What is New-Onset Refractory Status Epilepticus (NORSE)?

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Last updated: March 25, 2025View editorial policy

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From the Guidelines

New-onset refractory status epilepticus (NORSE) is a rare but severe condition characterized by prolonged seizures that don't respond to standard anti-seizure medications in patients without a history of epilepsy. The management of NORSE is crucial to prevent further brain damage and improve patient outcomes.

Key Characteristics of NORSE

  • Prolonged seizures that don't respond to standard anti-seizure medications
  • Patients without a history of epilepsy
  • Requires aggressive seizure control and comprehensive diagnostic workup

Management of NORSE

  • Initial management includes aggressive seizure control with benzodiazepines like lorazepam or midazolam, followed by second-line agents such as fosphenytoin, valproate, or levetiracetam 1
  • For refractory cases, anesthetic agents like propofol, midazolam, or ketamine may be necessary with continuous EEG monitoring in an ICU setting
  • Immunotherapy with IV methylprednisolone and/or IVIG should be considered early, as many NORSE cases have an autoimmune etiology

Diagnostic Workup

  • Comprehensive diagnostic workup including brain MRI, CSF analysis, autoimmune panels, and infectious disease testing is crucial to identify underlying causes
  • Multidisciplinary management involving neurologists, intensivists, and immunologists is necessary to address both seizure control and the underlying etiology, which improves outcomes in this life-threatening condition 1 Key points to consider in the management of NORSE include:
  • Aggressive seizure control
  • Comprehensive diagnostic workup
  • Multidisciplinary management
  • Early consideration of immunotherapy These key points are crucial in improving patient outcomes and preventing further brain damage in NORSE patients.

From the Research

Definition and Characteristics of New-Onset Refractory Status Epilepticus (NORSE)

  • NORSE is a recently described entity characterized by refractory status epilepticus in individuals without a prior history of epilepsy 2, 3, 4, 5.
  • It is often difficult to treat due to the cryptogenic etiology, with no clear acute or active structural, toxic, or metabolic cause 2, 3, 5.
  • NORSE mainly affects school-age children and young adults, with a prodromal phase of flu-like symptoms preceding the onset of status epilepticus in many cases 3.

Clinical Features and Diagnosis

  • Status epilepticus in NORSE usually starts with repeated focal seizures with secondary bilateralization, often evolving to super refractory status epilepticus (SRSE) 3.
  • No specific imaging or laboratory abnormalities have been identified for early diagnosis, and half of adult cases remain of unknown etiology 3.
  • A standardized diagnostic algorithm is recommended, including an extensive evaluation with MRI brain, CSF studies, radiologic scans, and serological autoimmune and infectious investigations 2, 3.

Treatment and Prognosis

  • Treatment of NORSE often involves antiepileptic medications, anesthetics, and immunotherapies, with variable success rates 2, 3, 4, 6.
  • Early recognition and treatment are crucial for improving outcomes, which are often poor, with high short-term mortality and long-term disability and epilepsy 3, 5.
  • Novel treatments, such as plasma exchange therapy 2 and vagus nerve stimulator (VNS) therapy 4, have shown promise in some cases, but further research is needed to establish their efficacy.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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