Unilateral papilledema: illustrative case.

Background: Idiopathic intracranial hypertension is caused by an elevation of intracranial pressure and can present with slowly progressive visual deterioration from bilateral papilledema. Unilateral papilledema is an exceedingly rare phenomenon, and the mechanisms underlying asymmetric optic nerve involvement remain unknown.

Observations: A 42-year-old woman presented with acute left-eye blurred vision and extraocular pain. Examination revealed unilateral left optic disc edema with an enlarged blind spot, while the right optic disc appeared flat. Neuroimaging examination was suggestive of intracranial hypertension, characterized by flattening of the posterior globes and narrowing of bilateral distal transverse sinuses. Increased intracranial pressure was confirmed by lumbar puncture. Acetazolamide and weight loss yielded initial improvement, but recurrence prompted cerebral arteriography, revealing a transstenotic gradient in the right distal transverse sinus and hypoplastic left sigmoid and transverse sinuses with extensive collateralization to the left cavernous sinus. Stenting of the right transverse sinus successfully alleviated the optic disc swelling.

Lessons: This case highlights the intricate interplay between venous sinus dynamics and unilateral papilledema, underscoring the importance of tailored interventions. https://thejns.org/doi/10.3171/CASE24385.