Week 1- CVA Introduction and Pathophysiology Flashcards
(99 cards)
1
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PART 1: INTRO AND BACKGROUND
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PART 1: INTRO AND BACKGROUND
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What is a stroke?
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Event unique to CNS when there is a stoppage of blood supply to vital neurons leading to loss of O2 and nutrients. This leads to irreversible neuronal death and subsequent neurological symptoms.
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What are the 2 ways a stroke can happen?
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- blockage
- hemorrhage
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PART 2: RISK FACTORS
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PART 2: RISK FACTORS
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__-__% of strokes are preventable.
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80-91%
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What are the non-modifiable risk factors associated with strokes?
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- Women > Men (early menopause, pregnancy)
- Age > 55 (x2 risk every decade after age 55)
- Race (minorities higher risk)
- Prior Stroke, TIA, and/or MI
- Genetics
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What is the most common modifiable risk factor for strokes?
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HYPERTENSION (>140/90)
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- What is the primary intervention for BP?
- What else can be done?
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-Medications
- Diet (Na restriction)
- Minimize alcohol
- Minimize dairy
- Aerobic activity
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What are the (3) most common modifiable risk factors for stroke?
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- HTN
- Diabetes
- CV Disease
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Is the association between diabetes and strokes higher in males or females?
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Females
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What are some other modifiable risk factors for stroke?
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- Obesity
- Obstructive Sleep Apnea
- Physical Inactivity
- Diet
- Blood Disorders
- Arrhythmias
- Hyperglycemia
- Smoking
- Alcohol
- Recreational Drug Use
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Obesity is defined as a BMI>__.
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30
17
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What is obstructive sleep apnea?
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- When going to bed, you don’t do as good a job at getting O2 through the body. People often enter state of hypoxia when asleep.
- Severe obstructive sleep apnea is associated with a 2x risk of stroke.
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Obstructive sleep apnea is associated with ____-__ strokes.
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wake-up strokes due to shift in O2 utilization
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Is malnutrition associated with increased risk of stroke?
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Yes
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What types of blood disorders are associated with increased risk of stroke?
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Ones that increase risk of clotting.
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- What is the biggest Arrhythmia associated with stroke?
- It increases your risk for stroke _x.
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- Atrial fibrillation (a.fib)
- 5x
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Current smokers have a _-_x increased risk compared with non-smokers or people who quit more than 10 years ago.
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-2-4x
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Can alcohol be preventative for strokes?
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Yes, 2 drinks for men and 1 for women. After that the risk goes up with ischemic strokes.
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PART 3: TYPES OF STROKE AND ISCHEMIC CASCADE
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PART 3: TYPES OF STROKE AND ISCHEMIC CASCADE
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Strokes are classified by what 2 things?
- Mechanism (why)
| - Location
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What are the 2 mechanisms for strokes?
- Ischemic- Clot blocks blood flow to an area of the brain.
| - Hemorrhage- Bleeding occurs inside or around brain tissue.
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What is the most common form of stroke?
Ischemic (70-80%)
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What is the cause of ischemic strokes?
| -What are 2 types of ischemic strokes?
- Atherosclerosis- Gradual worsening of fatty deposits lining arterial walls.
- Thrombotic and embolic
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What is the difference between thrombotic and embolic strokes?
- Thrombotic strokes are caused by a blood clot that develops in the blood vessels inside the brain.
- Embolic strokes are caused by a blood clot or plaque debris that develops elsewhere in the body and then travels to one of the blood vessels in the brain through the bloodstream.
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Is a thrombotic or embolic stroke more common?
Thrombotic are most common types of stroke.
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What is the main cause of embolic strokes?
A-fib (known to cause clots in heart)
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What percentage of strokes are Hemorrhagic strokes?
20-30%
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What is the cause of Hemorrhagic strokes?
Rupture of artery due to weakening of vessel wall.
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- What are the 2 types of Hemorrhagic strokes?
| - Which is more common?
