New-Onset Refractory Status Epilepticus (NORSE): Review and Update

Abstract

The New-Onset Refractory Status Epilepticus (NORSE) is a rare entity that is defined as a clinical presentation, in a patient without active epilepsy or other relevant neurological disorder, who presents a refractory status epilepticus (RSE) without an acute or active structural, toxic, or metabolic cause. NORSE constitutes a diagnostic challenge that implies high morbidity and mortality in the short and long term. Clinically, NORSE is characterized by a prodromal phase, an acute phase, where seizures with diverse semiology that evolve to an RSE occur, and a chronic phase, with neurological deterioration and drug-resistant epilepsy. After an extensive work-up, the cause of NORSE is identified in only half of the cases. The initial treatment is based on the use of conventional anti-seizure drugs, requiring most of patients the use of anesthetics and mechanical ventilation. Better results have been observed with immunotherapy, more recently with anti-cytokine drugs, such as tocilizumab and anakinra, consistent with the immunological/inflammatory mechanisms proposed for the pathophysiology of NORSE.