Febrile infection-related epilepsy syndrome (FIRES) was first reported in 2001 but was called by another name. It was called acute encephalitis with refractory, repetitive partial seizures” (AERRPS).1 It is still so called in Japan but called FIRES in Europe and much of the rest of the world. Among the authors of this article is Dr Rima Nabbout a colleague on the executive committee of the International Neurological Ketogenic Society (INKS). They also successfully used the ketogenic diet (KD) to treat this devastating disorder.
The clinical picture is one of acute frequent seizures or status epilepticus following a febrile episode (2 weeks to 24 hours prior to onset of seizures). It occurs in previously healthy children and its pathogenesis is still unknown. The diagnosis is usually one of exclusion as there are no biomarkers or genetic tests to diagnose FIRES. The seizures are usually resistant to pharmacological treatment, anesthetic treatment and immunological treatment. The outcome is often poor with 30% mortality and 60-100% resultant resistant epilepsy and neuropsychological regression. Treatment with AEDs is often disappointing. The status epilepticus usually proves refractory to AEDs and anesthesia. Suppression-burst coma also results in re-appearance of seizures on withdrawal. Treatment with KD however has had good results. The responder rate (>50% reduction is seizures) was 62% and good results are seen in over 50%.
Usually, the enteral route is used to initiate the KD either through a nasogastric tube or orally. However, due to enteral problems occasionally seen, intravenous administration may be required. The KD should be continued as in other patients for several years.
Prognosis is guarded with a high percentage having consequent mental regression and learning disabilities.
Various hypotheses have been mooted including infectious mechanisms, encephalitis, metabolic diseases, mitochondrial defects, de novo gene mutations, pre-existing immune systemic disease and de novo autoimmune antibodies. The cause of FIRES still remains uncertain.
- Sakuma H, Awaya Y, Shiomi M, et al. Acute encephalitis with refractory, repetitive partial seizures (AERRPS): a peculiar form of childhood encephalitis. Acta Neurol Scand. 2010;121(4):251–2562. doi:10.1111/j.1600-0404.2009.01198.x