Treatment of Status Epilepticus

Indications for the use of intravenous second-line antiseizure medications in an emergency room setting

BACKGROUND

Second-line iv antiseizure medications (ASMs) are used to treat status epilepticus (SE), but in the emergency room setting, there might be other intended and unintended indications for administration. We wanted to explore these different indications and assess the actual usage of first- and second-line ASMs for SE with reference to other uses, such as for SE mimics.

METHODS

In this retrospective study, we searched the electronic patient registry with the following terms: "epilepsy", "SE", and "seizure", during 2015. Patients at least 16 years old and treated with iv second-line ASMs were further analysed. We reassessed the indications for the use of iv ASMs based on clinical features and examinations performed.

RESULTS

A total of 166 episodes from 136 patients with a median age of 66 years were evaluated, constituting the following indication categories: ongoing SE (48.2%), recurrent seizures (19.3%), postictal (12.1%), seizure mimics (10.2%) and prophylactic use of ASMs (10.2%). Ongoing SE included the following subgroups: convulsive SE, focal aware SE, nonconvulsive SE (NCSE) and NCSE with coma. The seizure mimics group had a preexisting epilepsy diagnosis more often than the ongoing SE group (73% vs. 44%, p = 0.039). Ischaemic stroke was the most frequent seizure mimic. EEG was performed during hospital admission in 78% of patients with ongoing SE, 50% of patients with recurrent seizures, 75% of patients with postictal state, 53% of seizure mimic episodes and 12% of the prophylactic group. In NCSE and comatose NCSE, the diagnosis was made, and treatment was initiated only after an EEG in 52% and 30% of cases, respectively. The use of newer second-line ASMs (levetiracetam and lacosamide) was frequent in our study population. Immediate side effects of ASMs were infrequent.

CONCLUSIONS

Even though most of the use of ASMs was justified and administered for SE, it is a diagnostic challenge where a prior diagnosis of epilepsy can be a misleading factor, and EEG is an essential tool when clinical features are often overlapping with other acute seizure disorders. Side effects of the newer second-line ASMs after a single dose are infrequent.

Pre-hospital and emergency department treatment of convulsive status epilepticus in adults: an evidence synthesis

BACKGROUND

Convulsive status epilepticus is defined as ≥ 5 minutes of either continuous seizure activity or repetitive seizures without regaining consciousness. It is regarded as an emergency condition that requires prompt treatment to avoid hospitalisation and to reduce morbidity and mortality. Rapid pre-hospital first-line treatment of convulsive status epilepticus is currently benzodiazepines, administered either by trained caregivers in the community (e.g. buccal midazolam, rectal diazepam) or by trained health professionals via intramuscular or intravenous routes (e.g. midazolam, lorazepam). There is a lack of clarity about the optimal treatment for convulsive status epilepticus in the pre-hospital setting.

OBJECTIVES

To assess the current evidence on the clinical effectiveness and cost-effectiveness of treatments for adults with convulsive status epilepticus in the pre-hospital setting.

DATA SOURCES

We searched major electronic databases, including MEDLINE, EMBASE, PsycInfo®, CINAHL, CENTRAL, NHS Economic Evaluation Database, Health Technology Assessment Database, Research Papers in Economics, and the ISPOR Scientific Presentations Database, with no restrictions on publication date or language of publication. Final searches were carried out on 21 July 2020.

REVIEW METHODS

Systematic review of randomised controlled trials assessing adults with convulsive status epilepticus who received treatment before or on arrival at the emergency department. Eligible treatments were any antiepileptic drugs offered as first-line treatments, regardless of their route of administration. Primary outcomes were seizure cessation, seizure recurrence and adverse events. Two reviewers independently screened all citations identified by the search strategy, retrieved full-text articles, extracted data and assessed the risk of bias of the included trials. Results were described narratively.

RESULTS

Four trials (1345 randomised participants, of whom 1234 were adults) assessed the intravenous or intramuscular use of benzodiazepines or other antiepileptic drugs for the pre-hospital treatment of convulsive status epilepticus in adults. Three trials at a low risk of bias showed that benzodiazepines were effective in stopping seizures. In particular, intramuscular midazolam was non-inferior to intravenous lorazepam. The addition of levetiracetam to clonazepam did not show clear advantages over clonazepam alone. One trial at a high risk of bias showed that phenobarbital plus optional phenytoin was more effective in terminating seizures than diazepam plus phenytoin. The median time to seizure cessation from drug administration varied from 1.6 minutes to 15 minutes. The proportion of people with recurrence of seizures ranged from 10.4% to 19.1% in two trials reporting this outcome. Across trials, the rates of respiratory depression among participants receiving active treatments were generally low (from 6.4% to 10.6%). The mortality rate ranged from 2% to 7.6% in active treatment groups and from 6.2% to 15.5% in control groups. Only one study based on retrospective observational data met the criteria for economic evaluation; therefore, it was not possible to draw any robust conclusions on cost-effectiveness.

LIMITATIONS

The limited number of identified trials and their differences in terms of treatment comparisons and outcomes hindered any meaningful pooling of data. None of the included trials was conducted in the UK and none assessed the use of buccal midazolam or rectal diazepam. The review of economic evaluations was hampered by lack of suitable data.

CONCLUSIONS

Both intravenous lorazepam and intravenous diazepam administered by paramedics are more effective than a placebo in the treatments of adults with convulsive status epilepticus, and intramuscular midazolam is non-inferior to intravenous lorazepam. Large well-designed clinical trials are needed to establish which benzodiazepines are more effective and preferable in the pre-hospital setting.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42020201953.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 26, No. 20. See the NIHR Journals Library website for further project information.