Definition of Stroke
A clinical syndrome consisting of rapidly developing clinical signs of focal (or global in case of coma) disturbance of cerebral function lasting more than 24 hours or leading to death with no apparent cause other than a vascular origin • Symptoms less than 24 hours is considered transient ischaemic attacks (TIA)
Stroke epidemiology
- Stroke is 3rd largest cause of death in UK
- Accounts for ~11% of all deaths
- Every 5mins someone in the UK suffers a stroke. 110,000 strokes each year – 25% are recurrent
- Main cause of adult disability
Stroke : Risk Factors
- Hypertension •Smoking •Diabetes Mellitus •Hyperlipidaemia •AF
- Carotid Stenosis •Contraceptive Pill •Obesity •Polycythaemia •Excess Alcohol Intake •Physical inactivity •Illicit Drug Use
- Hx of Migraine
No-modifiable
•Age > 60 years
•Family History of stroke/TIA •Male Sex
•Race
Types of Stroke
Ischemic 80%
- thrombosis (small and large vessel 50%)
- embolism 30% but may be significantly higher
Hemourragic 20%
- intracebral (hypertension as risk)
- subarachnoid aneurism
pathophysiology of ischemic strokes
• Acute ischemic strokes result from vascular occlusion
• Ischemia causes cell hypoxia and depletion of cellular adenosine triphosphate (ATP)
• Influx of sodium and calcium ions and passive inflow of water into the cell lead to cytotoxic oedema.
• Affected regions with cerebral blood flow of lower than 10 mL/100 g of tissue/min are referred to collectively as the core. These cells are presumed to die within minutes of stroke onset
• Zones of decreased or marginal perfusion (cerebral blood flow < 25 mL/100g of tissue/min) the ischemic penumbra. Tissue in the penumbra can remain viable for several hours because of marginal tissue perfusion
• Haemorrhagic transformation represents the conversion of an ischemic infarction into an area of haemorrhage. This is estimated to occur in 5% of uncomplicated ischemic strokes
Post stroke cerebral oedema (10-20%)
seizures occur in 2-23% of patients within the first days after ischemic stroke.
Assessment of Stroke
FAST should be used outside hospital to screen for a diagnosis of stroke or TIA.
Facial asymmetry Arm weakness Speech disturbance Time/test
Recognition Of Stroke In ER (ROSIER)
Has there been loss of consciousness or syncope?-1 Has there been a seizure? -1 Asymmetric facial weakness? 1 Asymmetric hand weakness? 1 Asymmetric leg weakness? 1 Speech disturbance? 1 Visual field disturbance? 1 Total score if more than zero stroke is likely
Specialist assessment for stroke includes
- Full history
- exclusion of stroke mimics
- identification of vascular territory
- identification of likely causes
- appropriate investigation
What PMH is relevant for stroke when taking a history?
A focused medical history for patients with ischemic stroke aims to identify risk factors for atherosclerotic and cardiac disease, including the following
• Hypertension
• Diabetes mellitus
• Tobacco use
• High cholesterol
• History of coronary artery disease, coronary artery bypass, or atrial fibrillation
• In younger patients, elicit a history of the following:
• Recent trauma
• Coagulopathies
Consider stroke in any patient presenting with acute neurologic deficit or any alteration in level of consciousness such as:
- Abrupt onset of hemiparesis, monoparesis, or (rarely) quadriparesis
- Hemi sensory deficits
- Monocular or binocular visual loss
- Visual field deficits
- Diplopia
- Dysarthria
- Facial droop
- Ataxia
- Vertigo (rarely in isolation)
- Nystagmus
- Aphasia
- Sudden decrease in level of consciousness
What symptoms would you expect n a patient with a stroke affecting the Anterior Cerebral Artery?
Behaviour ,personality changes
What symptoms would you expect n a patient with a stroke affecting the Middle Cerebral Artery?
