Neuro17 - Stroke Flashcards
1
Q
5 stuctures supplied by the ACA and 6 consequences of an ACA infarct
Primary Motor Cortex Primary Somatosensory Cortex Paracentral Lobules Broca's Area Corpus Callosum Apraxia
A
- ) Primary Motor Cortex
- causes contralateral limb weakness
- lower limb affected > upper limb - ) Primary Somatosensory Cortex
- causes contralateral sensory changes
- ACA supplies mainly the lower limb distribution - ) Paracentral Lobules - located in the most medial part of the motor and sensory cortex
- causes urinary incontinence - ) Broca’s Area
- causes dysarthria (slurred speech) or aphasia
- however, this is more associated with MCA infarct - ) Corpus Callosum
- causes split brain/alien hand syndrome (very rare) - ) Apraxia - left frontal lobe
- inability to complete motor planning (e.g dressing oneself even when power is normal)
2
Q
5 structures supplied by the distal MCA and 6 consequences of a distal MCA infarct
Primary Motor Cortex Broca's Area Primary Sensory Cortex Wernicke's Area Both Optic Radiations Contralateral Neglect
A
- ) Primary Motor Cortex - superior division of MCA
- causes contralateral face and arm weakness
- supplies mainly the face and arms distribution - ) Broca’s Area - superior division of MCA
- causes expressive aphasia if left hemisphere affected - ) Primary Sensory Cortex - inferior division of MCA
- causes contralateral sensory loss in face and arms
- supplies mainly the face and arms distribution
- could involve larger areas if sensory fibres in internal capsule are also affected - ) Wernicke’s Area - inferior division of MCA
- causes receptive aphasia if left hemisphere affected
- if superior and inferior divisions are occluded, it can cause global aphasia (cannot understand or articulate) - ) Both Optic Radiations - inferior division of MCA
- homonymous hemianopia w/out macular sparing
- more distal occlusions may affect only one radiation causing quadrantanopias - ) Contralateral Neglect - right parietal lobe
- cannot acknowledge the left side of space
- visual extinction: e.g. half clock face
- tactile extinction: if you touch each side at the same time, they do not feel the affected side
3
Q
What are lacunar infarcts/strokes?
3 types of lacunar infarcts
A
Occlusion of lenticulostriate arteries
- causes destruction of small areas of the internal capsule and the basal ganglia
- they do not cause cortical features
- ) Pure Motor - contralateral full hemiparesis (face, arm, leg affected equally)
- damaged motor fibres going through internal capsule - ) Pure Sensory - face, arm, leg affected equally
- damaged sensory fibres through internal capsule
- can also be caused by occlusion of the thalamoperforator arteries (deep branch of PCA) - ) Sensorimotor - mixed motor and sensory features
- infarct occurs somewhere at boundary between motor and sensory fibres
4
Q
2 structures supplied by the PCA and 2 consequences of a PCA infarct
A
- ) Primary Visual Cortex
- homonymous hemianopia w/ macular sparing
- PVC contains info from both optic radiations - ) Thalamus - thalamogeniculate, thalamoperforater
- causes contralateral sensory loss in face, arm and legs
5
Q
Features of brainstem and cerebellar infarcts
Brainstem x2
Cerebellum x3
A
- ) Brainstem
- contralateral limb weakness w/ ipsilateral CN signs
- damage to to corticospinal tracts and damage to CN nuclei on the same side - ) Cerebellum - ipsilateral cerebellear signs (DANISH)
- possible ipsilateral brainstem signs since cerebellar arteries supply the brainstem aswell
- possible contralateral sensory deficit and ipsilateral Horner’s syndrome
- symptoms: nausea/vomiting, headache, vertigo
6
Q
3 features of a basilar artery occlusion
Sudden Death
Distal Occlusion x4
Proximal Occlusion
A
1.) Sudden Death - supplies the brainstem (via pontine arteries) which contains many vital centres
- ) Distal Occlusion - pontine arteries spared
- visual and oculomotor deficits (PCA and CNIII nuclei)
- behavioural abnormalities
- somnolence, hallucinations, and dreamlike behaviour (sleep regulation and reticular activating system)
- motor dysfunction often absent since midbrain gets supply from PCA via the posterior communicating artery - ) Proximal Occlusion - causes locked-in syndrome
- loss of movement of limbs but preserved ocular movement since midbrain gets supply from PCA
- preserved consciousness because midbrain and reticular formation is still intact
