Week 1 - CVA Flashcards
Non-modifiable risk factors for stroke
- woman > men
- age (Incidence rate doubles >55)
- Race - AA/Hispanic > white (2:1 between AA/hispanic and white and increases 4:1 between 45-54 y/o), Native Americans, Alaskan Natives
- Prior stroke - 23% have another stroke
- genetics - HTN, stroke, genetic disorders
What are the 3 most common modifiable risk factors for stroke?
HTN >140/> 90
Type 2 diabetes
CV disease
What are modifiable risk factors? (13)
- HTN - most common
- diabetes - leads to plaque buildup
- CV disease
- obesity
- Obstructive sleep apnea - 72% of stroke patients have sleep apnea and severe sleep apnea doubles risk for stroke
- physical inactivity
- diet
- blood disorders - clotting disorders
- arrhythmias - a-fib increases CVA risk 5x
- hyperglycemia - leads to plaque buildup
- smoking - 2-4x increased risk
- alcohol
- recreational drug use
What are the 2 major types of strokes? What causes them?
ischemic strokes - caused from fatty deposits in lining of artery (atherosclerosis)
hemorrhagic - rupture of artery due to weakening of vessel wall
What is the difference between embolic and thrombotic strokes?
embolic - blockage from clot that travels from elsewhere
thrombotic - blockage from clot within involved artery
Explain the difference between ischemia and infarction.
ischemia - the diminished volume of perfusion
infarction - cellular response to lack of perfusion
What are the two major types of hemorrhagic strokes? For each, what are the major causes?
Intracerebral hemorrhage - caused by HTN
Subarachnoid hemorrhage -caused by aneurysm and arteriovenous malformation (AVN)
What is TIA? What are its causes?
transient ischemic attack - mini-stroke or warning signs
- caused by focal brain, spinal cord, or retinal ischemia w/o acute infarction
- temporary blockage that dissolves on its own or gets dislodged naturally
What are the steps of the ischemic cascade?
1) Loss of ATP production
2) Stoppage of Na/K pump
3) Excess intracellular Na+ leads to influx of H2O, causing cytotoxic edema (swelling)
4) Excess intracellular Ca2+ build up due to stoppage of Na/K pump
- leads to increase in glutamate and hyper-excitability of neurons - this is toxic to neuron
- activates degradative enzymes that breakdown neuron
- free radicles released
5) Breakdown of mitochondria in response to toxins and unstable cell membrane
- release apoptotic factors - programmed cell death
What parts of the ischemic cascade are considered part of the necrotic responses versus apoptotic stages of stroke pathophysiology?
Necrosis
1) Loss of ATP production
2) Stoppage of Na/K pump
3) Excess intracellular Na+ leads to influx of H2O, causing cytotoxic edema (swelling)
4) Excess intracellular Ca2+ build up due to stoppage of Na/K pump
Apoptosis
5) Breakdown of mitochondria in response to toxins and unstable cell membrane
What is meant by the term, ‘penumbra?’
area of programmed cell death
- the area around stroke that is no longer salvageable due to apoptosis
How does the onset of a stroke differ based on the type of stroke occurring?
thrombotic - gradual onset, days to weeks
- most common in late Pm or first thing in AM (wake up strokes)
embolic - minutes to hours
hemorrhagic - immediate, severe
What does BEFAST stand for?
Balance Eyes Face Arms Speech Time
What does NIHSS measure?
Consciousness Vision Motor & Coordination Sensory & Perception Language & Fluency Behavior
What are NIHSS cut off scores?
> 25 very severe - typically require long-term skilled care
15-24 severe
5-14 mild-moderately severe - typically require acute patient rehab
1-5 mild - 80% discharged home from acute hospital
What is typically involved in the medical workup when a stroke is suspected?
- diagnostic imaging (CT, MRI, angiogram, ultrasound, arteriography)
- EKG
- Chest radiography
- CBC
- 24-hour cardiac monitoring
Under what specific circumstances is a CT preferred over an MRI? (8)
- head trauma
- financial concerns
- acute hemorrhage
- speed needed
- skull fx
- calcified lesion
- claustrophobic patient
- pacemaker or other metallic implants
Under what specific circumstances is an MRI preferred over a CT? (5)
- subtle areas of the tumor, infarct demyelination, etc
- brainstem lesion
- ischemia
- subacute or chronic hemorrhage
- anatomy detail needed
What is the major goal of ischemic stroke? How is this done?
revascularization using clot buster (tPA) or permissive HTN to push clot through
What is the major goal of hemorrhagic stroke? How is this done?
reduce intracranial pressure with anti-hypertensives (strict BP parameters)
What are some general PT considerations for intracranial pressure management post-stroke?
- monitor S & S
- avoid activity that may exacerbate
- mobility contraindicated if > 20 mmHg
Explain what a midline shift is. Why is it problematic post-stroke?
- shifting of structures into contralateral hemispheric space due to fluid buildup
- is a poor prognostic indicator for functional recovery
What are some general PT considerations for midline shifts seen post-stroke?
- evaluate for bilateral symptoms
- monitor closely for neurological decline
What are some general PT considerations when a patient is diagnosed with a brain herniation?
PT not indicated
