A case of late-onset and long term of anti-nmda-receptor encephalitis in a 50-year-old patient with psychosis and cognitive decline

INTRODUCTION: Anti-NMDA-receptor encephalitis is a severe rare acute form of encephalitis caused by an autoimmune process with the synthesis of autoantibodies to the glutamate receptors. The average age of onser is estimated to be 23-25 years. A typical clinical picture consist of prodromal, psychotic, areactive, hyperkinetic phases, and a phase of gradual regression of symptoms. The disease usually lasts for a several weeks with spontaneous recovery or fatal outcome and caused by neoplastic process. Our case demonstrates that the course of anti-NMDAR encephalitis is possible at more mature age in the form of a long process with cultural features, without significant catadrome, inflammation and associated neoplastic process. OBJECTIVES: 50-year-old woman complained about hypomnesia, anosmia and dissomnia. The disease began with impaired consciousness, disorientation, seizures and memory loss 4 years ago. After 3 weeks IgG to the herpes simplex and cytomegalovirus were detected. Then after a discharge with no improvement and visit of Lama, the symtoms described above spontaneously reduced and schizophrenia-like psychosis developed, accompanied by mild neurological and severe neurocognitive symptoms, weight loss, intolerance to antipsychotics in minimal daily doses. This state was mantained till 2020. METHODS: Examination included: CBC, metabolic panel, coagulogram, tumor markers, CSF, MRI, PET, specialists. RESULTS: CBC, metabolic blood analysis, tumor markers - within the reference values. CSF: cytosis 9/3, glucose 5.5 mmol/l, Pandi++, Nonnet-Apeltau+, antibodies to the NMDA receptor - 8. MRI: signs of the consequences of encephalitis. PET: no signs of metabolic activity of the malignant process. CONCLUSIONS: This case brings additional data about a couse, age of onset, duration and trigger factors for anti-NMDAR encephalitis.