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Clinical neuroscience > Stroke > Flashcards

Stroke Flashcards

1
Q

What is a stroke?

A
  • A serious, life-threatening condition that occurs when the blood supply to part of the brain is cut off
  • Symptoms and signs persist for more than 24 hours
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2
Q

What are transient ischaemic attacks?

A
  • Have similar clinical features of a stroke but completely resolve within 24 hours
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3
Q

What are the different types of stroke?

A
  • Ischaemic (85%) - thromboembolic
  • Haemorrhagic (10%) - intracerebral and subarachnoid
  • Other (15%) - dissection, venous sinus thrombosis, hypoxic brain injury
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4
Q

What is a dissection that causes stroke?

A
  • Separation of walls of artery, can occlude branches
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5
Q

What is a venous sinus thrombosis?

A
  • Occlusion of veins causes backpressure and ischaemia due to reduced blood flow
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6
Q

What are the two main principles of stroke management?

A
  • Is the patient within the window for thrombolysis (<4 hours)
  • Do a CT head to determine if it is a bleed (if there’s a bleed, cannot proceed with thrombolysis)
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7
Q

What are the different mechanisms of acute imaging of a stroke?

A
  • CT
  • MRI
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8
Q

How does stroke appear in a CT head?

A
  • Ischaemic area of brain not visible early on (as infarct becomes more established the ischaemic area will become hypodense)
  • A bled will show up as a bright white area, maybe with mass effect
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9
Q

How does stroke appear in an MRI?

A
  • Shows up as a high signal area
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10
Q

What are the classic stroke syndromes?

A
  • Anterior cerebral artery infarct
  • Middle cerebral artery infarct
  • Posterior cerebral artery infarct
  • Cerebellar infarct
  • Brainstem strokes
  • Basilar artery occlusion
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11
Q

What are the motor symptoms of an anterior cerebral artery infarct?

A
  • Contralateral weakness in lower limb (affected worse than upper limb and face)
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12
Q

What are the sensory symptoms of an anterior cerebral artery infarct?

A
  • Contralateral sensory changes in same pattern as motor deficits
  • Lower limb is affected worse than upper limb and face
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13
Q

What are the other symptoms of an anterior cerebral artery infarct?

A
  • Urinary incontinence due to paracentral lobules being affected
  • Apraxia
  • Dysarthria/aphasia
  • Split brain syndrome/alien hand syndrome
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14
Q

What are the paracentral lobules?

A
  • Essentially the most medial part of the motor/sensory cortices
  • Supplies perineal area
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15
Q

What is apraxia?

A
  • Inability to complete motor planning e.g. difficulty dressing oneself even when power is normal
  • Often caused by damage to left frontal lobe
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16
Q

Is it common to see dysarthria/aphasia in an ACA infarct?

A
  • Very unusual
  • Much more common in MCA infarcts
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17
Q

What causes split brain syndrome/alien hand syndrome?

A
  • ## Caused by involvement of corpus callosum which is normally supplied by the ACA
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18
Q

Give an overview of occlusion of the MCA?

A
  • MCA supplies a large area of brain
  • Effects are widespread
  • 80% mortality if main trunk of MCA is affected due to resulting cerebral oedema
  • Haemorrhagic transformation can occur if the vessels in the infarcted area break down
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19
Q

Where can the MCA be occluded?

A
  • Proximal
  • Lenticulostriate arteries
  • More distal branches
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20
Q

How much of the MCA is affected if the proximal part gets occluded?

A
  • All branches of MCA are affected, including lenticulostriates and distal branches to cortical areas
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21
Q

What are the motor effects of a proximal MCA stroke?

A
  • Contralateral hemiparesis (face, arm and leg affected)
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22
Q

Why does a proximal MCA stroke cause contralateral hemiparesis?

A
  • Internal capsule has been affected, which carries fibres to face, arm and leg
23
Q

What are the sensory effects of a proximal MCA stroke?

A
  • Contralateral sensory loss in the distribution of the primary sensory cortex supplied by the MCA (face and arm)
  • Could involve larger areas if sensory fibres in the internal capsule are affected
24
Q

What visual field defects are caused by a proximal MCA stroke?

A
  • Contralateral homonymous hemianopia without macula sparing
25
Q

Why does a proximal MCA stroke cause a contralateral homonymous hemianopia without macula sparing?

A
  • Due to destruction of both superior and inferior optic radiations as they run through the temporal and parietal lobes
  • More distal occlusions may affect one radiation alone, causing a quadrantanopia
26
Q

What are some other features of a proximal MCA stroke?

A
  • Aphasia
  • Contralateral neglect
27
Q

Why does a proximal MCA stroke cause aphasia?

A
  • Global if dominant (usually left) hemisphere is affected
  • Cannot understand or articulate words
28
Q

Why does a proximal MCA stroke cause contralateral neglect?

