Citation, DOI, disclosures and article data
Citation:
Weerakkody Y, Sharma R, Gaillard F, New-onset refractory status epilepticus. Reference article, Radiopaedia.org (Accessed on 24 Mar 2025) https://doi.org/10.53347/rID-60965
New-onset refractory status epilepticus (NORSE) is defined as refractory status epilepticus occurring in a previously healthy patient with no known history of epilepsy, who has no identifiable structural, toxic or metabolic cause for their refractory status epilepticus found on initial investigation.
When following a febrile illness, it is termed febrile infection-related epilepsy syndrome (FIRES) 5.
The cause is autoimmune encephalitis in approximately one-third of patients, but remains cryptogenic in approximately half of all patients 6.
MRI
There are no specific abnormalities on MRI brain except for perhaps mild T2/FLAIR hyperintense signal of the mesial temporal lobe 1. Bilateral lesions of the claustrum may also be present (claustrum sign), particularly in febrile infection-related epilepsy syndrome (FIRES).
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.) 7.
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1. Puoti G, Elefante A, Saracino D, Capasso A, Cotrufo R, Anello CB. New-onset refractory status epilepticus mimicking herpes virus encephalitis. (2013) Case reports in neurology. 5 (3): 162-7. doi:10.1159/000355273 - Pubmed
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2. Meletti S, Giovannini G, d'Orsi G, Toran L, Monti G, Guha R, Kiryttopoulos A, Pascarella MG, Martino T, Alexopoulos H, Spilioti M, Slonkova J. New-Onset Refractory Status Epilepticus with Claustrum Damage: Definition of the Clinical and Neuroimaging Features. (2017) Frontiers in neurology. 8: 111. doi:10.3389/fneur.2017.00111 - Pubmed
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3. Gaspard N, Hirsch LJ, Sculier C, Loddenkemper T, van Baalen A, Lancrenon J, Emmery M, Specchio N, Farias-Moeller R, Wong N, Nabbout R. New-onset refractory status epilepticus (NORSE) and febrile infection-related epilepsy syndrome (FIRES): State of the art and perspectives. (2018) Epilepsia. 59 (4): 745-752. doi:10.1111/epi.14022 - Pubmed
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4. Costello DJ, Kilbride RD, Cole AJ. Cryptogenic New Onset Refractory Status Epilepticus (NORSE) in adults-Infectious or not?. (2009) Journal of the neurological sciences. 277 (1-2): 26-31. doi:10.1016/j.jns.2008.10.007 - Pubmed
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5. Hon KLEL, Leung AKC, Torres AR. Febrile Infection-Related Epilepsy Syndrome (FIRES): An Overview of Treatment and Recent Patents. (2018) Recent patents on inflammation & allergy drug discovery. doi:10.2174/1872213X12666180508122450 - Pubmed
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6. Tharmaraja T, Ho J, Neligan A, Rajakulendran S. The Etiology and Mortality of New-Onset Refractory Status Epilepticus (NORSE) in Adults: A Systematic Review and Meta-Analysis. Epilepsia. 2023;64(5):1113-24. doi:10.1111/epi.17523 - Pubmed
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7. Wickström R, Taraschenko O, Dilena R et al. International Consensus Recommendations for Management of New Onset Refractory Status Epilepticus (NORSE) Including Febrile Infection‐related Epilepsy Syndrome (FIRES): Summary and Clinical Tools. Epilepsia. 2022;63(11):2827-39. doi:10.1111/epi.17391 - Pubmed
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