Incidence, management and short-term prognosis of status epilepticus in the emergency department: a population survey

Mortality, and life expectancy in Epilepsy and Status epilepticus-current trends and future aspects

Patients with epilepsy carry a risk of premature death which is on average two to three times higher than in the general population. The risk of death is not homogenously distributed over all ages, etiologies, and epilepsy syndromes. People with drug resistant seizures carry the highest risk of death compared to those who are seizure free, whose risk is similar as in the general population. Most of the increased risk is directly related to the cause of epilepsy itself. Sudden unexplained death in epilepsy patients (SUDEP) is the most important cause of epilepsy-related deaths especially in the young and middle-aged groups. Population based studies with long-term follow up demonstrated that the first years after diagnosis carry the highest risk of death, while in the later years the mortality decreases. Improved seizure control and being exposed to a specialized comprehensive care centre may help to reduce the risk of death in patients with epilepsy. The mortality of status epilepticus is substantially increased with case fatality rates between 4.6% and 39%, depending on its cause and duration, and the age of the population studied. The epidemiological data on overall and cause specific mortality as well as their determinants and risk factors are critically reviewed and methodological issues pertinent to the studies on mortality of epilepsy and Status epilepticus are discussed.

Insight into Drug Resistance in Status Epilepticus: Evidence from Animal Models

Status epilepticus (SE), a condition with abnormally prolonged seizures, is a severe type of epilepsy. At present, SE is not well controlled by clinical treatments. Antiepileptic drugs (AEDs) are the main therapeutic approaches, but they are effective for SE only with a narrow intervening window, and they easily induce resistance. Thus, in this review, we provide an updated summary for an insight into drug-resistant SE, hoping to add to the understanding of the mechanism of refractory SE and the development of active compounds. Firstly, we briefly outline the limitations of current drug treatments for SE by summarizing the extensive experimental literature and clinical data through a search of the PubMed database, and then summarize the common animal models of refractory SE with their advantages and disadvantages. Notably, we also briefly review some of the hypotheses about drug resistance in SE that are well accepted in the field, and furthermore, put forward future perspectives for follow-up research on SE.

Why won't it stop? The dynamics of benzodiazepine resistance in status epilepticus

Status epilepticus is a life-threatening neurological emergency that affects both adults and children. Approximately 36% of episodes of status epilepticus do not respond to the current preferred first-line treatment, benzodiazepines. The proportion of episodes that are refractory to benzodiazepines is higher in low-income and middle-income countries (LMICs) than in high-income countries (HICs). Evidence suggests that longer episodes of status epilepticus alter brain physiology, thereby contributing to the emergence of benzodiazepine resistance. Such changes include alterations in GABA_A receptor function and in the transmembrane gradient for chloride, both of which erode the ability of benzodiazepines to enhance inhibitory synaptic signalling. Often, current management guidelines for status epilepticus do not account for these duration-related changes in pathophysiology, which might differentially impact individuals in LMICs, where the average time taken to reach medical attention is longer than in HICs. In this Perspective article, we aim to combine clinical insights and the latest evidence from basic science to inspire a new, context-specific approach to efficiently managing status epilepticus.

Management of Status Epilepticus, Refractory Status Epilepticus, and Super-refractory Status Epilepticus

PURPOSE OF REVIEW

Status epilepticus is a serious condition caused by disorders and diseases that affect the central nervous system. In status epilepticus, hypersynchronous epileptic activity lasts longer than the usual duration of isolated self-limited seizures (time t1), which causes neuronal damage or alteration of neuronal networks at a certain time point (time t2), depending on the type of and duration of status epilepticus. The successful management of status epilepticus includes both the early termination of seizure activity and the earliest possible identification of a causative etiology, which may require independent acute treatment. In nonconvulsive status epilepticus, patients present only with subtle clinical signs or even without any visible clinical manifestations. In these cases, EEG allows for the assessment of cerebral function and identification of patterns in need of urgent treatment.

