Bridging the Gap: Tailoring an Approach to Treatment in Febrile Infection-Related Epilepsy Syndrome

Cytokine profiling before immunotherapy is increasingly prevalent in febrile infection-related epilepsy syndrome (FIRES). In this case, an 18-year-old man presented with first-onset seizure after a nonspecific febrile illness. He developed super-refractory status epilepticus requiring multiple antiseizure medications and general anesthetic infusions. He was treated with pulsed methylprednisolone and plasma exchange and started on ketogenic diet. Contrast-enhanced MRI brain revealed postictal changes. EEG findings showed multifocal ictal runs and generalized periodic epileptiform discharges. CSF analysis, autoantibody testing, and malignancy screening were unremarkable. Genetic testing revealed variants of uncertain significance in the CNKSR2 and OPN1LW genes. Initial serum and CSF cytokine analyses performed on days 6 and 21 revealed that interleukin (IL)-6, IL-1RA, monocyte chemoattractant protein-1, macrophage inflammatory protein 1β, and interferon γ were elevated predominantly in the CNS, a profile consistent with cytokine release syndrome. Tofacitinib was initially trialed on day 30 of admission. There was no clinical improvement, and IL-6 continued to rise. Tocilizumab was given on day 51 with significant clinical and electrographic response. Anakinra was subsequently trialed from days 99 to 103 because clinical ictal activity re-emerged on weaning anesthetics but stopped because of poor response. Serial cytokine profiles showed improvement after 7 doses of tocilizumab. There was corresponding improved seizure control. This case illustrates how personalized immunomonitoring may be helpful in cases of FIRES, where proinflammatory cytokines are postulated to act in epileptogenesis. There is an emerging role for cytokine profiling and close collaboration with immunologists for the treatment of FIRES. The use of tocilizumab may be considered in patients with FIRES with upregulated IL-6.