Strokes

Question 1

Where do the majority of stroke occur?

Answer 1

Territories supplied by middle cerebral artery

Question 2

What occurs when there is an infarct in the vertebral arteries?

Answer 2

Infarct in posterior inferior cerebellar artery (PICA - largest branch)

Lateral medullary syndrome (Wallenberg syndrome)

S&S:

• ipsilateral facial deficit in pain and temperature sensation (spinal trigeminal nucleus lost)
• ipsilateral cerebellar ataxia and incoordination (inferior cerebellar peduncle)
• dysarthria/dysphagia/reduced gag reflex (nucleus ambiguous)
• contralateral deficit in pain and temperature in trunk and limbs (spinothalamic tract)
• vertigo (vestibular nucleus)
• ipsilateral Horner’s syndrome

Question 3

What areas of the brain are supplied by the anterior cerebral artery?

Answer 3

Superior and medial parts of frontal lobe

• prefrontal cortex
• pre-central gyrus
• post-central gyrus
• Broca’s area

Corpus callosum

note: no collateral circulation

Question 4

What areas of the brain are supplied by the middle cerebral artery?

Answer 4

Majority of the lateral surface of cerebral hemisphere (apart from the superior parietal lobe and inferior temporal lobe and occipital lobe)

• Broca’s area
• Wernicke’s area
• pre-central gyrus
• post-central gyrus

+ internal capsule and basal ganglia

Question 5

What areas of the brain are supplied by the posterior cerebral artery?

Answer 5

Midbrain
Thalamus
Inferior parts of temporal and occipital lobes

Question 6

What areas of the brain are supplied by the basilar artery?

Answer 6

Most of the brainstem

Question 7

What are the symptoms associated with an infarct in the posterior cerebral artery?

Answer 7

Loss of colour vision
Visual agnosia
Visual field disturbances

Question 8

What is the definition of a stroke?

Answer 8

Clinical syndrome of abrupt loss of focal brain function lasting over 24hrs or causing death that is either due to spontaneous haemorrhage into brain substance or inadequate blood supply to a part of the brain

note: includes subarachnoid haemorrhage

Question 9

What is the definition of a transient ischaemic attack?

Answer 9

Sudden onset of focal disturbance of brain function (occasionally global) presumed to be of vascular origin which resolves completely within 24hrs

note: the more time it takes to resolve, the more likely it is to be a stroke
note: 24hrs is a controversial definition

Question 10

Contrast the incidence of the different types of stroke.

Answer 10

80%-85% are cerebral infarcts

10%-15% are intracerebral haemorrhages

5% are subarachnoid haemorrhages

Question 11

What are the different types of intracerebral haemorrhages?

Answer 11

Primary = spontaneous; no structural lesion

Secondary = underlying lesion e.g. tumour, arteriovenous malformation

Haemorrhagic transformation of infarct (extensive infarct —> cerebral oedema —> fragile blood vessels —> haemorrhage)

Question 12

What is the aetiology of cerebral infarcts?

Answer 12

• large vessel atheroma/embolism
• cardiac embolism
• small vessel disease/lacunae
• non-atheromatous arterial disease (arteritis)
• blood disorders
• cryptogenic (10%)

Question 13

What is the aetiology of intracerebral haemorrhages?

Answer 13

• hypertension microaneurysms/lipophyalinosis (vessel wall thickening and reduced lumen diameter) (40%)
• aneurysms or arteriovenous malformations (15%)
• amyloid angiopathy (amyloid deposits in CNS blood vessels) (10%)
• haemostatic anticoagulant, thrombolytic thrombocytopenia (10%)
• cocaine or amphetamines
• tumour
• venous thrombosis (esp. in diabetes)
• peri-partum pregnant women

Question 14

What are the classes within the Oxford Classification of Strokes?

Answer 14

Total anterior circulation stroke (TACS)

Partial anterior circulation stroke (PACS)

Lacunar stroke (LACS)

Posterior circulation stroke (POCS)

note: all are strokes due to cerebral infarcts

Question 15

Outline the incidence, pathophysiology, symptoms, and outcome of total anterior circulation strokes.

Answer 15

20% of strokes

Occlusion of internal carotid artery or proximal occlusion of middle cerebral artery

Large volume infarct (superficial and deep territories)

S&S (all 3 req.):

• contralateral hemiparesis +/- hemianaesthesia
• contralateral hemianopia
• higher cerebral dysfunction e.g. dysphasia, dyspraxia

50% die within 1yr

Question 16

Outline the incidence, pathophysiology, symptoms, and outcome of partial anterior circulation strokes.

Answer 16

35% of strokes

Occlusion of a branch of middle cerebral artery

Restricted area of infarct

S&S:

• 2 of the 3 symptoms seen in TACS (contralateral hemiparesis, contralateral hemianopia, higher cerebral dysfunction) OR
• restricted motor deficit in face OR arm OR leg only OR
• isolated cortical signs

High early recurrence rate

Question 17

Outline the incidence, pathophysiology, symptoms, and outcome of lacunar strokes.

