Age‐associated differences in FIRES: Characterizing prodromal presentation and long‐term outcomes via the web‐based NORSE/FIRES Family Registry

Abstract Febrile infection–related epilepsy syndrome (FIRES) is a rare clinical presentation of refractory status epilepticus following a febrile infection. This study analyzes data from the NORSE/FIRES Family Registry, an international web‐based registry available in six languages with data entered by patients, families, and clinicians to explore clinical presentations, survivorship, and long‐term outcomes in adult and pediatric FIRES patients. We characterize and examine differences in demographics, prodromal symptoms, seizure frequency, anti‐seizure medications (ASMs), quality of life, cognition, mood, and anxiety in adults vs pediatric populations with FIRES. Eighty‐six participants were included in the study. Pediatric patients ( n = 54) were predominantly male (77.8%) and experienced a significantly higher post‐FIRES seizure burden than adult survivors (67.7% ≥12 seizures/month in pediatrics vs 11.8% in adults, p <.001). Adults ( n = 32) were more likely to be female (59.4%) and have flu‐like prodromal symptoms (90.6%). At ≥6 months post‐FIRES, both groups exhibited high ASM use, with the majority (87.5%) taking three or more medications. Pediatric patients reported worse mood and anxiety outcomes compared to adults ( p <.005). Self‐reported quality of life and cognition were rated as moderate across in adults (5.2/10) and pediatric (4.7/10) patients, although pediatric patients indicated poorer cognition. Our findings highlight the challenges in managing post‐FIRES outcomes across different age groups, particularly in pediatric patients who face a higher seizure burden and report worse cognitive outcomes.