Oculomotor nerve palsy presenting with pupillary dilation in the context of a cerebral aneurysm is a recognised surgical emergency. The combination of third nerve dysfunction and pupil involvement points directly to compressive pathology requiring urgent evaluation and intervention.
Isolated unilateral pupillary dilation can arise from an aneurysm at the junction of the internal carotid and posterior communicating arteries, or from a basilar artery aneurysm. When this presentation is encountered, a cerebral aneurysm must be excluded without delay — this is a surgical emergency.
An aneurysm is a surgical emergency.
Isolated unilateral pupillary dilation may occur from an aneurysm of these vessels at the junction of the internal carotid and posterior communicating arteries or with a basilar artery aneurysm.
Of interest, treating the aneurysm with a coil or surgical clipping may result in complete or partial third nerve recovery in over 80% of patients.
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