Efficacy differences between tocilizumab and ketogenic diet during acute phase of febrile Infection-Related epilepsy syndrome in children: A retrospective cohort study.

Febrile infection-related epilepsy syndrome (FIRES) is a rare and devastating subtype of new-onset refractory status epilepticus (NORSE), characterized by rapid progression, high mortality, and poor response to conventional antiseizure therapies. The underlying pathophysiology remains elusive, and no standardized treatment has been established. This retrospective study evaluated 36 pediatric patients diagnosed with FIRES at the Children's Hospital of Chongqing Medical University from January 2019 to December 2024. Patients received first-line immunotherapy alone (n = 17), combined with tocilizumab (n = 8), or with ketogenic diet (KD) (n = 11). Compared to other groups, the tocilizumab cohort showed more rapid seizure control within the first week, improved EEG background activity, and earlier normalization of the neutrophil-to-lymphocyte ratio (NLR), an inflammatory biomarker. At three months, KD demonstrated superior EEG improvement, suggesting a delayed but sustained therapeutic effect. These findings suggest that early initiation of tocilizumab as a second-line therapy following first-line immunotherapy may effectively reduce seizure burden and improve clinical outcomes in children with FIRES.