Etiology, clinical course and response to the treatment of status epilepticus in children: A 16-year single-center experience based on 602 episodes of status epilepticus.

OBJECTIVE: evaluation of etiology, clinical course and response to the treatment of status epilepticus (SE) in children, with particular investigation of superrefractory SE.

MATERIALS AND METHODS: The retrospective study included children with convulsive SE aged 0.2-18 years, treated from 1995 to 2011. Status epilepticus is defined as a continuous seizure or intermittent seizures without full recovery of consciousness between seizures for at least 30 min. Refractory SE is diagnosed if SE lasts for more than 60 min, while superrefractory SE if SE continues or recurs 24 h or more after the onset of an anesthesia therapy, including those cases that recur after reduction or withdrawal of an anesthesia. The etiology was summarized in five categories: idiopathic/cryptogenic, remote symptomatic, febrile SE, acute symptomatic and progressive encephalopathy. The patients were treated according to the same hospital protocol. Midazolam iv and diazepam rectally were given as the first line drugs, phenobarbital/phenytoin iv as the second line drugs. If they failed, third line drugs, midazolam and thiopental were given in continuous intravenous infusion. The medication was defined as effective if seizure clinically stopped within 20 min, without recurrence within the next 6 h. Midazolam was assessed as effective even if it failed as the first line, but was effective in intravenous infusion as the third line drug.

RESULTS: The study consisted of 602 SE in 395 children. There were 305 (50.7%) refractory SE episodes, and 43 (7.1%) of superrefractory SE. Idiopathic/cryptogenic and febrile SE was the most common etiology in the first SE, while progressive encephalopathy and remote symptomatic was in recurrent and superrefractory SE. The most effective drugs were: midazolam (306/339) given in mean dose of 0.4 mg/kg (range 0.1-1.2 mg/kg), thiopental (47/57) in mean dose of 4 mg/kg (range 3-5 mg/kg), phenobarbital (91/135) in dose of 20 mg/kg. Midazolam successfully stopped 306/339 SE episodes (90.3%), 67 SE (21.9%) by equal or lower dose than 0.2 mg/kg as the first line drug, while all other 239 episodes (78.9%) were stopped by intravenous infusion in range 0.2-1.2 mg/kg/h (mean 0.4 mg/kg/h) as the third line drug. Adverse effects were frequent in superrefractory SE (60.5%). In 15 patients, corticosteroids contributed to the reduction of seizure recurrence after anesthetic withdrawal and cessation of epilepsia partialis continua. Case fatality rate was 5.1% in all patients, while 21.3% in patients with superrefractory SE.

CONCLUSION: Status epilepticus in children was characterized by heterogeneous etiology, prolonged duration and commonly good response to midazolam only given in high doses. Superrefractory SE was not so rare in children, especially among the patients with progressive encephalopathy.