Chapter 8 Stroke Flashcards
What is cerebral circulation?
Blood supply to the brain
What are the two main arteries that supply blood to brain?
1) internal Carotid arteries
2) Vertebral arteries
whats the other name for internal carotid arteries?
Anterior circulation
What is the other name for vertebral arteries?
Posterior circulation
where does the major artery systems ( anterior and posterior) connected?
Circle of Willis
what is circle of willis?
Interconnects both major artery systems ICA ( anterior) and VA (posterior)
what does brain requires?
Brain requires continuous flow of blood for glucose and oxygen
without blood flow, how long til metabolic disruption occurs?
- 30 seconds
without blood flow, how long till metabolism stops?
2 minutes
How long does cellular death occur without blood flow?
5 minutes :(
Blood flow to the brain is affected by? (3)
- Systemic BP
- Cardiac output ( how much blood the heart pumps per minute)
- Blood viscosity ( thickness of blood )
What is collateral circulation
- May develop in situations of low cerebral blood flow if the blood supply is cut off to one area of the brain due to blockage it can sometimes receive blood from different blood vessels
- Varies depending on individual patient and they develop to sustain perfusion when primary route are blocked.
What is Stroke?
Occurs when there is inadequate blood flow to the brain (ischemia) or hemorrhage into the brain
Stroke results in what?
results in death of brain cells
What area will be impaired or loss due to stroke? (3)
Functions such as movement, language, sensation that were controlled by the area of damage will be impaired or loss.
What is the leading cause of disability in Canada for adults
Stroke
Stroke is the __ leading cause of death in Canada
3rd
what is the major cause of stroke?
Atherosclerosis
What is Atherosclerosis
- Hardening and thickening of artery
Atherosclerosis is characterized by
- Characterized by deposits of lipids within intima of artery
- Soft deposits that hardens as we get older
What is the steps of Atherosclerosis?
1) Chronic endothelial Injury ( Damage endothelium)
2) Fatty streak
3) Fibrous Plaque
4) Complicated lesion
What causes endothelial Injury (Damaged endothelium) (7)
- Hypertension
- Tobacco use
- Hyperlipidemia
- Hyperhomocysteinemia
- Diabetes
- Infections
- Toxins
Explain what happens in fatty streak
- Lipids accumulate and migrate into smooth muscle cells
- Lipids comes and oxidize
- Ingested by macrophages becoming foam cells
- Foam cells creates fatty streaks
Fibrous Plaque
- Lipids and platelets stimulate arterial wall thickening
- Collagen covers fatty streak called fibrous plaque
- Vessels diameter becomes narrower
- Risk for plague rupture
Complicated lesions
- If plaque ruptures, the platelets aggregates to site leading to clot.
- Thrombus formation
- It can also break off and travel
Stroke Risk Factors
See Notes theres too much :(((
Which gender have more higher risk?
Men
How is age a risk factor?
Increase in age means higher risk for stroke due to effect of arteries. Over 65 years but can happen at any age.
How is genetics a risk factor?
- High cholesterol can be genetics
- Stroke family history have higher risk factor
How is ethnicity a risk factor?
- African, south asian, hispanic, Indigenous population
How is hypertention a risk factor?
- Highest risk factors
- increase pressure against intima of artery causes sheering stress leading to injury. Weakens artery which can cause clotting and bleeding.
What BP is high
BP of 140/90
How is dyslipidemia a risk factor?
- If its genetic then it is not modifiable
- increase LDL cholesterol causes more foam cells to develop and more fatty streaks
How is tobacco use a risk factor?
- Nicotine causes catecholamine release leading to increase HR and vasoconstriction which increase stress on arteries
- Carbon monoxide is a chemical irritant that causes further injury to endothelium.
How is diabetes a risk factor?
Lipid metabolism is affected with diabetes which increases cholesterol, endothelial dysfunction that leads to plaque formation.
How is obesity a risk factor?
- Associated with HTN, diabetes, increase cholesterol will predispose stroke because often times with high BMI comes those things hence why it would be helpful to engage in weight loss.
How is Elevated stress a risk factor?
Increase in stress results in increase SNS stimulation which increases BP
How is substance abuse a risk factor?
- Cocaine and meth can cause anterior spasm or cerebral vasospasm and can cause constriction of blood vessels
- oxygen demand can increase
why is vasospasm more dangerous in younger people who do meth and cocaine?
