A new onset of status epilepticus in a previously healthy adult preceded by a recent minor febrile infection represents a diagnostic and therapeutic challenge in clinical practice. Considering the broad spectrum of epileptic encephalopathies caused by autoimmune mechanisms, differential diagnosis for new-onset refractory status epilepticus (NORSE) should include febrile infection-related epilepsy syndrome (FIRES), in order to not underestimate the underlying etiological condition triggering epilepsy in non-epileptic patients (Hon et al. in Recent Pat Inflamm Allergy Drug Discov 12:128-135, 2018). We report a case of acute encephalopathy with refractory seizures after a febrile illness (FIRES) in a young adult with complete remission of symptoms as well as dramatic improvement of EEG abnormalities following intravenous immunoglobulin and proper antiepileptic medications. We conducted an extensive workup including lumbar puncture, blood tests, EEG serial monitoring, MRI brain, total body CT scan, and PET brain with FDG to shed light on the etiology of the disease.