BACKGROUND: Determine the prevalence of seizure clusters (two or more seizures in six hours), use of rescue medications, and adverse outcomes associated with seizure clusters in pediatric patients with a range of epilepsy severities, and identify risk factors predictive of seizure clusters.
METHODS: Prospective observational two-center study, including phone call and seizure diary follow-up for 12 months in patients with epilepsy aged one month to 18 years. We classified patients into three risk groups based on seizures within the prior year: high, seizure cluster (two or more seizures within one day); intermediate, at least one seizure but no days with two or more seizures; low, no seizures.
RESULTS: One-third (32.3%; high risk, 72.4%; intermediate risk, 30.4%; low risk, 3.1%) of 297 patients had a seizure cluster during the study, including half (46.2%) of the patients with active seizures at baseline (intermediate- and high-risk groups combined). Emergency room visits or injuries were no more likely due to a seizure cluster than an isolated seizure. Rescue medications were utilized in 15.8% of patients in the high-risk group and 19.2% in the intermediate-risk group. History of status epilepticus (adjusted odds ratio [aOR], 2.13; confidence interval [CI], 1.09 to 4.16]), seizure frequency greater than four per month (aOR, 4.27; CI, 1.92 to 9.50), and high-risk group status (aOR, 6.42; CI, 2.97 to 13.87) were associated with greater odds of seizure cluster.
CONCLUSIONS: Seizure clusters are common in pediatric patients with epilepsy. High seizure frequency was the strongest predictor of clusters. Rescue medications were underutilized. Future studies should evaluate the applicability and effectiveness of these medications for optimization of pediatric seizure cluster treatment and reduction of seizure-related emergency department visits, injuries, and mortality.

Purpose: This retrospective observational study aimed to investigate the self-reported prevalence of seizure clusters (SCs) in patients with epilepsy (PWE) and its relationship with clinical characteristics. Methods: We retrospectively analyzed data from consecutive PWE from our hospital in northeastern China. Data were collected from the databank of a tertiary epilepsy center. Logistic regression models were employed to investigate the relationships between the individual patient demographic/clinical variables and the occurrence of SC. Results: In total, 606 consecutive PWE were included in the final analysis, and 268 (44.2%) patients experienced at least one seizure cluster. In multivariate logistic regression models, age (OR: 1.014; 95% CI: 1.002-1.027; p = 0.02), seizure frequency (OR: 2.08; 95% CI: 1.555-2.783; p < 0.001), multiple seizure types (OR: 5.111; 95% CI: 1.737-15.043; p = 0.003), number of current anti-seizure medications (ASM) (OR: 1.533; 95% CI: 1.15-2.042; p = 0.004), drug-resistant epilepsy (OR: 1.987; 95% CI: 1.159-3.407; p = 0.013), and a history of status epilepticus (OR: 1.903; 95% CI: 1.24-2.922; p = 0.003) were independent variables associated with a history of SC in PWE. Conclusion: Seizure clusters (SCs) are common occurrences at our study center. The occurrence of SC in individuals with epilepsy, to some extent, is determined by the epilepsy severity.

Tolerance is a known consideration for maintenance use of benzodiazepines and other antiseizure drugs; however, clinical experience suggests that tolerance may not be anticipated with long-term intermittent use of benzodiazepines as rescue therapy. Diazepam nasal spray (Valtoco®) is a proprietary intranasal formulation approved for the acute treatment of intermittent, stereotypic episodes of frequent seizure activity (ie, seizure clusters, acute repetitive seizures) in patients with epilepsy aged ≥6 years. Reported here are exploratory analyses investigating whether there was evidence of development of tolerance in an interim analysis of a long-term, phase 3, open-label safety study of diazepam nasal spray.
Patients and care partners were trained to administer 5, 10, 15, or 20 mg of diazepam nasal spray (age- and weight-based dosing), with a second dose administered 4-12 hours later if needed. A series of analyses were performed to assess evidence of tolerance using 2 equal, adjacent time periods and data for each patient to compare the proportion of events for which second doses of diazepam nasal spray (as a proxy for effectiveness) were administered in period 1 compared with period 2.
A total of 175 patients were enrolled at interim cutoff, and 158 were treated with diazepam nasal spray for 3370 seizure-cluster events. For 73.4% of patients, duration of exposure to diazepam nasal spray was ≥12 months. A total of 191 analyses were conducted; the proportion of analyses in which second doses in period 2 were lower than in period 1 was 72.8%. Only 5 analyses showed nominally statistically significant changes (P < 0.05); this is fewer than expected by chance, and these differences were not directionally consistent. There was no safety signal with continued use.
These analyses found no statistical evidence of tolerance with the use of diazepam nasal spray over time based on use of a second dose in an initial period of the study compared with a subsequent period for each patient. These results are in agreement with prior studies of benzodiazepine rescue therapy.

