Stroke Flashcards
What is a stroke?
Acute onset of focal neurological symptoms and signs due to disruption of blood supply
What does it mean if symptoms are focal?
should be able to tell which part of brain is affected by symptoms
What are the types of stroke and which is most common?
Haemorrhagic and Ischaemic
15-20% and 80-85%
Describe the differences between a haemorrhagic and ischaemic stroke.
H: bleeding occurs in, or around, brain tissue - tissue tear.
I: a clot blocks flow to an area of brain - tissue blockage.
Causes of brain haemorrhage?
raised BP
weakened vessel walls; structural abnormalities and inflammation
What structural abnormalities could cause a brain bleed?
aneurysm arteriovenous malformation (AVM) - bypasses capillaries
An example of inflammation that could cause brain haemorrhage?
vasculitis - vessel walls inflamed and weakened
Causes of ischaemic stroke?
Thrombotic - clot blocking artery AT site of occlusion
Embolic - clot has traveled to occluded artery from proximal artery or the heart
Hypo-perfusion - due to reduced blood flow - STENOSED artery rather than occluded
What are the points of Virchow’s triad?
Hyper-coagulable state
Endothelial injury
Circulatory stasis
Every 8mmHg of diastolic pressure >85 doubles risk of stroke.
True/False?
true
What effect does smoking having on risk of ischaemic stroke?
double risk
Statin therapy is recommended in all patients with a stroke.
True/False?
False
Not recommended in haemorrhagic stroke
What are some mimic presentations of stroke?
hypoglycaemia - confusion, sweating
seizure
migrane
tumours
What is the only way to differentiate between an ischaemic and haemorrhagic stroke?
brain imaging;
CT brain ± angiography
MRI with DWI ± angio
MRI with SWI
What does MRI with SWI indicate?
old haemosiderin deposits (old bleed)
What is an atheroembolism?
an embolism from a thrombus forming on an atherosclerotic plaque
infarcts on the SAME side as affected carotid artery
What is a cardioembolism?
Embolism from clot formed in heart (usually LA)
infarcts in more than one arterial territory - bilateral
Which type of embolism is platelet-rich?
atheroembolism
Which type of embolism is clotting factor-rich?
cardioembolism
What is a thrombectomy?
used in ischaemic stroke - ‘unplugging’ procedure - usually after starting thrombolysis
What are the indications for thrombectomy?
only for large proximal arteries
up to 6hrs from onset of symptoms
when would you do thrombolysis?
ischaemic stroke - up to 4.5 hrs from onset of symptoms
How would prevent the next stroke in a patient, if the first was caused by a thrombus?
Anti-platelets - aspirin + dipyridamole/Clopidogrel Statins - to treat high lipids Diabetes management Hypertension management Lifestyle advice
How would you prevent the next stroke in a patient, if the first was due to AF?
Anti-coagulate ASAP; warfarin, rivaroxaban
Anti-hypertensives
What is a TIA?
Transient Ischaemic Attack
Temporary neurological symptoms due to occlusion of artery, stopping flow of blood
Why is a TIA temporary?
arteries are capable of dissolving small clots
Why is TIA an emergency?
high risk of stroke afterward
How long do TIA symptoms last?
24hrs
which arteries supply the brains?
internal carotids and vertebral arteries
What is the purpose of the Circle of Willis and which arteries are involved?
To maintain perfusion even if one carotid artery is obstructed.
Basilar & carotid arteries anastomose.
(Basilar formed by two vertebral arteries)
What does auto-regulation of cerebral blood flow ensure?
prevents MABP change outwit 60-160mmHg
What happens to vessels supplying brain if MABP falls?
resistance vessels dilate to maintain blood flow
What is the minimum MABP needed before you faint?
50mmHg
Normal intracranial pressure (ICP)?
8-13mmHg
What is cerebral perfusion pressure (CPP) equal to?
CPP = MAP - ICP
What is the result of hypoxaemia due to blood loss on cerebral flow and vessels?
less O2 = increased BP and HR
increased MABP = increased CPP
cerebral arterioles constrict to prevent CPP getting too high
