Abstracts

Rationale: Refractory status epilepticus is a life-threatening condition, which is characterized by the failure to respond to first- and second-line anticonvulsant therapy. The patients who previously-healthy adult with refractory status epilepticus as the first symptom is called new-onset refractory status epilepticus syndrome(NORSE syndrome). The etiology of NORSE syndrome include infection of central nervous system, metabolic encephalopathy and hypoxia. In some cases of these, the etiology is not found despite of extensive evaluation. It is called cryptogenic NORSE syndrome. We describe the clinical characteristics of our 11 patients with cryptogenic NORSE syndrome. Methods: Patients admitted to the neurological intensive care unit at Asan medical center for management of status epilepticus which was diagnosed by clinical history and electroencephalogram(EEG) between Jun2006 and Mar 2012 were eligible for inclusion. We included the patients who has highly refractory to lorazepam, intravenous phenytoin(initial bolus of 20mg per kilogram). They also has no clear cause of status epilepticus that proved by the previous medical history, CSF analysis, PCR of viral marker, antigen to parasite, autoimmune antibody, thyroid function test, serum glucose, chemical battery, electrolyte battery and imaging study including MRI or CT(Table 1). Also the patients with CSF leukocytosis above 10 were not included to except the meningoencephalitis. Results: A total of 11 patients(7 male, 4 female) were included. The mean age of onset was 29.8years(range 19 to 49 years). All of them has no previous medical problem and risk factor of epilepsy. Antecedent febrile illness was observed in 8 patients(72.7%). But Fever was not observed at the admission and the abnormality of general and cerebral inflammatory marker were not found. All of them presented with convulsive status epilepticus. Multifocal or generalized seizure activity were detected on EEG. Abnormal findings were observed on 4 patients, all of them were associated with ictal discharge on EEG. For the control of seizure, intravenous anesthetic agent was used in all patients. Two of them treated by inhalational anesthetic agent to control seizure. The mean duration of stay in the intensive care unit was 61 days (range 2-175 days). The 4 patients(36.4%) died on 2 to 20 days after intravenous phentobarbital therapy. And the others survived with frequent seizures with more than 3 anti-epileptic drugs and cognitive impairment, except 1 patient (Table 2). Conclusions: In this study, the characteristics of cryptogenic NORSE syndrome were young age, previous good health, antecedent febrile illness, extraordinarily prolonged status epilepticus and catastrophic outcome like other literatures. But male was more prominent in gender compared with other literatures. So further study of this poorly understood form of status epilepticus and aggressive management are needed.