Abstracts

Rationale: The effects of seizure clusters are profound, often leading to injuries and emergency room visits. As rapidly acting benzodiazepines are being developed for abortive treatment, it is important to understand the prevalence of seizure clusters and the current use and efficacy of rescue medications. The primary objectives of this study are to identify risk factors and patterns of clusters and to assess the use of rescue medication, occurrence of related injuries, and emergency room visits. This is an interim report on six month outcome from an ongoing prospective seizure diary study.Methods: Subjects were categorized according to their reported seizure frequency over the year prior to enrollment into one of the three groups: high-risk, medium-risk, and low-risk for developing clusters. Patients with daily seizures were excluded. The high-risk group included subjects reporting two or more seizures within a 24h period at least once in the past year. The medium-risk group had at least one seizure but never had two or more seizures within a 24h period, and the low-risk group had no seizures but were still on anti-epileptic medication for definite epilepsy. Subjects recorded time, duration, use of rescue medications, occurrence of injuries, and emergency room visits and were contacted monthly for six months. For the primary outcome, we defined clusters as the occurrence of two or more seizures in six hours.Results: Two hundred subjects reached the six month milestone – 62 were excluded due to inadequate compliance with their diaries, providing a sample size of 138. Of these 138, 31 (22.4%) were from the low risk group, 57 (41.3%) were from the medium risk group and 50 (36.2%) were from the high risk group. Forty four percent of the patients from the high risk group had clusters and 19% from the medium risk group had clusters. None of the patients in the low risk group reported clusters. There was no significant difference in the occurrence of emergency department (ED) visits and injuries between patients with clusters compared to patients with seizures but no clusters (Table 1). Similarly, the use of rescue medication was not different amongst the two groups. Although there was a greater proportion of patients with clusters among the extra-temporal epilepsy group compared to the temporal lobe epilepsy group, the difference was not significant (Figure 1).Conclusions: Seizure clusters are common in patients with epilepsy and rescue medications are utilized infrequently. Rates of seizure clusters at six months correlated with the designated risk groups identified at enrollment. Seizure related injuries and ED visits were not uncommon among patients with clusters and patients with seizures but no clusters. Further analysis of prospective data will better identify risks and precipitants of seizure clusters. Supported by Upsher-Smith Laboratories, Inc.