Persistent nonconvulsive status epilepticus after the control of convulsive status epilepticus

Safety and efficacy of lacosamide in the intensive care unit

BACKGROUND

Seizures are common in critically ill patients and can impact morbidity and mortality. Traditional anti-epileptic drugs (AEDs) in this setting are not always effective and are associated with adverse events and drug interactions. Lacosamide (LCM) is a new AED which is available in parental form although few studies have evaluated the safety and efficacy of LCM in critically ill patients.

METHODS

Critically ill patients at Emory University Hospital who received LCM from April 1, 2009 to February 1, 2010 were retrospectively reviewed. Primary outcome measure was incidence and time to seizure cessation. Adverse effects were also recorded.

RESULTS

LCM was administered in 24 patients including 13 episodes of refractory status epilepticus (RSE) occurring in 10 patients and for treatment of isolated seizures or following resolution of RSE in an additional 14 patients. Seizure cessation was achieved in 5/13 (38%) episodes of RSE (mean 11.2 h) while there was at least a 50% decrease in seizure frequency in 7/13 (54%). 11/14 patients (76%) who received LCM for treatment of isolated seizures or prevention of seizure recurrence remained seizure free. Three patients experienced a decline in systolic blood pressure (> 20 mmHg) while one patient experienced unexplained fever and one patient had elevation of liver function tests.

CONCLUSIONS

This preliminary data suggests that LCM may be a safe and effective alternative for treatment of seizures in critically ill patients. Further prospective, randomized controlled trials are needed to confirm these findings and further explore the incidence of adverse effects.

[Status epilepticus]

Status epilepticus (SE) is a medical emergency. For diagnostic purposes EEG is mandatory when motor phenomena are absent or when a single seizure evolves into SE with impaired consciousness. The EEG may show focal or generalized status patterns, which must be distinguished from encephalopathies. Initially benzodiazepines are recommended; lorazepam is the drug of choice. When the SE persists, phenytoin, valproate, levetiracetam, lacosamide, and phenobarbital are administered. The choice depends on the underlying comorbidities. In this phase, only phenytoin is licensed. A generalized tonic-clonic status which is refractory is then treated with anesthetics including midazolam, disoprivan, or thiopental. The goal is to achieve burst suppression in the EEG and coadministration of antiepileptic drugs.

Refractory status epilepticus

PURPOSE OF REVIEW

Refractory status epilepticus (RSE) has a high morbidity and mortality. There are currently no definitive data to guide both the optimal choice of therapy and treatment goals. This review focuses on RSE diagnosis and outcome and discusses both commonly used and anecdotal therapies for RSE.

RECENT FINDINGS

The challenges in performing randomized controlled trials (RCTs) in neurocritical care and more specifically for the treatment of RSE are illustrated by the early termination of the first RCT of RSE due to low recruitment that compared propofol to barbiturates. Recent case series include the successful treatment of recurrent RSE with ketamine, intravenous lacosamide as an add-on treatment, the use of combination antiepileptics (phenytoin, levetiracetam, and pregabalin), and surgical treatments (vagal nerve and deep brain stimulation) for the control of RSE.

SUMMARY

A number of different therapeutic options are available for the treatment of RSE but none have been shown to be superior to others at this point.

[EEG in intensive care unit: which indications, which material?]

There is a growing development of continuous EEG monitoring (cEEG) in the intensive care unit (ICU) management of neurological patients. Its main objective is the detection of epileptic seizures or status epilepticus because the sensitivity of standard short-duration EEG recording in the ICU is poor. The aim of monitoring is to allow rapid recognition and treatment of epileptic complications in order to decrease secondary insults to the brain and improve outcome. Several studies have demonstrated that a large proportion of patients has epileptic crisis after subarachnoid haemorrhage, stroke or brain trauma, without any clinical manifestation. The EEG feature has also demonstrated a prognosis value but its value for clinical management needs further studies. Another application of EEG in the ICU is monitoring depth of anaesthesia or barbiturate treatment. Due to artifacts contamination, this is possible only in deeply sedated of paralyzed patients. The impact or cEEG monitoring on clinical management and its indications have to be further defined.

The Value of Clinical Needs Assessments for Point-of-Care Diagnostics

Most entrepreneurial ventures fail long before the core technology can be brought to the marketplace because of disconnects in performance and usability measures such as accuracy, cost, complexity, assay stability, and time requirements between technology developers' specifications and needs of the end-users. By going through a clinical needs assessment (CNA) process, developers will gain vital information and a clear focus that will help minimize the risks associated with the development of new technologies available for use within the health care system. This article summarizes best practices of the principal investigators of the National Institute of Biomedical Imaging and Bioengineering point-of-care (POC) centers within the National Institute of Biomedical Imaging and Bioengineering POC Technologies Research Network. Clinical needs assessments are particularly important for product development areas that do not sufficiently benefit from traditional market research, such as grant-funded research and development, new product lines using cutting-edge technologies developed in start-up companies, and products developed through product development partnerships for low-resource settings. The objectives of this article were to (1) highlight the importance of CNAs for development of POC devices, (2) discuss methods applied by POC Technologies Research Network for assessing clinical needs, and (3) provide a road map for future CNAs.

