Lecture 3: Cerebrovascular Disorders (and first 12 slides SCI) Flashcards
What is the primary cause of a stroke?
Cerebrovascular disease
Words that mean stroke
* Brain attack
* Brain infarct or insult
* Cerebovascular accident
KNOW: Stroke is the second leading cause of death (behind heart disease)
Leading cause of long term disability in adults in the US
Strokes have an impact everywhere
Sudden, devastating focal vascular event that results in destruction of surrounding brain tissue
* Two different kinds
Stroke
Consequence of changes in both function of the heart and integrity of the vessels supplying blood to the brain
Etilogy: ischemic or hemorrgagic
* Ischmic through thrombous/embolism
Rupture / bleeding =
Hemorrhagic
* one of the two subclasses of strokes
Thrombosis, embolism, hypoperfusion = what kidn of stroke
Ischemic
Vascular terriotry = arterial supply
management categories of stroke:
* TIA
* Minor stroke
* Major stroke
* Deteriorating stroke
* Young stroke
Transient ischemic attack
* How long are symptomes
Symptoms no greater than 24 hours
* However, now they’re saying TIA’s might be longer than 24, however, were sticking w/ this defintion
Stable w/ minimal impairments is what kind of stroke?
Minor
Stable w/ severe impariements is what kind of stroke?
Major
Neuro status worsens after admission is what kind of stroke?
Deteriorating stroke
Young stroke is age less than
45
KNOW: TIA is often interchangeable w/ minor stroke because we think that 24 hours might not be a massive factor
What percent of strokes are ischemic? What about hemorrhagic
85% = ischemic
15% = hemorrhagic
at the bottom are things that might predispose someone to having a certain kind of stroke
KNOW: Several genes have been associated w/ ischemic strokes
what is the most important modifiable risk factor for strokes?
Hypertension
* strong direct and linear relationship of BP and stroke risk
Is diabetes a risk factor for stroke?
* How much does it increase the chance by?
Yes
2x increase risk of stroke
20% of deaths among people w/ diabetes are stroke releated
Diabites can cause large artery atherosclerosis, increased cholesterol levels and plaque formation
To help prevent a stroke
* maintain healthy diet
* Exercise
* Abstrain from tobacco
Infarct =
Cell death
Surrounding area of damaged tissue =
Penumbra
Stroke pathogensis
That penumbra will inflame and exaserbate that infarct (meaning the inflammatory response can worsen the damage in this area)
Penumbra = area that is damaged after a stroke but not dead yet
Metabolic cascade will continue
* NOTE stroke can be caused by TBI
It matters where the stroke is to what kind of deficits we see
This is what out glutamate is doing in a stroke
What are symptoms like initailly w/ stroke?
My be transient (come and go) w/ focal symptoms (not diffuse but more pinpointed)
But then whatever stays put is the actual damage
Defeicits w/ stroke
Good functional outcomes (acute ischemic stroke) begin with recognition of WHEN stroke symptoms occur
what is FAST?
FAST
* Face
* Arm
* Speech
* time
Also add education on pervention
Public awareness remains poor
Lack of knowledge leads to delay between symptom onset and hospitalization
reuslts in decreased access and benefits of thrombolysis (in an ischemic stroke)
* In this kind of stroke you can get a medication that can reverse the effects of this stroke (but need this medication quickly)
Organizaed inpatient care in a stroke unit reduces death and dependence and increases the likelihood of dischage to home
Decreased mortality includes
* Review by a stroke consultatnt within 24 hours of admission
* Nutrition screening and formal swallow assessment within 72 hours
* Antiplatelet therapy and adequate fluid and nutrition for the first 72 hours
* Antihypertensive medications are consisdered in extreme hypertension w/ systolic blood pressure 220 mmHg or greater
* Hypoglycemia with levels less than 60 mg/dL is frequently found in patients w/ stroke like symptoms; thus prehospital glucose testing is crtical
Warning signs of a stroke
Sudden weakness or numbness of the face, arm, or leg
* Because its a sudden cut off of blood supply
Sudden dimness or loss of vision, particiulary in one eye
Sudden difficulty speaking or understanding speech
Sudden severe HA with no known cause
Unexplained dizziness, unsteadiness, or sudden falls
normally its a combination of multiple factors listed here
What thrombolytics do we use for an ischemic stroke?
