Week 2 Flashcards
WHO definition of stroke
a clinical syndrome characterised by rapidly developing clinical signs of focal, and at times global disturbance of cerebral function
Symptoms last > twenty four hours or cause death
No apparent cause other than that of vascular origin
What is a transient ischaemic attack (TIA)
neurological deficit of presumed vascular origin lasting less than 24 hours
- typically last less than 10 minutes
- suggestions to change definition definition to <1 hour
Relatively benign in terms of immediate consequences as symptoms resolve
Warning Stroke more appropriate than mini stroke as it is a direct sign that a stroke may potentially occur
important to have investigated
Stroke types (2)
ischaemic (85%)
hemorrhagic (15%)
Types of ischaemic stroke
thrombotic
embolic
hypo-perfusion
Types of hemorrhagic stroke
subarachnoid
intracerebral
Pathogenesis of ischaemic stroke
large artery thromboembolism 50%
small artery disease - 20-25%
embolism associated with cardiac dysfunction 20%
non atheromatous arterial disease 5%
blood disease <5%
Ischaemic cascade
process of stroke injury at the cellular level
irreversible damage begins immediately at the core
the penumbra may be viable for up to 6 hours
ischaemic cascade continued
rapidly initiated within seconds to minutes after the loss of blood flow to a region of the brain
comprises a series of subsequent biochemical events that lead to disintegration of cell membranes and neuronal death at the core of the infarction
severe focal hypoperfusion leads to excitotoxicity and oxidative damage which in turn cause microvascular injury, BBB dysfunction and initiate inflammation
exacerbates initial injury and can lead to permanent cerebral damage
Amount of permanent damage is dependant on : degree and duration of ischemia and brain’s capability to recover
Pathogenesis of haemorrhagic stroke
hypertension - acute hypertension - alcohol -amphetamines arterial disease - vascular malformations
Diasthesis (bleeding disorders)
- Anticoagulants
- Antiplatelets
- Thrombolytic therapy
Trauma
Look up the pathogenesis of hemorrhagic and ischaemic stroke
Kahn’s academy?
Pathogenesis of haemorrhagic stroke cont
intracerebral haemorrhage activates a nuclear factor which then perpetuates inflammation
inflammation along with oxidative stress leads to secondary brain damage
induction of antioxidative defence components and inhibition of the nuclear factor protect affected area of the brain
phagocytosis mediated haematoma clean up also stimulated facilitating removal of the haematoma (source of toxicity and inflammation)
Dominant (usually left) hemisphere functions
language
skilled motor formulation (Praxis)
Arithmetic sequential and analytical calculating skills
musical ability : sequential and analytical skills in trained musicians
Sense of direction : following a set of written directions in sequence
Non dominant (usually right) hemisphere functions
Prosody (emotion conveyed by tone of voice
visual spatial analysis and spatial attention
arithmetic ability to estimate quantity to correctly line up columns of numbers on the page
musical ability : in untrained musicians, and for complex musical pieces in trained musicians
sense of direction : finding one’s way by overall sense of spatial orientation
Anterior circulation includes
internal carotid artery system
anterior cerebral artery
middle cerebral artery
Posterior circulation includes
vertebrobasilar artery system
vertebral artery posterior inferior cerebellar artery basilar artery anterior inferior cerebellar artery posterior cerebral artery
Symptomology of Middle Cerebral Artery - Right
L Hemiplegia ; upper limb affected more than lower limb L Hemianaesthesia L hemianopia / quadrantopia Gaze palsy Dysarthria Unilateral neglect / inattention agnosognosia autopagnosia motor impersistence disinterest/poor motivation/apathy impulsiveness dyspraxia - constructional /dressing impaired ability to judge distance astereognosis verticality problems coma- depending on extent of lesion
Symptomology middle cerebral artery -Left
R hemiplegia ; upper limb affected more than lower limb R hemianaesthesis R hemianopia /quadrantopia Dysphasia - receptive and/or expressive anomia dyspraxia - ideomotor/ideational Gerstmann's syndrome : R/L confusion, finger agnosia, acalculia, dysgraphia Coma - depending on extent of lesion
anterior cerebral artery
contralateral hemiplegia - lower limb affected more than upper limb cortical sensory loss to leg and foot urinary incontinence dyspraxia of left limbs Abulia Slow to respond to commands; decreased mental quickness flat affect, lack of spontaneity, apthy distractible perservation of movement notable reduction in speech output facial/tongue weakness grasp/sucking reflex may be present
Posterior cerebral artery
homonymous hemianopia (cortical blindness if bilateral lesions)
colour blindness
hemianaesthesia (mild to severe)
verbal dyslexia
memory deficits
poor orientation in space
gerstmann’s syndrome : R/L confusion, finger angosia, acalculia, dysgraphia
Posterior inferior cerebella artery
vertigo/nausea/vomiting/nystagmus at rest or with eye movement
ipsilateral loss of pain and temperature to face
contralateral loss of pain and temperature to body
diplopia
hoarseness
dysarthria
dysphagia
transient contralateral hemiparesis
Cerebellar ataxia - falling to side of lesion
Ipsilateral paralysis of muscles of the soft palate, pharynx and larynx causing dysphagia and dysarthria
Horner’s syndrome : ipsilateral small pupil, ptosis, enophthalmos (sunken eye ball), lack of sweating on one side of face
Vertebral artery or branch of vertebral / lower basilar artery
ipsilateral paralysis with atrophy of half the tongue (CN XII)
Contralteral hemiparesis of arm and leg (sparing face)
Contralateral impaired tactile and proprioceptive sense
Stroke classification
Stoke syndromes are usually divided into
Large vessel stroke within the anterior circulation
large vessel stroke within the posterior circulation
Small vessel disease of either vascular bed
Bamford oxfordshire stroke classifications
TACS: total anterior circulation syndrome (15%)
PACS: Partial anterior circulation syndrome (35%)
LACS: Lacunar syndrome (25%)
POCS: posterior circulation syndrome (25%)
Once the type of stroke is known (infarct vs hemorrhage) the letter S is replaced with I and H respectively
TACS
large cortical and subcortical stroke in MCA/ACA
high mortality, poor functional outcome (long term dependancy)
symptoms include all three of the following Higher cerebral dysfunction - neglect (right hemisphere) -Aphasia (L hemisphere) -Apraxia
Homonymous hemianopia
motor sensory deficit
>2/3 face + arm + leg
PACS
cortical stroke in MCA branch fair prognosis, high chance of functional recovery symptoms at maximum deficit include two of the following -higher cerebral dysfunction -homonymous hemianopia -motor sensory deficit or -higher cerebral dysfunction or -limited motor/sensory deficit
