Abstracts

Rationale: FIRES is a severe post-infectious epileptic encephalopathy in previously healthy individuals. This condition typically escalates to NORSE, a life-threatening condition characterized by the failure to achieve seizure remission after treatment with first- and second-line antiepileptic drug therapy. Because of the preceding infection, these cases are thought to progress through an immune-mediated pathomechanism and, therefore, may respond to immunotherapies.[1] [1] van Baalen A, et al. Febrile infection-related epilepsy syndrome without detectable autoantibodies and response to immunotherapy: a case series and discussion of epileptogenesis in FIRES. Neuropediatrics 2012; 43(4):209-16. Methods: We present a case of prolonged FIRES/NORSE (> 100 days), which resolved with plasma exchange (PLEX) followed by rituximab therapy. Results: A 23 yo woman presented with a 4-day history of URI with fevers and new-onset seizures. At admission, she had seizures of increasing frequency and duration despite treatment with IV Levetiracetam, IV valproic acid, and repeated doses of IV Lorazepam. She was brought to the ICU for continuous video-EEG monitoring (CEEG) and induction of a barbiturate coma. CEEG showed clinical and subclinical seizures that were electrographically characterized by independent, bitemporal seizure onset with rapid contralateral propagation (Figure 1). CSF revealed 18 WBC (91% segs) with normal protein and glucose. MRI brain showed an oval region of restricted diffusion in the splenium (Figure 2). An extensive work-up revealed elevated serum mycoplasma and Coxsackie B antibodies. She was treated with Lacosamide, Topiramate, Phenobarbital, Phenytoin, Clobazam, as well as trials of pentobarbital, midazolam, ketamine, magnesium, ketogenic diet and hypothermia, in various combinations. Methylprednisolone and IVIG were attempted and were ineffective. On week 7, PLEX was attempted and notably decreased her seizure activity and drip requirements. However, this effect lasted only 2-3 weeks before seizure activity increased. After another course of PLEX followed by a 4-week rituximab course, her drips were successfully weaned. The patient woke up and began following commands. She experienced infrequent clinical seizures on Phenobarbital, Topiramate, Lacosamide, Phenytoin, and Diazepam. Conclusions: In this case, we exhausted most treatment options for NORSE reported in the literature. We suspected a post-infectious autoimmune mechanism given the preceding febrile illness. We felt this hypothesis was confirmed by the initial response to PLEX. Treatment with rituximab expanded the gains made with PLEX allowing our patient to begin her recovery. There are several reports in the literature of rituximab treatment for FIRES, with limited success.[2] Yet, for cases of prolonged NORSE, PLEX followed by rituximab should be considered as there are few alternatives. [2] Caraballo RH, et al. Febrile infection-related epilepsy syndrome: a study of 12 patients. Seizure 2013; 22(7):553-9.