Neuron-specific enolase is increased after nonconvulsive status epilepticus

Fluid Biomarkers of Neuro-Glial Injury in Human Status Epilepticus: A Systematic Review

As per the latest ILAE definition, status epilepticus (SE) may lead to long-term irreversible consequences, such as neuronal death, neuronal injury, and alterations in neuronal networks. Consequently, there is growing interest in identifying biomarkers that can demonstrate and quantify the extent of neuronal and glial injury. Despite numerous studies conducted on animal models of status epilepticus, which clearly indicate seizure-induced neuronal and glial injury, as well as signs of atrophy and gliosis, evidence in humans remains limited to case reports and small case series. The implications of identifying such biomarkers in clinical practice are significant, including improved prognostic stratification of patients and the early identification of those at high risk of developing irreversible complications. Moreover, the clinical validation of these biomarkers could be crucial in promoting neuroprotective strategies in addition to antiseizure medications. In this study, we present a systematic review of research on biomarkers of neuro-glial injury in patients with status epilepticus.

Seizure activity and brain damage in a model of focal non-convulsive status epilepticus

AIMS

Focal non-convulsive status epilepticus (FncSE) is a common emergency condition that may present as the first epileptic manifestation. In recent years, it has become increasingly clear that de novo FncSE should be promptly treated to improve post-status outcome. Whether seizure activity occurring during the course of the FncSE contributes to ensuing brain damage has not been demonstrated unequivocally and is here addressed.

METHODS

We used continuous video-EEG monitoring to characterise an acute experimental FncSE model induced by unilateral intrahippocampal injection of kainic acid (KA) in guinea pigs. Immunohistochemistry and mRNA expression analysis were utilised to detect and quantify brain injury, 3-days and 1-month after FncSE.

RESULTS

Seizure activity occurring during the course of FncSE involved both hippocampi equally. Neuronal loss, blood-brain barrier permeability changes, gliosis and up-regulation of inflammation, activity-induced and astrocyte-specific genes were observed in the KA-injected hippocampus. Diazepam treatment reduced FncSE duration and KA-induced neuropathological damage. In the contralateral hippocampus, transient and possibly reversible gliosis with increase of aquaporin-4 and Kir4.1 genes were observed 3 days post-KA. No tissue injury and gene expression changes were found 1-month after FncSE.

CONCLUSIONS

In our model, focal seizures occurring during FncSE worsen ipsilateral KA-induced tissue damage. FncSE only transiently activated glia in regions remote from KA-injection, suggesting that seizure activity during FncSE without local pathogenic co-factors does not promote long-lasting detrimental changes in the brain. These findings demonstrate that in our experimental model, brain damage remains circumscribed to the area where the primary cause (KA) of the FncSE acts. Our study emphasises the need to use antiepileptic drugs to contain local damage induced by focal seizures that occur during FncSE.

Update on the management of status epilepticus

PURPOSE OF REVIEW

Randomized controlled trials investigating the initial pharmacological treatment of status epilepticus have been recently published. Furthermore, status epilepticus arising in comatose survivors after cardiac arrest has received increasing attention in the last years. This review offers an updated assessment of status epilepticus treatment in these different scenarios.

RECENT FINDINGS

Initial benzodiazepines underdosing is common and correlates with development of status epilepticus refractoriness. The recently published ESETT trial provides high-level evidence regarding the equivalence of fosphenytoin, valproate, and levetiracetam as a second-line option. Myoclonus or epileptiform transients on electroencephalography occur in up to 1/3 of patients surviving a cardiac arrest. Contrary to previous assumptions regarding an almost invariable association with death, at least 1/10 of them may awaken with reasonably good prognosis, if treated. Multimodal prognostication including clinical examination, EEG, somatosensory evoked potentials, biochemical markers, and neuroimaging help identifying patients with a chance to recover consciousness, in whom a trial with antimyoclonic compounds and at times general anesthetics is indicated.

SUMMARY

There is a continuous, albeit relatively slow progress in knowledge regarding different aspect of status epilepticus; recent findings refine some treatment strategies and help improving patients' outcomes. Further high-quality studies are clearly needed to further improve the management of these patients, especially those with severe, refractory status epilepticus forms.

Markers in Status Epilepticus Prognosis

Status epilepticus (SE) is a neurologic emergency with high morbidity and mortality. The assessment of a patient's prognosis is crucial in making treatment decisions. In this review, we discuss various markers that have been used to prognosticate SE in terms of recurrence, mortality, and functional outcome. These markers include demographic, clinical, electrophysiological, biochemical, and structural data. The heterogeneity of SE etiology and semiology renders development of prognostic markers challenging. Currently, prognostication in SE is limited to a few clinical scores. Future research should integrate clinical, genetic and epigenetic, metabolic, inflammatory, and structural biomarkers into prognostication models to approach "personalized medicine" in prognostication of outcomes after SE.