Young people does not have collaterals so if they get vasospasm brain cannot get blood flow.
How is alcohol a risk factor?
- Affects the liver causing low clotting factors and vitamin k
- If person cannot clot then theres a risk for hemorragic stroke
- Alcohol also increase in BP and contributes to weight gain
What is arteriovenous malformations?
Congenital abnormalities, Arteriovenous malformations (AVMs) happen when a group of blood vessels in your body forms incorrectly. In these malformations, arteries and veins are unusually tangled and form direct connections, bypassing normal tissues.
- Sometimes they are asymptomatic
How is arteriovenous malformation a risk factor?
- Stress or blood thinners can rupture the abnormal blood vessel which can cause hemorrhagic stroke
what kind of medications are risk factors for stroke?
- anticoagulant
- antiplatelets
How can Medications be a risk factor?
Increase risk for bleeding = hemorrhagic stroke
How can atrial fibrillation be a risk factor?
- clots can form due to atrial fibrillation ( heart shaking) which can lodge in the cerebral arteries and cause embolic stroke
How can sedentary be a risk factor?
- Lack of mobility and being sedentary can cause hypercuagulation (clots) state which can go to the brain and cause stroke
- higher risk for obesity and weight gain which can cause increase in BP and increase risk for stroke
How can birth control pills/ Hormone replacement therapy/pregnancy be a risk factor?
Increase in estrogen and progesterone can increase clotting factors, increase activity of clotting factors, enhance platelet aggregations, and hypercuagulable state.
- Dose dependent
How can TIA (transient ischemic attack) be a risk factor?
- It is a warning sign before full blown stroke
- High risk for stroke
- “mini stroke”
what are “modifiable” risk factors?
those factors that can potentially be altered through lifestyle changes and medical treatments, thus reducing the risk for stroke.
examples of modifiable risk factors?
- Hypertension
- Heart disease; Arterial fibrillation
- Diabetes
- ETC.. Look at notes
What does “non-modifiable” risk factor means? What does it include?
- Risk factors that we cannot change
- Age, race & ethnicity, gender, family history, heredity, and low birth weight.
What are the 2 classification of stroke?
1) Ischemic stroke
2) Hemorrhagic Stroke
What is Ischemic Stroke?
- Results of inadequate blood flow to the brain from partial or complete occlusion of an artery; there accounts for approximately 87% of all strokes.
Ischemic strokes are further divided into (subtypes):
1) Transient ischemic attack (TIA)
2) Thrombotic
3) Embolic
What is the precursor to the ischemic stroke?
Transient Ischemic Attack
What is transient ischemic attack (TIA)
- a temporary episode of neurological dysfunction caused by the focal brain, spinal cord, or retinal ischemia but without acute infarction of the brain.
How long does TIA symptom usually last?
- Symptoms usually last less than 24 hours
What are the symptoms of TIA? (5)
- Symptoms mimics stroke
- Weakness/ numbness to one side of the body
- Sudden vision changed
- Difficulty speaking and understanding language
- Slurred speech and confusion
TIA is a warning sign of?
Warning sign of cerebrovascular disease
Is TIA resolved?
Most resolved, but stroke risk increases immediately after the event
TIA signs and symptoms are based on?
depends on blood the blood vessels that is involved and the area of the brain that is ischemic.
What is TIA usually caused by? (2)
Atherosclerosis or atrial fibrillation
what is the most common type of ischemic stroke?
Thrombotic
What is Thrombotic Stroke
Blood clot form to the cerebral artery causing occlusion or blockage caused by arteriosclerosis
Where does thrombosis develops?
Develops in areas with atherosclerotic plaque
Thrombotic is associated with?
With atherosclerosis
What is the symptoms of Thrombotic symptoms?
- most patient with ischemic stroke do not have decrease level of consciousness (LOC) in the first 24 hour, unless it is owing to a brain stem stroke or other conditions such as seizure, increased ICP, or hemorrhage.
how long does symptoms progress? Thrombo
- First 72 hours
- Localize symptoms to cascade of events that happens which further damages.
Extent of thrombotic stroke depends on?
Depends on the size of lesion and presence of collateral circulation.
What percent of ischemic stroke, person had TIA previously?
30-50%
what is embolic Stroke
occurs when an embolus lodges in and occludes a cerebral artery, resulting in infarction and edema of the area supplied by the involved vessels.
