stroke Flashcards
Why study stroke?
no. ? leading cause of death
- increase our understanding of the pathophysiology of stroke
- understand impact of stroke (individual/ families/ NHS)
- develop effective prevention and intervention
- it’s interesting
- 3rd leasing cause of death
Stroke linked to: neuro cognitive health social clinical …. how?
neuroscience - affects brain function and behaviour
cognitive - cog impairments common eg. speech/ memory
health - risk factors associated = can reduce these behaviours
social - relationship dynamics, personality
clinical - mood can be affected (depression) - this can be neglected (can affect recovery)
Brain regions: 3 key areas?
1) cerebrum (larger)
2)brainstem
3)cerebellum
The 3 areas have different functions, but need to work together for optimum brain function
-Cerebellum = control and coordinate, balance and posture, fine muscle movements (bottom of brain)
- Brainstem = heart, breathing, consciousness, regulates ANS ( linked to spinal cord)
- Cerebrum = 4 lobes
left and right hemisphere divided into 4 lobes = occipital, temporal, frontal, parietal
frontal = motor cortex, judgement(decision + planning), inhibition, personality, emotions, language production
parietal = sensory processing and orientation (hand eye coordination)
occipital = vision
temporal = auditory perception, memory, language, LTM, facial processing
— to function properly = constant blood supply needed, due to glucose and oxygen being required
Blood supply in the brain requires how much of bodys o2? cardiac output? circle of willis? main artery?
cells require 02 and glucose (travel via blood)
- complex vascular system that feeds into the brain
- brain requires 20% of bodys oxygen
- 15% cardiac output
- anterior blood vessels = front of the brain
- posterior blood vessels = back of the brain
- -> come together to form ‘circle of willis’ –> a major artery that supplies brain originates here = ‘middle cerebral artery’
- the middle cerebral artery supplies a large portion of the brain and is one of the most common to get blocked in an ischaemic stroke
What is a stroke?
interruption of the blood supply in the brain –> causes significant cell death due to the lack of nutrients/ o2/ glucose
Classification of strokes: 3 types of stroke
3 types of I
3 types of H
1)Ischaemic stroke
- cerebral thrombosis
- cerebral embolism
- systemic hyperperfusion
2) haemorrhagic stroke
- intracerebral haemorrhage
- subarachnoid haemorrhage
- epidural haemorrhage
3) Transient ischaemic attach (TIA)
= temporary loss of bloody supply to brain (resolves itself within 24hrs)
Ischaemic
- cerebral thrombosis?
- cerebral embolism?
- systemic hypoperfusion?
most common (4/5 strokes ischaemic - Caplan et al)
currently no cure
- blockage that disrupts blood flow to the brain
CERBERAL THROMBOSIS
- where a blood clot forms in one of the major arteries in the brain (clot forms in the brain and causes blockage) - can cause ‘infarction’ = dead cells due to insufficient blood supply
CEREBRAL EMBOLISM
- blood clot formed elsewhere in the body and travels up to the brain
‘donor site’ = where it forms
‘recipient site’ = where it blocks (in brain)
SYSTEMIC HYPOPERFUSION
- general reduction in the blood supply across the whole body (due to cardiac output - the way the heart functions)
-reduced output = reduced bloodflow, therefore can slow and cause blockage if there’s a buildup
Haemorrhage stroke
-Intracerebral
- subarachnoid + epidural
Why do blood vessels burst/erupt?
damage to blood vessel, due to bursting, can cause cell death in subsequent brain regions due to lack of blood supply
INTRACEREBRAL HAEMORRHAGE
- blood vessel deep within the brain erupts
SUBARACHNOID HAEMORRHAGE + EPIDURAL HAEMORRHAGE
-in space around the brain
Subarachnoid = pia and arachnoid
subdural = arachnoid and dural
epidural = between dural and skull
(Caplan et al)
Why do blood vessels burst/ erupt?
-aneurysms = artery wall weakened and balloons out - so it can easily burst, especially with high blood pressure
(some people born with malformations in brain, and they know aneurysm can erupt at any time- can cause severe migraines)
Transient Ischaemic attack (TIA)
mini stroke
blood clot breaks down by itself = blood supply resumed
symptoms usually last less than 24 hours
- can be alarm bell to manage risk factors associated with stroke more
Area of damage and problems associated
Cerebrum
- left hemishphere: weakness/ paralysis, cognitive problems
- right hemisphere: weakness/ paralysis, vision/ perception
(remember: contralateral side of body affected to site of damage)
Cerebellum (less common)
- problems with orientation/ balance/ dizziness
Brainstem (less common, usually fatal)
- breathing, heart beat, swallowing (v. important functions)
Signs of a stroke
- numbness/ weakness in face, arm, leg
(especially when felt on just one side of the body) - confusion including confused speech
- trouble seeing from one or both eyes
- trouble walking, problems with balance/ dizziness
-headache esp. if severe or sudden
VERY time urgent, earlier detection = better (some treatment can only be done in 1st 3 hours)
- numbness occurs if theres damage in primary somatosensory cortex (area involved in sensation)
- weakness can occur if motor cortex is affected
- trouble speaking (Broca’s area = production) or understanding others (Wernicke’s = comprehension). Both Brocas and wernickes are supplied by the middle cerebral artery (MCA) but one may be more affected than the other
- Problems with vision - if patient had blockage that affected left side of occipital lobe, then right visual field of both eyes would be affected
(each eye has a left visual field and right visual field) - dizziness/ balance problems occur if theres a clot in cerebellum
-sudden severe headache = haemorrhagic - usually due to bleed on the brain that results in swelling= pushes against skull (fatal)
Factors that determine severity of the stroke
- timing - quicker treatment = less severe outcome
- which artery is affected/ brain region
- if someone had taken blood thinner = bleed more = worsen situation
- can be variable for different patients
Why is it important to identify if the individual is having an ischaemic or haemorrhagic stroke?
different treatments used
