Risk factors for recurrence of afebrile status epilepticus (SE), in residents of Rochester, MN, were determined by researchers at Columbia University, New York; Harvard School of Public Health, Boston, MA; and Mayo Clinic, Rochester, MN. Among 183 episodes of first afebrile SE recorded between Jan 1, 1965, and Dec 31, 1984, the risk of recurrence was 31.7% over a 10-year follow-up period. SE was acute symptomatic in 101 (55.2%) cases and unprovoked in 82 (44.8%). Most recurrences (81.8%) occurred during the first 2 years after the first episode. Among children, the risk for recurrence was 13.1% at 1 year and 16.9% at 2 years. The risk of recurrence in the total population was 100% for progressive symptomatic SE, 23.6% for remote symptomatic SE, 26.1% for idiopathic/cryptogenic SE, and 26.3% for acute symptomatic SE. Risk of recurrence was not related to patient age and duration of SE. It was significantly greater for females vs males (39.3% vs 24.6%, P=0.02). Risk was reduced in patients who responded to the first AED used to treat SE; 14.7% recurrence in those with response vs 38.2% in those with poor response, P=0.01. Predictors of recurrence of SE were sex, etiology, seizure type, and response to the first anticonvulsant drug. Risk was increased 2.3-fold for females, and 2.4-fold for progressive symptomatic SE cf idiopathic /cryptogenic SE. It was decreased for partial seizures without generalization, and for SE that responded to the first treatment. [1]

COMMENT. Status epilepticus (SE) was defined as a single clinical seizure lasting more than 30 min or repeated seizures over a period of more than 30 min without recovery of consciousness. Some authorities include seizures of shorter duration, 10 min or longer. Except for cases of progressive degenerative cerebral disease that were associated with a 100% risk of SE recurrence, patients with SE have a 1 in 4 chance of recurrence, regardless of age or duration of the initial SE episode. In a population-based study, one-third has a recurrence of SE, and the risk is doubled for females and for progressive symptomatic SE.

Efficacy of IV midazolam for status epilepticus was determined in a nationwide retrospective multicenter study reported from the Department of Pediatrics, Tokyo Women’s Medical University, Japan [2]. Among 358 inpatients treated, mean age 48.6 months, 195 had epilepsy and 163 had an acute symptomatic disease (encephalitis or encephalopathy in 88). A bolus dose of midazolam (0.25 +/- 0.21 mg/kg) followed when necessary by continuous infusion (0.26 +/- 0.25 mg/kg/hr) was effective in 56.6% cases, and final seizure suppression was obtained in 64.5%. Midazolam was less effective in patients treated late and more than 3 hours after seizure onset, especially those with epilepsy. Adverse events occurred in 19.2% of those receiving the bolus injection only, and in 28.2% - 58.6% of those who required continuous infusion in doses below or above 0.4 mg/kg/hr, respectively. Respiratory suppression occurred in 86 cases; symptoms were judged related to the underlying disease or the SE in 57. Ten deaths were also connected to the disease and not the treatment. Midazolam is not approved and has only off-label use.

In the United States, lorazepam, with its longer half-life compared to diazepam, is considered most appropriate as initial treatment for generalized tonic-clonic status epilepticus [3]. If the seizure continues despite the maximum dose of benzodiazepine, this is followed with IV fosphenytoin as the most appropriate second drug selection.