolic pannel, CBC, ect)
• EKG
• CXR
• Neuroimaging: CT (fast, cheap, available) w/ and/or w/o contrast, MRI (slower and more expensive but gives much better picture of brain)
• CT almost always used b/c its fast. The main purpose of CT is to rule-out hemorrhage since blood shows brightly on CT scan (infarcts are usually darker but very hard to see on CT)
• If its an ICH there will be one white spot of blood within the brain (on CT)
• If its a subarachnoid hemorrhage (SAH) there will be diffuse whitening of the whole brain

Question 10

Rx of stroke

Answer 10

• Many types of Rxs based on what kind of stroke
• The most important one is tPA, which is used only to Rx ischemic strokes and only w/in 3 hrs of the event
• Other important stroke Rxs (like aspirin or coumadin) only try to prevent the next stroke, but do not help a current one
• Also can do endovascular Rx for ischemic stroke, using catheter to grab the embolus and pull it out (recanalization)
• For hemorrhagic stroke the most important Rx is lowering BP
• The most important aspect of Rx for stroke is recognizing the symptoms so that the pt can be brought to the ED

Question 11

Prevention of stroke

Answer 11

• Identifying and Rx risk factors that are preventable/treatable (HTN, diabetes, high cholesterol, hypercoagulability/thrombosis, inflammation, lifestyle)
• The most important risk factor is HTN simply because it is so prevalent (best modifiable risk factor)
• Atrial fibrillation (afib) causes many cardioembolic strokes (due to stasis of blood in heart-> coagulation)
• 1/2 of all afib strokes are preventable w/ warfarin

Question 12

5 pillars of stroke prevention

Answer 12

• Lowering BP
• Lowering cholesterol
• Antithrombotics (aspirin)
• Rx of diabetes
• Changing lifestyle (diet, exercise, smoking/drinking)