Stroke Pathophysiology Flashcards
Definition of stroke
Work in progress
- trying to include all the clinical scenarios
What are the 2 types of classifications of stroke? Which one is more common
Subtypes?
Ischemic stroke (85%)
- including transient ischemic attack (TIA)
Hemorrhagic stroke (15%)
- intracerebreal hemorrhage
- subarachnoid hemorrhage
- subdural and epidural hematomas
Define ischemic stroke
Episode of neurological dysfunction caused by focal cerebral, spinal, or retinal infarction
- Evidence of focal ischemic injury
- Symptoms persisting 24hrs+
Define TIA
Same as ischemic stroke WITHOUT acute infarction
Symptoms lasting LESS than 24hrs
- “mini stroke”
- indicator or acute ischemia that can happen in near future
T/F is having symptoms alone good for diagnosis
True
What if a patients presents with no symptoms? What is it called
Silent CNS infaraction
Define thrombotic and embolic ischemic stroke
Thrombotic
- infarction located near the clot in the brain
Embolic
- Clot migrated from another source
- ex. Afib and valvular diseases
Define ischemic core or focal region
Tissue that has already sustained irreversible damage
- cannot be salvages
Define penumbra
Tissue at risk
- hypo-perfused tissue with disrupted function
May be salvaged by acute reperfusion therapy
- but delay can lead to permanent is irreversible
Which vessels off the aorta supply blood to brain? (2)
R common carotid artery
L common carotid artery
Which arteries in the head & neck supply blood to brain (2)
Vertebral artery
Internal carotid artery
Why is circle of willis important?
To be able to use alternate routes if a blockage happens
What are the 5 sources of ischemic stroke? %?
25% large artery
25% small artery (lacunes)
20% cardiogenic embolism (afib)
25% cryptogenic (unknown source)
5% Unusual dissections, arteritis
How can large artery atherosclerosis happen?
Commonly due to build of plaque
can be caused due to in-situ thrombosis or artery-artery embolization
Which large arteries are affected in stroke?
Internal carotid artery
Vertebral artery
How can small artery stroke happen (lacunar stroke)
Symptoms?
Endothelial dysfunction leading to occlusion in the small penetrating
- necrotic tissue from the infarct is removed by macrophages, resulting in a formation of a small cavity or lacune
Can be symptomatic or asymptomatic
How does cardiac embolism happen in afib?
Stats?
What are other reasons?
Stall blood in Left atrial appendage
Clot moves from L Atrium to L ventricle
Afib patients have 5 times greater risk
1 in 5 of all strokes can be due to Afib (20%)
Valvular heart disease
Patent Foramen Ovale
Usually attaches to a bifurcation point or narrowed vessel
Define intracerebral hemorrhage?
Where?
Cause?
Very fast neurological signs
within brain parenchyma or ventricular systems
Not caused by trauma
- Main cause is hypertension
Define subarachnoid hemorrhage
Where
Cause
Where
- bleeding into subarachnoid space
- not related to trauma
Cause
- not related due to trauma
- aneurysmal rupture
Define epidural and subdural hemotomas
Where
Cause
Where
- bleeding between the skull and dura
- outside of parenchyma
OR
- between the dura and the arachnoid mater
Cause
- result of trauma
Epidural vs subdural hemotomas
Associated with Head fracture?
Which is worse?
Easier to diagnose?
Associated with Head fracture?
Epidural
Which is worse?
Subdural
Easier to diagnose?
Epidural
How many % of patients die who have a stroke
Ischemic vs hemorrhagic?
15%
15% vs 30%
What % recover completely from stroke?
10%
Which gender is more likely to get a stroke? at what age is the spike?
Men
65+
T/F stroke is not the leading cause of adult disability
False
What is FAST for clinical presentation? What to ask patients?