Quality assessment of electroencephalography obtained from a "dry electrode" system

This study examines the difference in application times for routine electroencephalography (EEG) utilizing traditional electrodes and a "dry electrode" headset. The primary outcome measure was the time to interpretable EEG (TIE). A secondary outcome measure of recording quality and interpretability was obtained from EEG sample review by two blinded clinical neurophysiologists. With EEG samples obtained from 10 subjects, the average TIE for the "dry electrode" system was 139s, and for the conventional recording 873s (p<0.001). The results support the hypothesis that such a "dry electrode" system can be applied with more than an 80% reduction in the TIE while still obtaining interpretable EEG.

Initial EEG predicts outcomes in a trial of levetiracetam vs. fosphenytoin for seizure prevention

Continuous electroencephalography (cEEG) is increasingly used to detect both clinical and subclinical seizures in patients with traumatic brain injury (TBI) or subarachnoid hemorrhage (SAH). We assess whether EEG findings predict outcomes in TBI/SAH patients enrolled in a levetiracetam (LEV) vs. fosphenytoin (fos-PHT) seizure prevention trial (NCT00618436). This prospective, single-blinded, comparative trial randomized 52 patients with TBI or SAH to receive prophylactic LEV or fos-PHT. Continuous video EEG monitoring was conducted for the initial 72 h of medication administration. The association between EEG findings (degree of generalized and focal slowing, presence and frequency of epileptiform discharges and seizures) and outcomes (Glasgow Outcomes Scale-Extended (GOS-E) and Disability Rating Scale (DRS)) at discharge, 3 and 6 months was assessed using a generalized linear model. Severity of generalized slowing tended to be associated with outcomes in both treatment groups (discharge DRS, p=0.042; discharge GOS-E, p=0.026; 3 month DRS, p=0.051). The presence of focal slowing, the presence and frequency of epileptiform discharges and the presence of seizures were not predictive of outcome in either treatment group (all p>0.15). While it has been shown that LEV is associated with better outcome than fos-PHT when used as seizure prophylaxis in brain injury, aside from severity of generalized slowing, electrographic findings of focal slowing, epileptiform discharges, and seizures were not themselves associated with outcomes in patients with TBI or SAH enrolled in a randomized clinical trial.

Nonconvulsive status epilepticus: the encephalopathic pediatric patient

OBJECTIVE

A high prevalence of nonconvulsive status epilepticus (NCSE) has been reported in critically ill adults and neonates. Recent prospective pediatric studies focus on critically ill children and show wide variability in the frequency of NCSE. This study examines prevalence of pediatric NCSE regardless of inpatient setting and retrospectively identifies risk factors indicating a need for urgent continuous EEG.

METHODS

Medical records from patients aged 3 months to 21 years were identified either by (1) searching a clinical EEG database (n = 18) or (2) consecutive inpatient EEG referrals for NCSE over an 8-month period (n = 57).

RESULTS

Seventy-five children, mean age of 7.8 years, were studied. NCSE was identified in 26 patients (35%) and in 8 of 57 (14%) patients referred for possible NCSE. More than half of the patients referred were outside of the ICU. A witnessed clinical seizure was observed in 24 of 26 (92%) patients with NCSE. Acute cortical neuroimaging abnormalities were significantly more frequent in patients with NCSE. The presence of clinical seizures and acute neuroimaging abnormality was associated with an 82% probability of NCSE. All but 1 patient with NCSE had electrographic or electroclinical seizures within the first hour of monitoring.

CONCLUSIONS

A high prevalence of NCSE was observed, comparable to adult studies, but within a wider range of inpatient settings. Children with acute encephalopathy should undergo continuous EEG. This evaluation is more urgent if certain clinical risk factors are present. Optimal duration of monitoring and the effect of NCSE on prognosis should be studied.

Treatment of status epilepticus in a large community hospital

BACKGROUND

Status epilepticus (SE) is a neurological emergency usually requiring immediate medical treatment. Due to the lack of adequate studies, treatment guidelines and their application vary between countries and institutions. We intended to analyze current treatment of SE in a German community hospital.

METHODS

We retrospectively identified patients from a large community hospital in northern Germany who had been diagnosed with SE between August 2008 and December 2010. Their charts were reviewed regarding sociodemographic variables, treatment and outcome.

