Strokes Flashcards

1
Q

Define stroke

A

The damaging or killing of brain cells starved of oxygen as a result of the blood supply to part of the brain being cut off

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2
Q

Define TIA

A

A stroke that recovers within 24 hours from the onset of symptoms

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3
Q

State possible locations from where the clot may have come from

A
  • The clot may come from the carotid arteries, brain, heart, aorta, vertebral/basilar arteries
  • In the heart, it may be due to atrial fibrillation, valvular disease/prosthetic valves, endocarditis
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4
Q

What might be the differential diagnosis for stoke in younger patients

A
  • Younger patients are unlikely to have a stroke

- Those who have stroke symptoms may have vasculitis, sickle cell anaemia, cocaine

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5
Q

Describe the presentation of an anterior cerebral artery stroke

A
  • Motor - contralateral
    • Lower limb affected more than upper limb - medial homunculus more affected
    • Initially flaccid paralysis, followed by spasticity (upper motor neuron signs) - spinal shock
  • Sensory - contralateral
    • Loss of all sensory modalities in the lower limb - cortical problem thus spinothalamic and dorsal column both affected
  • Damage to paracentral lobules leads to loss of voluntary control of micturition
  • Damage to corpus callosum can lead to split brain syndrome or alien hand syndrome
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6
Q

What is malignant MCA syndrome

A
  • A main trunk occlusion causes considerable cerebral oedema - significant brain tissue damage
  • Known as malignant MCA syndrome
  • May lead to coma/death
  • Sometimes part of skull taken away to relieve pressure inside the pressure due to the build-up of oedema
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7
Q

Describe the presentation of a middle cerebral artery stroke

A
  • Motor - contralateral
    • Upper limb and face affected more than lower limb - lateral homunculus more affected
    • Initially flaccid paralysis, followed by spasticity (upper motor neuron signs) - spinal shock
  • Sensory - contralateral
    • Loss of all sensory modalities in the upper limb and face
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8
Q

Describe the difference in presentation between a proximal and distal MCA stroke

A
  • An occlusion at the proximal end will affect lateral motor cortex as well as the internal capsule
    • Therefore face, arm and leg will be affected as all motor fibres pass through internal capsule
  • An occlusion distal to the lenticulostriate artery branches spares the internal capsule so only motor function in face and upper limb affected
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9
Q

Discuss the visual effects problem of MCA strokes

A
  • Proximal occlusion of MCA leads to contralateral homonymous hemianopia
  • More distal occlusion of the MCA may lead to contralateral homonymous superior or inferior quadrantanopia
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10
Q

Describe the symptoms associated with speech in MCA strokes

A
  • Symptoms depend on dominant hemisphere and which branch of MCA is occluded
  • If dominant hemisphere (most likely left) is affected:
    • Global aphasia caused by main trunk occlusion
    • Broca’s aphasia if branches towards Broca’s area infarcted
    • Wernicke’s aphasia if branches towards Wernicke’s area infarcted
  • If non-dominant hemisphere (most likely right) side is affected:
    • Hemispatial neglect - neglect left side
    • Tactile extinction - when touched simultaneous on left and right arm, patient will only notice right arm touched
    • Visual extinction - when viewing object from both eyes, the left eye object is ignored
      • Anosognosia - denies disability
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11
Q

Describe the presentation of posterior cerebral artery stroke

A
  • Visual cortex symptoms
    - Contralateral homonymous hemianopia with macular sparing
  • More likely to present without other symptoms than in MCA infarct (no sensory/motor symptoms)
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12
Q

Describe the difference in presentation of proximal and distal strokes of cerebellar arteries

A
  • Proximal occlusion may cause brainstem and cerebellar signs
  • Distal occlusion may cause cerebellar signs alone
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13
Q

Describe signs of brainstem damage

A
  • Cranial nuclei reside in brainstem
  • ‘Crossed deficits’
    • Damage to ascending/descending tracts in the cerebral peduncle affects contralateral side of body
    • Damage to cranial nerves or their nuclei give ipsilateral signs
      • Eg. Infarct of right cerebellar arteries may cause right CN III nerve palsy
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14
Q

Describe symptoms of a distal basilar artery occlusion

A
  • Bilateral occipital lobe infarction - blindness
  • Bilateral thalamic infarction - anaesthetised (loss of sensory function)
  • Bilateral midbrain infarction - motor effects such as CN III nerve palsy
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15
Q

Describe symptoms of a proximal basilar artery occlusion

A
  • Locked-in syndrome
  • An occlusion of the basilar artery at the pons level causes:
    • Lose all CN function apart from CN I, II, III, IV - only able to move eyes
    • Anaesthetised at all levels
    • Full consciousness
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16
Q

Describe the presentation of a stroke affecting the lenticulostriate artery

A
  • Supplies the posterior limb of the internal capsule which carries descending motor fibres to the entire body
  • Patients present with pure motor hemiparesis
    • Contralateral
    • Paralysis - initially flaccid followed by spasticity)
    • Involves face, upper limb and lower limb
17
Q

Describe the presentation of a stroke affecting the thalamoperforator artery

A
  • Supplies thalamocortical fibres - relays sensory information from the thalamus to the post-central gyrus (somatosensory cortex)
  • Patients present with pure sensory stroke
    • Contralateral
    • Sensory loss of all modalities
      • Involved face, upper limb and lower limb
18
Q

Describe the oxford classification of strokes

A
  • Total anterior circulation syndrome - proximal MCA or ICA pcclusion
  • Partial anterior circulation syndrome - MCA branch occlusion
  • Posterior circulation syndrome - vertebral, basilar, cerebellar or PCA occlusion
  • Lacunar syndrome - - lenticulostriate, thalamoperforator occlusion
19
Q

Describe the imaging of strokes

A
  • In the acute phase, the most important thing is to look for bleeding - CT scan sufficient
    • Although MRI provides better quality imaging and shows damage to tissue, it takes more time therefore CT preferred acutely
  • Early parenchymal changes (>1 hr) - grey matter becomes hypodense (dark) and there is a loss of grey/white matter differentiation
20
Q

Describe the types of lacunar strokes

A
  • Pure motor stroke - lenticulostriate artery affecting the motor aspect of the internal capsule
  • Pure sensory stroke - thalamoperforator artery affecting the thalamocortical fibres of the internal capsule
  • Sensorimotor stroke - stroke affecting both the sensory and motor portions of the internal capsule