Intranasal formulations are commonly used for drug delivery, and the literature has shown that seasonal allergies do not affect nasal administration of some agents. Diazepam nasal spray (Valtoco®) is a proprietary intranasal formulation with n-dodecyl-beta-d-maltoside (Intravail® A3) that is indicated for acute treatment of seizure clusters in patients with epilepsy aged 6 years and older. The analysis presented here is from an interim cutoff of a phase 3 open-label study evaluating the safety and tolerability of diazepam nasal spray. This analysis assessed whether seasonal allergies alter control of seizures with an intranasal formulation, using administration of a second dose as a surrogate efficacy endpoint. Of 158 evaluated patients with epilepsy having seizures despite a stable anti-seizure regimen, 62 patients had medical histories that included seasonal allergies or rhinitis. The results of this analysis show that seasonal allergies did not appear to influence use of a second dose; the groups of patients with and without a history of seasonal allergies both presented with low rates of seizure episodes for which a second dose was used, which suggests that there is not a major difference in pattern of use. Diazepam nasal spray demonstrated a similar safety and tolerability profile in patients with and without a history of seasonal allergies.

The purpose of this prospective observational study was to describe the prevalence and adverse outcomes associated with seizure clusters (defined as ≥2 seizures in a 6-hour period) in a large sample of adult patients with a range of epilepsy severities and to identify clinical characteristics predictive of clustering.
Patients maintained a seizure diary and were contacted monthly to verify compliance and data accuracy. Logistic regression models were utilized to test associations between individual patient demographic/clinical characteristics and seizure clustering. Fisher\'s exact test was utilized to test associations between rescue medication use and adverse seizure-related outcomes.
A total of 300 patients were followed prospectively for one year; 247 patients qualified for final analysis. Six-hour seizure clusters occurred in 45.8% of patients with active epilepsy at enrollment, including 62.7% of those with prior day-clusters and 30.0% of those without prior day-clusters. The odds of clustering were markedly greater among patients who reported a higher seizure frequency (>4 seizures per year vs. 1-4 seizures per year) (adjusted odds ratio (OR): 8.9; 95% confidence interval (CI): 3.2-24.6; p < 0.0001) and among patients with prior day-clusters (adjusted OR: 11.0; 95% CI: 1.2-104.2; p = 0.036). Rescue medication use was associated with significantly fewer injuries and emergency department visits, but rescue medication was underutilized.
Seizure clusters are common, occurring in nearly half of adult patients with active epilepsy followed prospectively over one year, and are more frequent in those with higher seizure frequencies and prior day-clusters. Although underutilized, rescue medication was associated with fewer injuries and emergency department visit.

The yield of monitoring patients at an epilepsy monitoring unit (EMU) depends on the recording of paroxysmal events in a timely fashion, however, increasing the risk of safety adverse events (AEs). We aimed to retrospectively study the frequency and risk factors for AE occurrences in all consecutive admissions to an adult EMU in a tertiary medical center. We also compared our findings with published data from other centers. Between January 2011 and June 2014, there were 524 consecutive admissions to the adult EMU at the Tel Aviv Sourasky Medical Center. Adverse events were recorded in 47 (9.0%) admissions. The most common AE was 4-hour seizure cluster (58.7% of AEs) and, in decreasing frequency, AEs related to antiepileptic drugs (AEDs, 11.1%), falls and traumatic injuries (9.5%), intravenous line complications (9.5%), electrode-related (4.8%), status epilepticus (SE, 3.2%), and cardiac (1.6%) and psychiatric (1.6%) complications. There were significantly more AEs among patients with a younger age at disease onset (p=0.005), a history of temporal lobe epilepsy (p=0.046), a history of focal seizures with altered consciousness (p=0.008), a history of SE (p=0.022), use of a vagal nerve stimulator (p=0.039), and intellectual disability (p=0.016) and when the indication for EMU monitoring was noninvasive or invasive presurgical evaluation (p=0.001). Adverse events occurred more frequently when patients had more events in the EMU (p=0.001) and among those administered carbamazepine (p=0.037), levetiracetam (p=0.004), clobazam (p=0.008), and sulthiame (p=0.016). Patients with a history of psychogenic nonepileptic seizures (PNESs) had significantly fewer AEs (p=0.013). Adverse events were not associated with the age, gender, duration of hospitalization or monitoring, AED withdrawal and renewal, seizure frequency by history, presence of major psychiatric comorbidities, abnormal neurological exam, or the presence of a lesion as on brain magnetic resonance imaging. In conclusion, this study reveals that AEs are not unusual in the EMU and that seizure clustering is the most common among them. Adverse events occur more frequently in patients with more severe epilepsy and intellectual disability and in patients undergoing presurgical evaluations and less frequently in patients with PNESs.