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.
Keywords: ANTIEPILEPTIC DRUGS; BENZODIAZEPINES; ECONOMIC EVALUATION; PRE HOSPITAL; REVIEW; STATUS EPILEPTICUS.
Epilepsy is a common condition that results from abnormal electrical activity in the brain and causes seizures (stiffening and uncontrolled jerking – known as a ‘fit’). The most severe form of epilepsy is called ‘convulsive status epilepticus’, which involves continuous seizure activity for 5 minutes or more, or repetitive seizures without recovery of consciousness. Convulsive status epilepticus can be very dangerous and requires prompt treatment to avoid hospitalisation and prevent complications. Although several drugs are available for the treatment of convulsive status epilepticus in the community or in the emergency department, it is unclear which one is most effective in stopping seizures. We brought together results from all available clinical studies that looked at the use of drugs to treat adults with convulsive status epilepticus either before arriving at hospital or on arrival at the emergency department. In the literature, we found four studies (1234 adults) assessing drugs delivered by paramedics through an injection into a vein or into muscle. In general, the drugs used by paramedics (benzodiazepines) were effective in stopping seizures, but we were unable to identify any particular drug or way of administering it as being more successful than others. Future research is needed to establish which drugs are most effective and preferable. It is also important to improve adherence to clinical guidelines with regard to the use of these drugs. For the pre-hospital treatment of convulsive status epilepticus, little evidence was available to decide which drug treatment is the best in terms of value for money. Future studies could assess the (1) impact of treatments on costs and outcomes over the whole course of a seizure episode (2) long-term impact of different treatments on patients’ quality of life and (3) health and social care needs.