Stroke Flashcards
Define a stroke
A neurological deficit
Attributed to acute focal injury of CNS
By vascular cause (cerebral infarction/ intracerebral haemorrhage/ subarachnoid haemorrhage)
Define a TIA
Transient episode of neurological dysfunction
Caused focal brain/ spinal cord/ retinal ischaemia
WIThOUT acute infarction
How common are the causes of strokes? Common causes in the young and old
85% ischaemic (thromboembolic)
10% haemorrhagic (intracerebral/ subarachnoid)
5% other (dissection/ venous sinus thrombosis/ hypoxic Brain injury)
Young: vasculitis, thrombophilia, subarachnoid haemorrhage, venous sinus thrombosis, carotid artery dissection
Old: thrombosis in situ, athero- thromboembolism, heart emboli, CNS bleed, sudden BP drop >40mmHg, vasculitis, venous sinus thrombosis
Risk factors for strokes
Hypertension Smoking DM Heart disease Peripheral arterial disease Post TIA Carotid artery occlusion Polycythaemia Vera COCP Hyperlipidemia XS alcohol Clotting disorders
What are the symptoms of an anterior cerebral artery stroke and why?
Contralateral lower limb: weakness & sensory deficit - motor homunculus (along precentral gyrus of frontal lobe) & sensory (along postcentral gyrus of parietal lobe) similar areas
Split brain syndrome/ alien hand syndrome (rare) - corpus callosum
Urinary incontinence - supplies cortex which sends excitatory/ inhibitory neurones to M centre to decide whether to void
Frontal lobe features e.g. personality changes/ problems with motor planning
Which general areas of the brain are supplied by which cerebral arteries?
ACA - supplies large medial area
MCA - large lateral area
PCA - inferior and posterior sections
What are the symptoms of a proximal middle cerebral artery stroke and why?
Affects everything downstream so: lenticulostriate arteries, MCA inferior division, MCA superior division
Complete contralateral hemiparesis (flaccid or spastic) - supplies internal capsule (face, arm , leg, chest fibres)
Contralateral sensory loss more likely face & arm - lateral primary sensory cortex (sensory homunculus)
Contralateral homonomous hemianopia- superior (temporal lobe) & inferior (parietal lobe) optic radiation
Speech difficulties - Broca’s area (frontal) & Wernicke’s area (tempero- parietal lobe) e.g. left sided stroke = aphasia
(Left sided) contralateral hemispacious Neglect (more common if right parietal lobe affected as left has bilateral supply)
What are the symptoms of a singular lenticulostriate artery stroke and why?
Lacunar strokes
Very small
Normally only motor or sensory deficit
Or mixed
Internal capsule affected
V specific
No cortical symptoms
What are the symptoms of a distal middle cerebral artery stroke and why?
Superior division -> lateral frontal lobe
Broca’s area - expressive aphasia (if left affected)
Motor cortex - contralateral leg and arm weakness
Or
Inferior division -> superior temporal lobe & lateral parietal
Wernicke’s area - receptive aphasia (if left side affected)
PSC - contralateral sensory changes face/ arm
Both Optic radiations - contralateral visual field without macular sparing often homonymous hemianopia
What are the symptoms of a posterior cerebral artery stroke and why?
Supplies thalamus and midbrain
Contralateral homonomous hemianopia WITH macular sparing - (Dual blood supply from MCA)
Contralateral sensory loss - thalamic involvement (internal capsule)
What are the symptoms of a cerebellar artery stroke and why?
Ipsilateral DANISH signs (dysdiadochokinesia, ataxia, nystagmus, intention tremor, slurred/ staccato speech, hypotonia) - ipsilateral spinocerebellar tracts
Ipsilateral Horner’s syndrome (miosis, ptosis, anhidrosis) - supply Brainstem as loop around cerebellum - sympathetic involvement
Contralateral sensory deficit - sensory pathways run laterally through brainstem pre-decussation
What are the symptoms of a basilar artery stroke and why?
Either at level of pontine arteries or more commonly PCA
At PCA level - occulomotor nuclei
- visual & occulomotor defects (could prevent blood flowing into PCA -> occipital lobe -> cortical blindness
Sleep regulation problems - sleep centres in midbrain
If occludes 2 pontine arteries bilaterally - locked in syndrome (complete loss of movement limbs, preserved ocular movement as occulomotor nuclei above, preserved consciousness midbrain reticular formation intact)
What is the Bramford / Oxford classification for strokes?
TACS - total anterior circulation stroke
(large cortical stroke in middle/ anterior cerebral artery areas)
PACS - partial anterior circulation syndrome
(Cortical stroke in middle/ anterior cerebral artery areas)
POCS - posterior circulation syndrome
LACS - lacunar syndrome
(Subcortical stroke due to small vessels disease, no evidence higher cerebral dysfunction)
Criteria for TACS
Total anterior circulation stroke
All 3 of:
Unilateral weakness (+/- sensory) face/ arm/ leg
Homonymous hemianopia
Higher cerebral dysfunction (dysphasia/ aphasia or visuospatial disorder)
Criteria for PACS
Partial anterior circulation stroke
2 of:
Unilateral weakness (+/- sensory) face, arm, leg
Homonymous hemianopia
Higher cerebral dysfunction (dysphasia/ aphasia or visuospatial disorder)
