Stroke Flashcards
stroke definition
- A stroke occurs when the blood supply to parts of the brain are interrupted, usually due to a blocked or burst blood vessel.
- When oxygen and nutrients can no longer reach parts of the brain vital brain cells are damaged and may die
- The onset of stroke is sudden and the effects on the body are immediate
TIA
Transient Ischaemic Attack
- symptoms last for less than 24hours
brain degredation compared to motor function
- The right side of the brain controls the left side of the body and vice versa
- Therefore, a stroke which occurs in the right side of the brain will usually affect the left side of the body
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Ischaemic stroke
- the most common type of stroke
- the blood vessel is blocked by a blood clot, which interrupts the brain’s blood supply.
- Blood flow to the brain is impaired and the brain cells begin to die within minutes from lack of oxygen and nutrients.
- The area of tissue death is called an** infarct.**
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causes of ischemic stroke
- Narrowed arteries from cholesterol deposits (arteriosclerosis)
- A clot forming in an artery (thrombosis)
- A clot travelling from somewhere else & lodging in an artery (embolism)
atherosclerosis
Narrowed arteries from cholesterol deposits
thrombosis
A clot forming in an artery
embolism
A clot travelling from somewhere else & lodging in an artery
Haemorrhagic stroke
- a blood vessel in the brain ruptures and bleeds.
- When an artery bleeds into the brain, brain cells do not receive oxygen and nutrients.
- In addition, pressure builds up in surrounding tissues and swelling occurs causing further cell death
cause of heamorrhagic strokes
- caused by a number of disorders which affect the blood vessels
- long-standing high blood pressure
- cerebral aneurysms
what is an aneurysm
An aneurysm is a weak or thin spot on a blood vessel wall. Aneurysms develop over a number of years and usually don’t cause detectable problems until they burst
stroke incidence
85% ischemic
15% heamorragnic
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risk factors
- Smokers are at twice the risk
- diabetes almost doubles the risk of stroke.
- over the age of 55.
- high blood pressure is the major risk factor for stroke and Transient Ischaemic Attack (TIA).
- A diet high in salt and fatty foods is linked to high blood pressure which increases the risk of stroke.
- Existing blood vessel disease, angina, heart attack or a previous TIA and atrial fibrillation (a type of irregular heart beat) increase the risk of stroke.
post stroke symptoms
- Altered levels of consciousness
- Muscle weakness
- Loss of feeling/sensation
- Changes in vision
- Altered speech
- Impaired swallowing
- Altered skin integrity
- Issues with bladder and bowels
- Altered thinking processes and changes in behaviour
- Feeling emotional
And these may result in:
* Difficulties with moving and handling and altered safety awareness
Difficulties in carrying out activities of daily living
clonus
is an involuntary rapid movement in the leg as a result of high tone muscles being stretched. This is commonly seen in the gastroc.
Effects of leg weakness
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- Clonus - This is commonly seen in the gastroc
- Difficulty standing:
- Altered muscle tone: Muscle can become ‘floppy’ (low tone) or ‘tense’ (high tone).
- High tone in the leg is commonly seen in an ‘extensor’ pattern where the leg is held in a straight position with the foot turned in and pointed down.
- Increased risk of thrombosis: Blood clots can form inside a blood vessel causing deep vein thrombosis (DVT) which can restrict blood flow.
- Reduced mobility can increase the risk of thrombosis.
- Difficulty walking
- Spasticity
Difficulty standing:
Loss of muscle strength and numbness may make it difficult for a person to stand and keep their balance.
Pain
can limit movement and affect a person’s walking abilities.
Altered muscle tone:
Muscle can become ‘floppy’ (low tone) or ‘tense’ (high tone). We all tense and relax our muscles to allow us to move around normally. However, after a stroke muscles can become abnormally floppy or tense. High tone in the leg is commonly seen in an ‘extensor’ pattern where the leg is held in a straight position with the foot turned in and pointed down.
increased risk of thrombosis:
Blood clots can form inside a blood vessel causing deep vein thrombosis (DVT) which can restrict blood flow. Reduced mobility can increase the risk of thrombosis.
