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A6864 - Neurological Recovery After Autoimmune Encephalitis and Titrated Anti-N-Methyl-D-Aspartate-Receptor Antibody Levels: A Case Report
Author Block: L. Amado-Rodríguez1, E. Ocampos-Martínez2, R. Fernández2, M. Sánchez-Pérez2, S. Suárez-Fernández2, L. Velasco2, Á. García-Rodríguez2; 1Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain, 2Hospital Valle del Nalón, Langreo, Spain.
INTRODUCTION: Anti-N-Methyl-D-aspartate-receptor encephalitis (NMDARe) is observed in association with ovarian teratomas in young women. Clinical presentation can be confused with a psychiatric disorder or viral encephalitis delaying diagnosis. Early instauration of treatment has been associated with better outcomes. Given its rarely occurrence, the immunological and molecular underlying mechanisms remain unclear.
CASE REPORT: A 23-year-old woman with history of polycystic ovaries initially presented a psychotic disorder and was admitted to the psychiatric department, with rapid evolution to decreased level of consciousness and need for ventilatory support. After transferring her to the Intensive Care Unit (ICU), cerebrospinal fluid (CSF) analysis revealed lymphocytic pleocytosis, so anti-infectious treatment was initiated. Computed tomography and magnetic resonance imaging showed no visible injuries at admission. Initial electroencephalography showed extreme delta brush pattern. Suspecting NMDARe, anti-NMDAR antibodies presence was confirmed in CSF and serum. Ovarian teratomas resection was performed and immunotherapy was initiated before serological confirmation. The patient was treated with immunoglobulines, followed by Rituximab and Cyclophosphamide (4 cycles). Afterwards, she developed partial seizures and severe dysautonomia, requiring antiepileptic drugs and temporary endocavitary pacemaker implantation. During ICU stay, she presented several infectious episodes including urinary tract infection and secondary sepsis due to meticillin-resistant Staphylococcus aureus. Two months after ICU admission, serological and clinical progression motivated two additional Rituximab doses and bilateral oophorectomy, though no macroscopic tumour was described in image-tests. Anatomopathological exam confirmed the presence of mature teratoma cells in the resection pieces. Fifteen days after bilateral oophorectomy, neurological improvement was started and slowly continued during the following five months. Rehabilitation and occupational therapy were implemented. Flow cytometry analysis after partial clinical recovery revealed plasmablasts in peripheral blood, but CSF was found acellular. Antibody levels in CSF remained rising, while they were maintained in peripheral blood. The patient was discharged after 319 days of hospitalization. Two years after she has no neurological deficits and has returned to her University studies.
DISCUSSION: Neurological improvement was not followed by a synchronized decrease in anti-NMDAR antibody levels in CSF. On the contrary, antibody levels remained rising after two months of clinical recovery, while flow cytometry revealed acellularity in this fluid. At this time point, plasmablasts in peripheral blood and maintained antibody serum levels were demonstrated. This chronology may reflect antibody translocation from peripheral blood to central nervous system, irrespective of clinical improvement. These findings highlight the necessity for different biomarkers of treatment-response monitoring in NMDARe.