neurology Flashcards
What is a stroke
A stroke aka CVA happens when brain lacks oxygen due to a sudden interruption in the vascular supply resulting in long-term permanent damage
2 types of stroke
Ischaemic and Haemorrhagic
What is a TIA
A type of ischaemic stroke with a period of transient cerebral ischaemia (without infarction) resulting in a neurological deficit that is self-resolving within 24 hours
What is a crescendo TIA
where there are 2 or more TIAs in a week which puts pt at higher risk of stroke
Types of haemorrhagic stroke
Intraparenchymal: Intracerebral and Intraventricular (premature infants more @ risk)
SAH (subarachnoid haemorrhage)
what % of all strokes are Ischaemic
85%
categories of ischaemic stroke
thrombotic, embolic, lacunar
what leads to ishcaemic stroke
Reduction in cerebral blood flow due to arterial occlusion or stenosis (thickening + hardening)
causes of ischaemic stroke: Cardiac
cardiac embolisms:
AF (stagnant blood flow → clots)
Atherosclerosis (HTN, diabetes, smoking, high cholesterol)
Septal defect e.g patent formaen ovalae or ASD ‘paradoxial embolism’
causes of ischaemic stroke: Vascular
Aortic dissection
Vasculitis
Vertebral dissection
causes of ischaemic stroke: Haematological
hypercoagulability (APS)
sickle cell anaemia
polycythemia (hyperviscous blood)
causes of haemorragic stroke: SAH
trauma
berry aneurysm
AVM
causes of haemorrhagic strokes: intracerebral
AVM
Cerebral amyloid (beta amyloid protein build up)
HTN
what 2 haemorrhages are not classified as haemorrhagic stroke
extradural and subdural haemorrhage
other cause of ischaemic stroke
infective emboli: bacterial endocarditis
Risk factors for stroke
HTN age (most important non-modifiable risk) previous stroke/TIA CVD (angina, MI, PVD) smoking diabetes hyperlipidaemia AF carotid artery stenosis haematological disease (e.g sickle cell) Thrombophilic disorders (e.g. antiphospholipid syndrome) FHx HRT or COCP
what is the single greatest RF for stroke
HTN
where does the anterior circulation of the brain come from
BVs arising from the internal carotid arteries
where does the posterior circulation of the brain come from
BVs arising from the vertebrobasilar arteries
ACA supplies
frontal and parietal lobe (part of the anterior circulation of the brain)
MCA supplies
Large proportion of the lateral surface of each brain hemisphere including the internal capsule and basal ganglia.
Most common site of infarction.
Forms part of the anterior circulation of the brain
PCA supplies
Occipital lobe and inferior proportion of the temporal lobe as well as some deep structures (e.g. thalamus).