Rapid Response Electroencephalography for Urgent Evaluation of Patients in Community Hospital Intensive Care Practice

INTRODUCTION

Limited access to specialized technicians and trained neurologists results in delayed access to electroencephalography (EEG) and an accurate diagnosis of patients with critical neurological problems. This study evaluated the performance of Ceribell Rapid Response EEG System (RR-EEG), which promises fast EEG acquisition and interpretation without traditional technicians or EEG-trained specialists.

METHODS

The new technology was tested in a community hospital intensive care unit in Northern California. Three physicians (without previous training in EEG) were trained by the manufacturer of the RR-EEG and acquired EEG without the help of any EEG technicians. Time needed from order to EEG acquisition was noted. Quality of EEG and diagnostic information obtained with the new EEG technology were evaluated and compared with the same information from conventional clinical EEG system.

RESULTS

Ten patients were tested with this new EEG technology, and 6 of these patients went on to have conventional EEGs when the EEG technicians arrived at the site. In these cases, the conventional EEG was significantly delayed (11.2 ± 3.6 hours) compared with RR-EEG (5.0 ± 2.4 minutes; P < .005). Use of RR-EEG helped clinicians rule out status epilepticus and prevent overtreatment in 4 of 10 cases. RR-EEG and conventional EEG systems yielded similar diagnostic information.

CONCLUSION

RR-EEG can be set up by nurses, and diagnostic information about the presence or absence of seizures can be appreciated by nurses. The RR-EEG system, compared with the conventional EEG, did not require EEG technologists and enabled significantly faster access to diagnostic EEG information. This report confirms the ease of use and speed of acquisition and interpretation of EEG information at a community hospital setting using an RR-EEG device. This new technology has the potential to improve emergent clinical decision making and prevent overtreatment of patients in the intensive care unit setting while empowering nursing staff with useful diagnostic information in real time and at the bedside.

Current Status and Recommendations in Multimodal Neuromonitoring

Every patient in neurocritical care evolves through two phases. Acute pathologies are addressed first. These include trauma, hemorrhagic or ischemic stroke, or neuroinfection. Soon after, the concentration shifts to identifying secondary pathologies like fever, seizures, and ischemia, which may exacerbate the brain injury. Frequent bedside examinations are not sufficient for timely detection and prevention of secondary brain injury (SBI) as per the International Multidisciplinary Consensus Conference on Multimodality Monitoring in Neurocritical Care. Multimodality monitoring (MMM) can help in tailoring treatment decisions to prevent such a brain injury. Multimodal neuromonitoring involves data-guided therapeutic interventions by employing various tools and data integration to understand brain physiology. Monitors provide real-time information on cerebral hemodynamics, oxygenation, metabolism, and electrophysiology. The monitors may be invasive/noninvasive and global/regional. We have reviewed such technologies in this write-up. Novel themes like bioinformatics, clinical research, and device development will also be discussed.

Epilepsy Emergencies: Status Epilepticus, Acute Repetitive Seizures, and Autoimmune Encephalitis

PURPOSE OF REVIEW

This article reviews epilepsy emergencies, including status epilepticus, acute repetitive seizures, autoimmune encephalitis, and the current perspective on their diagnosis and treatment.

RECENT FINDINGS

Recent guidelines on the treatment of status epilepticus from the Neurocritical Care Society in 2012 and the American Epilepsy Society in 2016 highlight areas of consensus in the treatment of status epilepticus as well as areas of uncertainty. The TRENdS (Treatment of Recurrent Electrographic Nonconvulsive Seizures) trial is the first prospective randomized clinical trial to evaluate the efficacy of IV antiseizure medications in controlling nonconvulsive seizures on continuous EEG. It demonstrated that IV lacosamide is noninferior to fosphenytoin in this setting. Autoimmune encephalitis is an increasingly recognized cause of new-onset seizures or status epilepticus. Recently described scoring systems, the Antibody Prevalence in Epilepsy score and the Response to Immunotherapy in Epilepsy score, can help in the assessment of autoimmune encephalitis.

