FEBRILE INFECTION-RELATED EPILEPSY SYNDROME (FIRES)

OVERVIEW

Febrile infection-related epilepsy syndrome (FIRES), previously known as fever induced refractory epilepsy in school-aged children, devastating epileptic encephalopathy in school aged children (DESC) and acute encephalitis with refractory repetitive partial seizures (AERRPS), is one cause of new onset refractory status epilepticus (NORSE). It occurs predominantly in children and adolescents. An initial febrile infection occurs, followed later by an explosive onset of super-refractory status epilepticus that can last weeks to months. This is followed by a chronic phase, where most survivors are left with drug-resistant multifocal epilepsy and a variable degree of intellectual impairment. The cause of FIRES is unknown.

Clinical context

This syndrome usually presents 2-17 years of age (mean 8 years), with a slight male predominance. Birth and antecedent history is typically normal. Prior neurological exam and head size are normal. Seizures and encephalopathy emerge 2 weeks to 24 hours after a febrile illness (most commonly due to upper respiratory tract or gastrointestinal infection). Seizures escalate in frequency in the first days to week and are drug-resistant, culminating in super refractory status epilepticus. This phase, during which the seizure burden is very high, lasts 1–12 weeks. Patients usually require prolonged intensive care support. Mortality during this time is approximately 10%. In the chronic phase, most children have drug-resistant multifocal epilepsy and intellectual impairment. Approximately one third of survivors have normal or borderline cognition, one third have mild to moderate intellectual impairment, and one third have severe to profound disability. Worse outcome is seen in those with longer duration of medically induced burst-suppression coma and younger age at onset. Attention and behavior problems (e.g. aggression) and motor abnormalities are also common in survivors.