Posterior Circulation Stroke Syndromes

Question 1

Areas supplied by posterior circulation

Answer 1

1. Cortex - occipital cortex
2. Thalamus
3. Brainstem nuclei
4. Descending motor and ascending sensory pathways
5. Cerebellum

Question 2

PCA infarct

Answer 2

Possible involvement

Parieto-occipital involvement
1. Homonymous hemianopia with macula sparring
(Collateral vascular supply to occipital pole from posterior branch of MCA)
2. Cortical blindness with Anton syndrome
- Realistic visual hallucination
(Bilateral occipital infarct)
3. Balian syndrome: simultanagnosia (identifies parts of scene but cannot describe entire picture), optic ataxia (loss of hand-eye coordination), apraxia of gaze
4. Pure alexia (dominant occipital cortex infarct)

Thalamus involvement
1. Confusion, memory disturbance
2. Pure hemisensory loss (ventral posterolateral nucleus infarct)
3. Bilateral thalamic (butterfly) infarct - obtunded or comatose, severe memory dysfunction
4. Artery of Percheron occlusion (rare variant with single thalamoperforating artery arises from one P1 segment and bifurcates to supply both paramedial thalami)
- Bilatearl paramedian thalamic infarct +/- mesencephalic infarct

Others
1. Occlusion of posterior choroidal artery - hemianopia, hemidysaesthesia, memory disturbance
2. Posterior limb internal capsule infarct (PCA) - hemiparesis
3. Medial temporal lobe or medial thalamic nuclei infarct - anterograde amnesia