SUMMARY

Status epilepticus, acute repetitive seizures, and autoimmune encephalitis are neurologic emergencies. For all these conditions, rapid and appropriate treatment may influence patient prognosis and mitigate neuronal injury. For convulsive status epilepticus, there is reasonable consensus on the initial steps that need to be taken. There is less agreement about the management of acute repetitive seizures and nonconvulsive status epilepticus. An increasingly recognized etiology of status epilepticus is autoimmune encephalitis, which may not be as rare as previously thought.

Neuron specific enolase as a marker of seizure related neuronal injury

BACKGROUND

and purpose: Neuron specific enolase (NSE) is an established biomarker of neuronal damage. It is not clear how much seizures contribute to the neuronal damage, morbidity or mortality in critically ill neurology patients. The aim of this study is to determine the impact of seizures on neuronal injury in critically ill neurology patients by using neuron specific enolase as a biomarker.

MATERIAL AND METHODS

Forty patients with clinical evidence of acute central nervous system disease associated with seizures were included as critically ill neurology patients with seizures [CINPS] (age in years 38.8 ± 17.54, mean ± SD; 22 males) and 43 age and sex-matched acute central nervous system disease without seizures were recruited as critically ill neurology patients [CINP] (age in years 37.84 ± 17.38 years mean ± SD; 24 males) The serum NSE assays were performed in CINPS (within 24 h of last seizure) and in CINP using an enzyme immunoassay kit.

RESULTS

The level of serum neuron specific enolase was significantly higher in CINP with seizures compared to those without seizures. The length of ICU stay was more prolonged in those with seizures. There was a close correlation between the NSE levels and frequency of seizures. There was no significant difference in the mortality between both the groups.

CONCLUSIONS

NSE a marker of neuronal injury was elevated in patients with acute central nervous system diseases. It is significantly higher in patients with seizures in comparison to those without seizures. This warrants further studies to document aggressive treatment of seizures in acute neurologically ill patients can reduce neuronal damage.

Population of the ictal-interictal zone: The significance of periodic and rhythmic activity

Seizures contribute to patient mortality and are usually treated aggressively. Rhythmic and periodic patterns - the "ictal-interictal continuum" - are often associated with seizures, yet the optimum method of treating these patterns is not known: should they be aggressively suppressed, or monitored without treatment? Understanding which patterns are more strongly associated with seizures and which are highly associated with mortality is important to help the clinician decide how to treat these findings. We present an overview of the etiologies, association with seizures, and mortality of periodic and rhythmic patterns, and one approach to treatment.

Status Epilepticus and Beyond: A Clinical Review of Status Epilepticus and an Update on Current Management Strategies in Super-refractory Status Epilepticus

Status epilepticus and refractory status epilepticus represent some of the most complex conditions encountered in the neurological intensive care unit. Challenges in management are common as treatment options become limited and prolonged hospital courses are accompanied by complications and worsening patient outcomes. Antiepileptic drug treatments have become increasingly complex. Rational polytherapy should consider the pharmacodynamics and kinetics of medications. When seizures cannot be controlled with medical therapy, alternative treatments, including early surgical evaluation can be considered; however, evidence is limited. This review provides a brief overview of status epilepticus, and a recent update on the management of refractory status epilepticus based on evidence from the literature, evidence-based guidelines, and experiences at our institution.

Management of status epilepticus

Status epilepticus is a neurologic and medical emergency manifested by prolonged seizure activity or multiple seizures without return to baseline. It is associated with substantial medical cost, morbidity, and mortality. There is a spectrum of severity dependent on the type of seizure, underlying pathology, comorbidities, and appropriate and timely medical management. This chapter discusses the evolving definitions of status epilepticus and multiple patient and clinical factors which influence outcome. The pathophysiology of status epilepticus is reviewed to provide a better understanding of the mechanisms which contribute to status epilepticus, as well as the potential long-term effects. The clinical presentations of different types of status epilepticus in adults are discussed, with emphasis on the hospital course and management of the most dangerous type, generalized convulsive status epilepticus. Strategies for the evaluation and management of status epilepticus are provided based on available evidence from clinical trials and recommendations from the Neurocritical Care Society and the European Federation of Neurological Societies.

Seizures in the critically ill

Critically ill patients with seizures are either admitted to the intensive care unit because of uncontrolled seizures requiring aggressive treatment or are admitted for other reasons and develop seizures secondarily. These patients may have multiorgan failure and severe metabolic and electrolyte disarrangements, and may require complex medication regimens and interventions. Seizures can be seen as a result of an acute systemic illness, a primary neurologic pathology, or a medication side-effect and can present in a wide array of symptoms from convulsive activity, subtle twitching, to lethargy. In this population, untreated isolated seizures can quickly escalate to generalized convulsive status epilepticus or, more frequently, nonconvulsive status epileptics, which is associated with a high morbidity and mortality. Status epilepticus (SE) arises from a failure of inhibitory mechanisms and an enhancement of excitatory pathways causing permanent neuronal injury and other systemic sequelae. Carrying a high 30-day mortality rate, SE can be very difficult to treat in this complex setting, and a portion of these patients will become refractory, requiring narcotics and anesthetic medications. The most significant factor in successfully treating status epilepticus is initiating antiepileptic drugs as soon as possible, thus attentiveness and recognition of this disease are critical.

