Autoimmune epilepsy in drug resistent and in new onset refractory epilepsy

Background and aims: Autoimmune epilepsy (AE), is a rare condition, more responsive to immune treatments than to antiepileptic drugs (Graus et al 2016; Bien et al 2005), whose incidence and prevalence and frequency of anti-neuronal autoantibodies (AN-Abs) is unknown. Methods: Adults with New Onset Refractory Epilepsy (NORE) of unknown etiology showing more than 4 seizures per month and Drug Resistant (DR) focal epilepsy with known (controls) and unknown etiology (DRUE) were recruited between 2014- and 2016. In these patients the diagnostic workup included search for AN-Abs in sera and CSF analysis with AN-Abs when indicated. Follow up was at least one year. Results: Patients recruited, n=31. 29 gave consensus to the study: 13 DRUE, 9 NOE and 7 controls. 11 patients (6 NORE, 5 DRUE) received diagnosis of AE (6 autoimmune, 2 paraneoplastic, 3 Rasmussen encephalitis), resulting in an incidence of 75% and prevalence of 55%. Sensitivity of AN-Abs was 36,36%, while specifity 94,11%. Inflammatory MRI abnormalitis1 (p=0.036) and neuropsychiatric symptoms at onset (p=0.00034) and at follow up (p=0.017) were associated with AE, but not infectious prodromes, autoimmune diseases, new onset refractory status epilepticus. DR was similar between groups. Positive AN-Abs or an early immunosoppressive treatment did not result in different long-term outcome. Conclusion: High incidence and prevalence of AE was observed in this cohort with respect to other studies (Dubey et al, 2017). AN-Abs presence was not mandatory for the diagnosis of NORE or of DRUE, did not exclude other possible diagnosis and was not associate with longterm outcome. Disclosure: Nothing to disclose