Stroke Flashcards
what is stroke
acute focal neurological deficit resulting from cerebrovascular disease & lasting more than 24hrs or causing earlier death
death of brain tissue from hypoxia (lack of O2) so no local cerebral blood flow leading to infarction of tissue & haemorrhage into tissue
2 types of stroke
- ischaemic stroke
- haemorrhaginic
how is temporary ischaemia related to stroke
a TIA (transient ischaemic attack- localised loss of brain function but not haemorrhage) is rapid loss of function but rapid recovery (within 24hrs) & an indicator that ptx may be at risk of an actual stroke in the future
risk factors for stroke
hypertension - especially if diastolic >110mmHg compared to 80mmHg
smoking
alcohol
ischaemic heart disease
atrial fibrillation
diabetes mellitus
causes of ischaemic stroke
uncertain
causes of haemorrhaginic stroke
- intracranial bleed - aneurysm rupture
- embolic stroke - embolism from left side of heart can be from atrial fibrillation/ heart valve disease/ recent MI
- atheroma of cerebral vessels - carotid bifurcation, internal carotid artery, vertebral artery
stroke prevention
- reduce risk factors i.e. smoking, diabetes control, hypertension
- antiplatelet action (2ndary prevention only) i.e. aspirin, dipyridamole, clopidogrel
- anticoagulants (for embolic risk i.e. AF, LV thrombosis) e.g. warfarin, apixaban
- carotid endarterectomy - severe stenosis, previous TIAs, <85yrs
- preventative neurosurgery - aneurysm clips
what do you need to differentiate when diagnosing stroke
if it is an infarct or a bleed or a subarachnoid haemorrhage
how to investigate stroke
CT - rapid, easy access, poor for ischaemic stroke
MRI - difficult to get quickly, better at visualising early changes of damage
MRA - (angiography) best for visualising brain circulation
how to assess risk factors
carotid ultrasound
cardiac ultrasound (LV thrombus)
ECG (arrhythmia)
BP
diabetes screen
thrombophilia screen (higher tendency to form clots than normal)
effect of stroke
- loss of functional brain tissue, nerve cell ischaemia in penumbra around infarction, will die if not protected
- gradual / rapid loss of function
- inflammation in tissue surrounding infarct/bleed; recovery of some function with time
complications of stroke
motor function loss - cranial nerve or somatic (opposite side), autonomic in brainstem lesions, dysphonia, swallowing,
sensory loss - cranial nerve or somatic (opposite side), body perception i.e. neglect / phantom limbs
cognitive impairment - speech & language i.e. dysphasia, dyslexia, difficulty with speech & language, memory impairment
aim of acute phase management of stroke
to limit damage and reduce future risk
aim of chronic phase management of stroke
rehabilitation
reduce future risk
acute phase treatment of stroke
to reduce damage;
- penumbra region has survivable ischaemia; calcium channel blockers
- improve blood flow & O2; maintain perfusion pressure to brain
- normoglycaemia; hypo/hyper harmful
- remove haematoma; subarachnoid only
to prevent future risk;
- 300mg aspirin daily
- anticoag if indicated (delay 2wks) if AF of LV thrombus