Seizure Correlates with Prolonged Hospital Stay, Increased Costs, and Increased Mortality in Nontraumatic Subdural Hematoma

BACKGROUND

Nontraumatic subdural hematoma (NTSDH) is a common neurosurgical disease process, with mortality reported as high as 13%. Seizure has a known association with NTSDH, although patient outcomes have not previously been well studied in this population. The purpose of this study was to examine the relationship between in-hospital seizure and inpatient outcomes in NTSDH.

METHODS

Using the University HealthSystem Consortium (UHC) database, we performed a retrospective cohort study of adults with a principal diagnosis of NTSDH (International Classification of Diseases, Ninth Revision code 43.21) between 2011 and 2015. Patients with in-hospital seizure (International Classification of Diseases, Ninth Revision codes 34500-34591, 78033, 78039) were compared with those without. Patients with a history of seizure before arrival were excluded. Patient demographics, hospital length of stay (LOS), intensive care unit stay, in-hospital mortality, and direct costs were recorded.

RESULTS

A total 16,928 patients with NTSDH were identified. Mean age was 69.2 years, and 64.7% were male. In-hospital seizure was documented in 744 (4.40%) patients. Hospital LOS was 17.64 days in patients with seizure and 6.26 days in those without (P < 0.0001). Mean intensive care unit stay increased from 3.36 days without seizure to 9.36 days with seizure. In-hospital mortality was 9.19% in patients without seizure and 16.13% in those with seizure (P < 0.0001). Direct costs were $12,781 in patients without seizure and $38,110 in those with seizure (P < 0.0001).

CONCLUSIONS

Seizure in patients with NTSDH correlates with significantly increased total LOS and increased mortality. Direct costs are similarly increased. Further studies accounting for effects of illness severity are necessary to validate these results.

Nonconvulsive status epilepticus in adults - insights into the invisible

Nonconvulsive status epilepticus (NCSE) is a state of continuous or repetitive seizures without convulsions. Owing to the nonspecific symptoms and considerable morbidity and mortality associated with NCSE, clinical research has focused on early diagnosis, risk stratification and seizure termination. The subtle symptoms and the necessity for electroencephalographic confirmation of seizures result in under-diagnosis with deleterious consequences. The introduction of continuous EEG to clinical practice, and the characterization of electrographic criteria have delineated a number of NCSE types that are associated with different prognoses in several clinical settings. Epidemiological studies have uncovered risk factors for NCSE; knowledge of these factors, together with particular clinical characteristics and EEG observations, enables tailored treatment. Despite these advances, NCSE can be refractory to antiepileptic drugs, necessitating further escalation of treatment. The presumptive escalation to anaesthetics, however, has recently been questioned owing to an association with increased mortality. This Review compiles epidemiological, clinical and diagnostic aspects of NCSE, and considers current treatment options and prognosis.

Ictal-interictal continuum: A proposed treatment algorithm

The ictal-interictal continuum (IIC) is characterized by periodic and/or rhythmic EEG patterns that occur with relative high frequency in critically ill patients. Several studies have reported that some patterns seen within the continuum are independently associated with poor outcome. However there is no consensus regarding when to treat them or how aggressive treatment should be. In this review we examine peer-reviewed original scientific articles, guidelines and reviews indexed in PubMed and summarize current knowledge related to the ictal-interictal continuum. A treatment algorithm to guide management of critically ill patients with EEG patterns that fall along the IIC is proposed. The algorithm-based on best current practice in adults-takes into account associated clinical events, risk factors for developing seizures, response to medication trials and biomarkers of neuronal injury.

