Stroke: Anatomy, causes/risk factors, clinical syndromes/investigations

Question 1

Define stroke

Answer 1

Acute onset neurological symptoms/signs indicative of focal CNS dysfunction, from vascular cause (ishaemia/haemorrhage) >24hrs

Question 2

2 types of stroke?

Answer 2

Ischaemic (80%)
[- Arterial: AIS (acute ischaemic stroke) , Lacunar (slowly over time -> vascular dementia)
- Venous: central venous sinus thrombosis]

Haemorrhagic (20%)
[- Arterial: aneurysm (causing SAH) , arterio-venous malformation, PICH (primary intra-cerebral haemorrhage), EDH, AIS
- Venous: SDH (subdural haemorrhage), CVST, cavernoma]

Question 3

Virchow’s Triad?

Answer 3

• Stasis
• Vessel-wall injury
• Hypercoagulability

Question 4

What is a “silent stroke”

Answer 4

Right sided lesions can be a “silent stroke”, as the left side is more critical for speech and language

Question 5

Outcome of MCA infarct (clinical syndrome)

Answer 5

Hemiplegia (typically pts walk w/ arm flexed and leg extended)

Question 6

Outcome of ACA infarct (clinical syndrome)

Answer 6

leg weakness > arm weakness (due to motor homunculus)

Question 7

Outcome of PCA infarct (clinical syndrome)

Answer 7

Homonymous hemianopia (e.g. right occipital lobe damage -> can’t see left hand side of each eye)

Question 8

What is an endartery?

Answer 8

No collateral circulation- it is the only artery supplying that region of the brain and cannot be replaced

Question 9

Cognitive syndromes post stroke (left hemisphere damage) + what brain lobe?

Answer 9

aphasia, apraxia (temporo-parietal)

Question 10

Cognitive syndromes post stroke (right hemisphere damage) + what brain lobe?

Answer 10

neglect/ inattention (fronto-parietal)

Question 11

Cognitive syndromes post stroke (frontal) + what brain lobe?

Answer 11

apathy, dysexecutive syndrome (Frontal Lobe Right/Left damage)

Question 12

Posterior Inferior Cerebellar Artery (PICA) infact outcome?

Answer 12

ataxia in one limb, Horner’s syndrome, cranial nerve palsy

Question 13

[Stroke pathology] outcome of thromboembolism

Answer 13

Territorial Stroke

Question 14

[Stroke pathology] outcome of hypoperfusion i.e. complete blockage of an artery

Answer 14

infarction in “watershed zone” (area furthest away from each arterial branch)

Question 15

[Stroke pathology]

Lacunar infarction

Answer 15

infarction of small deep penetrating artery

caused by: HTN, ageing , diabetes, renal disease, migraine; (rare: CADASIL)

can result in dementia/parkinsonism

Question 16

In a stroke, damage to the ___ is usually irreversible

However damage to the ___ is potentially reversible

Answer 16

In a stroke, damage to the core (in middle) is usually irreversible
However damage to the penumbra (i.e. area surrounding the core) is potentially reversible

Question 17

Cerebral blood flow thresholds based on the core-penumbra model

Answer 17

<10 ml/100g/min: necrosis (irreversible)
10-20 ml/100g/min: reversible e.g. w/ tPA
35-50 ml/100g/min: normal brain

Question 18

What is supplied by the endarteries of the MCA?

Answer 18

Basal ganglia and internal capsule