Posterior Communicating Artery (PCOM) Aneurysm
Background
- Acute CN III palsy w/ ipsilateral pupil dilation is PCOM aneurysm until proven otherwise
- Aneurysm compresses the outer fibers (pupillomotor) of CN III -> dilation
- In contrast to CN III palsy due to DM or HTN in which pupil is spared
Clinical Features
- Inhibition of ipsilateral medial gaze, upward gaze, downward gaze, ptosis
- Lateral gaze (abduction) is preserved
- Ipsilateral dilated pupil
Treatment
- Emergent BP reduction if hypertensive
- Neuroimaging
- Neurosurgical consult
Source
Tintinalli
