Safety and Efficacy of Neuro-responsive Stimulator (RNS) in Bilateral Temporal Lobe GAD65 Antibody Positive Autoimmune Epilepsy in Patients on Immunosuppression
Lindsay Voltz1, Thandar Aung2
1Neurology, UPMC, 2Neurology, University of Pittsburgh
Objective:
In patients with drug resistant epilepsy (DRE) and bilateral epileptogenic zones (EZ), the chance of seizure freedom is implausible with only antiseizure medications (ASM). RNS has been proven to help decrease seizure frequency and improve cognitive outcomes in patients with bilateral medial temporal lobe epilepsy related to autoimmune encephalitis (AE). However, the risk of CNS infection is a major limiting concern for RNS placement in immunosuppressed patients with DRE. The goal of this article is to illustrate RNS as a safe option in treatment of a DRE patient with GAD65 antibody associated AE on immunosuppression and discuss a potential role in tracking disease activity while tapering immunosuppressant medications.
Background:
AE is an important cause of DRE, reported in 14-20% of patients with unclear etiology for their epilepsy. The pathophysiology involves autoantibodies that target neuronal proteins and thus can present as a DRE with bilateral EZ. While RNS is approved for patients with resistant focal epilepsy, few cases of autoimmune epilepsy treated with RNS exist in the literature.
Results:
We present a young female patient diagnosed with GAD65 antibody positive AE on multiple ASMs including Levetiracetam, Lamotrigine, Zonisamide, Phenobarbital, Clobazam, Lacosamide, and Ativan. Her immunomodulating therapies include IVIG maintenance therapy, mycophenolate, and daily prednisone. Despite multiple ASMs and immunosuppressant medications, she continued to have high seizure burden and thus underwent placement of RNS targeting bilateral hippocampi. Her post operative course was uncomplicated. After placement, several recorded events were demonstrated with increasing frequency during a planned steroid taper, thus giving us the ability to track disease activity while modifying immunotherapies.
Conclusions:
RNS has a role in tracking disease treatment in patients with AE on immunosuppression and provides a safe therapeutic option for these commonly immunosuppressed groups, as demonstrated with our patient with GAD65 positive AE.