14. Stroke Flashcards
What is a stroke?
The damaging or killing of brain cell starved of oxygen as a result of the blood supply to part of the brain being cut off.
What is a transient ischaemic attack?
A stroke that recovers within 24 hours from the onset of symptoms.
What is stroke syndrome?
Constellation of signs and symptoms produced due to occlusion or damage of an artery supplying part of the brain.
What are the two key types of stroke?
Ischaemic and haemorrhagic.
Where do clots in ischaemic strokes normally come from?
Carotid arteries, heart (in AF mainly), aorta, brain, vertebral/basilar arteries
What makes up the anterior circulation?
Anterior cerebral arteries and middle cerebral arteries.
What makes up the posterior circulation?
Vertebral arteries, posterior cerebral arteries, and the cerebellar arteries.
Which four questions should be considered in stroke presentation?
Which artery has been affected, the area of brain supplied by artery, what the area of brain does, and expected presentation of the patient.
Areas of which part of the brain will be lost in stroke of the left anterior cerebral artery?
- Medial aspects of the left frontal and parietal lobes, anterior part of the corpus callosum. 2. Paracentral lobules. 3. Corpus callosum.
What is the function of the parts of brain affected by left anterior cerebral artery stroke?
- The homunculus of the genitals, toes, foot and leg. 2. Also paracentral lobules have a role in voluntary control of micturition. 3. Connecting the two hemispheres of the brain.
How will a patient present with a left anterior cerebral artery stroke?
- Motor - contralateral, lower limb > upper limber, flaccid paralysis initially then spasticity.
Sensory - contralateral loss of all sensory modalities in lower limb. 2. Loss of voluntary control of micturition. 3. Split brain syndrome, alien hand syndrome.
Which areas of the brain will be impacted by stroke of the left middle cerebral artery?
Internal capsule and macular cortex.
If there is main trunk occlusion of the left middle cerebral artery, what could be fatal?
Considerable cerebral oedema from infarct, leading to coma/death and malignant MCA.
What are the functions of the parts of the brain affects by stroke of the left middle cerebral artery?
Homunculus affected of pre and post-central gyri of everything but the lower limb and genitals. Proximal occlusion of MCA causes contralateral homonymous hemianopia but distal causes contralateral homonymous superior or inferior quadrantanopia. Speech also affected if supply to dominant hemisphere is lost.
How will a patient present with a left middle cerebral artery stroke?
Motor - contralateral, upper limb and face > lower limb, initially flaccid paralysis then spasticity. Sensory - contralateral loss of all modalities in upper limb and face.
What is the difference in presentation between a proximal and distal occlusion of the middle cerebral artery?
Proximal - affects lateral motor cortex and internal capsule (carries descending motor fibres from all motor cortex) so fact, arm and leg may be affected. Distal - internal capsule supply is spared so only face and arm affected.
What are the types of aphasia possible with MCA strokes to the dominant hemisphere?
Global aphasia due to main trunk occlusion, or Broca’s or Wernicke’s aphasia.
What are the effects of MCA strokes to the non-dominant hemisphere?
Hemispatial neglect, tactile extinction (if touching one side, only feel one), visual extinction (same but sight), anosognosia (don’t believe they’ve had a stroke.
Which area of the brain would be affected in a left posterior cerebral artery stroke?
Occipital lobe predominantly.
How will a patient with a left PCA stroke present?
Visual cortex impacted so contralateral homonymous hemianopia with macular sparing.
Which area of the brain do the cerebellar arteries supply?
The cerebellum and the brainstem.
What are the key features of presentation in cerebellar strokes?
DANISH - dysdiadochokinesia, ataxia, nystagmus, intention tremor, slurred speech, hypotonia. Ipsilateral signs.
What’s the difference in presentation between proximal and distal occlusion of cerebellar arteries?
Proximal - brainstem and cerebellar signs. Distal - just cerebellar signs.
What are the brainstem signs in proximal occlusion of the cerebellar arteries?
Cranial nerve nuclei are in brainstem so they can be damaged. Crossed deficits - damage to ascending/descending tracts cause contralateral signs but cranial nerve nuclei damage cause ipsilateral signs.