Answer 17

20% of strokes

Single perforating artery occluded

Affects the basal ganglia or pons

S&S:

• pure motor OR
• pure sensory OR
• sensorimotor
• ataxic hemiparesis

Silent (therefore underdiagnosed)

Question 18

Outline the incidence, pathophysiology, symptoms, and outcome in posterior circulation strokes.

Answer 18

25% of strokes

Affects brainstem, cerebellum, or occipital lobe

Complex presentation

Question 19

Differentiate the symptoms which result from strokes affected the dominant and non-dominant hemispheres.

Answer 19

85% of people have left hemisphere as dominant (even in left-handed people)

Dominant cortex affected =

• dysphagia
• dysgraphia
• dyslexia

Non-dominant cortex affected =

• visual spatial disorder (visual association area affected)
• neglect (visual association area affected)

Question 20

What are some important considerations when taking a stroke history, and why?

Answer 20

Stroke or non-stroke? (different management)

TIA or stroke? (different investigations)

Type of stroke? (location/pathology cause different onset time and neurological symptoms)

Cause of stroke?

Suitable for thrombolysis (time is brain)

Question 21

What are some important red flag symptoms in a stroke history?

Answer 21

Bleeding

• headache
• seizure

Raised intracranial pressure

• headache
• vomiting
• drowsiness

Aetiology e.g. cardiac symptoms

note: atypical presentations (esp. in elderly) include delirium, confusion, collapse, and incontinence

Question 22

What might be seen on a CT head in a stroke?

Answer 22

Infarcts are grey

Blood is white

Oedema is dark grey and causes midline shift

note: if bleeding is in basal ganglia, it is too deep for neurosurgery

Question 23

Give some examples for differential diagnoses for stroke.

Answer 23

• hypoglycaemia = difficulty speaking, floppy one side (symptoms improve when [glucose] increases)
• migrainous aura
• epilepsy
• space occupying lesion
• demyelinating disorders e.g. MS
• labyrinthine disorders
• retinal bleed/infarct
• peripheral neuropathy
• myopathies
• delirium
• hyperventilation (transient)
• functional v.s. psychological

Question 24

What are some important signs seen on examination in stroke?

Answer 24

Baseline obs:

• BP
• pulse rate and rhythm
• proteinuria/haematuria

?genetic/hereditary:

• telangiectasia
• hyperlipidaemia
• endocarditis/stigmata of vasculitis
• neoplastic screen

CVS:

• ?cardiac source of embolism (arrhythmias, valvular defects)
• ?vascular source of embolism (carotid/renal bruits, peripheral pulses)

Resp:
- dysphagia may lead to aspiration pneumonia

Question 25

What are some important investigations for stroke?

Answer 25

- blood glucose (rule out hypoglycaemia) - FBC - INR - U&Es, LFTs, TFT, lipids (baseline for prescribed drugs e.g. statins) - ECG (look for AF which increases risk of mortality) - CXR (where indicated) - urgent CT head when thrombolysis is an option (look for bleeding which would contra-indicate thrombolysis) note: early normal CT does not rule out ischaemic stroke or infarct (just rules out bleeding) + MRI brain in certain situations + carotid ultrasound (?carotid embolism) + echocardiogram (if cause is unknown e.g. patent foramen ovale) + 24hr cardiac monitoring (if cause is unknown e.g. arrhythmias)

Question 26

What are some important additional investigations in cryptogenic strokes or in young patients with stroke?

Answer 26

- full coagulation profile (e.g. if unable to conceive) - thrombophilia screen (e.g. family history of DVT) - antiphospholipid antibodies - autoimmune screen - fasting plasma homocysteine - blood cultures - thyroid function - syphilis serology - HIV serology

Question 27

What is the management for an acute stroke?

Answer 27

IV thrombolysis (alteplase) IF: - CT has excluded bleeding and established infarct - no bleeding risk e.g. not on warfarin - any patient within 3hrs, consider anybody

Question 28

What is the outcome of IV thrombolysis in acute stroke?

Answer 28

1/3 will improve (of those 1/10 will fully recover) 3% will be worse overall 1/14 will have intracerebral haemorrhage ---> 1/20 of those will become worse

Question 29

Give some examples of how to prevent future strokes in stroke patients.

Answer 29

Anti-thrombotics Treat hypertension, hypercholesterolaemia, diabetes Carotid surgery in carotid stenosis

Question 30

What are the different segments of the internal carotid artery?

Answer 30

Bouthillier classification - cervical - petrous - lacerum - cavernous - opthalmic - posterior communicating (lesion causes 3rd nerve palsy) - anterior choroidal (supplies posterior limb of internal capsule and optic chiasm; lesion causes visual field disturbances)