Stroke Flashcards
Stroke definition
Acute onset of focal neurological symptoms and signs due to disruption of blood supply
Two types of stroke
Haemorrhagic and ischaemic
What is the most common type of stroke?
Ischaemic
Most common cause of haemorrhagic stroke
Hypertension
What is haemorrhagic stroke?
Stroke due to a burst blood vessel
What things can cause a weakened blood vessel wall eventually leading to stroke?
Structural abnormalities (aneurysm, arteriovenous malformation), vasculitis
What is ischaemic stroke?
Stroke caused by an occlusion in a blood vessel leading to the brain not receiving enough oxygenated blood
Thrombotic ischaemic stroke
Clot blocking an artery at the site of occlusion
Embolic ischaemic stroke
Clot blocking artery has travelled to the artery it occludes from somewhere more proximal in the arteries of the heart
Hypoperfusion ischaemic stroke
Due to reduced blood flow due to stenosed artery rather than occlusion of an artery
Non-modifiable risk factors for stroke
Age, family history, gender, race, previous stroke
Potentially modifiable risk factors for stroke
Hypertension, hyperlipidaemia, smoking, previous history of TIA, atrial fibrillation, diabetes, congestive heart failure, alcohol excess, obesity, physical inactivity, poor socioeconomic status
Rarer causes of stroke
Homocysteinemia, vasculitis, antiphospholipid antibody syndrome, protein S, C, antithrombin III deficiency, paradoxical embolism, cardioembolic, cervical artery dissection
Diet modification for the prevention of stroke
Mediterranean diet, decrease sodium intake, decrease intake of simple sugars, daily calorie intake
Behavioural modification efforts for the prevention of stroke
Diet modification, exercise, weight control, smoking cessation
6 essential questions when investigating as stroke
Is this a stroke?
What kind of stroke is this?
What caused the stroke?
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?
Stroke mimics examples
Hypoglycaemia, seizure-postictal states, migraine, hyperglycaemia, hyponatraemia, brain tumours
What is the only way to differentiate between ischaemic and haemorrhagic stroke
Brain imaging
Investigations for ischaemic stroke
Blood tests - glucose, lipids, thrombophilia screen (younger patients), assess for hypertension, any other suggestions that the patient has blood vessel disease
Atheroembolism
Embolism from a thrombus forming on an atherosclerotic plaque – platelet rich clots. It infarcts in the same side as the affected carotid artery
Cardioembolism
Embolism from a clot formed in the heart (usually left atrium). These are clotting factor rich clots. It infarcts in more than one arterial territory, bilateral
Investigations when an atheroembolism is suspected
CT/MRI angiography of aortic arch, carotid scanning
Investigations when a cardioembolism is suspected
ECG (AF, old ischaemic changes), echocardiogram, 5-day ECG to look for paroxysmal AF
Treatments for ischaemic stroke and when they can be given
Thrombolysis (IV injection of t-PA) - up to 4.5 hours from onset of symptoms
Thrombectomy (catheter injected to pull clot out) - up to 6 hours after onset of symptoms
Medical management to prevent next stroke if the first stroke was atheroembolic or due to thrombus
- Antiplatelets (aspirin 75mg and dipyridamole MR 200mg twice daily/clopidogrel 75mg daily)
- Statins to treat high lipids
- Diabetes management
- Hypertension management
- Lifestyle advice
Medical management to prevent next stroke if first stroke was due to atrial fibrillation
Warfarin, direct oral anticoagulants
Surgical management of stroke
Haematoma evacuation (although not really done anymore), obstructive hydrocephalus to relieve intracranial pressure, carotid endarterectomy
Transient ischaemic attack
Temporary neurological symptoms due to occlusion of artery stopping flow of blood. It is temporary because the arteries are capable of dissolving small clots
How long do symptoms of transient ischaemic attacks last?
Usually resolve within 24 hours
Risk of stroke after TIA within the first month and the next 5 years
First month = 11-15% risk of stroke
Next 5 years = 24-29% risk of stroke