Electrophysiologic monitoring in acute brain injury

To determine the optimal use and indications of electroencephalography (EEG) in critical care management of acute brain injury (ABI). An electronic literature search was conducted for articles in English describing electrophysiological monitoring in ABI from January 1990 to August 2013. A total of 165 studies were included. EEG is a useful monitor for seizure and ischemia detection. There is a well-described role for EEG in convulsive status epilepticus and cardiac arrest (CA). Data suggest EEG should be considered in all patients with ABI and unexplained and persistent altered consciousness and in comatose intensive care unit (ICU) patients without an acute primary brain condition who have an unexplained impairment of mental status. There remain uncertainties about certain technical details, e.g., the minimum duration of EEG studies, the montage, and electrodes. Data obtained from both EEG and EP studies may help estimate prognosis in ABI patients, particularly following CA and traumatic brain injury. Data supporting these recommendations is sparse, and high quality studies are needed. EEG is used to monitor and detect seizures and ischemia in ICU patients and indications for EEG are clear for certain disease states, however, uncertainty remains on other applications.

Non-convulsive seizures in children with infection-related altered mental status

BACKGROUND

In the intensive care unit, the use of continuous electroencephalography (cEEG) in children with altered mental status often results in the detection of non-convulsive seizures (NCS). Children with influenza can occasionally display altered mental status, but the prevalence of NCS in children with influenza with altered mental status is yet to be determined. This study determined the prevalence of NCS in pediatric patients with altered mental status associated with influenza A(H1N1)pdm09 infection.

METHODS

We retrospectively reviewed admissions to the pediatric intensive care unit between September 2009 and February 2010 and confirmed the presence of NCS on cEEG in children with influenza A(H1N1)pdm09 and with altered mental status.

RESULTS

Of the 15 patients (aged 41-159 months old), NCS was identified on cEEG in five children (33%).

CONCLUSIONS

Approximately one-third of the children infected with influenza A(H1N1)pdm09 with altered mental status had NCS. Further research is needed to determine if the detection and management of NCS improve outcome in these children.

Lacosamide in status epilepticus: Update on the TRENdS study

Many patients with critical illness have been noted to have nonconvulsive seizures (NCSs) and nonconvulsive status epilepticus (NCSE). How aggressively these seizures should be treated is unclear. Many investigators feel that the morbidity of NCSs and NCSE is different from that of generalized convulsive status epilepticus (GCSE), so treatment should be less urgent. Consequently, many nonsedating AEDs have been used to treat NCSs and NCSE in patients with critical illness. Randomized, controlled trials demonstrating the efficacy of AEDs in NCSs and NCSE are lacking. The Treatment of Recurrent Electrographic Nonconvulsive Seizures (TRENdS) study compared lacosamide to fosphenytoin in the treatment of NCSs. An update of the study is presented. This article is part of a Special Issue entitled "Status Epilepticus".

Status epilepticus in adults

Status epilepticus is a common neurological emergency with considerable associated health-care costs, morbidity, and mortality. The definition of status epilepticus as a prolonged seizure or a series of seizures with incomplete return to baseline is under reconsideration in an effort to establish a more practical definition to guide management. Clinical research has focused on early seizure termination in the prehospital setting. The approach of early escalation to anaesthetic agents for refractory generalised convulsive status epilepticus, rather than additional trials of second-line anti-epileptic drugs, to avoid neuronal injury and pharmaco-resistance associated with prolonged seizures is gaining momentum. Status epilepticus is also increasingly identified in the inpatient setting as the use of extended electroencephalography monitoring becomes more commonplace. Substantial further research to enable early identification of status epilepticus and efficacy of anti-epileptic drugs will be important to improve outcomes.

Nonconvulsive seizures and status epilepticus in pediatric head trauma: A national survey

OBJECTIVES

It remains uncertain whether nonconvulsive seizures and nonconvulsive status epilepticus in pediatric traumatic brain injury are deleterious to the brain and/or impact the recovery from injury. Consequently, optimal electroencephalographic surveillance and management is unknown. We aimed to determine specialists' opinion regarding the detection and treatment of nonconvulsive seizures or nonconvulsive status epilepticus in pediatric traumatic brain injury, regardless of their practice.

METHODS

In 2012, 183 surveys were sent to all 93 neurologists, 27 neurosurgeons, and 63 intensivists in the14 tertiary pediatric hospitals across Canada. The survey included an initial scenario of pediatric TBI that evolved into three further scenarios. Each scenario had required responses and an embedded branching logic algorithm ascertaining clinical management. The survey instrument assimilated data about the importance of nonconvulsive status epilepticus and nonconvulsive seizures detection and treatment, and whether they are a cause of brain injury that adversely affects neurologic outcomes.

