Febrile infection-related epilepsy syndrome (FIRES) is a rare severe epileptic syndrome occurring in previously healthy children and characterized by refractory status epilepticus (SE) following a febrile illness. Brain imaging findings in affected patients have been reported in few case series and some case reports. This article is a comprehensive review of the magnetic resonance imaging (MRI) characteristics in all reported patients with a diagnosis of FIRES, describing the findings in the acute and chronic phases of the disease, and discussing possible pathogenesis and radiologic differential diagnoses.
Most of the patients had normal brain scans in the acute phase (61%) and about 25% of the patients reported in literature had abnormalities in the temporal lobes. Changes in the basal ganglia and rarely in thalami or brainstem have also been described, as well as diffuse cerebral edema in a minority of patients during the acute phase. The chronic phase of the disease was characterized by atrophic changes and evidence of mesiotemporal sclerosis. An understanding of these MRI abnormalities is necessary to support the diagnosis of FIRES and exclude mimics.