stroke Flashcards
define TIA time scale?
<24hrs
most TIA are less than how long?
<1hr
define stroke?
Vascular compromise causes neuro deficit >24hrs.
Vascular compromise in the brain can be broadly split into what two categories.
how common are each at causing strokes?
-%
ischaemia 85%
haemorrhage 15%
why is Brain so susceptible to ischaemic damage?
can only do aerobic respiration
stroke pt can not take oral meds, what common symptom is the cause of this?
what tube can you use instead to deliver meds?
Dysphagia
NG tube
how can brain haemorrhage lead to a secondary stroke?
Haemorrhage, pool of blood hits on other blood vessels –> pool of blood has breakdown products –> these hit on vessels causing vasospasm –> secondary stroke
define ischaemic penumbra?
brain tissue will progress to infarction because of stroke but is still salvageable if perfused.
how long will ischaemic penumbra tissue last?
few hours
Broca’s and Wernicke’s is supplied by what artery?
MCA - middle cerebral artery
which protein that causes dementia can cause cerebellar bleeding.
how does it do this?
Amyloid
amyloid protein stiffens brain so bleeds more easily
which endocrine blood abnormality can mimic stroke symptoms?
Hypoglycaemia
why might a Toxicology screen be useful in pt with suspected stroke?
because intoxicants can mimic stroke symptoms
Smoking & HTN can cause what structures of brain to bleed?
basal ganglia
how will a superficial MCA stroke differ from a deeper MCA stroke in terms of symptoms?
superficial MCA stroke - symptoms more focal, .e. just arms, or just face, or just tongue effected.
deeper MCA stroke - arms, face & tongue all effect, not focal.
Vascular causes of stroke in the brain can be broadly split into what two categories.
how common are each at causing strokes?
-%
ischaemia 85%
haemorrhage 15%
blood clot risk factors for stroke?
blood clots that cause stroke can be split into two categories?
10
o HTN o Old Age o Atherosclerotic plaques (high LDL) o Diabetes o Smoking o Atrial fibrillation - creates emboli o Aortic dissection o Sickle cell disease o Polycythaemia o Hypercoagulability
thrombotic or embolic
Haemorrhage risk factors for stroke?
-8
o HTN o Age o Trauma o AV malformation o HTN o Anticoagulation therapy o Berry aneurysm o Cerebra amyloid
which ethnicity is at risk of HTN and thus stroke?
afro-carribean
why is ↑Age a risk factor for stroke?
with age:
walls become weaker = haemorrhage.
Walls become stiffer = HTN
how does HTN cause haemorrhage stroke?
-step by step
high pressure RBC bang on artery walls, –> walls swell out to make aneurysm –> high BP will make aneurysm burst –> bleeding.
how does HTN cause ischaemic stroke?
-step by step
based on this pathophysiology what kind of stroke is this?
small arterioles cannot take the pressure > thicken their walls to compensate > small lumen > eventually infarct –> called a lacunar stroke
define AV malformation?
how can this cause haemorrhage stroke?
direct connection between arteries and veins
high pressure arteries push blood into low pressure veins (no dampening capillaries), so they bleed.
how can hyperglycaemia cause ischaemic stroke?
-step by step
high glucose causes oxidative stress –> walls damaged, LDL will fill in the gap in the wall
–> atherosclerotic plaque.