RESULTS

Of the 79 specialists who replied (43% response rate), 68%-78% elected to order an electroencephalographic across all four scenarios, and one-third (31%-36%; scenario dependent) would request an urgent electroencephalographic (within the hour) in the comatose pediatric traumatic brain injury patient. In the absence of pharmacologic paralysis or intracranial pressure spikes, half-hour electroencephalographic (41%-55%) was preferred over ⩾24-h continuous electroencephalographic monitoring (29%-40%). Finally, nonconvulsive status epilepticus (81%-87%) and nonconvulsive seizures (61%-73%) were considered to be a cause of poor neurologic outcomes warranting aggressive pharmacologic management.

CONCLUSION

The Canadian specialists' opinion is that nonconvulsive seizures and nonconvulsive status epilepticus are biomarkers of brain injury and contribute to worsened outcomes. This suggests the urgency of future outcome-oriented research in the identification and management of nonconvulsive seizures or nonconvulsive status epilepticus.

Diagnostic yield of electroencephalography in the medical and surgical intensive care unit

BACKGROUND

To determine the incidence of electrographic seizures during continuous electroencephalography (cEEG) in the medical and surgical ICU.

METHODS

We retrospectively reviewed the records of all adults who underwent cEEG in our medical and surgical ICU over a 4.5 year period. Patients with acute brain injury were excluded. Our primary outcome was cEEG documentation of an electrographic seizure, defined as a rhythmic discharge or spike and wave pattern demonstrating definite evolution and lasting at least 10 s. To assess inter-rater variability in cEEG interpretation, two electrophysiologists independently reviewed all available cEEGs of subjects with electrographic seizures documented on their clinical cEEG report and those of an equal number of randomly selected subjects from the remaining cohort.

RESULTS

Kappa analysis showed a value of 0.88, indicating excellent inter-rater agreement. Electrographic seizures were identified in 12 of 105 patients (11 %, 95 % CI 5-18 %). This rate did not change after excluding patients with a history of seizure, remote brain injury, or seizure-like events before cEEG. In an ordinal logistic regression model controlling for age, sex, and SOFA score, electrographic seizures were associated with lower odds of good outcomes on the Glasgow Outcome Scale at discharge (OR 0.3, 95 % CI 0.1-0.8).

CONCLUSION

In a tertiary care medical and surgical ICU, electrographic seizures were seen on 11 % of cEEGs ordered for the evaluation of encephalopathy, and were associated with worse functional outcomes at discharge. Our findings confirm the results of a prior study suggesting a substantial burden of electrographic seizures in critically ill encephalopathic patients.

Utility of continuous EEG in children with acute traumatic brain injury

Traumatic brain injury is a leading cause of childhood morbidity and mortality. The use of continuous EEG monitoring in the pediatric intensive care unit setting to aid in the management of acute traumatic brain injury is becoming more common, although practice does vary between institutions. This variability is a product of the relative paucity of data, particularly as it applies to prospective studies, in evaluating the use of continuous EEG after traumatic brain injury in the pediatric population. This review will summarize the current literature involving the utility of continuous EEG monitoring in children with acute traumatic brain injury, with focus on specific indications, impact on management, and prognostic value.

Outcome predictors for status epilepticus--what really counts

In adult patients with status epilepticus (SE)-a life-threatening state of ongoing or repetitive seizures--the current evidence regarding outcome prediction is based on clinical, biochemical and EEG determinants. These predictors of outcome involve clinical features such as age, history of prior seizures or epilepsy, SE aetiology, level of consciousness, and seizure type at SE onset. The clinical risk-benefit calculation between the danger of undertreated persistent seizure activity and, conversely, the potential damage from unwarranted aggressive treatments remains a constant challenge. Improved knowledge of outcome determinants, as well as increased availability of reliable outcome prediction models early in the course of SE, is paramount for optimization of treatment of patients who develop this disorder. In this Review, we discuss the major prognostic determinants of outcome in SE. Through consideration of studies that provide measures of association between predictors of SE outcome and death, we propose a detailed--but as yet unvalidated--paradigm for assessment of these predictors during the course of SE. Such an algorithm could guide the organization of results from existing trials and provide direction with regard to the parameters that should be monitored in future studies of SE.

Clinical significance of serological biomarkers and neuropsychological performances in patients with temporal lobe epilepsy

Background

Temporal lobe epilepsy (TLE) is a common form of focal epilepsy. Serum biomarkers to predict cognitive performance in TLE patients without psychiatric comorbidities and the link with gray matter (GM) atrophy have not been fully explored.

Methods

Thirty-four patients with TLE and 34 sex - and age-matched controls were enrolled for standardized cognitive tests, neuroimaging studies as well as measurements of serum levels of heat shock protein 70 (HSP70), S100ß protein (S100ßP), neuronal specific enolase (NSE), plasma nuclear and mitochondrial DNA levels.

