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Slides and explanatory notes
available on
www.dcn.ed.ac.uk/studentnotes
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Aims of todays symposium
What is stroke?
Why is it important?
How can be recognise/diagnose it?How do we investigate it?
How can we localise the brain lesion?
How to distinguish different pathological
types?
How can we treat it?
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Aims of todays symposium
Also:
some epidemiological principles
incidence, prevalence, prognosis
simple, clinically relevant neuroanatomy
cerebral localisation
basics of evidence based medicine
randomised trials
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StrokeCerebrovascular Accident (CVA)
Definition
Asyndrome characterised by:
rapidly developingsymptoms and/orsignsoffocalloss ofcerebralfunction
symptoms last more than 24 hours or lead to
death no apparent cause other than a vascular
origin
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Transient Ischaemic Attack (TIA)
A stroke where the symptoms completely
resolve within 24 hours
An arbitrary concept which has some value
in clinical practice and research
may act as a warning
different differential diagnosis to stroke
more difficult to diagnose with certainty
therefore if excluded from stroke makes the
latter a more homogenous group.
Dont bother with other terms e.g. RIND
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Why is stroke important?
It is common
It is often fatal
Many survivors remain disabled It has major cognitive and psychological
effects
It accounts for about 5% of all NHSresources
It has a huge impact on families etc
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Stroke is common
Incidence (no. new cases/unit pop/yr)
about 200/100,000/yr
120,000/yr in UK
Prevalence (no. cases in population at a
single point in time)
about 800/100,000
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Stroke is often fatal
Case fatality is
20% by 30 days
30% by 6 months
3rd most common cause of death (after
coronary heart disease and cancer)
70,000 deaths per year in UK
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The Bath Principle
Prevalence
Incidence
Case fatality
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Other consequences
Impairments
weak limbs, absent speech, loss of vision,
depression
Disabilities
cannot walk, dress, feed themselves etc
Handicapcannot fulfil role in society e.g. breadwinner,
grand parent
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How do we diagnose a stroke?
Listen to the patients story (the history)
where were they?
what were they doing?
what did they first notice wrong?
how did their symptoms progress?
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Common symptoms of Stroke
Focal
weak/clumsy arm, leg
or both(mono/hemi paresis/plegia)
loss of feeling or
sensation
loss of speech
(dysarthria, dysphasia)
loss of balance
General
Headache
Vomiting
h d i d d
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The symptoms and signs depend on
which part of the brain and which
artery is affected
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Blocked blood vessels
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Remember
In stroke
the symptoms come on rapidly
the symptoms depend on which part of the
brain is affected
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The speed of onset influences
ones certainty of diagnosis
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Why do the symptoms come on rapidly?the relationship of blood flow and neuronal function
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Extension Of Infarction
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How do we diagnose a stroke?
If the patients story suggests a stroke
Is the patient the sort of person to have had
a stroke?
are they elderly?
have they got vascular disease elsewhere?
angina, heart attacks, bad circulation in the legs
have they got vascular risk factors? High blood pressure, smoking, diabetes, high
cholesterol
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What is a risk factor
Somebody with the characteristic or risk
factor has a greater risk of developing the
disease
The importance of a risk factor is
reflected by:
how common it is in the population
the strength of its association (relative risk)
the absolute risk of the person
It may or may not be on the causal pathway
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Causal Pathways
Atrial Fibrillation
Clots in the atrium
Embolism to the brain
Stroke
Hypertension
Disease of
cerebral vessels
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A typical story
A 75 year old woman wakes up and tries to
get out of bed
She falls over and cant get up She tries to speak to her husband but cannot
find the words
She cannot move her right arm or leg When she arrives at hospital the weakness
has improved a bit.
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A typical story
Her husband tells us:
she has been on treatment for high blood
pressure
she has angina and diabetes
she smoked until recently
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How do we diagnose a stroke?
We examine the patient looking for:
signs compatible with focal damage to the
brain - ones search is guided by the history
evidence of underlying vascular problems
irregular pulse, high blood pressure, heart
murmurs, bruits over arteries.
signs of other diseases which may cause strokes
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How do we diagnose a stroke?
Having made a diagnosis of a stroke based
on the story and examination we assess our
certainty that we are right. We carry out tests to confirm the diagnosis,
to identify risk factors and to screen for or
diagnose rare causes. The number of tests we do depends on how
able we are to answer the following
questions.
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Important questions to answer when
assessing a patient with a probable stroke How likely is it to be a stroke?
Which part of the brain is affected
What sort of stroke is it?
Ischaemic (blocked blood vessel)
Haemorrhagic (burst blood vessel)
What is the likely cause?
What problems has this caused?
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There are lots of causes of stroke
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Tests (Laboratory Investigations)
Full Blood Count tell us:
how many red cells (erythrocytes)
too many - polycythaemia
too few - anaemia
how many white and type of white cells
might indicate infection, leukaemia
how many platelets (sticky bits which form clot)
too many - thrombocythaemia
too few - thrombocytopenia
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Tests (Laboratory Investigations)
Erythrocyte Sedimentation Rate (ESR)
reflects the fibrinogen level in the blood and
is a non specificindicator of inflammation
Blood glucose will identify
too low (hypoglycaemia)
too high (hyperglycaemia) - diabetes
Cholesterol
Urea & Electrolytes (renal function and
hydration)
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Other tests
Electrocardiogram - ECG
Is the heart rhythm normal (e.g. AF)?
Has the patient had a heart attack?
Is there evidence of prolonged high blood
pressure?
Echocardiogram
Is there a structural abnormality in the heart
which could be a source of embolism to the
brain?
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Brain imaging
Computerised Tomography (CT)
Is there another pathology causing the
symptoms (e.g. brain tumour)?Are there signs of a stroke?
Is the stroke ischaemic or haemorrhagic?
Magnetic resonance imaging
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Computerised Tomography (CT)
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A cortical infarct
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An ischaemic stroke
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An haemorrhagic stroke
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A cerebellar
haemorrhage
withhydrocephalus
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Haemorrhage into an infarct
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Bilateral subdural haematoma
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A brain tumour
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Imaging the blood vessels
Carotid and Vertebral artery Ultrasoundcan show atheroma and occlusions of vessels in
neck
Transcranial Doppler (TCD)can show flow (or lack of flow) in large
intracerebral vessels
Magnetic resonance angiographycan show extra and intra cranial blood vessels
Catheter angiography
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Carotid Duplex
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Carotid Duplex
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Carotid
Angiography
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Stenosis of
the origin of
the InternalCarotid
Artery
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Aims of todays symposium
What is stroke?
Why is it important?
How can be recognise/diagnose it?
How do we investigate it?
How can we localise the brain lesion?
How to distinguish different pathological
types?
How can we treat it?
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Aims of todays symposium
Also:
some epidemiological principles
incidence, prevalence, prognosis
simple, clinically relevant neuroanatomy
cerebral localisation
basics of evidence based medicine
randomised trials