Difficulty walking:
Loss of muscle strength and numbness may make it difficult for a person to walk and keep their balance.
Spasticity
is a particular form of abnormally high muscle tone which can result in tightness and stiffness in the leg. In severe cases this may limit the movement available in the leg.
effects of arm weakness
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- altered muscle tone
- spasticity
- contractures
- pain
- subluxation
- swelling/odeoma
altered muscle tone:
High tone in the arm usually results in a ‘flexor’ pattern where the arm is bent up towards the chest with a clenched fist.
Spasticity
is a particular form of abnormally high muscle tone which can result in tightness and stiffness in the arm. In severe cases this may cause flexor synergy
Contractures
are a result of altered muscle tone and weakness in the arm. The joints become stiff and movement becomes restricted. It can be very painful for the person when their limbs are moved.
Subluxation:
This is a partial dislocation of a joint and occurs as a result of muscle weakness and abnormal muscle tone. It is most commonly seen in the shoulder joint after stroke. Poor moving and handling skills and lack of support for the arm can result in a person having a very painful shoulder.
Swelling/oedema:
The weak hand and arm can become swollen and stiff. This is most commonly caused when the arm hangs down by a person’s side rather than being properly supported.
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Middle cerebral artery location
- Arises from the anterolateral part of the circle of willis on the inferior aspect of the brain
- Passes through the sylvan fissure
- Gives off lenticular striate branches
Superior superficial branch
- Leaves the sylvian fissure and travels superiorly alog tha convexity
Inferior superficial branch
- Leaves the sylvian fissure and travels inferiorly along the convexity
Lenticular striate branches
Supply’s basal ganglia - motor control
somatosensory cortex
homunculous
MCA Superficial branches mainly left side brain areas supplied
- supply lateral parts of primary motor and somatosensory strips
- Broca’s and Wernicke area - speech production
Spatial awareness
- Broca’s and Wernicke area - speech production
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MCA functions
- Contralateral hemiparesis (one sided muscle weakness)
- Contralateral sensory loss
- Lower Face and arm weakness - sensory loss
- If stroke happens in dominant hemisphere - aphasia due to damage of Broca’s & Wernicke
- If infarction happens in non dominant hemisphere - disturbance of spatial awareness contralateral neglect
Anterior cerebral artery location
- Arises from anterior part of the circle of willis on the inferior aspect of the brain
ACA brain areas
- pre-frontal cortex - executive functions (personality, decision making, plannning & organising)
- Supplementary motor area - within has micturitien inhibitory area - prevents urination
- Paracentral lobule - contains parts of the primary, motor and sensory cortex that corresponds to the contralateral lower limb
ACA symptoms
- Sensory and motor disturbance of contralateral lower limb - hemiparasthesia (numbness tingles on one side), hemiparesis (muscle weakness one side)
- Executive dysfunction - personality
- Speech anomalies
- Urinary incontinence
PCA location
Areises from posterior part of circle of willis on the inferior aspect of the brain where they form the terminal branches of basilar artery
PCA brain areas
Thalamus
- Important relay center for ascending and descending tracts between the cortex and the body
Splenius of corpus collosum - carrys fibers between the 2 occipital lobes
Occipital lobe
Primary and association visual areas - sensation and perception of visual stimuli
PCA symptoms
- Contralateral homonymous hemianopia Visual field defect (occipital)
- Contralateral sensory deficits (thalamus)
- Alexia without agraphia can write but cant read (if the splenium or corpous collosum is involved)
hemiplegia
Whichever side of your brain is affected causes symptoms on the opposite side of your body.
* muscle weakness or stiffness on one side
* muscle spasticity or permanently contracted muscle
* poor fine motor skills
* trouble walking
* poor balance
* trouble grabbing objects