RECENT FINDINGS

In 2015, the International League Against Epilepsy proposed a new definition and classification of status epilepticus, encompassing four axes: symptomatology, etiology, EEG, and age. Various validation studies determined the practical usefulness of EEG criteria to identify nonconvulsive status epilepticus. The American Clinical Neurophysiology Society has incorporated these criteria into their most recent critical care EEG terminology in 2021. Etiology, age, symptomatology, and the metabolic demand associated with an increasing duration of status epilepticus are the most important determinants of prognosis. The consequences of status epilepticus can be visualized in vivo by MRI studies.

SUMMARY

The current knowledge about status epilepticus allows for a more reliable diagnosis, earlier treatment, and improved cerebral imaging of its consequences. Outcome prediction is a soft tool for estimating the need for intensive care resources.

Misdiagnosis of prolonged psychogenic non-epileptic seizures as status epilepticus: epidemiology and associated risks

OBJECTIVE

To determine the epidemiology of prolonged psychogenic non-epileptic seizures (pPNES) misdiagnosed as status epilepticus, as well as the risks associated with non-indicated treatment.

METHODS

We performed an individual patient data analysis from the Rapid Anticonvulsant Medication Prior to Arrival Trial (RAMPART) and the Established Status Epilepticus Treatment Trial (ESETT) to assess incidence, patient characteristics and clinical course of misdiagnosed pPNES.

RESULTS

Among 980 patients aged 8 years or older diagnosed and treated for status epilepticus in RAMPART and ESETT, 79 (8.1%) were discharged with a final diagnosis of pPNES. The relative incidence was highest in adolescents and young adults (20.1%). The typical female preponderance seen in that age bracket was not evident in children and older adults. Adverse effects, including respiratory depression and intubation, were documented in 26% of patients with pPNES receiving benzodiazepines in RAMPART and 33% of patients receiving additional second-line medication in ESETT. In ESETT, patients who were treated with benzodiazepines before hospital admission had higher rates of unresponsiveness and severe adverse effects than those treated after admission, suggesting cumulative effects of accelerated treatment momentum. Across trials, one in five patients with pPNES were admitted to an intensive care unit.

CONCLUSIONS

Misdiagnosis and treatment of pPNES as status epilepticus are a common and widespread problem with deleterious consequences. Mitigating it will require training of emergency staff in semiological diagnosis. Status epilepticus response protocols should incorporate appropriate diagnostic re-evaluations at each step of treatment escalation, especially in clinical trials.

Status epilepticus in the Canadian Arctic: A public health imperative hidden in plain sight

Objective

The World Health Organization, International League Against Epilepsy (ILAE), and International Bureau for Epilepsy have called epilepsy a public health imperative, with appropriate emphasis on low‐to‐middle‐income countries (LMIC). Although Canada is a high‐income country (HIC), income is not distributed uniformly. Furthermore, epilepsy data from the national statistical agency explicitly overlook the Arctic by excluding these territories. A common neurologic emergency, status epilepticus (SE) is a life‐threatening manifestation of epilepsy that demands prompt treatment to avoid death and long‐term sequelae. Therefore, we examined the rate of SE in a well‐defined Canadian Arctic region.

Methods

This study takes epidemiologic advantage of the Kivalliq Region's geographical isolation, which is accessible only by air. All SE patients requiring emergency care are consistently flown 1200‐1900 kilometers to a single designated hospital in a distinct southern part of Canada for further management and electroencephalography (EEG). We conducted a retrospective database and chart review at this “bottleneck” hospital to identify patients with seizure(s) severe enough to justify emergency airborne medical evacuation over a 11.25‐year period from 2009 to 2020.

Results

We screened 40 392 EEGs to yield 117 distinct medical evacuations for “operational SE” from 99 patients to derive estimated SE incidences of 99.9 evacuations per 100 000/year and 84.5 patients per 100 000/year. The average time from seizure onset to EEG was 3.2 days. Only 16.2% of SE patients had known epilepsy. For “confirmed SE” cases meeting ILAE criteria, or cases with persistently epileptiform EEG despite days of empiric treatment, estimated incidence was 77.7 evacuations per 100 000/year and 64.9 patients per 100 000/year.

Significance

High SE and epilepsy rates in the Canadian Arctic are consistent with LMIC rather than HIC. Our findings demonstrate the paradox of LMIC‐equivalent epilepsy populations camouflaged within HIC. Our findings also highlight the long‐standing plight of these under‐served and overlooked populations hidden in plain sight.

