Stroke

Question 1

What is a stroke?

Answer 1

Cerebrovascular accident is 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

Question 2

What is a TIA (transient ischaemic attack)?

Answer 2

Sometimes called a ‘mini stroke’. TIA’s also occur when blood supply to part of the brain is cut off however, symptoms and signs completely resolve after 24 hours.

Question 3

List the types of stroke

Answer 3

1. Ischaemic (85%) - Thromboembolic
2. Haemorrhagic (10%) - Intracerebral or Subarachnoid
3. Other (5%) - Dissection, Venuous sinus thrombosis or Hypoxic brain injury (e.g. post MI)

Question 4

Two principles of emergency management of Stroke?

Answer 4

1. Are they within the window for thrombolysis (< 4 hours)

2. Do a CT head to determine if it is a bleed (bleed = no thrombolysis)

Question 5

Explain the imaging of a stroke

Answer 5

CT - bleed will shop up as a bright white area (ischaemia will only later show hypodense/darker)
MRI - Ischaemia shows up as a high signal area

Question 6

Outline the basic’s of blood supply to the brain

Answer 6

ICA > Anterior cerebral circulation
Vertebral arteries > Posterior cerebral circulation
These 2 circulations above form the circle of willis

Question 7

Outline the classic stroke syndromes seen with an Anterior Cerebral Artery infarct

Answer 7

1. Contralateral weakness in lower limb (much worse than upper limb and face)
2. Contralateral sensory changes in same pattern as motor deficits
3. Incontinence (urinary) due to paracentral lobules affected
4. Split brain syndrome/Alien hand syndrome - involvement of corpus callosum
5. Apraxia - inabilty to complete motor planning, often caused by left frontal lobe damage
6. Dysarthria / Aphasia - unusual sign in ACA when compared to MCA

Question 8

What are the 3 types of Middle Cerebral Artery infarct

Answer 8

1. Proximal (to lenticulostriate arteries)
2. Lenticulostriate arteries
3. Distal (can be in the superior or inferior divisions)

Question 9

What is haemorrhagic transformation

Answer 9

Occurs when the vessels in an infarcted area break down. Occurs especially after thrombolytic therapy.

Question 10

Outline the classic stroke syndromes seen with a Proximal Middle Cerebral Artery infarct

Answer 10

Note, in this case all the branches of MCA will be affected…
1. Contralateral full hemiparesis (face, arm and leg affected) - due to involvement of the internal capsule
2. Contralateral sensory loss - probably in distribution of primary sensory cortex supplied by MCA but could be larger if sensory fibres of internal capsule affected
3. Aphasia - Global if dominant (usually left) hemisphere - cannot understand or articulate words
4. Contralateral neglect - usually in right parietal lobe (can occur in more distal branches aswell)
Other features include: tactile extinction, visual extinction, anosognosia

Question 11

What is tactile extinction, visual extinction and anosognosia?

Answer 11

Tactile extinction = if touch each side simultaneously doesnt feel the affected side.
Visual extinction (similar to hemispatial neglect) = as with half a clock face etc...
Anosognosia = literally does not acknowledge that they have had a stroke, so will confabulate to explain disability

Question 12

Outline the classic stroke syndromes seen with a Lenticulostriate artery occlusion

Answer 12

1. Pure motor (face, arm and leg affected - internal capsule damaged due to lenticulostriate artery occlusion)
2. Pure sensory (face, arm and leg affected - damage to sensory fibres travelling through internal capsule due to thalamoperforator artery and maybe also lentiulostriate artery occlusion)
3. Sensorimotor (infarction at boundary between motor and sensory fibres)

Question 13

What is a stroke caused by lenticulostriate artery occlusion called?
What is damaged in this stroke type?
How would you distinguish between this stroke and a proximal MCA stroke?

Answer 13

aka Lacunar strokes.
Cause destruction of internal capsule and basal ganglia.
Proximal MCA infarcts cause cortical features, these strokes do not.

Question 14

What does the superior division of the MCA supply?

Answer 14

Superior division essentially supplies the lateral frontal lobe. Including primary motor cortex and Broca’s area.

Question 15

What does the inferior division of the MCA supply?

Answer 15

Inferior division essentially supplies the lateral parietal lobe and superior temporal lobe. Including the primary sensory cortex and both optic radiations

Question 16

What is the presentation with a stroke in the superior MCA artery?

Answer 16

Occlusion will cause contralateral face and arm weakness and expressive aphasia if left hemisphere.

Question 17

What is the presentation with a stroke in the inferior MCA artery?

Answer 17

Occlusion will cause contralateral sensory change in face and arm, receptive aphasia if left hemisphere. Also get a contralateral visual field defect without macular sparing (often homonymous hemianopia)

Question 18

Outline the classic stroke syndromes seen with a Posterior cerebral artery infarct

Answer 18

Somatosensory and visual dysfunction typical. Contralateral homonymous hemianopia (with macula sparing). Contralateral sensory loss due to damage to the thalamus.

Question 19

Outline the classic stroke syndromes seen with a Cerebellar infarction.

Answer 19

Symptoms = Nausea, Vomiting, Headache, Vertigo/Dizziness.
Also get Ipsilateral cerebellar signs (DANISH)
Possible ipsilateral brainstem signs since cerebellar arteries supply brainstem as they loop around to the cerebellum.
Possible contralateral sensory deficit/ipsilateral Horners (due to brainstem involvement)

Question 20

Outline the syndromes seen with a Brainstem stroke

Answer 20

Typical feature is contralateral limb weakness, seen with ipsilateral cranial nerve signs.

This is explained by the damage to the corticospinal tracts (above decussation of pyramids) and damage to cranial nerve nuclei on the same side.

Question 21

Outline the syndromes seen in a Basilar artery occlusion.

Answer 21

Sudden death can often occur - due to brainstem supply.
Further symptoms depend whether the occlusion is distal (superior) basilar artery or proximal basilar artery
(at the level of pontine branches)

Question 22

Outline the syndromes seen in a distal (superior) basilar artery occlusion

Answer 22

Visual and oculomotor deficits (basilar sends banches to the midbrain which contains the ocluomotor nuclei; occlusion can also prevent blood flow to the PCA’s affecting occipital lobes)
Behavioural abnormalities
Somnolence, hallucinations and dreamlike behaviour (brainstem contains important centres for sleep regulation - reticular activating system etc…)

Motor dysfunction often absent (if cerebral puduncles can get blood from the PCAs which are in turn being filled by the posterior communicating arteries)

Question 23

Outline the stroke syndromes seen in a proximal basilar occlusion (at level of pontine branches)

Answer 23

Can cause locked in syndrome
Complete loss of movement of limbs however preserved ocular movement. Eye movement maintained as midbrain receives blood from PCAs via posterior communicating arteries. 
Preserved consciousness (maybe due to midbrain and reticular formation still in tact)

Question 24

What classification do we use for strokes?

Answer 24

Bamford (oxford) stroke classification

Question 25

What are the subtypes of strokes seen in the Bamford stroke classification

Answer 25

TACS (total anterior circulation stroke)
PACS (partial anterior circulation stroke)
POCS (posterior circulation syndrome)
LACS (lacunar stroke)