The Efficacy of a Ketogenic Diet in a Case With Febrile Infection-Related Epilepsy Syndrome in the Chronic Phase: A Case Report.

Although the treatment strategy for febrile infection-related epilepsy syndrome (FIRES) is improving, current research focuses on acute management. Evidence for the management of the chronic phase is limited. We present the case of a 19-year-old woman with FIRES who showed excellent response to a ketogenic diet (KD) administered in the chronic phase. At the age of four years, she presented with new-onset super-refractory status epilepticus after a febrile episode. She was diagnosed with FIRES and had profound motor and cognitive deterioration and drug-resistant epilepsy. From the age of 17, she experienced numerous seizures that often led to status epilepticus with respiratory failure, necessitating laryngotracheal separation and nocturnal mechanical ventilation. To improve seizure control, we planned a KD for the first time 15 years after the onset of FIRES. We introduced a classic KD (ketogenic ratio, 3:1) using blended meals through gastrotomy. Two months after starting the KD, she experienced a decrease in seizure frequency and duration. Moreover, as unexpected stabilization of respiration was achieved, mechanical ventilation was stopped. Our case implies that KD may be a promising treatment option for patients with FIRES in the chronic phase, as is believed to be the case in the acute phase.