RESULTS

We studied the first SE episode in 172 patients with a median age of 69 years (range 18-90 years). The etiology was acute symptomatic in 30 patients, progressive symptomatic in 22 patients and remote symptomatic in 120 patients. Presentation was generalized convulsive in 60 patients, non-convulsive in 72 patients and simple motor/aura in 40 patients. Median latency from onset to treatment start was 0.75 h (range 0.2-336 h). Initial treatment had a success rate (SR) of 40%. Second line treatment had a success rate of 54%. In patients whose seizures were refractory to the first two drugs, success rates were between 31% and 55%, with only a minority of the patients receiving established drugs such as phenytoin or barbiturates. Multivariate analysis revealed non-convulsive semiology as the only factor significantly associated with refractoriness. SE could be terminated in 95% of the patients and in-hospital mortality was 10%. Benzodiazepines and phenytoin had the most severe side effects.

CONCLUSIONS

Status epilepticus can be terminated successfully and with low in-hospital mortality in the vast majority of the patients treated in a large community hospital. The success rate of each treatment step is between 30% and 55% regardless of the substances used.

The utility of EEG, SSEP, and other neurophysiologic tools to guide neurocritical care

Neuromonitoring is an emerging field that aims to characterize real-time neurophysiology to tailor therapy for acute injuries of the central nervous system. While cardiac telemetry has been used for decades among patients requiring critical care of all kinds, neurophysiology and neurotelemetry has only recently emerged as a routine screening tool in comatose patients. The increasing utilization of electroencephalography in comatose patients is primarily due to the recognition of the common occurrence of nonconvulsive seizures among comatose patients, the development of quantitative measures to detect regional ischemia, and the appreciation of electroencephalography phenotypes that indicate prognosis after cardiac arrest. Other neuromonitoring tools, such as somatosensory evoked potentials have a complementary role, surveying the integrity of the neuroaxis as an indicator of prognosis or illness progression in both acute brain and spinal injuries.

Quantitative EEG analysis for automated detection of nonconvulsive seizures in intensive care units

Because of increased awareness of the high prevalence of nonconvulsive seizures in critically ill patients, use of continuous EEG (cEEG) monitoring is rapidly increasing in ICUs. However, cEEG monitoring is labor intensive, and manual review and interpretation of the EEG are impractical in most ICUs. Effective methods to assist in rapid and accurate detection of nonconvulsive seizures would greatly reduce the cost of cEEG monitoring and enhance the quality of patient care. In this study, we report a preliminary investigation of a novel ICU EEG analysis and seizure detection algorithm. Twenty-four prolonged cEEG recordings were included in this study. Seizure detection sensitivity and specificity were assessed for the new algorithm and for the two commercial seizure detection software systems. The new algorithm performed with a mean sensitivity of 90.4% and a mean false detection rate of 0.066/hour. The two commercial detection products performed with low sensitivities (12.9 and 10.1%) and false detection rates of 1.036/hour and 0.013/hour, respectively. These findings suggest that the novel algorithm has potential to be the basis of clinically useful software that can assist ICU staff in timely identification of nonconvulsive seizures. This study also suggests that currently available seizure detection software does not perform sufficiently in detection of nonconvulsive seizures in critically ill patients. This article is part of a Supplemental Special Issue entitled The Future of Automated Seizure Detection and Prediction.

Artifact: recording EEG in special care units

Artifacts may be obtained during routine recording but are more common in special care units (SCUs) outside of the EEG laboratory, where complex electrical currents are present that create a "hostile" environment. Special care units include the epilepsy monitoring unit, neurologic intensive care unit, and operating room, where artifact is present in virtually every recording, increasing with prolonged use. Nonepileptic attacks treated as epileptic seizures have been incorrectly diagnosed and treated due to a misinterpreted EEG. The recent emergence of continuous EEG as a neurophysiologic surrogate for brain function in the neurologic intensive care unit and operating room has also brought a greater amount and new types of EEG artifact. The artifacts encountered in special care units during continuous EEG are becoming more complex and may have adverse therapeutic implications. Our knowledge of artifact needs to parallel our growth in technology to avoid the pitfalls that may be incurred during visual analysis of the EEG.

Single-channel amplitude integrated EEG recording for the identification of epileptic seizures by nonexpert physicians in the adult acute care setting

OBJECTIVE

Although several studies have shown the potential of amplitude integrated electroencephalography (aEEG) in detecting neonatal seizures, no publications have evaluated the diagnostic use of aEEG for the detection of seizures in adult patients.

METHODS

In this prospective blinded observational study, bifrontal single-channel electroencephalography (EEG) recordings were performed with a portable EEG monitor (CSM M3 ICU, Danmeter-Goalwick Holdings Limited, Odense, Denmark) during the out-of-hospital care of emergency cases. Four intensive care unit (ICU) physicians received training in the interpretation of aEEG recordings. After the training they evaluated the stored aEEG traces for the presence of epileptic seizure activity during the recording time. The physicians were blinded to the clinical data of the patients. The results obtained were compared with the clinical diagnosis and the evaluation of the raw EEG signal. The level of interrater agreement was quantified using Fleiss' ĸ.

