Nonchalant Midterm-taker Develops Altered Mental Status (video)

Repeat MRI and LP were performed, along with a complete autoimmune and paraneoplastic panel. MRI demonstrated persistent mild patchy bilateral optic nerve enhancement as well as subtle leptomeningeal enhancement. ANA titer was positive; ESR, CRP, and anti-thyroid peroxidase antibody were elevated. CSF testing revealed negative aquaporin-4, with positive oligoclonal bands, elevated IgG index, and positive NMDA receptor antibody. NMDA receptor antibody was positive in serum, consistent with anti-NMDA receptor encephalitis with optic neuritis. Repeat PET and ultrasound examinations showed no teratoma or other malignancy. Anti-NMDA receptor encephalitis was first described in 2007, in association with ovarian teratoma. The classic presentation is with a prodromal illness, psychiatric symptoms, and decreased responsiveness. Since its description, it has become the second most common immune-mediated cause of encephalitis after acute disseminated encephalomyelitis. 80% of patients are women, 60% of whom have an associated tumor (5% of men). 75% of patients with anti-NMDA receptor encephalitis have a good recovery with treatment. Brain MRI is normal in up to 67% of patients, and EEG is abnormal in 90% of patients. Brain biopsy is unhelpful in diagnosis. Tumor-negative anti-NMDA receptor encephalitis with optic neuritis is very rare. There have been two adult cases reported since 2007: a 29 year-old male with history of presumed lymphocytic meningitis and a 32 year-old female with chronic depression. No standard of care exists, but case studies report promising results with concurrent IVIG (0.4 g/kg per day for 5 days) and methylprednisolone (1 g/day for 5 days) as first line therapy, and then second-line therapy of rituximab and cyclophosphamide. Our patient continued to deteriorate despite receiving IVIG with methylprednisolone. She was subsequently treated with rituximab and methylprednisolone with taper, and has returned to her baseline, with no recurrences to date.