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Clinical Neuroscience > Stroke > Flashcards

Stroke Flashcards

1
Q

what is the definition of a stroke?

A

A serious life threatening condition that occurs when the blood supply to part of the brain is cut off
Signs and symptoms persist >24hrs

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2
Q

What is a TIA - transient ischaemic attack?

A

Similar clinical features of stroke but resolves within 24 hrs

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3
Q

Types of stroke and common?

A
  • Ischaemic - 85% usually caused by thromboemolism
  • Haemorrhagic - 10% intracerebral or subarachnoid
  • Other - 5% dissection, venous sinus thrombosis, hypoxic brain injury (eg from cardiac arrest)
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4
Q

Principles of emergency management of stroke

A
  • Suitable for immediate thrombolysis or thromboectomy? - too late or haemorrhagic?
  • Imaging to establish type and location - CT- eg if haemorrhagic do not want to give thrombolysis, MRI sometimes as ischaemia is high signal
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5
Q

CT appearance of haemorrhagic stroke

A

Blood white
SAH - Star shape shows base of brain bleed into basal cisterns from circle of willis bleed

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6
Q

What can blood cause when it comes into contact with vessels?

A

Blood can cause vasospasm leading to stroke as well as ruptured vessel problem

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7
Q

Acute appearance of ischaemic stroke for CT vs MRI

A

CT very difficult - can maybe see thrombus but difficult to see infarction early on

MRI - obvious change in brain parenchyma early on in ischaemia, pale high signal area

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8
Q

How does ischaemic stroke CT change from early to 8 weeks post stroke?

A

Early - no obvious ischaemic changes

8 weeks later - large area of blacker appearance due to oedematous tissue as it is infarcted/hypoxic

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9
Q

What are the effects of an anterior cerebral artery infarct?

A

Known as ‘artery of lower limb’ - medial parietal and frontal lobe so medial area of homunculus. Also corpus callosum
* Contralateral lower limb weakness
* Contralateral sensory change in lower limb
* Urinary incontinence - paracentral lobules in medial central sulcus affected so loss of EUS tone
* Apraxia - parietal lobe damage so difficulty doing things without necessarily having weakness
* Dysarthria/aphasia - RARE
* Split brain syndrome - corpus callosum affected (eg alien hand syndrome)

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10
Q

Principles of middle cerebral artery infarct

A

Largest territory - most commonly affected in stroke
More proximal vessel affected = more devastating as distal branches are affected too
Are cortical features present or not? If not involved could be lenticulostriate deep branches alone involved

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11
Q

5 points where middle cerebral infarcts can occur

A

A - main stem
B - lenticulostriate branches
C - cortical branches only
D - inferior division of cortical branches
E - superior division of cortical branches

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12
Q

What are the effects of a middle cerebral artery main stem occlusion?

A

Entire territory involved = lateral parietal, frontal and superior temporal lobe inc lenticulostriate arteries which supply basal ganglia and internal capsule
* Contralateral hemiparesis (half side motor weakness) of face, arm and leg)
* Contralateral sensory loss
* Contralateral homonymous hemianopia
* Global aphasia if left sided - Brocas and Wernickes area supplied
* Left side neglect if right side affected - R parietal lobe

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13
Q

Why does MCA main stem occlusion cause weakness and sensory loss in face arm and leg? and not just face as it supplies lateral cortex?

A

UMNs for leg and arm and 3rd order sensory neurones go through internal capsule supplied by lenticulostriate branches = these taken out so whole contralateral sensory loss and contalateral weakness

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14
Q

What is ‘neglect’?

A

Failure to acknowledge the existance of usually the left side of space, left side of objects and even left hand side of own body (due to right parietal lobe damage)

exists even in presence of normal visual fields

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15
Q

Signs of neglect - weird

(3)

A
  • Tactile extinction - touch both sides but only feel the right hand side
  • Visual extinction - ignore left side, draw right side of clock only with all numbers on right
  • Anosognosia - failure to acknowledge there is anything wrong with left side, eg left arm etc
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16
Q

What effects does an occlusion of the lenticulostriate arteries have? (aka lacunar infarct) - what does it supply

A
  • This feeds basal gagnlia and internal capsule
  • UMNs for face arm and leg are in anterior portion of posterior limb of internal capsule
  • 3rd order sensory neurones are in posterior portion of posterior limb of internal capsule
  • Axons distributed randomly within these two areas so face arm and leg affected equally when these regions are affected
17
Q

Effects of lacunar infarcts and where these occur

A
  • Lack cortical features such as neglect or aphasia
  • Affects face arm and leg functions equally
  • Can get pure motor stroke - face, arm and leg weakness - affecting anterior posterior limb if IC
  • Can get pure sensory stroke - changes in face arm and leg sesnation - affecting posterior ppsterior limb if IC
  • Sensorimotor stroke - mixture of above - affecting watershed area of boundary between motor and sensory area in posterior limb
18
Q

What do the inferior and superior divisions of MCA supply?