RESULTS

The aEEG traces from 10 patients with generalized epileptic seizures and 46 patients without seizures were analysed. Overall, the nonexpert ICU physicians failed to identify recordings obtained from patients with seizures reliably, when compared with clinical diagnosis and the single-channel EEG results (mean sensitivity 40%, range 40-60%; mean specificity 89%, range 87-93%). Agreement between observers was high for the cases with seizures ( ĸ = 0.80 ± 0.13). Patients who suffered status epilepticus during the recordings were difficult to identify by most raters.

CONCLUSION

Recording of aEEG without access to the raw EEG data is not a reliable diagnostic tool for the identification of epileptic seizures in the hands of nonexpert ICU physicians.

Electroencephalography in clinical epilepsy research

Electroencephalography (EEG) remains central to the investigation of epilepsy. This review discusses two clinical problems at the temporal extremes of neurophysiologic recording: evaluation of the clinical significance of individual spike discharges in benign epilepsy of childhood with centrotemporal spikes (BECTS), and prolonged (several days) continuous EEG monitoring in the ICU. BECTS is misdiagnosed often, and probably mis-treated often as well. Though the long-term outcome is usually excellent, it remains unclear whether the individual epileptiform discharges have a clinical effect. Answering this question is difficult, in part because of the natural evolution of the epilepsy and its different appearance depending on wakefulness or sleep state, and also due to substantial methodologic problems in measuring short and long-term cognitive effects. Continuous EEG (CEEG) recording has grown remarkably over the last 10 years. It has proved crucial in the diagnosis of nonconvulsive status epilepticus (NCSE), especially in the ICU, given the usual lack of obvious clinical signs of seizures in most of these patients, many of whom are critically ill. Much progress has been made in agreeing on terminology for the EEG findings, but diagnosis is still complicated. More efficient and reliable technology is being developed to help process the massive amount of data captured by CEEG and make it more useful (and in a timely fashion) clinically. Still, it is not completely clear which patients should be monitored, for how long, and what is the best role for CEEG in assessing and adjusting treatment once the diagnosis has been made. Investigators are using CEEG to study "seizure burden," to help determine what are the long-term effects of nonconvulsive seizures and NCSE, and to help guide treatment and improve outcome.

Urgent continuous EEG (cEEG) monitoring leads to changes in treatment in half of cases

How Seizure Detection by Continuous Electroencephalographic Monitoring Affects the Prescribing of Antiepileptic Medications. Kilbride RD, Costello DJ, Chiappa KH. Arch Neurol 2009;66(6):723–728.

Objectives

To assess the effect of continuous electroencephalographic monitoring on the decision to treat seizures in the inpatient setting, particularly in the intensive care unit.

Design

Retrospective cohort study.

Setting

Medical and neuroscience intensive care units and neurological wards.

Patients

Three hundred consecutive nonelective continuous electroencephalographic monitoring studies, performed on 287 individual inpatients over a 27-month period.

Main Outcome Measures

Epileptiform electroencephalographic abnormalities and changes in antiepileptic drug (AED) therapy based on the electroencephalographic findings.

Results

The findings from the continuous electroencephalographic monitoring led to a change in AED prescribing in 52% of all studies with initiation of an AED therapy in 14%, modification of AED therapy in 33%, and discontinuation of AED therapy in 5% of all studies. Specifically, the detection of electrographic seizures led to a change in AED therapy in 28% of all studies.

Conclusions

The findings of continuous electroencephalographic monitoring resulted in a change in AED prescribing during or after half of the studies performed. Most AED changes were made as a result of the detection of electrographic seizures.

Recent and future advances in the treatment of status epilepticus

Status epilepticus (SE) is one of the most frequent neurological emergencies with an incidence of 20/100,000 per year and a mortality between 3% and 40% depending on etiology, age, SE type and duration. Generalized convulsive forms of SE (GTCSE), in particular, require aggressive treatment. Presently, only 55-80% of cases of GTCSE are controlled by initial therapy. Therefore, there is a need for new options for the treatment of SE. Here we review the current standard treatment including recent advances and provide a summary of preclinical and clinical data regarding treatment options which may become available in the near future. The initial treatment of SE usually consists of a benzodiazepine (preferably lorazepam 0.1 mg/kg) followed by phenytoin or fosphenytoin or valproic acid (where approved for SE therapy). With intravenous formulations of levetiracetam, available since 2006, and lacosamide, which is expected for autumn of 2008, new treatment options have become available, that should be evaluated in prospective controlled trials. If SE remains refractory, the induction of general anaesthesia using propofol, midazolam, thiopental, or pentobarbital is warranted in GTCSE.

Nonconvulsive status epilepticus: An unusual cause of postoperative unresponsiveness following general anaesthesia

Any altered behaviour or sensorium following general anaesthesia is of concern to the anaesthesiologist, as it could be attributed to the anaesthetic itself or to a hypoxic insult, both of which can have medicolegal implications. It is important to be aware of a relatively unfamiliar entity known as nonconvulsive status epilepticus in this context. We report two cases to highlight this condition.

