Download Stroke: an introduction

What is a stroke?
A stroke occurs when an artery supplying the brain
either blocks or bursts
Definition of a stroke
• Sudden onset
• Focal neurological disturbance e.g. speech problem,
limb weakness
• Vascular in origin (i.e. blood clot or bleed)
• Symptoms last more than 24 hours
• Definition includes subarachnoid haemorrhage
(bleeding which occurs from a small swelling in blood vessel in
the brain) which presents with severe headache with or
without focal neurology.
Definition of Transient Ischaemic Attack
(TIA)
•
•
•
•
Sudden onset
Focal neurological disturbance
Assumed to be vascular in origin
Lasts <24 hours
• Symptoms improve because blocked blood
vessel spontaneously unblocks and blood
supply returns
How common is a stroke?
• 3rd most common cause of death
• Commonest cause of disability; 50% survivors disabled
at 6 months
• 120,000 strokes per year in UK
• 15,000 strokes per year in Scotland
• Approx. 700 hospital admissions per year in Edinburgh
• 2.3 million deaths due to stroke per year in U.S
3rd Most Common Cause of Death
Symptoms Depend on part of Brain Affected
Cortex
(movement, sensation,
intellect, language etc)
Cerebellum
(balance and control of
movement)
Brain stem
(controls breathing,
blood pressure, sleep
etc)
Neurological effects of stroke (and TIA)
• Weakness down one side of body (opposite side of brain)
• Poor balance
• Sensory symptoms (e.g. numbness)
• Speech problems: language (usually dominant i.e. left side of
brain) (affects both production of language and understanding)
• Speech: articulation
• Swallowing problems
• Visual problems (e.g. double vision, loss of visual field)
• Dyspraxia (difficulty with complex tasks)
• Perceptual problems e.g. neglect
• Memory and thinking
• Incontinence
Symptoms Depend on part of Brain Affected
Is it a Stroke or not?
• Other medical conditions can ‘mimic’ a stroke (brain
tumour, seizure, migraine, low blood sugar, infection)
• About a fifth of patients with suspected stroke turn
out not to have had a stroke
• Brain scans essential to exclude stroke ‘mimics’
• Two main types of brain scans: CT and MR
• CT is the most accessible type of imaging. MR less
widely available
Two Main Types of Stroke
• Haemorrhage (due to bleeding into the brain):
cause about 15% of strokes
• Ischaemic (due to a blocked blood vessel):
cause about 80% of strokes
CT Scan of a Patient with a Haemorrhagic
Stroke
Fresh blood shows up as a white ‘blob’
http://www.strokecenter.org/radiology/browser.aspx, case #14832
Examples of Scans - Ischaemic Stroke
Oxfordshire Community Stroke Project
Classification for: Haemorrhagic and Ischaemic Stroke
TACS
• Visual field loss
• Weakness arm or leg
• Dysphasia or inattention
or dyspraxia
LACS
• Weakness or sensory
loss
• No other symptoms
PACS
• Only two of the three
symptoms of TACS
POCS
• (brain stem or cerebella
symptoms)
Total Anterior Circulation Syndrome
(TACS)
• 60 year old lady
• Found on floor by husband
• Right sided weakness (no movement in arm, slight
movement leg)
• Looking to left and ‘ignoring’ right side
• Right facial droop
• Right visual field loss
• Drowsy
• No speech and not following commands
• Sounded ‘chesty’
Partial anterior circulation syndrome
(PACS)
• 80 year old man
• Sudden onset right hand weakness whilst drinking a
cup of tea, spilt tea
• Difficulty finding the ‘right words’
• Able to understand people
• Vision fine, leg fine
• Symptoms improved over 48 hours, only mild right
hand weakness remained
Typical stroke (Lacunar Syndrome)
• 58 year old lady
• Walking down the road
• Suddenly noted tingling in right arm and then
some weakness in right arm and leg
• Speech was normal
• 5 years ago had had a similar episode on left side of
body
Typical Stroke
(Posterior Circulation Syndrome)
•
•
•
•
•
•
65 year old man
Sitting in a chair
Suddenly room starting spinning
Tried to get up, felt like he was ‘drunk’ and fell over
Double vision
Vomited
Referral for exercise:
Classification of Patients
(data from STARTER)
35
30
25
20
number
15
10
5
0
TACS
PACS
LACS
POCS
Possible descriptions of stroke
when patients referred for exercise
Pathological subtype
• Ischaemic, infarction
• Description of likely
cause e.g. embolic
• Haemorrhagic,
‘intracerebral
haemorrhage’, ‘ICH’,
‘PICH’
Classification
• Oxfordshire Community
classification
• Site of lesion on brain
scan
– Middle cerebral
artery territory,
posterior cerebral
artery territory
Risk Factors for Ischaemic Stroke
Common
• Hypertension
• Diabetes mellitus
• Cigarette smoking
• Atrial fibrillation
• Carotid stenosis
• Cardiac disease
• Alcohol
• High cholesterol
• Obesity
• Reduced physical activity
• Diet
Rarer
• Vasculitis
• Polycythaemia
• Leukaemia
• Hyperviscosity
• Thrombophilias
• Anti-phospholipid syndrome
• Neurosyphilis
• Endocarditis
Risk Factors and Causes of Haemorrhage
Primary Intracerebral Haemorrhage
• Hypertension
• Coagulation disorder
• Aneurysm
• Arterio-venous malformation (AVM)
• Cigarette smoking
• Amyloid angiopathy
• Drug abuse
Causes of Ischaemic Stroke
• Blood clot forms in artery in brain e.g. middle
cerebral, or small deep artery in brain
• Blood clot forms at another site and ‘travels’ to brain
(embolism)
– Aorta (main artery in chest)
– Carotid artery (in neck)
– Heart
Left Atrial Thrombus
http://content.nejm.org/cgi/content/full/328/11/771/F1
Blood Tests for Stroke
• Blood glucose (for diabetes and low sugar)
• Cholesterol
• Full blood count
– Anaemia (low haemoglobin) or polycythemia (too
many red cells)
– White cells (? Infection)
– Platelets (? Too many or too few)
•
•
•
•
Electrolytes (e.g. sodium and potassium)
Urea and creatinine (kidney function and hydration)
ESR (for inflammation)
Blood clotting (for haemorrhagic stroke)
Other tests
• Chest X-ray (heart size, lungs)
• Electrocardiogram (ECG)
• Some patients may have carotid Dopplers (to look for
narrowing of carotid artery)
• Some patients may have echocardiography (i.e.
ultrasound of the heart) to look for blood clot in heart
and abnormalities of the heart valves)
Electrocardiogram
(shows electrical rhythm of heart)
Echocardiography
(left ventricular thrombus)
http://content.nejm.org/cgi/content/full/346/18/e5
Colour duplex Doppler from tight internal
carotid stenosis
Summary
• Stroke is 3rd most common cause of death
• Most common cause of disability
• 85% are Ischaemic (blocked artery)
• Symptoms depend on part of brain affected
• Oxfordshire Community Stroke Project
Classification in widespread use
• Different causes and risk factors for stroke