Week 1- CVA Introduction and Pathophysiology Flashcards
PART 1: INTRO AND BACKGROUND
PART 1: INTRO AND BACKGROUND
What is a stroke?
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.
What are the 2 ways a stroke can happen?
- blockage
- hemorrhage
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PART 2: RISK FACTORS
PART 2: RISK FACTORS
__-__% of strokes are preventable.
80-91%
What are the non-modifiable risk factors associated with strokes?
- 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
What is the most common modifiable risk factor for strokes?
HYPERTENSION (>140/90)
- What is the primary intervention for BP?
- What else can be done?
-Medications
- Diet (Na restriction)
- Minimize alcohol
- Minimize dairy
- Aerobic activity
What are the (3) most common modifiable risk factors for stroke?
- HTN
- Diabetes
- CV Disease
Is the association between diabetes and strokes higher in males or females?
Females
What are some other modifiable risk factors for stroke?
- Obesity
- Obstructive Sleep Apnea
- Physical Inactivity
- Diet
- Blood Disorders
- Arrhythmias
- Hyperglycemia
- Smoking
- Alcohol
- Recreational Drug Use
Obesity is defined as a BMI>__.
30
What is obstructive sleep apnea?
- 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.
Obstructive sleep apnea is associated with ____-__ strokes.
wake-up strokes due to shift in O2 utilization
Is malnutrition associated with increased risk of stroke?
Yes
What types of blood disorders are associated with increased risk of stroke?
Ones that increase risk of clotting.
- What is the biggest Arrhythmia associated with stroke?
- It increases your risk for stroke _x.
- Atrial fibrillation (a.fib)
- 5x
Current smokers have a _-_x increased risk compared with non-smokers or people who quit more than 10 years ago.
-2-4x
Can alcohol be preventative for strokes?
Yes, 2 drinks for men and 1 for women. After that the risk goes up with ischemic strokes.
PART 3: TYPES OF STROKE AND ISCHEMIC CASCADE
PART 3: TYPES OF STROKE AND ISCHEMIC CASCADE
Strokes are classified by what 2 things?
- Mechanism (why)
- Location
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.
What is the most common form of stroke?
Ischemic (70-80%)
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
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.
Is a thrombotic or embolic stroke more common?
Thrombotic are most common types of stroke.
What is the main cause of embolic strokes?
A-fib (known to cause clots in heart)
What percentage of strokes are Hemorrhagic strokes?
20-30%
What is the cause of Hemorrhagic strokes?
Rupture of artery due to weakening of vessel wall.
- What are the 2 types of Hemorrhagic strokes?
- Which is more common?
- Intracerebral Hemorrhage (ICH)
- Subarachnoid Hemorrhage (SAH)
-ICH more common
What is the number 1 cause of ICH?
HTN
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
- AVMs are __________.
- What are the symptoms of AVM?
- Congenital
- Seizures, HA, weakness, speech and vision, OR can be asymptomatic
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”
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
What is the Ischemic Cascade?
After a stroke, a cascade of damaging cellular events triggered by ischemia begins to spread across brain tissue.
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.
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)
- Steps 3 and 4 of the Ischemic Cascade causes neuronal death via ___________.
- Step 5 of the Ischemic Cascade causes neuronal death via ___________.
- NECROSIS
- APOPTOSIS
- What area of an ischemic stroke is unsalvageable?
- What area of an ischemic stroke is salvegeable?
- Infarct Core
- Penumbra
Neuronal death within the core occurs within ________. Surrounding tissue (penumbra) death occurs within _________.
- MINUTES
- HOURS
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
PART 4: DIAGNOSIS
PART 4: DIAGNOSIS
What are the 3 components to a diagnosis of a stroke?
- History of Present Illness (HPI)
- Clinical Examination
- Medical Workup
What are the 2 parts of the HPI?
- PMHx/Systems Review
- Description of Symptoms
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)
Types of symptoms are largely dependent of what?
Location of insult
What are some common complaints of stroke patients?
