111 Recurrent headaches with psychosis, CSF lymphocytosis, vessel beading and papilloedema- autoimmune/viral encephalitis with vasculopathy or unusual presentation of reversible cerebral vasoconstriction syndrome (RCVS)?

Introduction Headache is a common Neurology presentation in both outpatient and ED settings. We present a challenging headache in a previously asymptomatic young female patient. Case A 27 year old female patient presented to ED with severe headache, vomiting and photophobia, after multiple presentations elsewhere, diagnosed as migraine, with normal neurological examination and MRI. Episodes of excruciating headache were associated with writhing and vomiting but spontaneously resolved with residual background pain. Indomethacin helped but she re-presented with headache and psychosis requiring intubation and ICU admission. Investigations included CSF - protein 0.85, leucocytosis 58 cells (lymphocytic) and normal cerebral venography. Acyclovir was commenced but viral PCRs were negative and she was extubated. MRI was suspicious for subtle posterior sulcal hyperintensity and beading in occipital and posterior cerebral arteries. Another episode occurred ten days later requiring intubation, examination showed papilloedema. CSF examination showed raised pressure, normal protein and 48 lymphocytes; flow cytometry and cytology were unrevealing. NMDA receptor antibody returned positive in serum but not CSF. Subtle beading in right PCA branches remained. IVIG and steroids were used with dramatic response. Further investigation revealed positive EBV serology only and papilloedema resolved. Steroids were weaned and she remains in remission. Conclusion We present an interesting case of recurrent acute headaches with intracranial hypertension, psychosis and CSF lymphocytosis. The recurrent headaches and vessel beading suggest RCVS, perhaps triggered by viral or autoimmune encephalitis. The NMDA receptor antibody result should be interpreted with caution given the absence of antibody in CSF and dramatic recovery.