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Aims of today’s 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?


Also:

some epidemiological principlesincidence, prevalence, prognosis

simple, clinically relevant neuroanatomycerebral localisation

basics of evidence based medicinerandomised trials

Stroke Cerebrovascular Accident (CVA)

Definition

A syndrome characterised by:

• rapidly developing symptoms and/or signs of focal loss of cerebral function

• symptoms last more than 24 hours or lead to death

• no apparent cause other than a vascular origin

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.

• Don’t bother with other terms e.g. RIND

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 NHS resources

• It has a huge impact on families etc

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

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

The Bath Principle

Prevalence

Incidence

Case fatality

Other consequences

• Impairments – weak limbs, absent speech, loss of vision,

depression

• Disabilities– cannot walk, dress, feed themselves etc

• Handicap– cannot fulfil role in society e.g. breadwinner,

grand parent

How do we diagnose a stroke?

• Listen to the patient’s story (the history)– where were they?– what were they doing?– what did they first notice wrong?– how did their symptoms progress?

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

The symptoms and signs depend on which part of the brain and which

artery is affected

Blocked blood vessels

Remember

In stroke

• the symptoms come on rapidly

• the symptoms depend on which part of the brain is affected

The speed of onset influences ones certainty of diagnosis

Why do the symptoms come on rapidly?the relationship of blood flow and neuronal function

Extension Of Infarction


If the patient’s 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

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

Causal Pathways

Atrial Fibrillation

Clots in the atrium

Embolism to the brain

Stroke

Hypertension

Disease ofcerebral vessels

A typical story

• A 75 year old woman wakes up and tries to get out of bed

• She falls over and can’t 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.

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


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


• 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.

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?

There are lots of causes of stroke

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

Tests (Laboratory Investigations)

Erythrocyte Sedimentation Rate (ESR)

• reflects the fibrinogen level in the blood and is a non specific indicator of “inflammation”

• Blood glucose will identify – too low (hypoglycaemia)– too high (hyperglycaemia) - diabetes

• Cholesterol

• Urea & Electrolytes (renal function and hydration)

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?

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

Computerised Tomography (CT)

A cortical infarct

An ischaemic stroke

An haemorrhagic stroke

A cerebellar haemorrhage

with hydrocephalus

Haemorrhage into an infarct

Bilateral subdural haematoma

A brain tumour

Imaging the blood vessels

• Carotid and Vertebral artery Ultrasound– can show atheroma and occlusions of vessels in

neck

• Transcranial Doppler (TCD) – can show flow (or lack of flow) in large

intracerebral vessels

• Magnetic resonance angiography– can show extra and intra cranial blood vessels

• Catheter angiography

Carotid Duplex

CarotidAngiography

Stenosis of the origin of the Internal

Carotid Artery


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?


Also:

some epidemiological principles incidence, prevalence, prognosis

simple, clinically relevant neuroanatomycerebral localisation

basics of evidence based medicinerandomised trials

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