Stroke Flashcards
What is a stroke?
Acute onset of focal neurological symptoms and signs due to disruption of blood supply
(a clinical diagnosis)
What are the 2 types of stroke?
Haemorrhagic (15-20%) - bleeding occurs inside or around brain tissue
Ischaemic (80-85%) - a clot blocks blood flow to an area of the brain
What predisposes to a haemorrhagic stroke?
Raised BP
weakened blood vessel wall due to stuctural abnormalities like aneurysm, ateriovenous malformation (AVM) or inflammation of the vessel walls (vasculitis)
Types of ischemic stroke
Thrombotic- clot blocking artery at the site of occlusion
Embolic- clot blocking artery has travelled to artery it occludes from somewhere more proximal in the arteries or the heart
Hypoperfusion- due to reduced flow of blood due to stenosed artery rather than occlusion of artery
What is the cause of arterial clots?
atherosclerotic disease
Non-modifiable risk factors for stroke
Age Family history of stroke Gender Race Previous stroke
Risk factors for strokes which are potentially modifiable
most important at top down to AF
Hypertension Hyperlipidaemia Smoking Prior history of TIA especially if recent and recurrent Atrial fibrillation Diabetes Congestive heart failure Alcohol excess Obesity Physical inactivity Poor socioeconomic status
Why are statins not given to people who’ve had a haemorrhagic stoke
They have the effect of increasing the risk of haemorrhagic stroke
Rare causes of clots
Homocysteinemia
Vasculitis, Antiphospholipid antibody syndrome
Protein S, C, Antithrombin III deficiency
Paradoxical embolism(venous clot to arterial side) through patent foramen ovale/pulmonary AV shunts(these are openings large enough between arterial and venous circulations)
Genetic- Factor V Leiden mutation, common prothrombin mutation, MELAS, CADASIL,Fabry’s disease
Cardioembolic- mural thrombi, infective endocarditis, myxoma
Cervical artery dissection
Aims of stroke management
minimising disability
stopping further strokes
through rehab helping the patient to adjust
What is the relation of hypertension to stroke risk?
even a 10 mm reduction in SBP reduces risk of cardiovascular events by over 20%
even isolated systolic hypertension can increase stroke risk
What is the relationship between smoking and risk of stroke?
smoking doubles the risk of stroke
What is the relationship between hyperlipidaemia and risk of stroke?
Statin therapy recommended in everyone with ischaemic stroke and not recommended for hemorrhagic stroke
Other conditions which present similarly to stroke
Hypoglycaemia
Seizure- postictal states
Migraine
Other metabolic –hyperglycaemia, hyponatremia
Space occupying lesions like brain tumours
Functional hemiparesis
How do you determine whether the stoke is hemorrhagic or ischemic?
Brain imaging
CT brain
MRI with DWI
MRI with SWI (looks for old haemosiderin - old bleeds)
What further investigations are used in ischaemic stroke?
Blood tests (glucose, lipids, thrombophillia screen in young patients
Assess for hypertension
any clues the patient has any blood vessel diseases
What investigations are used to look for the cause of the bleeding in hemorrhagic stroke?
Hypertensive - tend to be deep in the brain and in older patients
In young people tends to be an aneurysm or malformed blood vessel (tends to be lobar haemorrhage)
If multiple haemorrhages look into
vasculitis
moya moya disease
cerebral amyloid angiopathy
Treatment of ischemic stroke
Thrombolysis - within 4.5 hrs from symptom onset
Thrombectomy within 6 hrs from symptom onset usually follows thrombolysis
What is a thrombectomy?
passing a wire into the clot and pulling it out
How do you prevent further strokes in someone who has had a atheroembolic 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
How do you prevent further strokes in someone who has had stroke 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
It is more important to control hypertension in stroke than in CHD what are some medications recommended
perindopril + indapamide (even in normotensive patients)
What is an atheroembolism?
It is from a thrombus forming on a atherosclerotic plaque, rich in blood platelets, the infarct will be on the same side as the carotid artery
What is cardioembolism?
embolism from a clot formed in the heart (usually the left atrium)
infarct will be in more than one artery territory - bilateral
What do you investigations do you in a large vessel stroke suspected to be an atheroembolism?
carotid scanning
CT/MRI angiography of the aortic arch
What do you investigations do you in a large vessel stroke suspected to be an cardiooembolism?
ECG
Echocardiogram
24hr, 5 day ECG monitor tests
