Status Epilepticus in EMS

In 2012, the Neurocritical Care Society updated the diagnostic guidelines for status epilepticus (SE). The diagnosis for status epilepticus are only two simple diagnostic criteria:

1. Five or more minutes of continuous clinical and/or electrical seizure activity.¹
2. Recurrent seizure activity without recovering between seizures.¹

Status epilepticus is a substantial contributor to worldwide neurological morbidity and mortality. Between 50,000 and 150,000 Americans each year have status epilepticus, with mortality estimated at less than 3% in children but up to 30% in adults.²

Previously, clinical criteria required a seizure to last longer than 30 minutes to meet the diagnostic criteria for status epilepticus. However, the literature shows seizures that last less than five minutes usually subside without intervention. Seizures lasting longer than five minutes do not spontaneously stop and do not react to anticonvulsive medications well.¹

There is also permanent neurological damage that can occur before the traditional definition of 30 minutes or more of seizure activity. Due to this the guidelines have been shifted to stop the seizure before the 30 minutes of seizure activity to avoid permanent neurological damage and to have the anticonvulsant medications efficacy intact.

Treatment of Status Epilepticus

Once SE is properly recognized clinically by EMS professionals, the goal of treatment is to stop the seizure activity. As usual the priority is to simultaneously secure airway, breathing, circulation and treat as soon as possible the etiology of the seizures such as hypoglycemia or hypoxia or poisoning.

As EMS professionals, after the ABC’s have been secured, treatment is a short acting benzodiazepine which is been recommended by the American Epilepsy Society. They recommend using midazolam 10 milligrams IM, lorazepam 4 milligrams IV, or diazepam 6 to 10 milligrams IV as first line treatment for status epilepticus.³

In children less than 40kg, these medication needs to be dosed per weight. For the prehospital settings or where the three first-line benzodiazepine options are not available, rectal diazepam, intranasal midazolam and buccal midazolam are reasonable initial therapy alternatives. 

Even though these guidelines have been readily available and are widely known, prehospital SE treatment is rarely consistent with the application of these guidelines. Most patients treated for SE received benzodiazepines at a lower dose or other than the recommended route via these recommendations.⁴

In a study by Guterman et al., the midazolam mean dose was 4 milligrams across all agencies which is underdosed by more than half according to the American Epilepsy guidelines.⁴

Also, the recommended route of administration for midazolam shows it was only given at 34.5% of the time resulting in treatment delays and ineffective seizure cessation. Evidence from single-EMS-agency cohort studies has suggested that both lower midazolam dosing and intranasal administration lead to less effective seizure termination.⁵

Many EMS and ER healthcare providers are weary of the respiratory and cardiac adverse events with the benzodiazepine. However, the rate of respiratory depression in patients with status epilepticus treated with benzodiazepines is lower than in patients with status epilepticus treated with placebo indicating that respiratory problems are an important consequence of untreated status epilepticus.⁵

Be prepared to help ventilate and oxygenate the patient after giving the rescue treatment of a benzodiazepine during status epilepticus. By not treating the seizure, patients have a high risk of long-term adverse effects.

Conclusion and Application to Patient Care

When assessing a seizing patients ask bystanders or caregivers how long the seizure had been occurring, events preceding, if the patient has a diagnosed seizure disorder, what medications they take, are they taking the medications, if they see a neurologist and if they have treatment plan they are supposed to follow.

Document all these findings. EMS professionals must apply the 5-minute criteria of status epilepticus to seizing patients. While continuing to maintain the ABC’s, EMS must administer a first-line anti-epileptic medication as quickly as possible, preferably those mentioned in Figure 1.1. This is of particular concern, as most EMS agencies are currently underdosing midazolam for status epilepticus, which should be no less than 10mg IM for adult patients.

Patients must continue to be monitored for possible ventilatory support and may require further drug administration if the seizure activity does not stop. Second-line treatments are out of the scope of this article but should align with current guidelines from the American Epileptic Society and the Neurocritical Care Society.

References

1. Brophy GM, Bell R, Claassen J, Alldredge B, Bleck TP, Glauser T, Laroche SM, Riviello JJ Jr, Shutter L, Sperling MR, Treiman DM, Vespa PM; Neurocritical Care Society Status Epilepticus Guideline Writing Committee. Guidelines for the evaluation and management of status epilepticus. Neurocrit Care. 2012 Aug;17(1):3-23. doi: 10.1007/s12028-012-9695-z. PMID: 22528274.
2. Neligan A, Noyce AJ, Gosavi TD, Shorvon SD, Köhler S, Walker MC. Change in Mortality of Generalized Convulsive Status Epilepticus in High-Income Countries Over Time: A Systematic Review and Meta-analysis. JAMA Neurol. 2019 Aug 1;76(8):897-905. doi: 10.1001/jamaneurol.2019.1268. PMID: 31135807; PMCID: PMC6547079.
3. Glauser T, Shinnar S, Gloss D, Alldredge B, Arya R, Bainbridge J, Bare M, Bleck T, Dodson WE, Garrity L, Jagoda A, Lowenstein D, Pellock J, Riviello J, Sloan E, Treiman DM. Evidence-Based Guideline: Treatment of Convulsive Status Epilepticus in Children and Adults: Report of the Guideline Committee of the American Epilepsy Society. Epilepsy Curr. 2016 Jan-Feb;16(1):48-61. doi: 10.5698/1535-7597-16.1.48. PMID: 26900382; PMCID: PMC4749120.
4. Guterman EL, Burke JF, Sporer KA. Prehospital Treatment of Status Epilepticus in the United States. JAMA. 2021 Nov 16;326(19):1970-1971. doi: 10.1001/jama.2021.15964. PMID: 34783848; PMCID: PMC8596193.
5. Guterman E.L.Sanford J.K.,Betjemann J.P.et al. Prehospital midazolam use and outcomes among patients with out-of-hospital status epilepticus. Neurology. 2020; 95: e3203-e3212