Epidemiology of status epilepticus in adults: Apples, pears, and oranges - A critical review

OBJECTIVE

Status epilepticus (SE) is a severe neurologic condition associated with high morbidity and mortality. Population-based studies in adults have found a wide range of incidences in various regions in the world. Although the incidence of SE increases almost exponentially in the elderly, data on census-based population statistics in these studies are scarce. This study provides a critical review with an emphasis on census-based population statistics and study characteristics in adults.

METHODS

We performed a systematic search of population-based studies on SE in adults in PubMed using "status epilepticus" in combination with "epidemiology", "population", and "incidence" as search terms, and also screened references. For each identified study, we assessed and extracted the respective population pyramids of study and reference population, and study characteristics.

RESULTS

We identified 22 population-based studies (eleven from Europe, six from North America, three from Asia, one from Africa, and one from Australasia). Incidence rates of patients with SE ranged from 1.29 to 73.7/100,000 adults (95% confidence interval (CI): 76.6-80.3) and of SE episodes up to 81.1/100,000 adults (95% CI: 75.8-87.0). The proportions of elderly and very old patients varied by a factor of 2.6 and 8.5, respectively, depending on study period and place. Further major reasons for heterogeneity were retrospective or prospective study design, definition of time to diagnose SE, variable detection of nonconvulsive SE (NCSE), different etiologies, inclusion of children, recurrent episodes, postanoxic patients, exclusion of patients with preexisting epilepsy or patients identified outside the emergency department, and choice of reference population for age- and gender adjustment. The most recent definition and classification of SE by the International League Against Epilepsy (ILAE) 2015 was used in two studies. Four studies (18.2%) reported incidences per ten-year age strata necessary for age adjustment to various reference populations.

CONCLUSIONS

This critical review reveals a marked heterogeneity among population-based studies on SE in adults. It provides comprehensive details on census-based population statistics in study and reference populations and various study designs and characteristics essential for direct comparisons between studies. Reporting on these essential key features should be improved in population-based studies on SE.

Incidence of the different stages of status epilepticus in Eastern Finland: A population-based study

OBJECTIVE

The objective of this study was to determine the incidence in Eastern Finland of the different stages of status epilepticus (SE): 1) at the early stage of SE (a prolonged seizure lasting over 5 min);, 2) refractory SE (RSE), and 3) super-refractory SE (SRSE).

METHODS

Firstly, we conducted a retrospective study on the incidence and outcome of intensive care unit (ICU)-treated RSE and SRSE in the adult population (≥16 years) in Kuopio University Hospital (KUH)'s special care responsibility area (840,000 inhabitants). Secondly, we conducted a prospective study using the International League Against Epilepsy (ILAE)'s new definition for SE (prolonged seizures lasting over 5 min), in adult (≥16 years) patients in the KUH municipality district (North Savo, 248,000 inhabitants).

RESULTS

The retrospective study on ICU-treated RSE and SRSE from 2010 to 2012 identified 75 patients with RSE, of whom 21% were treated as SRSE, resulting in an annual age-adjusted incidence of ICU-treated RSE of 3.0/100,000 (95% confidence interval [CI]: 2.4-3.8) and 0.6/100,000 (95% CI: 0.4-1.0) for SRSE. In the prospective study of early stage SE (seizures lasting over 5 min), we identified 151 consecutive episodes during the 9-month study period in 2015, corresponding to an annual age-adjusted incidence of 81.1/100,000 (95% CI: 75.8-87.0). In this study, 11 seizure episodes became refractory, resulting in an age-adjusted incidence of RSE of 6.0/100,000 (95% CI: 3.4-10.4), of which seven were treated in the ICU [3.8/100,000 (95% CI: 1.8-7.8)], four were treated palliatively [2.2/100,000 (95% CI: 0.82-5.7)], and two evolved to SRSE [1.1/100,000 (95% CI: 0.3-4.3)].

CONCLUSIONS

The new ILAE 2015 definition of SE resulted in a four-fold increase in incidence of SE compared to the earlier 30-min definition reported earlier in Europe. In the epidemiology of RSE, the incidence of ICU-treated RSE, palliatively treated RSE, and SRSE needs to be separated. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures.