Abstracts

Rationale: Status epilepticus (SE) is defined as presence of continuous seizure activity for more than 30 minutes or two or more seizures in succession without recovery and return to consciousness in between. Causes of SE include noncompliance or discontinuation of AEDs, trauma to the head, acute structural injury of brain (tumor or metastasis, infection, hemorrhage, cerebral anoxia, etc). This is a case of new onset refractory SE (NORSE), for which no cause was determined despite extensive work-up Methods: A 23 year old female was admitted to the hospital after she was found unresponsive by a friend. She was unresponsive and febrile on arrival to the ED. While in the ED, she had one episode of generalized tonic clonic seizure. She received dose of lorazepam IV. Preliminary work up in the ED included a CT brain which was normal. A lumbar puncture was performed which showed leukocytosis with neutrophil predominance (WBC 21, with neutrophils 87%). She was admitted to the ICU and treated empirically with acyclovir, vancomycin and cefriaxone. An EEG was performed the next day, which showed diffuse slowing. The next day, she developed frequent complex partial seizures, with head and eye deviation to the left and oral automatisms, which became secondarily generalized. She received valproic acid and levetiracetam IV, in addition to fosphenytoin. She was intubated for airway protection, and started on midazolam drip, and propofol was added in increasing doses, with limited success. Continuous video-EEG monitoring at the bedside revealed frequent seizures arising from the right temporal region initially, and then from either temporal region, with secondary generalization, despite high doses of midazolam, propofol and pentobarb infusions Results: Cultures for bacteria, virus and fungus were negative in blood and CSF. Tests for cryptococcal antigen, HSV PCR, EBV, West Nile, CMV, toxoplasma, RMSF and HIV were negative. Toxicology profile was negative except for cannabis. NMDA receptor antibody, ACE levels in CSF, ANA, ANCA and anti-HU protein antibodies were negative as well. MRI of the brain was performed twice with and without gadolinium, which did not reveal any abnormalities. Pelvic sonogram did not reveal any ovarian tumors. In addition to continuous infusion of anticonvulsants, she also received a course of IVIG and methylprednisolone, and a dose of pyridoxine. She continued to experience seizure activity despite being on 6 different anti-seizure medications (midazolam, pentobarbital, propofol, phosphenytoin, valproic acid and levetiracetam). Burst suppression was achieved after several days. Each attempt to decrease the dose of any of the medications resulted in recurrence of seizures. The patient died 48 days after admission. Neuropathology report revealed right hippocampus sclerosis, cerebral edema, transtentorial uncal herniation, pontine hemorrhage and metabolic gliosis Conclusions: Refractory SE results from excitation of a group of neurons and a failure of centrally mediated mechanisms to suppress the seizure activity. Finding an etiology and understanding the mechanism of NORSE will help to identify new treatment options.