Abstracts

Rationale: We hypothesize that the termination of persistent seizures is related to total drug dosing (number of drugs, and dose of each drug) rather than to individual agent . We test this hypothesis in a cohort of patients in whom the times of seizure onset and cessation are specified to the hour by continuous EEG. Methods: This is a single center, retrospective, case review of data on the clinical, EEG, and drug treatment outcome of a cohort of 135 patients with Status Epilepticus (SE: continuous clinical and/or EEG seizure activity for 50% or more time in a 20-30 min EEG record, or 6 or more EEG seizures per hour during continuous EEG without recovery of awareness); or Persistent Repetitive Seizures (PRS: <6 seizures/hour and minimum of 6 seizures/day during continuous EEG) from December 1, 2008 until October 1, 2011 at the Cleveland Clinic who are 16 years or older. The time of seizure onset was defined by the first witnessed seizure in the medical record or by the first EEG seizure on continuous EEG. The time of seizure cessation was the last recorded EEG seizure before a 48 hour seizure free period. We excluded patients with seizures complicating cerebral anoxia. We excluded PLEDs, BiPLEDs, Generalized Periodic Discharges, or Burst Suppression as EEG seizures. Results: 70 patients were female, 65 male. The mean age was 62.4 16.9 years. 63 (46.7%) patients had SE, and 72 ( 53.3%) PRS. 40 ( 29.6%) patients had a prior history of epilepsy. Seizures were focal by EEG in 128 ( 94.8%), generalized in 3 ( 2.2%) and nonlocalizable in 4 ( 3 %) patients. Seizure duration was: mean 50.6, median 38, range 1 to 281 hours and were not different between SE or PRS . 111 ( 82.2%) patients survived at discharge with the majority dependent on care, and 24 ( 17.8%) died. Survival was significantly reduced in acute provoked (76%), as compared to remote symptomatic or epilepsy related seizures ( -Square 0.043), but not related to seizure duration (t-test). First AED was administered in 135 ( 100%) patients, second AED in 130 ( 96.3%), third AED in 108 ( 80 %), fourth AED in 71 (52.6%) and fifth AED in 31 ( 23%) patients before seizure termination. Linear regression with seizure duration as the dependent variable showed a significant positive correlation between duration and number of drugs used. There was no correlation of seizure duration to time to first drug, or number of drugs in the first 24 hours. There was no correlation of seizure duration with first drug as a benzodiazepine, focal v other seizures, or etiology of status. Conclusions: In this preliminary analysis of prolonged seizures during continuous EEG, the longer the seizure duration, the more drugs were used. Survival related to seizure etiology but not to seizure duration. Further analysis on cumulative drug dosing effects will be next.