Faciobrachial Dystonic Seizures as a Sign of Relapse in a Child with LGI-1 Encephalitis.

We report an interesting case of a young girl with LGI1-antibody encephalitis who presented at 7 years old with very frequent seizures and severe neurocognitive decline. She responded very well to high dose corticosteroids and intravenous immunoglobulin (IVIG) initially but relapsed after 7 months. The relapse included frequent faciobrachial dystonic seizures (FBDS) that were successfully treated with rituximab. This case report highlights a few important points about LGI1-antibody encephalitis in children to help clinicians recognize this condition early and start prompt treatment with immunosuppressants. Data is lacking about LGI1-antibody encephalitis in children as it is mostly reported in adults. Our patient presented with frequent drug-resistant seizures including FBDS, along with amnesia, confusion, medial temporal lobe involvement, and hyponatremia similar to the presentation in adults. In contrast, none of the patients in the recent systematic review had FBDS or hyponatremia, making our case unique and suggesting variability in clinical presentation in children similar to adults. To our knowledge, FBDS have never been reported in children and our patient was initially misdiagnosed as having Childhood Epilepsy with Centrotemporal spikes. Since receiving rituximab, our patient is seizure-free for 1 year and 9 months and was successfully weaned of topiramate. She is going to school and has normal attention, concentration, memory, and mood. We propose early consideration of rituximab to accelerate recovery and prevent relapse.