Session 10: Stroke Flashcards

1
Q

What is a stroke?

A

A neurological deficit attributed to an acute focal injury of the CNS by a vascular cause, this includes a cerebral infarction, intracerebral haemorrhage, and subarachnoid haemorrhage.

The symptoms and signs persist for more than 24 hours

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2
Q

What is a transischaemic attack?

A

TIA sometimes called in lay terms mini-stroke.

Similar clinical features of a stroke but completely resolve within 24 hours.

It is a transiet episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction.

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3
Q

Types of stroke.

A

Ischaemic (85%) E.g. thromboembolic

Haemorrhagic (10%)

Other (5%)

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4
Q

Haemorrhagic strokes.

A

Intracerebral (rupture of a vessel in brain parenchyma)

Subarachnoid haemorrhage

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5
Q

Give other types of stroke.

A

Dissection (separation of walls of artery)

Venous sinus thrombosis

Hypoxic brain injury e.g. after cardiac arrest.

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6
Q

Two principles of management of stroke.

A

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

Always do a CT head.

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7
Q

Why do we do a CT head?

A

If there is a bleed or not.

We do not want a bleed.

We try to exclude the 10% of haemorrhagic strokes

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8
Q

Features of an acute CT head.

A

Ischaemic area of brain is not visible early on however a bleed will show up.

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9
Q

Features of an acute MRI.

A

Is sometimes performed and will show ischaemia.

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10
Q

What will a late stroke look like on a CT?

A

WIll show the ischaemic area

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11
Q

Clinical presentation of anterior cerebral artery infarct.

A

Motor loss

Sensory loss

Urinary incontinence

Apraxia

Dysarthria

Aphasia

Split brain syndrome / alien hand syndrome

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12
Q

Explain the motor loss in ACA stroke.

A

Contralateral weakness in lower limb.

This lower limb will be affected much worse than upper limb and face.

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13
Q

Explain the sensory losses of an ACA stroke.

A

Similar to motor loss.

Contralateral of mostly lower limb.

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14
Q

Urinary incontinence in ACA stroke?

A

Paracentral lobules being affects which are the most medial parts of the motor/sensory cortices and supply the perineal area.

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15
Q

What is apraxia and why can that be a sign of ACA stroke?

A

Inability to complete motor planning where the patient might have difficulties dressing themselves.

Often caused by damage to the left frontal lobe (dominant hemisphere)

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16
Q

What does split brain syndrome / alien hand syndrome involve?

A

The corpus callosum (ACA)

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17
Q

Mortality of MCA stroke.

A

80%.

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18
Q

Why is there such a high risk of mortality of MCA stroke?

A

Can cause cerebral oedema

Can also cause haemorrhagic transformation if the vessels in the infarcted area break down.

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19
Q

Why might MCA strokes differ in presentation?

A

Because the MCA can be occluded at three main points.

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20
Q

What three main points might the MCA be occluded at?

A

Proximal (before lenticulostriate arteries)

Lenticulostriate arteries occluded

Distal (after lenticulostriate arteries)

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21
Q

Clinical presentation of a proximal MCA stroke.

A

Contralateral full hemiparesis

Contralateral sensory loss

Visual field defects

Aphasia

Contralateral neglect

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22
Q

What motor losses are associated with proximal MCA stroke?

A

Face arm and leg all affected contralaterally.

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23
Q

Why is there full motor loss in proximal MCA stroke?

A

Because the lenticulostriate arteries supply the internal capsule and will affect the posterior limb of the IC.

This means that even though MCA supplies the face and arm area of the homonculus that is irrelevant if the internal capsule is damaged.

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24
Q

Sensory loss of proximal MCA stroke.

A

Usually arms and face (supplied by MCA) but can also involve larger areas if sensory fibres in the internal capsule are affected.

25
Q

Visual field defects in proximal MCA stroke and why.

A

Contralateral homonymous hemianopia without macular sparing.

Because there is destruction of both superior and inferior optic radiations.

26
Q

Explain the aphasia in proximal MCA stroke.

A

Global if it is in the dominant (usually left) hemisphere.

Can’t understand nor articulate words.

27
Q

Why would you get contralateral neglect in proximal MCA stroke?

A

Usually in right parietal where there is loss of acknowledgment of the contralateral side even though visual fields are normal.

28
Q

Give other features of proximal MCA stroke.

A

Tactile extinction (if touch each side simultaneously won’t feel affected side)

Visual extinction (half clock)

Anosognosia

29
Q

What is anosognosia?

A

Does not acknowledge that they have had a stroke so won’t be able to explain that they have disabilities.

30
Q

What is a lenticulostriate artery stroke?

A

Also called a lacunar stroke.

