Stroke Flashcards
what is a stroke?
sudden onset of focal or global neurological symptoms caused by ischaemia or haemorrhage and lasting more than 24 hours
what is a transient ischaemic attack?
symptoms of a stroke but resolves within 24 hours and often precedes a full stroke
what are the causes of an ischaemic stroke?
large artery atherosclerosis eg carotid, cardioembolid eg AF, small artery occlusion, undetermined
what are the causes of a haemorrhagic stroke?
primary intracerebral commonly linked to age, high BP and amyloidosis and secondary haemorrhage if have structural abnormality eg SAH
how does a stroke present?
symptoms are typically asymmetrical: sudden weakness of limbs, sudden facial weakness, sudden onset dysphasia, sudden onset visual or sensory loss
what are the risk factors for a stroke?
cardiovascular disease, previous stroke or TIA, AF, carotid artery disease, hypertension, diabetes, smoking, vasculitis, thrombophilila
what tool is used for identifying stroke in the community?
FAST - face, arm, speech, time to call 999
what tool is used for identifying stroke in the ER?
ROSIER tool based on clinical features and duration- any score above 0 means a stroke is likely
how is a stroke managed?
admit to specialist stroke centre, exclude hypoglycaemia, immediate head CT to exclude primary intracerebral haemorrhage and aspirin start after CT and continued for 2 weeks
what treatment can then be given after the CT has excluded an intracranial haemorrhage?
thrombolysis with alteplase which is a tissue plasminogen activator (TPA) which rapidly breaks down clots and can reverse the effects of a stroke but needs to be given within 4.5 hours of symptoms onset and the quicker it is given the better it will work
what are the possible complications of thrombolysis and so how to we avoid this?
intracranial or systemic haemorrhages which can be monitored by repeated CT scans
why should BP not be lowered during a stroke?
this risks reducing perfusion to the brain
what is the Oxford community stroke project classification (OCSP)?
total anterior circulation stroke (TACS), partial anterior circulation stroke (PACS), lacunar stroke (LACS) and posterior circulation stroke (POCS)
what is a TACS?
main artery to one hemisphere affected so get 3/3 effects= complete hemiparesis/numbness, loss of vision on one side (hemianopia) and loss of awareness on one side (inattention) non-dominant or dysphasia dominant- often due to blocked carotid or MCA
what is a PACS?
branch of the main artery affects, in between LACS and TACS- 2/3 RACS criteria or one higher cortical deficit (inattention or dysphasia) or monoparesis
what is a LACS?
small perforating arteries affected, movement and sensation pathways, weakness/numbness of face + arm + leg or face + arm or arm + leg, may have dysarthria, ataxic hemiparesis, no effect on higher function so will not have dysphasia, inattention or hemianopia as not damaging the cortex, only damaging the white matter tracts deep in the brain so tends to be pure sensory or pure motor
what is a POCS?
any posterior artery, get a combination of symptoms including loss of balance/coordiation, vertigo, double vision, dysarthria, hemianopia
why is a basilar artery occlusion one of the worst strokes to have?
it supplies the brainstem which helps you breathe and keeps you conscious so blocking it can cause locked in syndrome or a coma and can cause ischaemia in the pons and predominantly motor/oculomotor signs/symptoms, reduced consciousness is common and may progress over 12-24 hours
what is the gold-standard imaging for strokes?
diffusion-weighted MRI but CT is an alternative and is used to establish the vascular territory that is affected
what is used instead of TPA if excluded the required criteria?
thrombectomy which is used for large vessel occlusion and involves stents
what are the secondary prevention of strokes?
clopidogrel, atorvastatin, carotid endarectomy or stunting in patients with carotid artery disease, warfarin for AF and treat modifiable risk factors like hypertension and diabetes