* What is our time frame that they are useful?
*
Tissue plasminogen activator (tPA) - essentially a thrombolytic that dissolves blood clots
Must be used in 4.5 hour or less window in appropriate patients
NOTE: drugs to decrease excitotoxic damage post stroke are also utilized
Neurotrophic factors:
* Nerve frowth factor - suppports survivial and growth of neural cells
* Brain derived neurotrophic factor - neuron survival
Prophalyaxis medications
* Anticoagulants - thin blood to reuce clotting risk and prevent existing clots from expanding
* Antiplatelet therapy - prevents clumbing or platelets (asprin)
* Antihypertensive agents - control HTN
* Lipid lowering agents
Other
* Angiotensin II receptor antagonists, anticholesterol agents, antispasmodics, antispastics, anticonvulsants, antidepressants, GABA receptor antagonists, neurotoxins
Blood clot that forms int he vein but is stagnant
Thrombosis
Moving clot, obstruction of an artery, heart most common source
Embolic occulusion (embolism)
What is the most common site of artherosclerosis and atherothrombosis leading to a stroke?
Proximal ICA
* Think about how much else is occluded if this area gets occluded (because it supplies tons of areas)
Secondary vascular responses w/ ischemic stroke
* Further microvascular occulsions increase and continue to impair blood flow
* Cell death
* Astroctyte swelling –> single artery occulsion
* Narrowing of lumina of microvessels
Parenchyma
* Is it vulnerable or not vulnerable to interruptions in its blood supply?
* When does neural death occur due to lack of BF?
Tissue of brain
NOTE: It is highly vulnerable to an interruption in its blood supply
Neuronal death or infarction, occurs when CBF is less than 8 to 10 mL/100 mg/minute
Frequently, in an acute infarction, a portion of the affected brain receives no BF, and is not salveragble. What is this area of unsalvagable brain tissue called?
Ischemic core
What is worse in a stroke. When the blockage is more proximal or when its more distal?
Proximal - more will be cut off
* results in the area of hypoxia being greated than if the clot is lodged in a more distal part of the artery
Because of the collatearl circulation provided by the circle of Willis, some areas of the brain are supplied by more than one artery, When one artery is blocked, circulation is provided to the tissues through the blood supply of other arteries
Group of pathologies that share common characteristics
Syndromes
Knowing what kind of stroke the pt had will help us tailor their treatment (if i know 1 affects leg more than arm)
* she said to listen for what she underscored because theres a lot here
What is the most common site of occulsion in stroke?
Middle cerebral artery
What does the middle cerebral artery supply?
* What does it stem from?
* 4 possible deficits (from stroke)
* whats more affected the UE or LE
Supplies:
1) Basal ganglia
2) Internal capsule
3) Most of latearl hemisphere
Stems from the ICA
Possible deficits:
1) Contralateral (because the track crosses) spastic hemiparesis and sensory loss of the face, UE, and LE -W/ the face and UE more involved than the LE
* This is important to pick up on because it hels us dilinate it from other kinds of strokes
2) Aphasia - difficulty speaking
3) Perceptual deficits (EX: unilatearl neglect, anasognosia (lack of awareness of whats going on), apraxia, and spatial disorganization) - most common w/ R hemisphere damage
4) Homonymous Hemianopsia - vision deficit
aphasia
speaking
Anterior cerebral artery
* Supplies (3)
* Stems from
* Possible deficits (1)
* whats affected more UE or LE
Supplies:
1) Frontal lobe
2) Paretal lobe
3) part of internal capsule
Stems from ICA
Possible deficits
1) Contralatearl hemiparesis (because of tract crossing) and sensory loss with greater involvement of the LE than the upper extremeity because the somatoptopic organization of the medial aspect of the cortex includes the functional area for the LE
Which stroke has greater involvement of the LE the MCA or ACA?
ACA