Predictors of Outcome in Refractory Status Epilepticus

Objective: To further characterize the demographics, outcomes, and prognostic factors for refractory status epilepticus (RSE).

Design: Retrospective analysis of all the episodes of RSE treated between January 1, 1999, and August 30, 2011.

Setting: Neurointensive care unit within a tertiary referral center, Mayo Clinic, Rochester, Minnesota.

Patients: Refractory status epilepticus was defined as generalized convulsive or nonconvulsive status epilepticus (SE) that continued despite initial first- and second-line therapies. Exclusion criteria were aged younger than 18 years, anoxic/myoclonic SE, psychogenic SE, simple partial SE, and absence SE.

Main Outcome Measures: Functional outcome was defined by modified Rankin scale (mRS) dichotomized into good (mRS, 0-3) and poor (mRS, 4-6). Functional decline was defined as a change in mRS greater than 1 from hospital admission to discharge.

Results: We identified 63 consecutive episodes of non-anoxic RSE in 54 patients. Anesthetic agents were used in 55 episodes (87.30%), and duration of drug-induced coma was (mean [SD]) 11.0 (17.9) days. In-hospital mortality was 31.75% (20 of 63 episodes). Poor functional outcome at discharge occurred in 48 of 63 episodes (76.19%). Hospital length of stay was (mean [SD]) 27.7 (37.3) days. Duration of drug-induced coma (P=.03), arrhythmias requiring intervention (P=.01), and pneumonia (P=.01) were associated with poor functional outcome. Prolonged mechanical ventilation was associated with mortality (P=.04). Seizure control without suppression-burst or isoelectric electroencephalogram predicted good functional recovery (P=.01). Age, history of epilepsy, previous SE, type of SE, and anesthetic drug used were not associated with functional outcome.

Conclusions: Three-quarters of patients with RSE have a poor outcome. Achieving control of the SE without requiring prolonged drug-induced coma or severe electroencephalographic suppression portends better prognosis.