Results

Compared with the controls, the patients with TLE had poorer cognitive performances and higher HSP70 and S100ßP levels (p < 0.01). The patients with higher frequencies of seizures had higher levels of HSP70, NSE and S100ßP (p < 0.01). Serum HSP70 level correlated positively with duration of epilepsy (σ = 0.413, p < 0.01), and inversely with memory scores in the late registration (σ = −0.276, p = 0.01) and early recall score (σ = −0.304, p = 0.007). Compared with the controls, gray matter atrophy in the hippocampal and parahippocampal areas, putamen, thalamus and supplementary motor areas were found in the patient group. The HSP70 levels showed an inverse correlation with hippocampal volume (R square = 0.22, p = 0.007) after controlling for the effect of age.

Conclusions

Our results suggest that serum biomarkers were predictive of higher frequencies of seizures in the TLE group. HSP70 may be considered to be a stress biomarker in patients with TLE in that it correlated inversely with memory scores and hippocampal volume. In addition, the symmetric extratemporal atrophic patterns may be related to damage of neuronal networks and epileptogenesis in TLE.

Nonconvulsive seizures in traumatic brain injury: what you don't see can hurt you

Nonconvulsive Electrographic Seizures after Traumatic Brain Injury Result in a Delayed, Prolonged Increase in Intracranial Pressure and Metabolic Crisis. Vespa PM, Miller C, McArthur D, Eliseo M, Etchepare M, Hirt D, Glenn TC, Martin N, Hovda D. Crit Care Med 2007; [Epub ahead of print]. OBJECTIVE: To determine whether nonconvulsive electrographic post-traumatic seizures result in increases in intracranial pressure and microdialysis lactate/pyruvate ratio. DESIGN: Prospective monitoring with retrospective data analysis. SETTING: Single center academic neurologic intensive care unit. PATIENTS: Twenty moderate to severe traumatic brain injury patients (Glasgow Coma Score 3–13). MEASUREMENTS AND MAIN RESULTS: Continuous electroencephalography and cerebral microdialysis were performed for 7 days after injury. Ten patients had seizures and were compared with a matched cohort of traumatic brain injury patients without seizures. The seizures were repetitive and constituted status epilepticus in seven of ten patients. Using a within-subject design, post-traumatic seizures resulted in episodic increases in intracranial pressure (22.4 ± 7 vs. 12.8 ± 4.3 mm Hg; p < .001) and an episodic increase in lactate/pyruvate ratio (49.4 ± 16 vs. 23.8 ± 7.6; p < .001) in the seizure group. Using a between-subjects comparison, the seizure group demonstrated a higher mean intracranial pressure (17.6 ± 6.5 vs. 12.2 ± 4.2 mm Hg; p < .001), a higher mean lactate/pyruvate ratio (38.6 ± 18 vs. 27 ± 9; p < .001) compared with nonseizure patients. The intracranial pressure and lactate/pyruvate ratio remained elevated beyond postinjury hour 100 in the seizure group but not the nonseizure group (p < .02). CONCLUSION: Post-traumatic seizures result in episodic as well as long-lasting increases in intracranial pressure and microdialysis lactate/pyruvate ratio. These data suggest that post-traumatic seizures represent a therapeutic target for patients with traumatic brain injury.

Nonconvulsive status epilepticus

Nonconvulsive status epilepticus (NCSE) is a heterogeneous disorder with multiple subtypes. Although attempts have been made to define and classify this disorder, there is yet no universally accepted definition or classification that encompasses all subtypes or electroclinical scenarios. Developing such a classification scheme is becoming increasingly important, because NCSE is more common than previously thought, with a bimodal peak, in children and the elderly. Recent studies have also shown a high incidence of NCSE in the critically ill. Although strong epidemiological data are lacking, NCSE constitutes about 25-50% of all cases of status epilepticus. For the purposes of this review, we propose an etiological classification for NCSE including NCSE in metabolic disorders, NCSE in coma, NCSE in acute cerebral lesions, and NCSE in those with preexisting epilepsy with or without epileptic encephalopathy. NCSE is still underrecognized, yet potentially fatal if untreated. Diagnosis can be established using an electroencephalogram (EEG) in most cases, sometimes requiring continuous monitoring. However, in comatose patients, diagnosis can be difficult, and the EEG can show a variety of rhythmic or periodic patterns, some of which are of unclear significance. Although some subtypes of NCSE are easily treatable, such as absence status epilepticus, others do not respond well to treatment, and debate exists over how aggressively clinicians should treat NCSE. In particular, the appropriate treatment of NCSE in patients who are critically ill and/or comatose is not well established, and large-scale trials are needed. Overall, further work is needed to better define NCSE, to determine which EEG patterns represent NCSE, and to establish treatment paradigms for different subtypes of NCSE.

