Sore eyes and psychosis.

We present the case of a 30-year-old woman who presented with sexual disinhibition and altered behaviour following an episode of optic neuritis. Her only history was of anxiety disorder. Her differential diagnosis was neurological versus psychiatric. Routine blood tests were unremarkable at this stage. MRI revealed non-specific change and lumbar puncture revealed a slight lymphocytosis and elevated protein and glucose in the cerebrospinal fluid (CSF). PCR on the CSF was negative for viruses: Adenovirus, varicella zoster virus, herpes simplex virus, enterovirus and parechovirus. She was initially treated with intravenous acyclovir to little effect. Antipsychotics olanzapine and haloperidol were also trialled and continued for 3 weeks in total. Once again these medications failed to affect the patient's behaviour but she did begin to show the side effects associated with these medications. Further test results became available at this point-she was anti-N-methyl D-aspartate (NMDA) receptor antibody positive. A diagnosis of anti-NMDA receptor antibody encephalitis was made. The patient was started on cyclophosphamide and methylprednisolone to good effect. 2014 BMJ Publishing Group Ltd.