Status epilepticus

Status epilepticus (SE) is a medical emergency associated with significant morbidity and mortality. SE is defined as a continuous seizure lasting more than 30 min, or two or more seizures without full recovery of consciousness between any of them. Based on recent understanding of the pathophysiology, it is now considered that any seizure that lasts more than 5 min probably needs to be treated as SE. GABAergic mechanisms play a crucial role in terminating seizures. When the seizure persists, GABA-mediated mechanisms become ineffective and several other putative mechanisms of seizure suppression have been recognized. Early treatment of SE with benzodiazepines, followed if necessary by fosphenytoin administration, is the most widely followed strategy. About a third of patients with SE may have persistent seizures refractory to the first-line medications. They require aggressive management with second-line medications such as barbiturates, propofol, or other agents. In developing countries where facilities for assisted ventilation are not readily available, it may be helpful to use nonsedating antiepileptic drugs (such as sodium valproate, levetiracetam, or topiramate) at this stage. It is important to recognize SE and institute treatment as early as possible in order to avoid a refractory state. It is equally important to attend to the general condition of the patient and to ensure that the patient is hemodynamically stable. This article reviews current knowledge regarding the management of convulsive SE in adults.

The new wave: time to bring EEG to the emergency department

Emergency electroencephalography (EEG) is indicated in the diagnosis and management of non-convulsive status epilepticus (NCSE) underlying an alteration in the level of consciousness. NCSE is a frequent, treatable, and under-diagnosed entity that can result in neurological injury. This justifies the need for EEG availability in the emergency department (ED). There is now emerging evidence for the potential benefits of EEG monitoring in various acute conditions commonly encountered in the ED, including convulsive status after treatment, breakthrough seizures in chronic epilepsy patients who are otherwise controlled, acute head trauma, and pseudo seizures. However, attempts to allow for routine EEG monitoring in the ED face numerous obstacles. The main hurdles to an optimized use of EEG in the ED are lack of space, the high cost of EEG machines, difficulty of finding time, as well as the expertise needed to apply electrodes, use the machines, and interpret the recordings. We reviewed the necessity for EEGs in the ED, and to meet the need, we envision a product that is comprised of an inexpensive single-use kit used to wirelessly collect and send EEG data to a local and/or remote neurologist and obtain an interpretation for managing an ED patient.

High prevalence of nonconvulsive and subtle status epilepticus in an ICU of a tertiary care center: a three-year observational cohort study

BACKGROUND

Status epilepticus is one of the most important neurological emergencies and requires immediate therapy and admission to the intensive care unit. We hypothesized that nonconvulsive and subtle status epilepticus are more frequent than reported.

METHODS

This observational cohort study describes types, courses, duration, length of hospital stay, outcome and case fatality rate of status epilepticus in adults in relation to demographic and clinical variables. It was conducted in an intensive care unit of a tertiary care center over three years.

RESULTS

111 status epilepticus episodes had a median duration of 48h. Hospitalization length was 18±15.3 days. 81% of the status epilepticus episodes were nonconvulsive and subtle. Case fatality rate was 17%. Age over 70 years had independent positive influence on status epilepticus course (OR: 5.135; p=0.0029). Hospital stay increased by 1.13h with each additional hour of status epilepticus (p=0.02). Subtle status epilepticus was a risk factor for refractoriness (p=0.0065).

CONCLUSIONS

Prevalence of nonconvulsive and subtle status epilepticus was higher than reported, emphasising the importance of clinical awareness. Older age was associated with more favorable course. This unexpected and contradictory result has to be taken into account during therapeutic interventions in the elderly and should warn from early resignation regarding treatment.

Valproate versus diazepam for generalized convulsive status epilepticus: a pilot study

BACKGROUND AND PURPOSE

Evidence-based data to guide the management of status epilepticus (SE) after failure of primary treatment are still scarce and the alternate needs to be found when phenytoin (PHT) is not available or contraindicated. Comparison of intravenous (IV) valproate (VPA) and diazepam (DZP) infusion has not been conducted in adults with SE. This prospective randomized controlled trial is thus designed to evaluate the relative efficacy and safety of IV VPA and continuous DZP infusion as second-line anticonvulsants.

METHODS

After failure of first-line anticonvulsants treatment, patients with generalized convulsive status epilepticus (GCSE) were randomized to receive either IV VPA or continuous DZP infusion. Primary outcome was the proportion of patients with effective control. Side effects were also evaluated.

RESULTS

There were 66 cases enrolled, with the mean age of 41 ± 21 years. Seizure was controlled in 56% (20/36) of the DZP group and 50% (15/30) of the VPA group (P = 0.652). No patient in the VPA group developed respiratory depression, hypotension, or hepatic dysfunction, whereas in the DZP group, 5.5% required ventilation and 5.5% developed hypotension. Time (hour) for regaining consciousness after control was near-significantly longer in the DZP group [13(3.15-21.5)] than in the VPA group [3(0.75-11)] (P = 0.057). Virus encephalitis and long duration of GCSE were independent risk factors of drug resistance.

