LOS ANGELES — The definition of seizure clusters varies significantly across epilepsy monitoring units (EMUs), according to a new survey of expert opinion. The findings should prompt the development of a standard definition as well as guidelines, according to the study authors.
Seizure clusters are often defined as two or more seizures occurring within close proximity; a survey published in 2017 defined it as two seizures in 24 hours that occurred outside the patient’s typical seizure pattern and found that it had a moderate to major impact on patient and caregiver quality of life.
“We wanted to look at what happens before, during, and following the EMU use of acute, repetitive seizure rescue medication. We found that there's a high degree of injury from acute repetitive seizures, [and] there's a very high incidence of people that require transfer with acute repetitive seizures to a higher level of care, such as the intensive care system. Fractures were seen. Aspiration pneumonia was seen in more than half of people at some point in time during their careers," said William Tatum, DO, professor of neurology at Mayo Clinic, Jacksonville, Florida, in an interview.
Tatum presented the findings on December 8 during a poster session at the American Epilepsy Society (AES) 78th Annual Meeting.
Little Consensus
The researchers also sought to identify a general definition of seizure clusters, which has no standardized definition. “It's important in that they have it outside of the hospital, but you see it with an increased incidence when they come into the hospital. Maybe 20% of people have been described to have acute, repetitive seizures when they come to the hospital. The reason is because we take them off their medication,” said Tatum.
It was surprisingly difficult to find consensus, he said. “It was very disparate. There was very limited agreement on what people referred to as acute repetitive seizures. The call [to action is that] there's more education needed so that people are aware of acute seizure urgencies with repetitive seizures and also a standardization of what we refer to when we talk about seizure clusters. Both diagnosis and treatment and management issues come into play,” said Tatum.
“These are all well-known people in the field, and the fact that they can't decide [on a definition of seizure clusters] really behooves us all to step back and think about how we manage these patients, both in the unit as well as when they go home,” said Alison Pack, MD, who was asked to comment on the study.
She added that the variable definitions of seizure cluster are important. “You want to be proactive and not reactive. There are a couple of factors that you need to think about. One, how do you define it? When are you going to intervene, and what agent are you going to use?” said Pack, who is a professor of neurology at Columbia University in New York City.
EMU healthcare providers must walk a fine line between recording seizures and ensuring patient safety. “You've taken an epileptogenic brain, and you're tinkering with it; you're withdrawing meds, so you have to anticipate that, even if they've not [had seizure clusters] before. So proactively defining what you mean by a cluster and how you're going to manage that is really important,” said Pack.
Even Experts Disagree on Definition
The authors sent a 55-question survey to 24 experts who attend within an EMU and received 15 responses. The questions asked them to characterize seizure clusters and rescue medication treatment practices before, during, and after long-term video electroencephalogram monitoring. The respondents were between 43 and 77 years old, and nearly all were physicians (93.3%) and worked at level 4 epilepsy centers (93.3%), while 66.7% worked primarily with adult patients.
The 15 experts produced eight different definitions of seizure cluster, ranging from two to three seizures in 1 hour to three seizures in 24 hours. The five respondents that primarily treat pediatric patients defined seizure clusters as three seizures during a 1-hour period. Overall, respondents reported seizure cluster frequencies among EMU patients as 5%-8% (6.7% of respondents), 10% (33.3% of respondents), 20% (33.3% of respondents), or 25% (26.7% of respondents). They also frequently reported that seizure clusters led to emergencies, including compromised presurgical evaluation (60% of respondents), requirement for higher level of care (80% of respondents), and serious injury (46.7% of respondents).
Treatment
Most respondents (80.0%) said that they prescribe immediate-use rescue medications (RMs) during EMU stay, and 66.7% said they believed that cluster seizures are likely related to the rapidity of antiseizure medication tapering.
Nearly all the experts (93.3%) reported that they use a benzodiazepine to treat seizure clusters in the EMU, and the same proportion said they would newly prescribe immediate-use RMs on discharge, even if they were not the primary care physician. About half (53.3%) prioritized the half-life of RM over the specific medication, and most (86.7%) said that they would follow recommendations for immediate-use RMs if they were created.
Tatum has financial relationships with Synergy Medical Solutions, BioSerenity/DigiTrace Care Services, Neurelis, and Zimmer Biomet, Eisai, LivaNova, Xenon, and Cerevel. Pack had no relevant financial disclosures.