A 36-year-old woman presenting with occipital headache, neck stiffness, and severe bilateral vision loss

Fulminant idiopathic intracranial hypertension (FIH) is a rare condition of elevated intracranial pressure that can result in sudden and rapidly progressive vision loss. A 36-year-old woman with a body mass index of 45 kg/m2 presented with a 2-week history of occipital headache and neck stiffness and a 1-week history of severe bilateral vision loss. Examination showed profound optic disc swelling with hemorrhages and exudates. Neuroimaging demonstrated bilateral optic nerve and optic nerve sheath enhancement. Her vision continued to deteriorate while on steroids and plasmapheresis. Serum and cerebrospinal fluid testing for atypical optic neuritis were negative. A repeat lumbar puncture revealed an elevated opening pressure. She underwent urgent venous sinus stenting which resolved her disc edema and significantly improved bilateral vision. This highlights the importance of considering FIH in cases of acute vision loss even when neuroimaging findings are most consistent with optic neuritis. When patients with presumed optic neuritis are refractory to therapy, further workup for alternative diagnoses can prevent irreversible vision loss.