- imbalance
- paresthesias
- weakness
- blurry/double vision
- “worst HA of my life” common with hemorrhages, particularly aneurysms
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
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
What is the NIHSS?
National Institutes of Health Stroke Scale
-Quantitative measure of symptoms associated with cerebral infarcts.
The NIHSS is most commonly used in the _______ phases of CVA.
acute
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
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%
What are the parts of a Medical Workup?
- Diagnostic Imaging (head CT, later MRI)
- EKG
- Chest Radiography
- CBC
- 24h cardiac monitoring
What are the most common imaging that we will do of brain/brainstem?
CT or MRI
When is an MRI preferred over a CT?
- subtle areas of tumor, infarct, demyelination
- brainstem lesion
- ischemia
- subacute or chronic imaging
- anatomy detail needed
When is a CT preferred over an MRI?
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PART 5: ACUTE MANAGEMENT
PART 5: ACUTE MANAGEMENT
What are the (3) main acute CVA complications?
- Cerebral Edema
- Vasospasms
- Seizures
What (3) things can cerebral edema lead to?
- ↑ Intracranial Pressure (ICP)
- Midline shift
- Brain herniation
What is ICP?
Pressure exerted by fluids in the brain (CSF, interstitial fluid) that if elevated, can lead to further damage to brain tissue.
What are the PT considerations for ↑ICP?
- Monitor for S/S
- Avoid activity that may exacerbate
- Mobility usually contraindicated if >20mmHg
What is midline shift?
- Shifting of structures into contralateral hemispheric space due to fluid buildup.
- Poor indicator for functional recovery.
What are the PT considerations for midline shift?
- evaluate for bilateral symptoms
- monitor for neurological decline
What is brain herniation?
Protrusion of brain tissue through intracranial barrier (ex. foramen magnum)
-Very poor prognostic indicator, typically leads to mortality.
What are the PT considerations for brain herniation?
PT usually not indicated.
What is Vasospasm?
Persistent vasoconstriction and dilation of the blood vessels. It is typically asymptomatic, but can be highly dangerous.
Vasospasm is most commonly seen post ______ and has a greater risk ___ days post bleed.
- SAH
- 7 days
- How are Vasospasms monitored?
- What is the treatment?
- Transcranial Doppler (TCD)
- Permissive HTN
What are the PT considerations for Vasospasms?
Mobility contraindicated with mod-severe vasospasm, consult MD prior to mobility
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.
Seizures are most commonly seen post _____ and has a greater risk in the first ____ hours post.
- ICH
- 48 hours
- How are Seizures monitored?
- What is the treatment?
- Electroencephalogram (EEG)
- Anti-seizure medication, surgery rare
What are the PT considerations for Seizures?
Mobility usually deferred until >24hr after quiet EEG.
What are some other Acute CVA complications in addition to the main 3?
- HTN
- Infection
- Fever
- Pneumonia
- Pressure Ulcers
- Hyperglycemia
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.
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)
What are the surgical interventions done for Ischemic Strokes?
- Mechanical Embolectomy
- Mechanical Thrombectomy
- Carotid Endarterectomy
-ALL involve breaking up clots
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.
PART 6: PROGNOSTIC CONSIDERATIONS
PART 6: PROGNOSTIC CONSIDERATIONS
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
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?
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)
- ____________ 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
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
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
What are some common impairments seen with UE recovery?
- paresis
- loss of isolated movement
- abnormal muscle tone
- sensory changes
Are the UE or LE usually more involved in strokes?
UE
80% of patients experience acute paresis of the UE with only __% reported to achieve full functional recovery.
33%
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.
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)
Gait Speed:
- _______: household ambulation
- _______: limited community ambulation
- _______: unlimited community ambulation
- <0.4m/s
- 0.4-0.8m/s
- 0.8-1.2m/s
__-__% of stroke survivors regain functional independence.
-__% of survivors achieve a full recovery in physical function.
- 50-70%
- 14%
What are some additional prognostic considerations?
- Cognitive deficits
- Activity intolerance
- Cardiac disease (75% of stroke survivors)
- Depression
- Fatigue