Abstracts

Rationale: Status epilepticus (SE), defined as seizures lasting at least 30 minutes in duration, is the most common neurological emergency of childhood. In 30-50% of cases, SE is refractory to conventional anticonvulsant therapy, necessitating high-dose suppressive therapy. Despite such high-dose therapy, some cases of refractory SE remain sustained for more than 24 hours. The clinical features of children with sustained refractory SE remain poorly understood. Methods: Single-centre case series of children diagnosed with SE who were admitted to the Paediatric Intensive Care Unit (PICU) at The Hospital for Sick Children between January 2002 and June 2010. Children receiving high-dose suppressive therapy (HDST) for greater than 24 hours (midazolam, thiopental, pentobarbital, propofol, ketamine or paraldehyde infusions or high-dose phenobarbital with daily trough levels >300 mol/L) were classified as having sustained refractory status epilepticus (SRSE), and their charts were reviewed in detail. The etiology of patient SE was classified as Acute Symptomatic (AS), Remote Symptomatic (RS), Remote Symptomatic with Acute Precipitant (RSAP) or Progressive Encephalopathy (PE).Results: 54 patients (34 males; 20 females) were identified. Age ranged from 4 days to 17 years. The most common etiological classification of SE was AS (40.7%). Almost half of the patients (48.1%) had a prior history of epilepsy. The median duration of high-dose suppressive therapy was 5 days (Range: 1-58 days). Eighty-seven percent of patients required ventilator support, while 48.1% were treated with inotropes while on HDST. The overall mortality was 13.0%. Twenty-eight percent of patients were seizure free at PICU discharge, and 56.8% were seizure free at hospital discharge. Results of univariate analyses suggested that patient age, etiology and duration of HDST were factors that influence patient outcome. These variables were entered into a logistic regression model, which indicated that patient age and etiology had a significant effect on patient outcome at discharge from hospital. Younger children were more likely to be seizure free at discharge (P=0.0103). Additionally, children with RSAP etiologies were more likely to have a seizure free outcome compared to the other groups: AS (P=0.0135), RS (P=0.0124), PE (P=0.0040). Conclusions: This large single-center case series confirms prior reports that AS etiologies were the most common cause of sustained refractory SE in children. However, nearly half of the children also had a prior history of epilepsy. Despite aggressive therapy, seizures frequently remained difficult to control, and the need for ventilatory and inotropic support was common. Although only 28% were seizure-free at PICU discharge, 57% were seizure-free by hospital discharge. Younger age and RSAP etiology were associated with freedom from seizures at hospital discharge. Long-term follow-up studies are required to better characterize long-term outcomes and their relationship to etiology and therapy.