What is the definition of a stroke?
Acute onset of focal neurological symptoms and signs due to disruption of blood supply
What are the two types of stroke, their definitions and their chances?
- Haemorrhagic - bleeding occurs inside or outside brain tissue (15-20%)
- Ischaemic - a clot blocks blood flow to an area of the brain (80-85%)
What is haemorrhagic stroke usually due to?
- Raised BP
- Weakened vessel wall due to:
- Structural abnormalities e.g. aneurysm, arteriovenous malformation (AVM)
- Vasculitis
What are the three usual causes of ischaemic stroke?
- Thrombotic - clot blocking artery at site of occlusion
- Emboli - clot blocking artery has travelled to artery from somewhere more proximal in the arteries or heart
- Hypoperfusion - due to reduced blood flow because of stenoses (rather than occluded) artery
What are the 5 non modifiable risk factors for stroke?
- Age (>55 risk doubles/decade)
- Family history
- Gender (higher in younger men, overall more common in women (as live longer))
- Race (AA 2x as likely)
- Previous stroke
What are the 6 important questions when dealing with a stroke?
- Is this a stroke?
- What kind of stroke is this?
- What caused this stroke/TIA?
- Have I tried my best to answer question 3?
- Is the patient on the appropriate secondary prevention following investigations?
- Have I answered any questions the patient has?
What do strokes mimic?
Conditions that present acutely with focal neurological signs but are not due to interrupted blood flow
- Hypoglycaemia
- Seizue
- Migrane
- Space occupying lesions like brain tumours
- Functional hemiparesis
What are the three parts of identifying the type of stroke?
- History
- Exam - General (AF) and Neurological (disability)
- Brain imaging - only way to differentiate between ischaemic and haemorrhagic stroke - CT/MRI with or without contrast
If the stroke is identified to be ischaemic, what investigations should be done and why?
Investigations to try and find the cause
- Bloods - glucose, lipids, thrombophilia screen in young patients
- Assess for hypertension
- Any other potential causes
What is an artheroembolism?
- Embolism from thrombus forming on atherosclerotic plaque
- Platelet rich clot
- Infarcts in same side as affected carotid artery
What is a cardioembolism?
- Embolism from clot formed in heart
- Usually LA
- Clotting factor rich clot
- Infarct in more than one arterial territory, bilateral
If it is a large vessel/embolic stroke, what are you thinking and what are you doing?
- ?Atheroembolism - Carotid scanning, CT/MR angiography of aortic arch
- ?Cardioembolism - ECG (AF?, old ischaemic changes?, LVH?), echo, 24hr-5day ECG (Paroxysmal AF?)
What can cause haemorrhagic shock (deep, superficial and multiple)?
- Hypertension (usually deep in brain, older patients)
- If young, not hypertensive and lobar (superficial) haemorrhage, investigate for underlying aneurysm, AVM
- If multiple - ?vasculitis, ?Moya Moya disease, ?cerebral amyloid angioplasty
What can be done to reverse the disability caused by ischaemic stroke?
- Thrombolysis - up to 4.5hrs after symptom onset
- Thrombectomy - up to 6hrs after symptom onset, usually after having started thrombolysis
What drug and route is used for thrombolysis in ischaemic stroke?
t-PA - tissue plasminogen activator (IV injection)
What is the preventative treatment post artheroembolic or thrombotic stroke?
- Antiplatelets (Aspirin 75 mg + Dipyridamole MR 200 mg twice daily/Clopidogrel 75 mg daily)
- Statins to treat high lipids
- Diabetes management
- Hypertension management
- Lifestyle advice
When do you anticoagulate post stroke? How?
If due to AF
- Warfarin (Vitamin K antagonist)
- Direct acting oral anticoagulants (act by inhibiting clotting factors directly like factor X and thrombin) Rivaroxaban, Dabigatran, Apixaban, Edoxaban
What is a TIA?
Transient Ischaemic Attack
- Temporary neurological symptoms due to occlusion of artery to brain (temporary as arteries can dissolve small clots)
When does a TIA show on an ECG?
If symptoms last over 1hr
What should be done if you suspect someone had a TIA?
- HIGH RISK OF STROKES - Asprin and further tests within 24 hrs
- LOW RISK OF STROKES - Asprin and further tests within 1 week
What should be done if someone is high;y symptomatic of carotid stenosis by criteria?
Carotid endarterectomy
