Stroke Flashcards
what is a stroke?
ACUTE onset of focal neurological symptoms and signs due to DISRUPTION OF BLOOD SUPPLY
= end organ complication of poor vascular health
what are the 2 types of stroke?
1) haemorrhagic
2) ischaemic
what happens haemorrhagic stroke?
= when bleeding occurs in inside or around brain tissue
what happens in ischaemic stroke?
= a clot blocks blood flow to an area of the brain
what type of blood pressure causes haemorrhagic shock?
raised high blood pressure
= HYPERTENSION
what does a haemorrhagic shock to the vessel walls?
= weakening and rupturing blood vessel walls
in haemorrhagic shock, what causes the weakened blood vessels?
- structural abnormalities e.g. aneurysm, arteriovenous malformation (AVM) = abnormal and poorly formed blood vessels that have a higher rate of bleeding
- inflammation of vessel wall
what 3 things happen in ischaemic stroke?
1) thrombotic
2) embolic
3) hypo perfusion
what is a thrombosis, in iscahemic stroke?
= clot blocking the artery AT SITE OF OCCLUSION
what is an embolic, in iscahemic stroke?
= clot blocking artery that has TRAVELLED to an artery to occlude from somewhere more proximal in the arteries of the heart
what causes hypo perfusion in ischaemic stroke?
= due to reduced flow of blood due to stenosed artery rather than occlusion of artery
what are the 3 components that encompass thrombosis?
1) endothelial injury
2) circulatory stasis
3) hyper-coagulable state
what is the mechanism of athero- thrombotic stroke?
1) atherogenesis
2) plaque
3) platelet aggregation
4) thrombosis
5) ischaemia
what 2 things can happen between plaque and platelet aggregation?
1) plaque rupture
2) vessel stenosis
what does vessel stenosis cause?
causes low blood flow
what are the non-modifiable risk factors for stroke?
- age (incidence rises with age)
- family history of stroke
- gender
- race
- previous stroke
what are the modifiable risk factors for stroke?
- hypertension
- hyper-lipidaemia
- smoking
- alcohol excess
- obesity
- physical inactivity
- poor socioeconomic status
- prior history of transient ischaemic attack
- atrial fibrillation
- diabetes
- congestive heart failure
how can improvement in hypertension improve stroke?
= a 10mm reduction in systolic BP reduces risk of CV events
- isolated systolic hypertension canincrease stroke risk
how can smoking affect stroke?
= doubles risk of ishaemic stroke
when should statins be used?
- statins recommended in all patients with iscahemic stroke
NOT RECOMENDED in haemorrhagic stroke
what are the 3 essential questions to ask yourself when investigating a stroke?
1) is this a stroke?
2) what kind of stroke is it?
3) what has caused this?
what is a stroke mimic?
= conditions that present acutely with focal neurological signs but aren’t due to interrupted blood flow
give examples of what might be the causes of stroke mimics?
- hypoglycaemia
- seizures = postical states
- migraine
- other metabolic, hyperglycaemia, hyponatremia
- space occupying lesions like brain tumours
- functional hemiparesis (weakened one side of the body)
what is the only way to differentiate between ischaemic and hemorrhagic stroke?
= imaging
what are the possibilities of imaging that could be done?
- CT brain +/- angiography
- MRI with DWI (diffusion weighting imaging) +/- angiography
- MRI with SWI (susceptibility weighing imaging) = looks for old haemosiderin deposits (old bleed)
what is the imaging preference?
CT scan - NOT MRI
in investigating iscahemic stroke, what are you trying to find?
- cause of thrombosis
- cause of embolism
what tests would you perform in investigating iscahemic stroke?
Blood tests;
- glucose
- lipids
- thrombophilia screen in young patients
- assess for hypertension
what is athero-embolism?
= embolism from a thrombus forming on an atherosclerosis plaque = platelet rich clots
- infarcts in same side as affected carotid artery
what is a cardioembolism?
= embolism forms a clot formed in heart (usually left atrium) = clothing factor rich clots
- infarcts in more than one arteries territory, bilateral
if query atheroembolism, what investigations would you do?
- carotid scanninng
- CT/MR angiography of aortic arch
if query cardioembolism, what investigations would you do?
- ECG
= AF
= old iscahemic changes (mural thrombus)
= LVH (suggests uncontrolled hypertension = commonest cause of AF) - echocardiogram (transthoracic, transeosphageal, bubble contrast study to look for intertribal connection)
= 24hour, 5 day ECG monitor tests
what are you trying to investigate in haemorrhagic stroke?
the cause of bleeding
when and where is hypertension often seen?
- older patients
- deeper in the brian
if theres a young person, who is not hypersensitive & has lobar (superficial) haemorrhage, what are you investigating for?
- aneurysm
- AVM
what 2 things can you do to reverse iscahemic stroke?
1) thrombolysis
= upto 4.5hours from onset of symptoms
2) thrombectomy
= upto 6hours from symptoms onset, usually after having started thrombolysis
= both are trim dependent treatments as brain tissue dies rapidly with any delay
what does thrombolysis help with?
= tPA helps DISSOLVE BLOOD CLOT if given IV
what is thrombectomy?
= REMOVES BLOOD CLOT
= pass a catheter up vessel and integrate into blood clot and taken into catheter and removed
what drugs should you give to prevent next stroke?
- if atheroembolic or thrombus has caused it?
- Ant-iplatelets = (Aspirin 75 mg + Dipyridamole MR 200 mg twice daily/Clopidogrel 75 mg daily) - Statins to treat high lipids - Diabetes management - Hypertension management - Lifestyle advice
what drugs should be given to prevent next stroke if stroke is due to atrial fibrillation?
= warfarin (Vit K antagonists)
= direct acting oral anticoagulants (act by inhibiting clotting factors directly like factor X and thrombin)
- rivaroxaban
- dabigatran
- apixaban
- edoxaban
what do anti-hypertensives do?
when are anti-hypersensitive most important?
= control hypertension
- mort important in coronary heart disease & peripheral heart disease
what combination of drugs could reduce recurrent of stroke?
perindopril + indapamide
what surgical management techniques could be done?
1) Haematoma evacuation
2) Relief of raised intracranial pressure
- Obstructive hydrocephalus
- Large total MCA infarctions
3) Carotid endarterectomy
>70% stenosis in same sided internal carotid artery(as affected side of brain)
what is transient ischaemic attacks (TIA)?
= temporary neurological symptoms due to occlusion of artery stopping flow of blood.
- temporary b’cos arteries capable of dissolving small clots
in a TIA, when do focal neurological symptoms resolve?
within 24houurs
what are the chances of having a stroke after having had a TIA?
quite high
what are some rarer causes of stroke?
- homocysteinemia
- protein S, C antithrombin III deficiency
- vasculitis
- paradoxical embolism
