cerebral infarction (clinical) Flashcards
what is a stroke defined as?
sudden onset of focal or global neurological symptoms caused by ischaemia or haemorrhage and lasting more than 24 hours
what percentage of strokes are ischaemic?
about 85%
what differentiates a transient ischaemic attack from a stroke?
symptoms resolve within 24 hours
most TIAs resolve within 1-60mins
what is the most common cause of ischaemic stroke?
large artery atherosclerosis
what is the most common cause of haemorrhagic stroke?
primary intracerebral haemorrhage
what does prolonged hypoxia lead to?
anoxia
what does anoxia lead to?
infarction (complete cell death, which leads to necrosis)
what can cause further damage in a stroke patient?
edema depending on the size and location of the stroke
secondary haemorrhage into the stroke
what are some non modifiable risk factors for stroke?
previous stroke
being old
being male
having a horrible family history
what is the effect of diabetes on the chances of having a stroke?
increases the incidence of stroke up to 3 fold in both sexes
what is the effect of smoking on the chances of having a stroke?
2 fold increased risk of cerebral infarction
3 fold risk of sub arachnoid haemorrhage
what is the effect of increased serum lipids?
increase stroke risk due to blood vessel wall atheroma
what does increased plasma level of LDL result in?
excessive amounts of LDL within the arterial wall
what is the effect of alcohol on stroke risk?
small amounts of alcohol decrease stroke risk
heavy drinking increases the chances of having a stroke 2.5 times
what comprises the anterior arterial supply to the brain
2 anterior cerebral arteries
2 middle cerebral arteries
what comprises the posterior arterial supply to the brain?
2 vertebral arteries
3 pairs of cerebellar arteries
2 posterior cerebral arteries
where are borderzone anastomoses located?
between the peripheral branches of the anterior, middle and posterior cerebral arteries
what are some symptoms of anterior cerebral artery occlusion?
contra lateral-
paralysis of the foot and leg
sensory loss over foot and leg
impairment of gait and stance
what are some symptoms of middle cerebral artery occlusion?
contra lateral:
paralysis of face/arm/leg
sensory loss face/arm/leg
homonymous hemianopia
gaze paralysis to opposite side
aphasia if stroke is on the dominant side
unilateral neglect and agnosia for half of the external space if non dominant stroke
what are some symptoms of right hemisphere damage?
left hemiplegia
homonymous hemaniopia
agnosias (neglect syndromes)
what are 4 types of agnosias?
visual agnosia
sensory agnosia
anosagnosia (denial of hemiplegia)
prosopagnosia (failure to recognise faces)
what structures are involved in a stroke affecting the posterior circulation of the brain?
brainstem
cerebellum
thalamus
occiptal and medial temporal lobes
what should acute ischaemic stroke therapies aim to do?
restore blood supply
prevent extension of ischaemic damage
protect vulnerable brain tissue
what is the criteria for tissue plasminogen activator use
less than 4.5 hours from symptom onset
disabling neurological deficit
symptoms present for more than 60 minutes
consent obtained
what is the exclusion criteria for IV TPA?
anything that increases the possibility of haemorrhage
BP > 185 systolic or ?110 diastolic
glucose <2.8 or ?22mmol/L
what can increase the possibility of haemorrhage?
blood on CT scan
recent surgery
recent episodes of bleeding
coagulation problems
what is an effective treatment for symptomatic internal carotid artery stenosis?
carotid endarterectomy
what investigations are appropriate for stroke?
routine blood tests CT or MRI head ECG echo carotid doppler cerebral angiogram hyper coagulable blood screen
what are some common secondary prevention medications for stroke?
anti hypertensives anti platelets lipid lowering agents warfarin for AF carotid endarterectomy
