2026 American Academy of Neurology Abstract Website

Objective:

Treponema pallidum can affect the CNS and visual system at any stage. Optic nerve involvement is a major cause of vision loss in neurosyphilis, with ocular manifestations like uveitis, neuroretinitis, and optic neuritis occurring either independently or as part of the disease spectrum. We present a case of bilateral papillitis initially misdiagnosed as IIH and autoimmune optic neuritis, ultimately confirmed as neurosyphilis.

Background:

A 64-year-old woman with hypertension, diabetes, and prior stroke presented with one month of intermittent blurry vision and headaches. Exam revealed bilateral optic disc swelling concerning for papilledema. Brain MRI and venography were normal. Lumbar puncture (LP) showed normal opening pressure but lymphocytic pleocytosis and elevated protein, favoring papillitis over papilledema. She was discharged on acetazolamide.

Three weeks later, she returned with worsening vision. Repeat LP showed marked lymphocytic pleocytosis (450 cells/µL), elevated protein (116 mg/dL), and normal glucose. Empiric steroids and plasmapheresis were started for presumed autoimmune etiology, with transient improvement. Infectious evaluation revealed serum RPR 1:16 and positive CSF VDRL, confirming neurosyphilis. HIV and Lyme testing were negative. She was treated with high-dose IV penicillin, resulting in substantial visual recovery and near-complete resolution of papillitis.

Design/Methods:

Not applicable

Results:

Neurosyphilis is more common in HIV-positive individuals but can affect immunocompetent patients too. Ocular syphilis often mimics autoimmune optic neuritis, risking misdiagnosis and vision loss. Treatment involves high-dose IV penicillin G for 10–14 days. Adjunctive corticosteroids may reduce inflammation but lack definitive evidence and are not routinely recommended. Early diagnosis and prompt treatment are crucial to improving visual outcomes and preventing irreversible damage.

Conclusions:

Neurosyphilis can mimic autoimmune diseases, complicating diagnosis, especially when presenting as bilateral papillitis (optic neuritis specifically affecting the optic nerve head). The diagnosis should be considered in patients with unexplained optic disc swelling and lymphocytic CSF pleocytosis to ensure timely diagnosis and treatment.