7
Q
Bamford Classification for Strokes
Total Anterior Circulation Stroke (TACS)
Partial Anterior Circulation Stroke (PACS)
Posterior Circulation Stroke (POCS)
Lacunar Stroke (LACS)
A
- ) TACS - all 3 of:
- unilateral weakness +/- sensory deficit of FAL
- homonymous hemianopia w/o macular sparing
- higher cerebral dysfunction: dysphasia, visuospatial disorder - ) PACS - any 2 of the 3:
- unilateral weakness +/- sensory deficit of FAL
- homonymous hemianopia w/o macular sparing
- higher cerebral dysfunction: dysphasia, visuospatial disorder - ) POCS - one of the following:
- CN palsy and contralateral motor/sensory deficit
- bilateral motor/sensory deficit
- conjugate eye movement disorder
- cerebellar dysfunction
- homonymous hemianopia w/ macular sparing - ) LACS - one of the following:
- pure sensory or motor deficit
- sensorimotor deficit
- ataxic hemiparesis
8
Q
Types of Strokes
Ischaemic
Haemorrhagic
Others
A
- ) Ischaemic (85%)
- TOAST classification used for underlying aetiology:
- 1: large artery atherosclerosis (embolus/thrombosis)
- 2: small-vessel occlusion, 3: cardioembolism
- 4: other aetiology, 5: undetermined aetiology - ) Haemorrhagic (10%) - intracerebral or subarachnoid
- primary: hypertension, cerebral amyloid angiopathy
- secondary: trauma, anticoagulation-associated - ) Other (5%)
- dissection: separation of artery walls –> occlusion
- venous sinus thrombosis: vein occlusion causes back pressure and ischaemia due to ↓blood flow
- hypoxic brain injury: e.g post-MI
9
Q
Transient Ischaemic Attacks (TIAs)
Definition
ABCD2 Score
Investigations
Management
A
1.) Definition - focal neurological deficits due to reduced blood supply to the brain, lasting <24 hours
- ) ABCD2 Score - risk assessment tool to predict the short-term risk of a stroke after a TIA
- uses age, BP, clinical features, duration, diabetes
- score of 4 and above suggests high risk
- crescendo TIA (2+ in a week) also seen as high risk
- high risk should be seen in TIA clinic or seen by a stroke physician - ) Investigations
- blood tests, carotid USS, CT head, MRI brain - ) Management
- PO aspirin (300mg) OD started immediately
- lifestyle modification, control BP and hyperlipidemia
- carotid endarterectomy if carotid stenosis
- cannot drive for 1 month (3 months if recurrent)
10
Q
Stroke
Definition Assessment Tools Investigations Enteral Feeding Differential Diagnoses
A
1.) Definition - focal neurological deficit lasting >24hrs or w/ imaging evidence of brain damage
- ) Assessment Tools
- Bamford classification: identify the vascular region
- FAST: quick recognition of stroke in public
- ROSIER scale: distinguish stroke and stroke mimic
- NIHSS: measures stroke severity, 15 different criteria
- CHADS-VASC2: suitability for anticoagulation in AF
- HAS-BLED: risk of bleeding if on anticoagulation - ) Investigations
- CT-Head to exclude haemorrhagic stroke: ischaemic area becomes hypodense, bleed glows bright white
- MRI-Brain: ischaemia shows a high signal area
- carotid USS to examine carotid stenosis - ) Enteral Feeding - NG or PEG
- patients with poor swallowing to ↓risk of aspiration
- aspiration can still occur with enteral feeding - ) Differential Diagnoses
- seizures, space-occupying lesions, multiple sclerosis
- hemiplegic migraine, sepsis in pre-existing weakness
11
Q
Management of Strokes
General Management of Ischaemic Stroke
Carotid Endarterectomy
General Management of Haemorrhagic Stroke
Decompressive Hemicraniectomy
A
- ) General Management of Ischaemic Stroke
- thrombolysis with alteplase if < 4.5hrs of onset
- contraindications: bleeding disorders, recent trauma, haemorrhage, surgery, acute cerebrovascular event
- lifestyle modification, control BP and hyperlipidemia
- cannot drive for 1 month - ) Carotid Endarterectomy - ischaemic stroke or TIA
- patients with stable neurological symptoms
- carotid stenosis >50%(NASCET) or >70% (ECST)
- referred w/in 1wk, treated w/in 2wks of onset of sx - ) General Management of Haemorrhagic Stroke
- PO aspirin (300mg) (rectal/enterally if dysphagic)
- aspirin until 2wks after the onset of the stroke
- reversal of anticoagulation - ) Decompressive Hemicraniectomy - haemorrhagic
- in severe MCA infarct showing rapid neurological deterioration to prevent malignant MCA syndrome
- referred w/in 24h, treated w/in 48h of onset of sx
- <60, NIHSS 15+, infarct >50% of MCA (on CT)
