Abstracts

Rationale: Background/Rationale: Status epilepticus (SE) is a life-threatening condition, requiring immediate medical therapy. Refractory status epilepticus (RSE) is defined as status epilepticus persisting beyond 60 minutes despite appropriate treatment. Several case reports have suggested that vagus nerve stimulation (VNS) appeared to result in cessation of RSE not responding to conventional medical treatment. Since published reports of children so managed remain few, we retrospectively reviewed children with RSE deemed candidates for VNS in our institution from 2003 through 2011 to describe our experience. Methods: We retrospectively reviewed charts of all patients who underwent VNS implantation as treatment of RSE at Cook Chidren's Medical Center between January 2003 and January 2011. For the purpose of this study, RSE is defined as seizure > 60 minutes not responding to appropriate treatment or the re-emergence of SE following discontinuation of high-dose suppressive therapy.. For each patient, we recorded precipitating factors for SE, duration of RSE before VNS, number of anticonvulsants administered prior to institution of VNS, duration of RSE after implantation, VNS stimulation parameters, and outcome. Results: Five patients met inclusion criteria. Patients ranged in age from 0.7 to 9 years (mean 5.3 years). Presumed precipitating factors for SE included: anticonvulsant withdrawal (1); metabolic complications associated with Leigh's Disease (1); and viral encephalitis (3). None were considered candidates for focal cortical resection. Patients received a median of 10 AEDs (range 5-11) and had been in RSE a median 26 days (range 4-50) prior to institution of VNS. Initial stimulation parameters for each patient were: output current 0.25 mA; 30 Hz frequency; Pulse width 250 us; signal ‘on & off' time: 30s ‘on,' 3 min ‘off.'. All 5 children required aggressive increment in output current and duty-cycles [on/(on + off times)] before RSE ceased. Two patients were considered responders to treatment with cessation of RSE within 7 days, while the others had persistent RSE for 21-84 days following implantation. Three children have continued VNS for over six years, achieving better seizure control, but none are seizure free. Conclusions: VNS may be associated with interruption of RSE in patients who fail standard medical treatment. Aggressive adjustment of stimulation parameters may contribute to response, though the contribution of individual parameters to outcome is unknown. In patients with RSE who have failed standard treatments, VNS may be considered as an alternative treatment option.