- Intracerebral Hemorrhage (ICH)
- Subarachnoid Hemorrhage (SAH)
-ICH more common
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What is the number 1 cause of ICH?
HTN
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What is the number 1 cause of SAH and what is it?
- Aneurysm- enlargement/ballooning of weakened vessel wall (typically asymptomatic until rupture)
- Arteriovenous Malformation (AVM)- tangle of abnormal blood vessels connecting arteries and veins
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- AVMs are __________.
| - What are the symptoms of AVM?
- Congenital
| - Seizures, HA, weakness, speech and vision, OR can be asymptomatic
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What is a Transient Ischemic Attack (TIA)?
- Transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction.
- Known as "mini stroke" or "warning stroke"
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Patients who have had a TIA are at a __x increased chance for eventual CVA. The highest risk for stroke is in the first ___ days post TIA.
- 10x
| - 90 days
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What is the Ischemic Cascade?
After a stroke, a cascade of damaging cellular events triggered by ischemia begins to spread across brain tissue.
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What are the (5) steps in 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".
4.)Excess intracellular Ca2+ build up due to stoppage of Na/K pump.
-Leads to excess glutamate release at axon terminal
-Hyper-excitable cycle transpires throughout
nearby neurons
- ="Excitotoxicity"
-Activates enzymes that break down proteins in
neuron and cell membrane.
-Release of free radicals.
5.) Breakdown of mitochondria in response to toxins and unstable cell membrane.
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What happens with the loss of ATP production in the ischemic cascade?
- Switch from aerobic to anaerobic.
- Build up of lactic acid.
- Causes step 2 (stoppage of Na/K pump)
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- Steps 3 and 4 of the Ischemic Cascade causes neuronal death via ___________.
- Step 5 of the Ischemic Cascade causes neuronal death via ___________.
- NECROSIS
| - APOPTOSIS
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- What area of an ischemic stroke is unsalvageable?
| - What area of an ischemic stroke is salvegeable?
- Infarct Core
| - Penumbra
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Neuronal death within the core occurs within ________. Surrounding tissue (penumbra) death occurs within _________.
- MINUTES
| - HOURS
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Every minute in which a large vessel ischemic stroke goes untreated:
___ million neurons lost
____ billion synapses lost
__ miles of myelinated axonal fibers lost
- 1.9 million
- 1.38 billion
- 7 miles
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PART 4: DIAGNOSIS
PART 4: DIAGNOSIS
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What are the 3 components to a diagnosis of a stroke?
- History of Present Illness (HPI)
- Clinical Examination
- Medical Workup
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What are the 2 parts of the HPI?
- PMHx/Systems Review
| - Description of Symptoms
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Onset of Symptoms:
- Thrombotic = ?
- Embolic = ?
- Hemorrhagic = ?
- Aneurysm = ?
- AVM = ?
Thrombotic= gradual onset, days to weeks (most common in late PM or first thing AM, may see "wake-up" strokes")
Embolic=more abrupt than thrombotic, minutes to hours
Hemorrhagic= immediate, severe
- Aneurysm= asymptomatic until rupture
- AVM= may have preceding symptoms (seizures, etc)
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Types of symptoms are largely dependent of what?
Location of insult
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What are some common complaints of stroke patients?
- imbalance
- paresthesias
- weakness
- blurry/double vision
- "worst HA of my life" common with hemorrhages, particularly aneurysms
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Acutely a ___________ screen is done during the Clinical Examination to determine the need for further workup. Eventually a complete neurological evaluation will be completed.
neurological
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What is the (B.E.) F.A.S.T. pneumonic for spotting a stroke?
- Balance (sudden loss?)
- Eyes (lost vision?)
- Face (face look uneven?)
- Arms (weak or numb?)
- Speech (slurred? confused?)
- Time
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What is the NIHSS?
National Institutes of Health Stroke Scale
| -Quantitative measure of symptoms associated with cerebral infarcts.