A

Inferior - lateral parietal and superior temporal

Superior - Lateral frontal lobe

19
Q

What does occlusion of inferior MCA division cause?

A
  • Contralateral sensory chnage in face and arm - lateral PSC
  • Wernickes aphasia if left sided - superior temporal lobe and parietal
  • Contralateral field defect - homonymous hemianopia - superior and inferior radiations
20
Q

What are the effects of a MCA superior division occlusion?

A

Contralateral face and arm weakness - supplies lateral frontal lobe
Broca’s aphasia if left sided - L frontal lobe

21
Q

What are the effects of an occlusion in all cortical branches of MCA -superior and inferior divisions taken out

A

Mix of both superior and inferior division occlusions eg
Brocas/Wernickes aphasia if left sided
Contralateral sensory and motor weakness of face and arm
Contralateral field defect - inferior division supplies temporal lobe and parietal lobe containing superior and inferior optic radiations - homonymous hemianopia

22
Q

What occurs in occlusion of posterior cerebral artery?

A

Supplies occipital lobe and inferior temporal lobe and thalamus
* Contralateral homonymous hemianopia with macula sparing - as MCA branch can supply macula area
* Contralateral sensory loss/change due to involvement of thalamoperforator branches

23
Q

What are the three arteries supplying the cerebellum?

A

Posterior inferior cerebellar artery - off vertebral
Superior cerebellar artery - of basilar artery
Anterior inferior cerebeller artery - off basilar

24
Q

Symptoms of cerebellar stroke

A
  • Nausea
  • Vomitting
  • Vertigo/dizziness
  • Headache - posterior fossa is small
25
Q

Signs of cerebellar strokes

A
  • Ipsilateral cerebellar signs - DANISH
  • Possible ispilateral cranial nerve signs - the cerebellar arteries feed brainstem as they travel to cerebellum
  • Contralateral sensory defecit - sensory pathways run through brainstem
  • Ipsilateral horners syndrome (ptosis, miosis, anhidrosis) as sympathetic pathways run down brainstem too
26
Q

What are the DANISH ipsilateral signs of cerebellar stroke

A
  • Dysdiadochokinesia
  • Ataxia (gait and posture)
  • Nystagmus - rhythmical, repetitive and involuntary movement of the eyes
  • Intention tremor
  • Slurred, staccato speech
  • Hypotonia/heel-shin test
27
Q

Key point about brainstem strokes

A

Crossed deficit
= ispilateral brainstem signs (eg CNs etc)
BUT contralateral long tract signs (eg motor and sensory)

As long tracts cross in medulla to other side so if stroke on L this supplies R side of brain and body

28
Q

Two points where basilar artery can be occluded

A

A - tip of basilar where it splits into posterior cerebral arteries
B - middle of basilar where pontine branches come off

29
Q

What occurs in tip of basilar stroke/occlusion?

A
  • Visual and oculomotor defecits - posterior cerebral taken out, but may be rescued by posterior communicating artery
  • Behavioural abnormalities
  • Somnolence (sleepy), hallucinations and dream like behaviour - midbrain supplied by cerebellar branches of basilar as they loop around and contains reticular formation important for consciousness
  • Motor dysfunction absent as cerebral peduncles (midbrain) rescued by posterior communicating
30
Q

What does occulusion of middle of basilar artery where pontine branches come off lead to?

A
  • Locked in syndrome if pontine branches are blocked bilaterally
  • = body is paralysed but eye movement intact as midbrain is spared
  • = Consciousness preserved as midbrain reticular formation spared
31
Q

What are the 4 Oxfordshire community stroke project classifications? (OCSPC) and what vessel is occluded in each?

A
  • Total anterior circulation syndrome - usually proximal MCA or ICA
  • Partial anterior circulation syndrome - branch of MCA
  • Posterior circulation syndrome - occluded vertebral, basilar, cerebellar or PCA
  • Lacunar syndrome - lenticulostriate branches of MCA or supply to brainstem or deep white matter
32
Q

Clinical features of each OCSP classification

A
  • Total anterior circulation syndrome - Hemiparesis AND cortical dysfunction (dysphasia, visuospatial neglect) AND homonymous hemianopia
  • Partial anterior circulation syndrome - isolated higher cortical dysfunction OR two of: hemiparesis, higher cortical dysfunction, hemianopia
  • Posterior circulation syndrome - isolated hemianopia, brainstem or cerebellar syndromes
  • Lacunar syndrome - Pure motor stroke OR pure sensory stroke OR sensorimotor stroke OR ataxic hemiparesis OR clumsy hand-dysarthria
33
Q

Check lecture for CT and MRIs of OCSP images of each syndrome

A

:)

Clinical Neuroscience (24 decks)

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