Will cause destruction of small areas of internal capsule and the basal ganglia.

31
Q

How can you distinguish between a proximal MCA stroke and a LSA stroke?

A

Do not cause cortical features such as neglect or aphasia.

32
Q

Types of LSA strokes.

A

Pure motor

Pure sensory

Sensorimotor (mixed)

33
Q

Explain pure motor LSA stroke.

A

Face, arm and leg affected equally.

Caused by damage to the motor fibres as they descend the internal capsule.

34
Q

Explain pure sensory LSA stroke.

A

Face, arm and leg affected equally caused by damage to sensory fibres travelling through internal capsule.

Probably due to occlusion of thalamoperforator arteries and maybe also lenticulostriate.

35
Q

How does the MCA travel post lenticulostriate arteries?

A

Along the lateral fissure and divide into a superior and inferior division.

36
Q

What does the superior division supply of MCA?

A

Lateral frontal lobe including the PMC and Broca’s area.

37
Q

What does the inferior division of MCA supply?

A

Lateral parietal lobe and superior temporal lobe

PSC

Wernicke’s area

Both optic radiations

38
Q

CP of superior division MCA stroke.

A

Contralateral weakness of face and arm and also expressive aphasia if left is affected.

39
Q

CP of inferior division MCA stroke.

A

Contralateral sensory change in face and arm.

Receptive aphasia (if left)

Contralateral homonymous hemianopia without macular sparing.

40
Q

CP of PCA stroke.

A

Somatosensory and visual dysfunction.

Contralateral homonymous hemianopia with macular sparing.

Contralateral sensory loss due to damage to thalamus.

41
Q

Why is there contralateral homonymous hemianopia with macular sparing in PCA stroke?

A

There is macular sparing because of the collateral supply from the MCA.

42
Q

Symptoms of cerebellar infarcts.

A

Nausea

Vomiting

Headache

Vertigo/dizziness

43
Q

CP of cerebellar infarcts.

A

Ipsilateral cerebellar signs (DANISH)

Dysdiadochokinesia

Ataxia

Nystagmus

Intention tremors

Slurred speech

Hypotonia

Can have brainstem signs (cerebellar arteries loop around the brainstem)

Possible contralateral sensory deficit

Possible ipsilateral Horner’s

44
Q

CP of brainstem strokes.

A

Contralateral limb weakness (above decussation)

Ipsilateral cranial nerve signs

45
Q

Risk of basilar artery occlusion

A

Sudden death

46
Q

Distal superior basilar artery stroke.

A

Visual and oculomotor deficits.

Behavioural abnormalities

Somnolence

Hallucinations

Dreamlike behaviour (reticular formation disturbances)

Motor function usually preserveed.

47
Q

Why are visual and oculomotor deficits seen in distal superior basilar artery stroke?

A

Because the basilar send some branches to the midbrain which contains the oculomotor nuclei.

Can also prevent blood flowing into the PCA affecting the occipital lobes.

48
Q

Expain why motor functions are usually preserved in distal superior basilar artery stroke

A

Because the cerebral peduncles can usually get blood still from the posterior communicating arteries.

49
Q

CP of proximal basilar stroke at the level of pontine branches.

A

Locked in syndrome

Complete loss of movement of limbs but preserved ocular movement

Preserved consciousness

50
Q

Why can the eyes still move in locked in syndrome?

A

Midbrain is getting supply from PCAs via posterior communicating arteries.

Also preserved consciousness because of this.

51
Q

Give the classifications of the Bamford (Oxford) stroke classification.

A

Total anterior circulation stroke (TACS)

Partial anterior circulation stroke (PACS)

Posterior circulation stroke (POCS)

Lacunar syndrome

52
Q

Req. for TACS

A

All three:

Unilateral motor/sensory weakness

Homonymous hemianopia

Higher cerebral dysfunction

53
Q

Req. for PACS.

A

2 of the following:

Unilateral weakness

Homonymous hemianopia

Higher cerebral dysfunction

54
Q

Req. for POCS.

A

One of the following:

Bilateral motor/sensory deficit

Conjugate eye movement disorder

Cerebellar dysfunction

Isolated homonymous hemianopia with macular sparing

Cranial nerve palsy and contralateral motor/sensory deficit

55
Q

Req. for lacunar syndrome.

A

One of the following:

Pure sensory deficit

Pure motor deficit

Sensorimotor deficit

Ataxic hemiparesis (basal ganglia)

56
Q

Causes of stroke in young people.

A

Vasculitis

Thrombophilia

SAH

Venous sinus thrombosis

Carotid artery dissection

57
Q

Causes of stroke in old people.

A

Thrombosis

Athero-thromboembolism

Heart emboli

CNS bleed

etc…

58
Q
A