Clinical presentation of Posterior Cerebral Artery (PCA) occlusion

The clinical presentation varies with the site of occlusion and availability of collaterals. Partial syndromes are common,Symptoms depends on the vessel of occlusion

• Hemisphere branch occlusion
• Bilateral hemisphere branches occlusion 
• Callosal branch occlusion
• Penetrating branch to thalamus occlusion
• Penetrating branch to midbrain occlusion

A. Hemisphere branch occlusion :

• Contralateral homonymous hemianopia with occasional macular sparing
•  Visual and Color agnosia

B. Bilateral hemisphere branches occlusion 

• Bilateral homonymous hemianopia
• Cerebral blindness - bilateral visual loss with normal pupillary reflexes and fundus
• Apraxia for ocular movements
• Agnosia for familiar faces (Prosopagnosia)
• Agitated delirium (mesiotemporo-occipital lesion)
• Anton syndrome or denial of blindness(parietal lobes involved)
• Balint syndrome- optic ataxia, psychic paralysis of fixation, inability to look to the peripheral field and disturbance of visual attention.

C. Callosal branch occlusion

This affects the left occipital region and splenium of corpus callosus and results in Alexia without agraphia (agnostic alexia)

D. Penetrating branch to thalamus occlusion

1. Dejerine and Roussy's Syndrome :

• Contralateral hemianesthesia.
• Transient contralateral hemiparesis.
• Dysesthesia on the affected side (Thalamic Pain)
• Involuntary movements - Choreoathetosis, hemiballismus, etc. (Ventral posteromedial and postero - lateral nuclei are affected).

2. Aphasia (Left pulvinar nuclei affected).

3. Amnesia (Mesial Thalamoperforators affected)

4. Akinetic mutism

E. Penetrating branch to midbrain occlusion

1. Ipsilateral oculomotor palsy with contralateral hemiplegia (Weber's Syndrome)

2. Ipsilateral oculomotor palsy with contralateral cerebellar ataxia (Nothnagel Syndrome)

3. Ipsilateral oculomotor palsy with contralateral ataxia and choreoathetosis (Benedikt's syndrome)

4. Parinaud's syndrome

• Supranuclear paralysis of elevation
• Defective convergence
• Convergence retraction nystagmus
• Lid retraction (Collier’s sign)
• Skew deviation
• Light near dissociation

5. Unilateral or bilateral Internuclear ophthalmoplegia

6. Pseudoabducent palsy

7. Peduncular hallucinations - often silent, mobile and colorful and frequently pleasurable

8. Decerebrate rigidity, Locked-in syndrome and disturbances in consciousness.