Stroke Flashcards
Which two major arteries supply blood to the brain?
internal carotid arteries
Vertebral arteries
Which of the two major arteries that supply the brain is anterior?
Internal carotid arteries
Which of the two major arteries that supply blood to the brain is posterior?
vertebral arteries
What supplies all of the blood to the cerebral cortex?
Circle of Willis
What do the internal coratid arteries divide to form?
The anterior cerebral artery and the middle cerebral artery
What do the anterior cerebral arteries join to form?
Anterior communicating artery
What do the vertebral arteries pass up through?
They pass up through foramina in transverse processes of cervical vertebrae
What do the vertebral arteries join to form?
Basilar artery
What does the basilar artery divide into and where does it divide?
It divides at the upper brainstem into 2 posterior cerebral arteries
What connects the posterior part of the circle of Willis to the anterior part?
Posterior communicating arteries
What does the circle of Willis do?
protects the brain via collateral circulation
What does the ACA supply?
the medial and superior parts of the frontal lobe and then anterior parietal lobe
This includes the frontal, pre-frontal and supplementary motor cortex as well as parts of the primary motor and primary sensory cortex
What does the frontal lobe control?
voluntary movement
attention
personality
emotion
memory
speech
What does the parietal lobe control?
perception and integration of sensory information
visuospatial processing
spatial attention
What does the MCA supply?
The greater part of the lateral cerebral surface (including the main motor and sensory areas) and supplies deep structures including the internal capsule and the basal ganglia
What does the basal ganglia control?
Involved in cognitive and emotional behaviours
Plays an important role in reward and reinforcement, addictive behaviours and habit formation
What does the PCA supply?
occipital lobe, the inferomedial surface of the temporal lobe and thalamus
What does the PCA supply?
occipital lobe, the inferomedial surface of the temporal lobe and thalamus
What does the temporal lobe control?
perception
face recognition
object recognition
memory acquisition
language understanding
emotional reactions
What does the occipital lobe control?
Primary visual area of the brain
What does the thalamus control?
It is the principle relay station for sensory input
What does the basilar artery supply?
It supplies blood to all of the brain stem and the cerebellum
What is the pons responsible for?
breathing and respiratory rhythm
What is the medulla responsible for?
cardiac, respiratory, vomiting and vasomotor centres
What does the midbrain control?
vision
hearing
motor control
sleep
wakefulness
alertness
temperature regulation
What are the symptoms of a MCA infarct?
upper limb motor deficit
facial droop
sensory symptoms
speech deficits
What is a stroke caused by?
Disruption of blood supply to the brain resulting in sudden and lasting neurological deficits
What is the medical name for a mini stroke?
Transient ischaemic attack
What causes a TIA?
a temporary disruption in the blood supply to part of the brain
How long do the effects of a TIA last?
a few minutes to a few hours and fully resolve within 24 hours
What are the two types of stroke?
ischaemic
Haemorrhagic
Which type of stroke is more prevalent?
Ischaemic (85%)
Which type of stroke is less common?
Haemorrhagic (15%)
What is used to classify strokes?
Bamford/Oxford classification
What are strokes categorised by?
Categorisation is based on initial clinical symptoms alone and not on imaging
What are the 4 classifications of stroke?
total anterior circulation stroke (TACS)
partial anterior circulation stroke (PACS)
Lacunar stroke (LACS)
Posterior circulation stroke (POCS)
What 3 symptoms can patients with TACS and PACS have?
unilateral weakness (and/or sensory deficit) of the face, arm and leg
Homonymous hemianopia
higher cerebral dysfunction (dysphasia, visuospatial disorder)
How many of the 3 symptoms does a TACS patient have?
3
How many of the 3 symptoms does a PACS patient have?
2
What are the symptoms that a patient with LACS will have one of?
Pure sensory stroke
Pure motor stroke
Sensori-motor stroke
Ataxic hemiparesis
There is no loss of higher cerebral functions
What are the symptoms that a patient with POCS will have one of?
Cranial nerve palsy and a contralateral motor/sensory deficit
Bilateral motor/sensory deficit
Conjugate eye movement disorder
cerebellar dysfunction (e.g. vertigo, nystagmus, ataxia)
Isolated homonymous hemianopia
What is an ischaemic stroke due to?
occlusion of the blood vessel in the brain
Which blood vessels are most common to cause ischaemic strokes?
MCA>PCA>ACA
What are haemorrhagic strokes due to?
rupture of the blood vessels in the brain
What is an ICH?
intercranial or intracerebral haemorrhage (bleeding o the brain)
What is SAH?
Subacromial haemorrhage - bleeding on the surface of the brain in the subarachnoid space
In what timeframe do we aim to do brain scanning for a stroke?
within an hour
In what timeframe do we aim to give thrombolysis on a stroke patient?
within 4 hours for patients with acute ischaemic stroke
What is thrombolysis?
Clot busting drug given to patients only with ischaemic stroke
What is the aim of thrombolysis?
Restoring blood flow to the area thereby preventing cell death
What are the benefits of thrombolysis?
can significantly increase post stroke recovery
available 24 hours a day, 7 days a week in england
What are the risks of thrombolysis?
