CVA intro and pathophysiology Flashcards
In the US, how many people have a stroke every year?
795,000 (1 in 4 have already had a previous stroke)
What is the leading cause of serious long-term neurological disability?
Stroke (reduces mobility in over half of stroke survivors ages 65 and up)
What is the “stroke belt” of the United states? Are the incidence rates higher than national average?
The southeast, 30% higher than the national average
What are the five non-modifiable risk factors for a stroke?
-women > men
-Age > 55 years old
-Race (black/hispanic> than white
American indian
Alaskan native
-Prior stroke (TIA and/or MI)
-Genetics
What are the modifiable risk factors for a stroke?
HTN (# 1 and most common preventable cause of stroke)
Diabetes (hyperglycemia = increased arterial plaque buildup)
CV disease
Obesity
Obstructive sleep apnea (72% of patients who had a stroke were found to have sleep apnea)
Blood disorders (specifically clotting disorders)
Arrhythmias (A-fib increases stroke risk x 5)
Physical inactivity
Diet
Smoking
Alcohol
Recreational drug use
What is an ischemic stroke?
Terminology explained:
Ischemia denotes diminished volume of perfusion…Infarction is the cellular response to lack of perfusion.
Cause: Gradual worsening of fatty deposits lining arterial walls (atherosclerosis)
ischemic strokes account for 87% of all strokes
What are two types of ischemic stroke?
Thrombotic
-Blockage caused by clot form within involved artery
-Can occur anywhere!
Embolic
-Blockage caused by clot that travels from elsewhere in circulatory system
-Common origins of clot: heart, large arteries of upper chest and neck
-Typically affect distal portions of arteries and smaller arteries
What is a hemorrhagic stroke?
Rupture of artery due to a weakened vessel wall
What are two types of hemorrhagic stroke?
-Intracerebral Hemorrhage (ICH)*
Most common hemorrhagic CVA
1o Cause: HTN
-Subarachnoid Hemorrhage (SAH)
1o Cause: Aneurysm and Arteriovenous Malformation (AVM)
These are named based off of where they occur in the nervous system
What are two types of subarachnoid hemorrhage?
Aneurysm: enlargement/ballooning of weakened vessel wall
Typically, asymptomatic until rupture
Arteriovenous malformation (AVM): tangle of abnormal blood vessels connecting arteries and veins (50% will go onto causing CVA)
Symptoms: seizures, HA, weakness, speech and vision, or can be asymptomatic
arteriorvenous malformations are congenital
What is a transient ischemic attack (TIA)?
“A transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction.” (AHA 2014)
“Mini stroke” or “Warning stroke”
Symptoms last < 24 hours
There is a higher risk of a full stroke up to 90 days following a TIA
What is the difference between the infarct core and the penumbra of a stroke?
Infarct core is damaged badly via necrosis and results in neuronal cell death (the main area of the infarct)
Penumbra is potentially salvageable brain tissue surrounding the infarct core that is damaged as a result of apoptosis during a stroke
Leading intervention is to get care ASAP
What are some aspects of diagnosing a stroke?
-PMH
-Description of symptoms
Type of Symptoms
Largely dependent on location of insult
Common complaints: imbalance, paraesthesias, weakness, blurry or double vision,
“Worse HA of my my life” common with hemorrhages, particularly aneurysms
Aspects of diagnosing a stroke (part 2)
Description of Symptoms
Onset of Symptoms
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)
What does (B.E.F.A.S.T) stand for? (clinical examination s and s to look for)
Balance: does person have lack of balance all of a sudden?
Eyes: Has person lost vision in one or both eyes?
Face: Does the person’s face look uneven?
Arms: Is one arm weak or numb?
Speech: Is the person’s speech slurred?
Time: Call 911 fast
What is the National Institutes of Strokes Scale? (NIHSS)
Quantitative measure of symptoms associated with cerebral infarcts
Most commonly used in acute phases of CVA
What are the items and cut-off scores associated with NIHSS?
15 Items
Consciousness
Vision
Motor & Coordination
Sensory & Perception
Language & Fluency
Behavior
Cut-Off Scores: identify stroke severity
> 25 Very Severe
15-24 Severe : Frequently require long-term skilled care
5-14 Mild-Moderately Severe : Typically require acute patient rehabilitation
1-5 Mild: 80% will be discharged home from acute hospital
Research connecting these scores to prognostic outcomes in recovery, as well as placement after acute care
What is always used to confirm and determine severity of injury with stroke?
Brain imaging
Diagnostic Imaging
Head CT
Later, MRI
Additional tests: magnetic resonance angiogram, ultrasound, arteriography
Electrocardiography (EKG)
Chest radiography
Complete blood cell count (CBC)
24-hour cardiac monitoring
Which strokes show up better on MRIs?
Ischemic (review slide 23 for more info on what is preferred CT or MRI)
Which strokes are seen better on CT scans?
Hemorrhagic
What is the acute medical management of an ischemic stroke?
Major goal: Revascularization
Tissue plasminogen activator (tPA)
Up to 3-8 hour window
Permissive HTN
< 220/110
Antiplatelets for first 24-48 hours
tPA helps break up clots
What is the acute medical management of a hemorrhagic stroke?
Major goal: Reduce intracranial pressure (ICP) by minimizing bleeding
Sedation, hyperosmolar agents, hyperventilation
Anti-hypertensives for BP control
Strict BP parameters (< 130/80)
Vasospasm prevention and management (SAH)
Antiseizure prophylaxis (ICH)
What is acute surgical management of an ischemic stroke?
Surgical intervention
Mechanical Embolectomy
Mechanical Thrombectomy
Carotid Endarterectomy
Typically less invasive procedures
What is acute surgical management of a hemorrhagic stroke
Surgical intervention
Craniotomy
Craniectomy
Endovascular Coiling
Surgical Clipping
Resection
Embolization
Endoscopic Evacuation
typically more invasive procedures
What are some acute CVA complications related to cerebral edema?
↑ intracranial pressure (ICP)
ICP: pressure exerted by fluids in brain (CSF, interstitial fluid)
If elevated, can lead to further damage to brain tissue
PT Considerations: monitor for S&S of ↑ ICP, avoid activity that may exacerbate, mobility usually contraindicated if >20mmHg
Midline shift
Shifting of structures into contralateral hemispheric space due to fluid buildup
Poor prognostic indicator for functional recovery
PT Considerations: evaluate for bilateral symptoms, monitor closely for neurological decline
Brain herniation
Protrusion of brain tissue through rigid intracranial barrier (ex: foramen magnum
Very poor prognostic indicator, typically leads to mortality
PT Considerations: PT usually not indicated
What is a vasospasm?
Most commonly seen post SAH
Great risk: 7 days post bleed
Persistent vasoconstriction and dilation of the blood vessels
Typically asymptomatic, but can be highly dangerous
Monitoring: Transcranial Doppler (TCD)
Treatment: Permissive HTN
PT Considerations: Mobility contraindicated with moderate to severe vasospasm – consult MD prior to mobility
Info about seizures following a CVA?
Most commonly seen post ICH
Greatest risk: first 48 hours post ICH
Monitoring: Electroencephalogram (EEG)
Treatment: Anti-seizure medication, surgery rare
PT Considerations: Mobility usually deferred until >24hr after quiet EEG. Monitor closely for seizure activity