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The NIHSS is most commonly used in the _______ phases of CVA.
acute
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What are the NIHSS cut-off scores for identifying stroke severity?
- >25 = Very Severe
- 15-24 = Severe
- 5-14 = Mild-Moderately Severe
- 1-5 = Mild
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NIHSS Scores:
- Severe and Very Severe NIHSS scores frequently require what?
- Mild-Moderately Severe NIHSS scores typically require what?
- __% of Mild scores will be discharged home from acute hospital.
- Frequently require long-term skilled care.
- Typically require acute patient rehabilitation.
- 80%
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What are the parts of a Medical Workup?
- Diagnostic Imaging (head CT, later MRI)
- EKG
- Chest Radiography
- CBC
- 24h cardiac monitoring
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What are the most common imaging that we will do of brain/brainstem?
CT or MRI
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When is an MRI preferred over a CT?
- subtle areas of tumor, infarct, demyelination
- brainstem lesion
- ischemia
- subacute or chronic imaging
- anatomy detail needed
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When is a CT preferred over an MRI?
1
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PART 5: ACUTE MANAGEMENT
PART 5: ACUTE MANAGEMENT
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What are the (3) main acute CVA complications?
- Cerebral Edema
- Vasospasms
- Seizures
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What (3) things can cerebral edema lead to?
- ↑ Intracranial Pressure (ICP)
- Midline shift
- Brain herniation
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What is ICP?
Pressure exerted by fluids in the brain (CSF, interstitial fluid) that if elevated, can lead to further damage to brain tissue.
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What are the PT considerations for ↑ICP?
- Monitor for S/S
- Avoid activity that may exacerbate
- Mobility usually contraindicated if >20mmHg
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What is midline shift?
- Shifting of structures into contralateral hemispheric space due to fluid buildup.
- Poor indicator for functional recovery.
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What are the PT considerations for midline shift?
- evaluate for bilateral symptoms
| - monitor for neurological decline
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What is brain herniation?
Protrusion of brain tissue through intracranial barrier (ex. foramen magnum)
-Very poor prognostic indicator, typically leads to mortality.
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What are the PT considerations for brain herniation?
PT usually not indicated.
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What is Vasospasm?
Persistent vasoconstriction and dilation of the blood vessels. It is typically asymptomatic, but can be highly dangerous.
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Vasospasm is most commonly seen post ______ and has a greater risk ___ days post bleed.
- SAH
| - 7 days
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- How are Vasospasms monitored?
| - What is the treatment?
- Transcranial Doppler (TCD)
| - Permissive HTN
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What are the PT considerations for Vasospasms?
Mobility contraindicated with mod-severe vasospasm, consult MD prior to mobility
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What is a seizure?
burst of uncontrolled electrical activity between brain cells that causes temporary abnormalities in muscle tone or movements, behaviors, sensations or states of awareness.
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Seizures are most commonly seen post _____ and has a greater risk in the first ____ hours post.
- ICH
| - 48 hours
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- How are Seizures monitored?
| - What is the treatment?
- Electroencephalogram (EEG)
| - Anti-seizure medication, surgery rare
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What are the PT considerations for Seizures?
Mobility usually deferred until >24hr after quiet EEG.
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What are some other Acute CVA complications in addition to the main 3?
- HTN
- Infection
- Fever
- Pneumonia
- Pressure Ulcers
- Hyperglycemia
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Ischemic Stroke:
- What is the major goal when treating ischemic strokes?
- What are some ways this is done?
-Revascularization
- Tissue Plasminogen Activator (tPA) "clot buster" given within 3-8hr window.
- Permissive HTN (<220/110) to force blood flow through.
- Antiplatelets for first 24-48 hours.
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Hemorrhagic Stroke:
- What is the major goal when treating hemorrhagic strokes?
- What are some ways this is done?
-Reduce ICP
- Sedation, hyperosmolar agents, hyperventilation.
- Anti-hypertensives for BP control (<130/80)
- Vasospasm prevention and management (SAH)
- Antiseizure prophylaxis (ICH)
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What are the surgical interventions done for Ischemic Strokes?
