14. Stroke

Question 1

What is a stroke?

Answer 1

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.

Question 2

What is a transient ischaemic attack?

Answer 2

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

Question 3

What is stroke syndrome?

Answer 3

Constellation of signs and symptoms produced due to occlusion or damage of an artery supplying part of the brain.

Question 4

What are the two key types of stroke?

Answer 4

Ischaemic and haemorrhagic.

Question 5

Where do clots in ischaemic strokes normally come from?

Answer 5

Carotid arteries, heart (in AF mainly), aorta, brain, vertebral/basilar arteries

Question 6

What makes up the anterior circulation?

Answer 6

Anterior cerebral arteries and middle cerebral arteries.

Question 7

What makes up the posterior circulation?

Answer 7

Vertebral arteries, posterior cerebral arteries, and the cerebellar arteries.

Question 8

Which four questions should be considered in stroke presentation?

Answer 8

Which artery has been affected, the area of brain supplied by artery, what the area of brain does, and expected presentation of the patient.

Question 9

Areas of which part of the brain will be lost in stroke of the left anterior cerebral artery?

Answer 9

1. Medial aspects of the left frontal and parietal lobes, anterior part of the corpus callosum. 2. Paracentral lobules. 3. Corpus callosum.

Question 10

What is the function of the parts of brain affected by left anterior cerebral artery stroke?

Answer 10

1. 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.

Question 11

How will a patient present with a left anterior cerebral artery stroke?

Answer 11

1. 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.

Question 12

Which areas of the brain will be impacted by stroke of the left middle cerebral artery?

Answer 12

Internal capsule and macular cortex.

Question 13

If there is main trunk occlusion of the left middle cerebral artery, what could be fatal?

Answer 13

Considerable cerebral oedema from infarct, leading to coma/death and malignant MCA.

Question 14

What are the functions of the parts of the brain affects by stroke of the left middle cerebral artery?

Answer 14

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.

Question 15

How will a patient present with a left middle cerebral artery stroke?

Answer 15

Motor - contralateral, upper limb and face > lower limb, initially flaccid paralysis then spasticity. Sensory - contralateral loss of all modalities in upper limb and face.

Question 16

What is the difference in presentation between a proximal and distal occlusion of the middle cerebral artery?

Answer 16

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.

Question 17

What are the types of aphasia possible with MCA strokes to the dominant hemisphere?

Answer 17

Global aphasia due to main trunk occlusion, or Broca’s or Wernicke’s aphasia.

Question 18

What are the effects of MCA strokes to the non-dominant hemisphere?

Answer 18

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.

Question 19

Which area of the brain would be affected in a left posterior cerebral artery stroke?

Answer 19

Occipital lobe predominantly.

Question 20

How will a patient with a left PCA stroke present?

Answer 20

Visual cortex impacted so contralateral homonymous hemianopia with macular sparing.

Question 21

Which area of the brain do the cerebellar arteries supply?

Answer 21

The cerebellum and the brainstem.

Question 22

What are the key features of presentation in cerebellar strokes?

Answer 22

DANISH - dysdiadochokinesia, ataxia, nystagmus, intention tremor, slurred speech, hypotonia. Ipsilateral signs.

Question 23

What’s the difference in presentation between proximal and distal occlusion of cerebellar arteries?

Answer 23

Proximal - brainstem and cerebellar signs. Distal - just cerebellar signs.

Question 24

What are the brainstem signs in proximal occlusion of the cerebellar arteries?

Answer 24

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.

Question 25

Which part of the CNS would be affects by a basilar artery stroke?

Answer 25

Midbrain.

Question 26

What will be the presentation of a patient with a proximal or distal basilar artery stroke?

Answer 26

Bilateral symptoms. Distal - bilateral occipital lobe infarction -> cortical blindness, bilateral thalamic infarction -> sensory symptoms and decreased consciousness, bilateral midbrain involvement -> CN nuclei signs. Proximal - locked in syndrome.

Question 27

Which part of the brain would be affected by occlusion of the left lenticulostriate artery?

Answer 27

Internal capsule.

Question 28

What would be the presentation of someone with a left lenticulostriate artery stroke?

Answer 28

Pure motor signs on contralateral side involving face, upper limb, and lower limb. Flaccid paralysis then spasticity.

Question 29

Which part of the brain would be affected by stroke of the left thalamoperforator artery?

Answer 29

Part of the thalamus

Question 30

What would be the presentation of someone with a left thalamoperforator artery?

Answer 30

Pure sensory signs on contralateral side. Sensory loss of all modalities to face, upper limb, and lower limb.

Question 31

What are the stroke mimics?

Answer 31

HEMI - hypoglycaemia, epilepsy, migraine, intracranial tumours/infections.

Question 32

What is the key feature that needs to be identified on imaging of strokes?

Answer 32

If it is haemorrhagic, in which case, thrombolytic therapy should be avoided.