Where does emboli originate from?
originate in the endocardium, break off, travel, and lodge in the cerebral circulation
What are the heart conditions associated with emboli? (6)
- valvular heart disease
- MI
- infective endocarditis
- rheumatic heart disease
- congenital heart defects
- Atrial fibrillation
Does embolic stroke have more or less warning signs compared to thrombotic stroke?
less warning signs
What is the onset of embolic stroke?
The of an embolic stroke is usually sudden and may or may not be related to activity.
hemorrhagic stroke accounts for __% of all strokes?
15%
What is hemorrhagic stroke?
They result from bleeding into the brain tissue itself ( intracerebral or intraparenchymal hemorrhage) or into the subarachnoid space or the ventricle.
What are the two subtypes of hemorrhagic stroke?
- Intracerebral hemorrhage
- Subarachnoid hemorrhage
which one has a high mortality rate? ischemic or hemorrhage?
Hemorrhage Stroke
What is intracerebral hemorrhage?
Bleeding within brain caused by a ruptured vessel; it accounts for about 10% of strokes.
What is the most important risk factor of intercerebral hemorrhage?Other causes?
- Hypertension and anterio-venous malformations
- others: aneurysm, Brain trauma, medication (anticoagulants)
When does intracerebral Hemorrhage usually occurs?
Usually occurs during periods of activity
what is the onset of intracerebral hemorrhage?
- Sudden onset of symptoms with progression over minutes and hours because of ongoing bleeding.
What are the symptoms of Intracerebral hemorrhage? (7)
- begins with severe headache “ worst headache of my life”
- neurological deficits
- nausea
- vomiting
- decrease LOC ( 50% of patient)
- symptoms of high ICP
- hypertension
What is subarachnoid hemorrhage?
Intracranial bleeding into space between pia matter and arachnoid layers ( where CSF is)
SAH is mostly caused by? Other causes?
- rupture or cerebral aneurysm
- other causes: AVM, Trauma, illicit drug use
SAH higher in men or women?
more common in women
Why are brain aneurysms considered “silent killers?”
Because there are usually no warning signs until they rupture
People who survive SAH gets?
Permanent neurological deficits
What is penumbra?
Around the core of area of ischemia is a boarder zone of reduced blood flow called penumbra, where ischemia is potentially reversible.
What are the clinical manifestations of : Acute stroke?(6)
- Sudden numbness/ weakness in the face, arm, or leg on one side of the body
- Sudden Confusion
- Difficulty speaking, slurring speech
- sudden trouble seeing, blurred vision
- sudden trouble walking, dizziness, loss of balance
- Sudden severe headache ( more of hemorrhagic tho)
What are the clinical manifestations of : High ICP ( hemorrhage) (6)
- Severe headache
- Vomiting
- Change in level of consciousness
- Pupil changes
- Posturing
- Seizures
Clinical Manifestations - Deficits ( What will most likely happen to patient?)
- Related to location of stroke ( focus on general stroke symptoms, not specific arteries)
- Ischemic and hemorrhagic strokes have similar manifestations
- Functions affected are directly related to artery involved and area it supplies
what functions are affected by stroke? (6)
- Motor functions
- Communication
- Affect
- Intellectual Function
- Spatial-Perceptual Alterations
- Elimination
What is the most obvious effect of stroke?
Motor deficits
Motor deficits include? (5)
- Impairment of mobility
- respiratory functions
- swallowing and speech
- gag reflex
- Ability to perform ADLs
Motor deficits of stroke follow certain specific patterns:
- affects facial features on the same side of the lesion (ipsilateral)
- motor function on the opposite side of the brain lesion becomes impaired (contralateral) due to pyramidal pathway crosses at the medulla
How is communication affected with stroke?
- Receptive language
- Expressive language
What is aphasia?
- affecting the comprehension of language, the ability to speak, or both
What is dysphasia?
- impaired ability to communicate ( usually common term as aphasia)
What is receptive language?
- how we understand language
how is receptive language affected by stroke ?
- difficulty understanding spoken or written language
- can speak words but words used are incorrect
What is Receptive aphasia ( Wernickes aphasia)
- difficulty understanding spoken or written language
- they can speak without hesitation, but words may be used incorrectly and sentence might be ungrammatical.
how is expressive language affected by stroke?
