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

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.