CONCLUSIONS

  Both IV VPA and continuous DZP infusion are effective second-line anticonvulsants for GCSE. IV VPA was well tolerated and free of respiratory depression and hypotension, which may develop in the DZP group. Outcome parameters were not significantly different between groups.

Treatment of refractory status epilepticus in childhood

Refractory status epilepticus (RSE) is characterized by a prolonged seizure that persists despite adequate initial management. RSE accounts for almost one quarter of all status epilepticus and carries significant risk for morbidity and mortality. Treatment varies widely between institutions regarding medication choice, dose, and monitoring. Several agents including nonanesthetic antiepileptic drugs (AEDs), anesthetic AEDs, enteral AEDs, and other therapies have been used in RSE. We review the current treatment strategies for RSE, focusing on patient selection, monitoring, optimal dosing and administration of medications, efficacy, adverse effects, and treatment duration.

Review article: Convulsive and non-convulsive status epilepticus: an emergency medicine perspective

Status epilepticus (SE) is divided into convulsive and non-convulsive types; both are associated with significant morbidity and mortality. Although convulsive SE is easily recognized, non-convulsive SE remains an elusive diagnosis as physical signs are varied and subtle. Successful management depends on a comprehensive approach that involves diagnostic testing and pharmacological interventions while ensuring cerebral oxygenation and perfusion at all times. There are a limited number of well-designed studies to support the development of evidence-based recommendations for the management of SE, especially for the management of non-convulsive status. Benzodiazepines, specifically lorazepam, continue to be the most commonly recommended first-line therapy; best treatment for refractory status cases depends on resources available and must be tailored to the individual institution. In order to facilitate care, it is recommended that each institution develop a management protocol for these patients.

Continuous video-EEG monitoring increases detection rate of nonconvulsive status epilepticus in the ICU

PURPOSE

Status epilepticus (SE) is an important neurologic emergency requiring treatment on an intensive care unit (ICU). Although convulsive SE is self-evident, the diagnosis of nonconvulsive SE (NCSE) depends on electroencephalography (EEG) confirmation. Previous work showed that 82% of patients with SE had NCSE in our ICU. We hypothesize that continuous video-EEG monitoring (CVEM) may increase the diagnostic yield in patients with SE, especially NCSE, and leave fewer patients undiagnosed.

METHODS

We retrospectively assessed the EEG reports of 537 patients with suspected SE during three comparable 9-month periods, two groups before (groups 1 and 2) and one (group 3) after CVEM introduction. Differences in monthly rates of SE between groups were assessed using the Mann-Whitney U-test.

KEY FINDINGS

The rates of diagnosis increased significantly after implementation of CVEM (p = 0.0546). There was no significant difference in monthly rates of NCSE diagnosis between groups 2 and 1 (difference = 0.78 new diagnosis/month; p = 0.374). Differences between groups 3 and 2 (2.89; p = 0.0173), between groups 3 and 1 (3.67; p = 0.006) and between group 3 and pooled groups 1 and 2 (3.28; p = 0.002) were statistically significant.

SIGNIFICANCE

Frequency of NCSE diagnosis increased significantly after implementation of CVEM and was higher than the increment of performed investigations alone. Such an effect may result from the combination of longer observation periods during CVEM, greater and permanent availability of EEG recordings, and heightened awareness of NCSE. Future studies may corroborate improvement of diagnosis and outcomes in patients with disorders of consciousness by CVEM.

Recurrent aphasic status epilepticus after prolonged generalized tonic-clonic seizures versus a special feature of Todd's paralysis

Postictal aphasia may be a feature of Todd's paralysis or the presentation of aphasic nonconvulsive status epilepticus (NCSE). We describe a 74-year-old woman with three episodes of aphasic status epilepticus after prolonged generalized tonic-clonic seizures. In the first episode, the NCSE was not definitively diagnosed, but an increase in the epileptic medication led to resolution of the epileptic activity within 2 weeks. During the second episode, NCSE was terminated within 7 days under intensified antiepileptic treatment. In the third episode, phenytoin treatment led to intoxication and resulted in further treatment on an intensive care unit. The patient required several months to recover from this episode. NCSE in the elderly is difficult to recognize, especially when it presents as a prolonged postictal deficit like aphasia. Once diagnosed it has to be treated carefully, because in the elderly, aggressive treatment strategies may be associated with a high risk of adverse events.

Nonconvulsive status epilepticus

Nonconvulsive status epilepticus (NCSE) refers to a prolonged seizure that manifests primarily as altered mental status as opposed to the dramatic convulsions seen in generalized tonic-clonic status epilepticus. There are 2 main types of NCSE, each of which has a different presentation, cause, and expected outcome. In the first type of NCSE, patients present with confusion or abnormal behavior, suggesting the diagnosis of absence status epilepticus (ASE) or complex partial status epilepticus (CPSE). The second type of NCSE (subtle status epilepticus [SSE]) must be considered in comatose patients who present after a prolonged generalized tonic-clonic seizure and who may have only subtle motor manifestations of a seizure, such as facial or hand twitchings. Whereas the morbidity and mortality in patients with prolonged ASE or CPSE is low, the mortality associated with SSE can exceed 30% if the seizure duration is greater than 60 minutes.