Face drooping
- ask person to smile
Arm Weakness
- Ask person to raise both arms
Speech Difficulty
- ask person to repeat a simple phrase
Time to call 911
What are signs and symptoms of stroke
- Weakness on one side of body
- numbness or tingling (face, arm, leg)
- Trouble speaking/understanding
- Vision problems, double vision, especially in one eye
- Dizziness, losing balance
- Neurological deficit: slurred speech, paralysis, blindness
Some patients: headache, vomiting, seizures, ECG abnormalities, stiff neck
What are signs and symptoms of hemorrhagic stroke?
Similar to stroke but more severe
What features are associated with anterior cerebral artery stroke (4)
Examples
Sensorimotor deficits (in the contralateral foot/leg)
Urinary incontinence
Language disturbaces
- dysarthria (unclear speach)
- Mutism (speaking in whispers)
Behavioural disturbances
- abulia (no reflex)
- distractibility
- mood changes
What are features of middle cerebral artery stroke (most common in M1 and M2) in the M1
Hemiplegia: (paralysis, droopy)
Hemiaanesthesia: Loss of sensation
Hemianopia: visual field loss on same side of both eyes
Deviation of head and eyes to side of the lesion
Dystharia: slurred/slow speach (if Left hemisphere
What are features of posterior cerebral artery stroke (3)
Mainly visusal fields
- homonymous Hemianopia
- partial or complete vision loss
Anomia: inability to name objects but can describe them
Memory loss (long or short-term) due to temporal lobe
What are non-modifiable risk factors of ischemic stroke? (5)
Compare the features to likeliness
Age (doubling every 10 years after 55)
Race (Black > hispanics > Whites)
Sex (males > females)
Low birth weight (2.5kg)
Family history of stroke (paternal > maternal)
What are modifiable risk factors (12)
Diabetes
Dyslipidemia
HTN
Smoking
CVD (CAD, HF, PAD)
Afib
Asymptomatic cartoid stenosis
Sickle cell disease
Diet factors (Na <2300mg/day, K < 4700mg/day)
Obesity
Physical inactivity
Postmenopausal hormone therapy
What is the RRR of physical activity in stroke
40%
How much does having HTN increase chance of getting stroke? How much does HTN control reduce stroke by?
If you have HTN, 3x higher risk of stroke
HTN control reduces risk of stroke by 60%
What do the composite of all 10 risk factors control mean in stroke?
Contributes to 90% of overall risk of stroke
- 90% RRR
What does the NIHSS (national institute of health stroke scale) measure?
Predictive of long-term outcomes post-stroke
7-day outcome
- 11 item scale
- maximum score 42
What does the TIA-ABCD2 score help predict?
Helps predict recurrence of stroke post TIA (<24 hours of symptoms)
What are brain imaging useful for? (4)
- differentiating between ischemia vs hemorrhage
- rule out stroke mimics (i.e tumour)
- Assess status of large intracranial arteries
- guide acute treatment
When are the following used?
CT
CT angiography
MRI
Carotid Doppler
CT (computed tomography):
- readily accessible
- preferred when ruling out hemorrhage
CT angiography:
- used to locate a clot in large intracranial vessels
MRI (magnetic resonance imaging):
- NOT readily accessible, provides higher-res images than CT
Carotid doppler:
- to find clots in carotid artery (CT is preferred - more sensitive)
Differentiate between ECG, Holter monitoring and echocardiogram
ECG:
- identify abnormal rhythm in a snapshot of time
Holter monitoring:
- identify abnormal rhythm over a period of time
Echocardiogram:
- visualize heart chambers and valves to rule out clots
What are differential diagnosis of stroke (8)
- Todd paralysis (post-seizure)
- Brain abscess
- Herpes simplex encephailitis
- Hypoglycemia
- Brain tumor
- multiple sclerosis
- Migraine
- Conversion disorder
What are goals of therapy with stroke (4)
- Minimize brain damage
- Prevent complications from stroke eg. pneumonia, VTE
- Reduce risk of recurrence
- Restore function and minimize long-term disability
What is the purpose of neuroimaging (4)
- Allows for differentiating between ischemia and hemorrhage
- Rule out stroke mimics (tumour)
- Assess status of large intracranial arteries
- Guide acute treatment
