A 41 year old man with recently diagnosed stage IIIC colon adenocarcinoma status post laparoscopic left segmental colectomy developed episodes of transient, positional visual obscuration four weeks after initiation of oxaliplatin (FOLFOX schedule). He reported no headaches, diplopia, or pulsatile tinnitus. Neuro-ophthalmic exam revealed visual acuity of 20/20 in both eyes, full color vision, no afferent pupillary defect, and Frisen grade 3-4 bilateral optic disc edema. Retinal nerve fiber layer thickness was 266 microns right eye, and 400 microns left eye, with normal visual fields. 

MRI brain and orbits demonstrated no intracranial lesion or enhancement, but revealed increased CSF signal around optic nerves without empty sella. CT venogram was negative for sinus thrombosis or major stenosis, the right dominant sinus system was patent. MRI spine was unremarkable. Lumbar puncture revealed opening pressure of 53 cm H2O with normal cell count, chemistry, and negative cytology. The temporal association and exclusion of other causes suggested oxaliplatin-associated intracranial hypertension. 

Oxaliplatin was subsequently discontinued and high dose acetazolamide treatment was initiated. Visual symptoms resolved within 2 weeks and papilledema gradually improved.