Clinical Heterogeneity in Acute Symptomatic Seizures due to Autoimmune Encephalitis Related to GAD65 Antibodies

Introduction: This study aimed to explore the diversity and clinical features of acute symptomatic seizures due to autoimmune encephalitis related to anti-glutamate decarboxylase (GAD) 65 antibodies. Methods: Clinical data of a series of 6 patients positive for anti-GAD65 antibodies were retrospectively analyzed. Results: Five of the patients were male and 1 was a female, with a median age of 44.1 years (range 18-70 years). Seizure forms were varied in 6 patients when they were admitted to the hospital: 3 cases of seizures only and 3 accompanied by other symptoms, such as mental disorder, cognitive impairment, cerebellar ataxia, and ocular movement disorder. Three patients (50%) had coexisting systemic autoimmune diseases, including diabetes mellitus, vitiligo, and hyperthyroidism. Five patients (83%) had abnormal brain MRI findings. They were all treated by immunotherapy, 5 of 6 patients improved significantly but relapsed after withdrawing methylprednisolone, and 1 patient got deteriorated. None of them were diagnosed with tumors. Conclusions: Clinical features of acute symptomatic seizures related to GAD65 antibodies are diverse, and early and continuous immunotherapy is necessary for patients.