Emergency department seizure epidemiology

Although only 3% of people in the United States are diagnosed with epilepsy, 11% will have at least one seizure during their lifetime. Seizures account for about 1% of all emergency department (ED) visits, and about 2% of visits to children's hospital EDs. Seizure accounts for about 3% of prehospital transports. In adult ED patients, common causes of seizure are alcoholism, stroke, tumor, trauma, and central nervous system infection. In children, febrile seizures are most common. In infants younger than 6 months, hyponatremia and infection are important considerations. Epilepsy is an uncommon cause of seizures in the ED, accounting for a minority of seizure-related visits. Of ED patients with seizure, about 7% have status epilepticus, which has an age-dependent mortality averaging 22%.

Seizure detection using digital trend analysis: Factors affecting utility

BACKGROUND

EEG monitoring is important for the early detection of seizures during the course of critical illness. However, the logistics of real time EEG interpretation is challenging for the neurophysiology and critical care medicine teams. This study evaluated factors affecting the utility of digital trend analysis (DTA) for rapid seizure identification in children.

METHODS

digital EEG files of seizures in critically ill children were retrieved for DTA. The envelop trend (ET) and compressed spectral array (CSA) were applied to the raw EEG data and presented to an experienced and inexperienced user for interpretation who were blinded to conventional EEG findings. The EEG findings with and without presence of seizures and features of seizures were analyzed.

RESULTS

we found that a number of factors affected accurate seizure detection including factors related to interpreter's experiences, display size and type of DTA methods used for analysis in addition to baseline EEG findings. ET was more dependent on user experience, furthermore, display size and multimodal DTA application (CSA and ET combined) increased the sensitivity of seizure detection for the experienced user compared to inexperience users. The artifacts were reported as seizures regardless of experience without presence of conventional EEG recording. The maximum spike amplitude, seizure duration, and seizure frequency were other important determinants for accuracy. Electrographic seizures with shorter duration were better detected by ET, and the maximum spike amplitude was important for both the ET and CSA. Repetitive seizures are readily detected by both digital trending methods. Artifacts may be reported as seizures regardless of experience if conventional EEG recording is not available for the interpretation.

CONCLUSION

DTA applied to the raw EEG data does produce a graphic display that facilitates identification of seizures. The actual characteristics of the electrographic seizure may predict which DTA method is better and the overall accuracy of seizure detection may increase when multimodal trending is used simultaneously. Application of DTA alone with display of conventional EEG is beneficial for rapid interpretation of EEG findings regardless of experience.

Nonconvulsive status epilepticus and the postictal state

Postictal symptoms, because of activation of inhibitory systems, have to be distinguished from ongoing ictal activity. The categorical concept of pure ictal and pure postictal symptoms cannot be supported by clinical observation alone. Differentiation between postictal and ictal behavioral phenomena can be difficult even with the use of electroencephalography, as clear-cut definitions of ictal and postictal changes are not available. Five different aspects can be considered: (1) hallucinatory symptoms recorded during and after a seizure, (2) prolonged postictal confusional states, (3) prolonged postictal psychotic states, (4) epileptic and other encephalopathies, and (5) coma with or without clinical signs of nonconvulsive status epilepticus. Presenting symptoms and conceptual considerations are presented in this review.

Seizure identification in the ICU using quantitative EEG displays

OBJECTIVE

To evaluate the diagnostic accuracy of 2 quantitative EEG display tools, color density spectral array (CDSA) and amplitude-integrated EEG (aEEG), for seizure identification in the intensive care unit (ICU).

METHODS

A set of 27 continuous EEG recordings performed in pediatric ICU patients was transformed into 8-channel CDSA and aEEG displays. Three neurophysiologists underwent 2 hours of training to identify seizures using these techniques. They were then individually presented with a series of CDSA and aEEG displays, blinded to the raw EEG, and asked to mark any events suspected to be seizures. Their performance was compared to seizures identified on the underlying conventional EEG.

RESULTS

The 27 EEG recordings contained 553 discrete seizures over 487 hours. The median sensitivity for seizure identification across all recordings was 83.3% using CDSA and 81.5% using aEEG. However, among individual recordings, the sensitivity ranged from 0% to 100%. Factors reducing the sensitivity included low-amplitude, short, and focal seizures. False-positive rates were generally very low, with misidentified seizures occurring once every 17-20 hours.

CONCLUSIONS

Both CDSA and aEEG demonstrate acceptable sensitivity and false-positive rates for seizure identification among critically ill children. Accuracy of these tools would likely improve during clinical use, when findings can be correlated in real-time with the underlying raw EEG. In the hands of neurophysiologists, CDSA and aEEG displays represent useful screening tools for seizures during continuous EEG monitoring in the ICU. The suitability of these tools for bedside use by ICU nurses and physicians requires further study.