Has risks of causing bleeding anywhere in the body
What is a thrombectomy?
clot removal with catheter inserted through femoral vein and guided via imaging to the site of the clot in the brain
What are the benefits of thrombectomy?
can significantly increase post stroke recovery
What are the problems/risks with thrombectomy?
there are risk associated with the procedure
availability is variable
What is carotid endarterectomy?
treatment of carotid artery stenosis (plaque build up in carotid artery) by removing the plaque build up in the carotid artery
What are the risks of carotid endarterectomy?
risks of bleeding and further strokes associated
What should patients admitted with ICH have?
anticoagulant urgently reversed
Blood pressure lowered
for those who develop hydrocephalus they should be considered for surgical intervention such as insertion of a external ventricular vein
What does secondary prevention of strokes involve?
reviewing risk factors and providing treatment and advice to reverse these if possible
establishing the cause of current stroke and treating this if possible
Name some motor symptoms of a stroke
lack of muscle innervation
changes in muscle tone
ataxia
muscle weakness balance problems
asymmetry
loss of normal movement patterns
loss of postural adjustments
compensations
What is muscle tone?
a state of readiness in a muscle at rest
What do alpha motor neurons stimulate?
extrafusal muscle fibres which causes muscle contraction
What do gamma motor neurons stimulate?
muscle spindles
What neural factors produce muscle tone?
active contraction
reflex contraction
What mechanical factors produce muscle tone?
physical inertia of limb
viscoelastic properties of muscle
thixotropy
What is thixotropy?
stickiness of the muscle and resistance to the movement the longer its at rest
What can hypotonicity be caused by?
CNS or PNS lesion
What is hypertonicity caused by?
damage to CNS
What is atrophy?
The partial or complete wasting away of a part of the body
Name some sensory impairments
impaired cutaneous sensation (light and deep touch, temperature, sharp blunt, 2 point discriminant)
Impaired stereognosis
impaired proprioceptive awareness
visual field deficits (homonymous hemianopia, quadrantanopia)
What is stereognosis?
The ability to identify the shape and form of a 3D object and therefore its identity
Name some speech symptoms associated with stroke
dysarthria (slurred speech)
expressive dysphasia
receptive dysphasia
What is expressive dysphasia?
Difficulty in expressing words
Name some cognitive symptoms associated with stroke
perceptual problems
dyspraxia
memory
retention
inattention
Name some factors affecting the recovery of a stroke
size and location of stroke
pre-morbid status
patient motivation
patient insight
patient engagement
nutrition and hydration
environment
therapy
age
Does neural regeneration occur in the CNS?
NO
When is the greatest amount of true and spontaneous recovery seen post stroke?
in the first 1-3 month
What is neuroplasticity?
The adaptive capacity of the CNS and its ability to modify its own structural organisation and functioning
What is the name of the cerebral blood supply?
Circle of Willis
How would you define a stroke?
a stroke is caused by disruption of blood supply to the brain resulting in sudden and lasting neurological deficits
What are the two medical treatments of stroke?
thrombolysis
thrombectomy
What is muscle tone?
a state of readiness in a muscle at rest
Is spasticity a CNS or PNS problem?
CNS
What is ataxia?
impaired coordination of voluntary muscle movement
What is hemiparesis?
muscle weakness on one side of the body
What is dyspraxia?
impaired ability to plan and process motor tasks
What is unilateral neglect or inattention?
Inability to recognise and/or respond to stimuli on one side of the body
What is receptive dysphasia?
difficulty understanding either written or spoken language
What is expressive dysphasia?
difficulty communicating thoughts, ideas and messages to others. This may affect speech, writing, gestures or drawing
What is dysarthria?
Inability to control the muscles used in speech resulting in slurred speech
What area of the brain is expressive dysphasia associated with?
Brocas area
What area of the brain is apraxia associated with?
parietal lobe
What area of the brain is ataxia associated with?
cerebellum
What area of the brain is agnosia associated with?
parietal lobe
What area of the brain is neglect associated with?
occipital/parietal lobe
What area of the brain is hemiparesis associated with?
left or right hemisphere
What area of the brain is spasticity associated with?
motor pathways
What area of the brain is low tone associated with?
motor pathways
What area of the brain is receptive dysphasia associated with?
wernikes area
Name some risk factors for stroke
age
gender
ethnicity
previous stroke or TIA
hypertension
ischaemic heart disease
atrial fibrillation
high blood cholesterol
diabetes
high salt diet
pregnancy
contraceptive pill
migraines
Name the 2 main principles of neuroplasticity and explain how they work
unmasking of dormant pathways -> these pathways increase in synaptic strength with continued use
collateral sprouting -> adjacent neurons may sprout axons in order to strengthen neuronal pathways as part of neuroplasticity mechanisms
What are the 10 principles of neuroplasticity?
use it or lose it
use it and improve it
specificity
repetition matters
intensity matters
time matters
salience matters
age matters
transference
interference
Explain the use it or lose it principle of neuroplasticity
Failure to drive specific brain functions can lead to functional degradation
Explain the use it and improve it principle of neuroplasticity
training that drives a specific brain function can lead to an enhancement of that function
Explain the specificity principle of neuroplasticity
The nature of training experience dictates the nature of plasticity
Explain the repetition matters principle of neuroplasticity
induction of plasticity requires sufficient repetition
Explain the intensity matters principle of neuroplasticity
induction of plasticity requires sufficient training intensity
Explain the time matters principle of neuroplasticity
different forms of plasticity occur at different times during training
Explain the salience matters principle of neuroplasticity
The training experience must be sufficiently salient to induce plasticity
Explain the age matters principle of neuroplasticity
Training induced plasticity occurs more readily in younger brains
Explain the transference principle of neuroplasticity
plasticity in response to one training experience can enhance the acquisition of similar behaviours
Explain the interference principle of neuroplasticity
plasticity in response to one experience can interfere with the acquisition of other behaviours