- Mechanical Embolectomy
- Mechanical Thrombectomy
- Carotid Endarterectomy
-ALL involve breaking up clots
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What are the surgical interventions done for Hemorrhagic Strokes?
- Endovascular Coiling (Aneurysm) = Inserts tube and places wires/coils which mesh up into ball and causes a blood clot to form and block spot of aneurysm.
- Surgical Clipping (Aneurysm) = Clip and mechanically close at neck of aneurysm.
- Resection (AVM) = Removal of AVM
- Embolization (AVM, Hemorrhage) = Surgical glue at area of rupture.
- Endoscopic Evacuation (Hemorrhage) = Sucking out blood.
- Craniotomy (Any) = Removal of flap of bone to allow access to area.
- Craniectomy (Any) = More involved surgery where large piece of bone is removed and kept off to help manage swelling.
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PART 6: PROGNOSTIC CONSIDERATIONS
PART 6: PROGNOSTIC CONSIDERATIONS
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What type of information should we consider when predicting outcomes?
- Type, stage, and location of diagnosis
- Severity of impairments
- Age
- Comorbidities
- Medical course
- Prior level of function
- Current level of function
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What are some questions the PT may ask when predicting patient outcomes?
- Is the patient a good rehab candidate?
- Will the patient be able to return home? Family supports?
- What type of locomotion will this patient likely rely on long-term?
- Prognosis for UE? ADL prognosis?
- What can we expect from this patient in 6 months? 12 months?
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What are the major prognostic indicators for CVA?
- Time to medical intervention
- Type of medical intervention
- Initial NIHSS score
- Age
- Education level
- Family support
- PLOF
- Ambulatory on evaluation (IP rehab)
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- ____________ Strokes have a higher mortality rate acutely, but a better prognosis for neuro-recovery long-term.
- ____________ Strokes have a lower mortality rate, but tend to demonstrate slower and less recovery.
- Hemorrhagic
| - Ischemic
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The first ___ months is the crucial period for rehabilitation and neuro recovery. Evidence supports possibility of significant neuro recovery up to ___ months post injury.
- 3 months
| - 18 months
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List these areas of strokes from most disability to least disability:
- ACA
- PCA
- MCA
- Brainstem
- Multiple vascular territories
- Cerebellar
- Small Vessel Stroke
- Multiple vascular territories
- MCA
- ACA
- PCA
- Brainstem
- Small Vessel Stroke
- Cerebellar
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What are some common impairments seen with UE recovery?
- paresis
- loss of isolated movement
- abnormal muscle tone
- sensory changes
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Are the UE or LE usually more involved in strokes?
UE
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80% of patients experience acute paresis of the UE with only __% reported to achieve full functional recovery.
33%
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What are some positive prognostic indicators for UE recovery (4 weeks post injury)?
- Early active finger extension, grasp release, shoulder shrug and shoulder abduction observed.
- Absence of additional nonmotor impairments, such as somatosensory loss, visual field loss and/or neglect.
- Presence of a measurable grip strength or active shoulder flexion.
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What are some positive prognostic indicators for return to ambulation?
- Ambulation on evaluation (IRF)*
- Balance scores on evaluation (BBS, Romberg, DGI)*
- Minimal loss of LE strength* and somatosensory function
- No evidence of perceptual, visual, or cognitive deficits
- Healthy BMI
- Younger age (<65)
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Gait Speed:
- _______: household ambulation
- _______: limited community ambulation
- _______: unlimited community ambulation
- <0.4m/s
- 0.4-0.8m/s
- 0.8-1.2m/s
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__-__% of stroke survivors regain functional independence.
| -__% of survivors achieve a full recovery in physical function.
- 50-70%
| - 14%
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What are some additional prognostic considerations?
- Cognitive deficits
- Activity intolerance
- Cardiac disease (75% of stroke survivors)
- Depression
- Fatigue