Outcome and prognosis of status epilepticus in children

The ultimate goal of treating status epilepticus is to provide the best opportunity for a good outcome. This review discusses the current literature on the outcome after status epilepticus in children, including the risk of recurrence, morbidity, and mortality. The outcome seems most dependent on etiology, with age and duration of status epilepticus also contributing. Convulsive status epilepticus has considerably more supporting literature, whereas the data on nonconvulsive status epilepticus are hindered by the lack of a standard definition and presumed under recognition. Future studies will need to address some of these methodological issues to provide the best information when discussing outcome with the family members of children with status epilepticus.

Nonconvulsive status epilepticus and continuous spike and slow wave of sleep in children

Nonconvulsive status epilepticus (NCSE) is a special epileptic state that can be more common than previously thought in children and adult patients. Currently, there is no universally accepted definition for NCSE. Early and accurate diagnosis depends on a high index of suspicion and rapid availability of electroencephalographic recording. The clinical presentation of NCSE can vary from a mild confusional state to a coma. The underlying etiology is also quite diverse. In critically ill patients, NCSE has been reported with convulsive status epilepticus (CSE), hypoxemia, acute ischemic or hemorrhagic stroke, encephalitis, or trauma. The estimated incidence of NCSE is 15% to 40% in post-CSE, 8% in subarachnoid hemorrhage, and 8% to 10% in coma. As seen in CSE, there is a bimodal distribution with NCSE in critically ill patients; children (age <1 year) and elderly appear to be at great risk. NCSE has also been reported in a number of epilepsy syndromes, such as childhood absence epilepsy, Panayiotopoulos syndrome, Lennox-Gastaut syndrome, and Dravet syndrome. However, it is difficult to determine the incidence of NCSE in an ambulatory setting because of the great variation in clinical presentation and underlying etiology. This review examines the clinical features, outcome, and treatment approach for NCSE in 2 different clinical settings, in ambulatory and critically ill patients. NCSE is reviewed in children and adults to distinguish similarities and differences in their clinical presentation.

The status of intravenous valproate for status

Sodium Valproate vs Phenytoin in Status Epilepticus: A Pilot Study. Misra UK, Kalita J, Patel R. Neurology 2006;67(2):340–342. Sixty-eight patients with convulsive status epilepticus (SE) were randomly assigned to two groups to study the efficacy of sodium valproate (VPA) and phenytoin (PHT). Seizures were aborted in 66% in the VPA group and 42% in the PHT group. As a second choice in refractory patients, VPA was effective in 79% and PHT was effective in 25%. The side effects in the two groups did not differ. Sodium valproate may be preferred in convulsive SE because of its higher efficacy.

Use of EEG monitoring and management of non-convulsive seizures in critically ill patients: a survey of neurologists

BACKGROUND

Continuous EEG monitoring (cEEG) of critically ill patients is frequently utilized to detect non-convulsive seizures (NCS) and status epilepticus (NCSE). The indications for cEEG, as well as when and how to treat NCS, remain unclear. We aimed to describe the current practice of cEEG in critically ill patients to define areas of uncertainty that could aid in designing future research.

METHODS

We conducted an international survey of neurologists focused on cEEG utilization and NCS management.

RESULTS

Three-hundred and thirty physicians completed the survey. 83% use cEEG at least once per month and 86% manage NCS at least five times per year. The use of cEEG in patients with altered mental status was common (69%), with higher use if the patient had a prior convulsion (89%) or abnormal eye movements (85%). Most respondents would continue cEEG for 24 h. If NCS or NCSE is identified, the most common anticonvulsants administered were phenytoin/fosphenytoin, lorazepam, or levetiracetam, with slightly more use of levetiracetam for NCS than NCSE.

CONCLUSIONS

Continuous EEG monitoring (cEEG) is commonly employed in critically ill patients to detect NCS and NCSE. However, there is substantial variability in current practice related to cEEG indications and duration and to management of NCS and NCSE. The fact that such variability exists in the management of this common clinical problem suggests that further prospective study is needed. Multiple points of uncertainty are identified that require investigation.

Status epilepticus

Status epilepticus (SE) is one of the most commonly occurring neurologic emergencies. About 40% of SE cases occur in people with epilepsy. Convulsive SE is easily recognized, but nonconvulsive SE is not and requires both a high index of suspicion and EEG confirmation. SE has a high mortality risk and requires rapid effective treatment for optimal response to therapy and outcome. The goal of treatment is to stop all clinical and electrographic seizures while maintaining vital functions. If seizures continue after initial treatment with a benzodiazepine, additional antiepileptic therapy should be administered. When SE is refractory to these treatments, continuous IV infusion with midazolam, propofol, or a barbiturate suppresses seizure activity. Standard treatment protocols are useful in promoting rapid intervention with appropriate medications.