Febrile infection-related epilepsy syndrome (FIRES) is a severe postinfectious neurological disorder that presents with new-onset refractory status epilepticus (NORSE) in a previously normal child (or less commonly adult) after a febrile illness.
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Terminology
FIRES has received several names in the literature:
acute encephalopathy of obscure origin in infants and children
acute encephalitis with refractory, repetitive partial seizures (AERRPS)
acute encephalopathy with inflammation-mediated status epilepticus
devastating epilepsy in school-aged children (DESC)
idiopathic catastrophic epileptic encephalopathy
fever-induced refractory epileptic encephalopathy in school-age children
severe refractory status epilepticus owing to presumed encephalitis
Clinical presentation
The clinical presentation is with new-onset refractory status epilepticus (NORSE) following (2 weeks to 24 hours prior to development of seizures) a nonspecific febrile illness 2. CSF analysis reveals pleocytosis or elevated protein levels in nearly 75% of cases 3,4.
Radiographic features
MRI
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T2 and FLAIR: hyperintensity (acute phase), hypointensity (chronic phase)
bilateral claustrum involvement (claustrum sign) 3,4
DWI/ADC: no restricted diffusion
T1 C+ (Gd): no enhancement
Treatment and prognosis
Treatment is with aggressive initiation and uptitration of antiseizure medications (including anesthesia and ketogenic diet) and early consideration of immunomodulatory treatments (e.g. corticosteroids, intravenous immunoglobulin, rituximab, tocilizumab, anakinra, etc.) 2.
Two-thirds of the surviving children suffer from mild to severe cognitive impairment ref.
Differential diagnosis
acute encephalopathy with biphasic seizures and late reduced diffusion (clinical differential diagnosis)