L14 - Stroke Flashcards
Stroke
Neurological deficit due to an acute focal injury of the CNS by a vascular cause
TIA
Transient episode of neurological dysfunction without acute infarction due to lack of oxygen.
LASTS LESS THAN 24 HOURS
Types of vascular causes of stroke
Ischaemic - 85%
- thromboembolism
Haemorrhagic - 10%
- intracerebral
- subarachnoid
Other - 5%
- dissection
- Venous sinus thrombosis
- Hypoxia brain injury
Which type of stroke occurs in young people more?
Haemorrhagic : vasculitis
Which type of stroke occurs in old people more?
Ischaemic stroke due to thromboembolism
Risk factors for stroke
Hypertension Diabetes Smoking CHD Post TIA Polycythaemia Vera Hyperlipidaemia COCP Excess alcohol Clotting disorders
CHADS2
Estimate stroke risk in AF patients
ROSIER
Recognition of stroke in the emergency room scale
Anterior cerebral artery stroke
Supplies:
- medial frontal and parietal lobe
- paracentral lobule
- corpus callosum
Motor loss:
- contralateral lower limb
- incontinence - loss of excitatory and inhibitory projections in the cerebral cortex to the M centre
- alien hands syndrome
Sensory loss
- contralateral lower limb
Other features:
- personality change
- innapropriate behaviour
Proximal middle cerebral artery
Supplies:
- lateral parietal lobe and frontal lobe
- superior temporal lobe
- internal capsule (lenticulostriate arteries)
Motor deficit:
- contralateral flaccid hemiparalysis of arm, leg and face (internal capsule affected)
Sensory deficit:
- contralateral upper limb affected
Visual deficit:
- contralateral homonymous hemianopia
Dysphasia: (left sided)
- Broca’s
- Wernicke’s
Other:
- left sided hemispacial neglect - when the right parietal lobe is affected
Lenticulostriate artery occlusion
Lacuna stroke
15mm infarct
May only have contralateral motor, sensory or mixed deficits depending on where in the internal capsule is affected
Distal middle cerebral artery occlusion of superior division
Supplies:
- lateral frontal lobe
- primary motor cortex
- Broca’s area
Deficit:
- contralateral motor impairment of the upper limb and face
- Broca’s dysphasia
Distal middle cerebral artery occlusion of inferior division
Supplies:
- lateral parietal lobe
- superior temporal lobe
- primary sensory cortex
- Wernicke’s area
- both optic radiations
- macula
Deficits:
- contralateral sensory loss of the upper limb and face
- Wernicke’s dysphasia
- contralateral homonomous hemianopia with no macula sparing
Posterior cerebral artery stroke
Supplies:
- occipital lobe
- primary visual cortex
- thalamus
- midbrain
Deficit:
- contralateral homonomous hemianopia with macula sparring
- contralateral sensory loss due to thalamus involvement
Cerebellum lesion symptoms
Ipsilateral:
- dysdiadochokinesis
- ataxia
- nystagmus
- intention tremor
- slurred speech
- hypotonia
+ ipsilateral horner’s syndrome due to disruption of the sympathetic that run laterally around the brainstem
+ contralateral sensory signs as pre-decussation
Basilar artery occlusion PCA
- can occlude blood supply to the PCA
- can cause sudden death
PCA: (at superior aspect of brainstem)
- visual and occulomotor deficits - occulomotor nulcei
- cortical blindness with macula sparring
- hallucinations
- sleep regulation (as PCA supplies the brainstem RAS)
- motor movement sparred as cerebral peduncles receives blood from the posterior communicating artery
Basillar artery occlusion - pontine arteries
Pontine arteries on both side are affected
- locked in syndrome - complete loss of motor movement except for ocular movement
Why is ocular movement sparred in a basillar artery occlusion affected the pontine arteries?
Occulomotor nuclei in the midbrain which is supplied by the PCA
TACS
Total anterior circulation stroke
Large cortical stroke in the middle or anterior cerebral arteries
- unilateral weakness and/ or sensory deficit
- contralateral homonomous hemianopia
- higher cerebral dysfunction - dysphasia or neglect
PACS
Partial anterior circulation stroke
Cortical stroke in the middle or anterior cerebral artery areas
2 of:
- unilateral weakness and/ or sensory deficit
- contralateral homonomous hemianopia
- higher cerebral dysfunction - dysphasia or neglect
POCS
Posterior circulation syndrome
- cerebrallar or brainstem syndromes
- loss of consciousness
- isolated homonomous hemianopia
LACS
Lacunar syndrome
- subcortical stroke due to smaller vessels
- no higher cerebral dysfunction
- unilateral weakened
- ataxia hemiparesis
- sensory stroke
Rule of 4
4 cranial nerves above, in and below the pons
Motor nuclei rule
The motor nuclei in the pons and medulla that can be divided into 12 are central and the others are lateral
4 midline Ms
Motor pathways - corticospinal tract
Medial lemniscus - dorsal column
Medial longitudinal fasciculus
Motor nuclei - 3,4,6,12
4 side Ms
Spinocerebellar pathways
Spinothalamic pathways
Sensory nuclei (trigeminal)
Sympathetic
Brainstem pathology
Ipsilateral cranial nerve signs
Contralateral sensory and motor tract deficits