- Motor and Sensory symptoms
- Dysphasia in dominant hemisphere
- Neglect and dyspraxia -non dominant hemisphere
What symptoms would you expect n a patient with a stroke affecting the Posterior Cerebral Artery?
visual disturbances
Motor or sensory
Cerebellar signs
What is involved in a full neurological exam?
• Full Neurological examination
1. Motor function
2. Sensory function
3. Cerebellar function
4. Visual field
5. Gait
6. Language (expressive and receptive capabilities)
7. Mental status and level of consciousness
8. Cranial nerves
• Ocular fundi (retinopathy, emboli, haemorrhage)
• Heart (irregular rhythm, murmur, gallop)
• Peripheral vasculature (palpation of carotid, radial, and femoral pulses; auscultation for carotid bruit)
The NIHSS is easily performed; it focuses on the following 6 major areas of the neurologic examination:
- Level of consciousness
- Visual function
- Motor function
- Sensation and neglect
- Cerebellar function
- Language
- The NIHSS is a 42-point scale.
- Patients with minor strokes usually have a score of less than 5.
- An NIHSS score of greater than 10 correlates with an 80% likelihood of proximal vessel occlusions
Investigations in stroke
- FBC/ ESR, Urea and Electrolytes, Glucose, Coagulation studies.
- ECG
- Lipid
- CXR
Every patient with stroke should have brain imaging as soon as practical. Indications for urgent imaging include:
– Indications for thrombolysis
– On anticoagulant treatment or a known bleeding tendency
- History of head injury
– Depressed level of consciousness (Glasgow Coma Score below 13) – Unexplained progressive or fluctuating symptoms
– Papilloedema, neck stiffness or fever
– Severe headache at onset of stroke symptoms.
When is carotid duplex scanning indicated?
Carotid Duplex scanning when carotid artery disease is suspected
MRA of carotid arteries
Echocardiography in patients where cardiogenic embolism is suspected.
Initial management of Acute Stroke
Airway and Breathing Nutrition/ swallowing Antiplatelet Sao2 above 94% Thrombolysis Diabetic control aiming 4-10 Blood pressure control: in acute stage ,185/95, lowering BPs may cause under perfusion of ischaemic penumbra. Antipyretics (hyperthermia increases ischaemic neuronal injury) Surgery if required
Criteria for surgical referral for decompressive hemicraniectomy
- They should be referred within 24 hours of onset of symptoms and treated within a maximum of 48 hours.
- Aged 60 years or under.
- Clinical deficits suggestive of infarction in the territory of the middle cerebral artery, with a score on the National Institutes of Health Stroke Scale (NIHSS) of above 15.
- Decrease in the level of consciousness to give a score of 1 or more on item 1a of the NIHSS.
- Signs on CT of an infarct of at least 50% of the middle cerebral artery territory,
Thrombolysis in Acute Ischaemic Stroke: Inclusion criteria
• Acute disabling stroke with a clearly defined time of onset NIHSS
>4
• No sings of acute stroke in CT brain
• Likely disabling with no significant improvement or recovery NIHSS >4
• Treatment initiated within 4.30 hours of symptom onset
Procedures PRIOR to t-PA infusion
- History and physical exam consistent with acute ischaemic stroke
- CT brain (axial with 5mm cuts)
- FBC, U+E, glucose, clotting, ECG
- Compatible with inclusion criteria and contraindications
Absolute contraindications to thrombolysis
- Any intracranial haemorrhage
- BP>185/110 after 2 attempts to reduce BP
- Surgery or internal trauma in past 14 days
- INR>1.7, APTT>40, or platelets <100,000 mm3
- Arterial puncture at a non compressible site in the past 7 days
Secondary Prevention of Ischaemic Stroke
- Antiplatelet Agent
- Reduction in Cholesterol levels
- Anticoagulants in patients with AF
- Reduction in Blood Pressure
- Carotid Endarterectomy