A
  • Usually due to lesions of right parietal lobe
  • Is essentially an issue with not acknowledging that one half of the body and space does not exist
  • Visual fields normal
  • Can result in tactile extinction, visual extinction and anosognosia on affected side
29
Q

What is the name given to a stroke caused by occlusion of the lenticulostriate arteries?

A
  • Lacunar stroke
30
Q

What does lacunar infarct do to the brain?

A
  • Destruction of small areas of internal capsule and basal ganglia
31
Q

What distinguishes a lacunar infarct from other kinds of stroke?

A
  • These do not cause cortical features e.g. neglect or aphasia
32
Q

What are the types of lacunar infarct?

A
  • Pure motor
  • Pure sensory
  • Sensorimotor
33
Q

What are the features of a pure motor lacunar infarct?

A
  • Face, arm and leg are affected equally
  • Caused by damage to motor fibres travelling through the internal capsule
  • Due to occlusion of lenticulostriate vessels
34
Q

What are the features of a pure sensory lacunar infarct?

A
  • Face, arm and leg affected equally, caused by damage to sensory fibres travelling through internal capsule
  • Most likely due to occlusion of thalamoperforator arteries
35
Q

What causes a sensorimotor lacunar infarct?

A
  • Caused by infarct occurring somewhere at boundary between motor and sensory fibres
36
Q

What are the divisions of the MCA?

A
  • Superior and inferior
37
Q

What does the superior division of the MCA supply?

A
  • Essentially supplies lateral front lobe
  • Including primary motor cortex and Broca’s area
38
Q

What will occlusion of the superior division of the MCA result in?

A
  • Contralateral face and arm weakness
  • Expressive aphasia if left hemisphere is affected
39
Q

What does the inferior division of the MCA supply?

A
  • Lateral parietal lobe and superior temporal lobe
  • Includes primary sensory cortex, Wernicke’s area and both optic radiations
40
Q

What will occlusion of the inferior division of the MCA result in?

A
  • Contralateral sensory change in face and arm
  • Receptive aphasia if left hemisphere
  • Contralateral visual field defect without macula sparing (often homonymous hemianopia as both radiations are damaged)
41
Q

What can occlusion of branches distal to the superior/inferior division of the MCA cause?

A
  • Very specific effects
  • E.g. taking out Broca’s areas specifically with no motor deficit
42
Q

What are the symptoms of PCA occlusion?

A
  • Somatosensory and visual dysfunction typical
  • Contralateral homonymous hemianopia (with macular sparing due to collateral supply from MCA)
  • Contralateral sensory loss due to damage to thalamus
43
Q

What does Danish stand for in terms of cerebellar signs?

A

Dysdiadochokinesia
Ataxia (gait and posture)
Nystagmus
Intention tremor
Slurred, staccato speech
Hypotonia/heel-shin test

44
Q

What are the symptoms of a cerebellar stroke?

A
  • Nausea
  • Vomiting
  • Headache
  • Vertigo/dizziness
  • Ipsilateral cerebellar signs
  • Possible ipsilateral brainstem signs
  • Possible contralateral sensory deficit
  • Ipsilateral Horner’s
45
Q

Why do we get ipsilateral brainstem signs during a cerebellar stroke?

A
  • Cerebellar arteries supply the brainstem as they loop around the cerebellum
46
Q

What are the symptoms of brainstem strokes?

A
  • A huge number of named syndromes
  • Typical feature is contralateral limb weakness seen with ipsilateral cranial nerve signs
47
Q

Why do brainstem strokes cause contralateral limb weakness and ipsilateral cranial nerve signs?

A
  • This can be explained by damage to corticospinal tracts (above the decussation of the pyramids) and damage to cranial nerve nuclei on same side
48
Q

What can basilar artery occlusion cause?

A
  • Sudden death because this vessel supplies the brainstem
49
Q

What does occlusion of the superior basilar artery cause?

A
  • Visual and oculomotor deficits
  • Behavioural abnormalities
  • Somnolence, hallucinations, and dreamlike behaviour
  • Motor dysfunction often absent
50
Q

Why do superior basilar artery occlusions cause visual and oculomotor deficits?

A
  • Basilar artery sends some branches to the midbrain which contains oculomotor nuclei
  • Also, occlusion at this site can prevent blood flowing into the PCAs, affect the occipital lobes
51
Q

What are the symptoms of proximal basilar artery occlusion?

A
  • Can cause locked in syndrome
  • Complete loss of movement of limbs
  • Preserved ocular movement
  • Preserved consciousness
52
Q

Why does proximal basilar artery occlusion preserve ocular movement?

A
  • Midbrain is getting supply from PCAs via posterior communicating arteries
53
Q

What is the Bamford (Oxford) stroke classification?

A
  • Clinical tool used to quickly diagnose strokes

Clinical neuroscience (19 decks)

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