Slides and explanatory notes available on

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?

Aims of today’s symposium Also: some epidemiological principles incidence, prevalence, prognosis simple, clinically relevant neuroanatomy cerebral localisation basics of evidence based medicine randomised 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

How do we diagnose a stroke? 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 of cerebral 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

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

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.

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

Carotid Angiography

Stenosis of the origin of the Internal Carotid Artery

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?

Aims of today’s symposium Also: some epidemiological principles  incidence, prevalence, prognosis simple, clinically relevant neuroanatomy cerebral localisation basics of evidence based medicine randomised trials