- patient develops expressive aphasia ( Broca’s aphasia)
What is expressive aphasia (Broca’s Aphasia?)
- Difficulty in expressing thoughts through speech or writing.
- the patient cannot find the words needed but does know what he or she wants to say.
- Stroke survivors words reduced to fewer than 4
what is anomic or amnesic aphasia?
- least severe form of aphasia
- involves problems finding the correct names for specific objects, peoples, places, or events
what is global aphasia?
- results in loss of all expressive and receptive functions.
what is dysarthria?
- a disturbance in the muscular control of speech.
- impairment involves pronunciation, articulation, and phonation (use of the voice).
- does not affect the meaning of communication or comprehension of language, but it does affect the mechanics of speech.
How is affect affected by stroke?
- patients who have had stroke may have difficulty controlling their emotions, and so emotional response may be exaggerated or unpredictable.
How is intellectual function/ cognition affected? (7)
- Impaired memory
- impaired judgement
- Impulsive and to move quickly ( right - brain stroke)
- overly cautious or slow ( left brain stroke)
- impaired math skills
- short attention span
- safety
Which side of stroke is more likely to cause problems in spatial-perceptual orientation? can it also occur on the other side?
- Right side stroke
- can also occur with left-brain side stroke
Spatial-perceptual problems may be divided into 4 categories:
1) anosognosia
2) homonymous hemianopia
3) Agnosia
4) Apraxia
What is anosognosia (First phase)
- The patient’s incorrect perception of self and illness.
- Patients may deny their illness or their own body parts
- Ex. patient with dementia doesn’t know that they have dementia.
What is the second phase? and what is homonymous hemianopia?
- The patient’s erroneous (incorrect) perception of self in space.
- The patient may neglect all input from the affected side . This maybe worsened by homonymous hemianopia, in which blindness occurs in the same half of the visual fields of both eyes.
- patient also had difficulty with spatial orientation such as judging distance.
What is Agnosia ( 3RD Phase)
inability to recognize an object by sight, touch, or hearing.
What is apraxia ( 4th phase)
- Inability to carry out learned sequential movements or command.
ex. Hard time tying shoe laces
How is elimination affected by stroke?
- Most issues of bladder and bowel are temporary and eventually resolved
- patient may experience frequency, urgency and incontinence of urine
- Patient can become constipated due to immobility, weak abdominal muscles, and dehydration.
what are the acute clinical manifestations of ischemic stroke? (5)
- sudden numbness/ weakness in the face, arm, or leg on one side of the body
- sudden confusion
- difficulty speaking, slurring speech
- sudden trouble seeing, blurred vision
- Sudden trouble walking, dizziness, loss of balance
What are the clinical manifestation of hemorrhage? (6)
- severe headache
- vomiting
- change in level of consciousness
- pupil change
- posturing
- seizures
summarize stroke deficits
see notes
explain contralateral motor deficits
- face ( ipsilateral)
- motor functions ( contralateral)
define aphasia
Loss of receptive or expressive language
What are the complication of stroke? (8)
- aspiration pneumonia
- deep vein thrombosis
- urinary tract infection
- falls and injury
- dehydration
- constipation
- depression
- seizures
What lead to all of the complications?
deficits
what to nurses need to do?
- Asses complications
- Monitor to prevent complications
Thrombotic
1) what is the warning/ onset
2) course
- Warning : TIA ( 30% - 50% of cases )
- Onset: Often during or after sleep
- course: stepwise progression, signs and symptoms develop slowly, usually some improvement
- recurrence in 20% - 25% of survivors
embolic
1) what is the warning/ onset
2) course
- Warning: TIA ( uncommon)
- Onset: Lack of relationship to activity, sudden onset
- course: single event, signs and symptoms develop quickly, usually some improvement
- recurrence common without aggressive treatment of underlying disease
(Hemorrhagic) Intracerebral
1) what is the warning/ onset
2) course
- Warning: Headache ( 25% of cases)
- Onset: Activity (often)
- Course: Progression over 24 hours; fatality more likely with presence of coma
(Hemorrhagic) Subarachnoid
1) what is the warning/ onset
2) course
- Warning: Headache (common)
- Onset: Activity (often), sudden onset
- Course: Acute onset, usually single sudden even described as the “worse headache of the patient’s life,” fatality more likely with presence of coma