Advances in the management of seizures and status epilepticus in critically ill patients

Seizures and status epilepticus are common in critically ill patients. They can be difficult to recognize because most are non-convulsive and require electroencephalogram monitoring to detect; hence, they are currently underdiagnosed. Early recognition and treatment are essential to obtain maximal response to first-line treatment and to prevent neurologic and systemic sequelae. Anti-seizure medication should be combined with management of the underlying cause and reversal of factors that can lower the seizure threshold, including many medications, fever, hypoxia, and metabolic imbalances. This article discusses specific treatments and specific situations, such as hepatic and renal failure patients and organ transplant patients.

Status epilepticus: pathophysiology and management in adults

As in Clark and Prout's classic work, we identify three phases of generalised convulsive status epilepticus, which we call impending, established, and subtle. We review physiological and subcellular changes that might play a part in the transition from single seizures to status epilepticus and in the development of time-dependent pharmacoresistance. We review the principles underlying the treatment of status epilepticus and suggest that prehospital treatment is beneficial, that therapeutic drugs should be used in rapid sequence according to a defined protocol, and that refractory status epilepticus should be treated with general anaesthesia. We comment on our preference for drugs with a short elimination half-life and discuss some therapeutic choices.

Which EEG Patterns Warrant Treatment in the Critically Ill? Reviewing the Evidence for Treatment of Periodic Epileptiform Discharges and Related Patterns

Continuous electroencephalographic monitoring in critically ill patients has improved detection of nonconvulsive seizures and periodic discharges, but when and how aggressively to treat these electrographic patterns is unclear. A review of the literature was conducted to understand the nature of periodic discharges and the strength of the data on which management recommendations have been based. Periodic discharges are seen from a wide variety of etiologies, and the discharges themselves are electrographically heterogeneous. This spectrum suggests a need to consider these phenomena along a continuum between interictal and ictal, but more important clinically is the need to consider the likelihood of neuronal injury from each type of discharge in a given clinical setting. Recommendations for treatment are given, and a modification to current criteria for the diagnosis of nonconvulsive seizures is suggested.

The Management of Status Epilepticus

Status epilepticus is a major medical emergency associated with significant morbidity and mortality. Status epilepticus is best defined as a continuous, generalized, convulsive seizure lasting > 5 min, or two or more seizures during which the patient does not return to baseline consciousness. Lorazepam in a dose of 0.1 mg/kg is the drug of first choice for terminating status epilepticus. Patients who continue to have clinical or EEG evidence of seizure activity after treatment with lorazepam should be considered to have refractory status epileptics and should be treated with a continuous infusion of propofol or midazolam. This article reviews current information regarding the management of status epilepticus in adults.

Recurrent absence status epilepticus: clinical and EEG characteristics

In order to outline the clinical and EEG characteristics of recurrent absence status epilepticus (ASE), eight cases with more than two attacks of ASE were studied. Their current ages were between 13 and 84 years, and five of the patients were women. There was a history of epilepsy in five of the patients before the first ASE episode. A varying degree of confusion was the main clinical symptom with associated mild motor signs like perioral, eyelid and generalised myoclonus, seen in one, two and four patients respectively. Two of the patients had juvenile myoclonic epilepsy. One patient had an atypical form of childhood absence epilepsy characterised by recurrent ASE attacks on awakening. There were two patients with phantom absences and late onset generalised convulsions, one patient with perioral myoclonia and absences, and finally two patients with eyelid myoclonia with absences, which are proposed syndromes. On the EEGs that revealed the diagnosis of ASE, there was a marked variability of the generalised multispike and wave discharges. The EEG findings appeared to be syndrome-related with some exceptions. IV Clonazepam lead to a dramatic improvement. Our study shows that the majority of recurrent ASE cases do not fit into the International syndrome classification.

Normal CSF neuron-specific enolase and S-100 protein levels in patients with recent non-complicated tonic-clonic seizures

PURPOSE

Increased concentrations of the nervous-system-specific proteins neuron-specific enolase (NSE) and S-100 protein (S-100) have been measured with lesions in the CNS. Elevated levels of serum NSE (s-NSE) have been found in status epilepticus, but also after single epileptic seizures. Because larger studies addressing cerebrospinal fluid (CSF) levels of NSE or S-100 have not been performed, we measured CSF NSE and S-100 after tonic-clonic seizures to search for evidence of neuronal and glial damage.

METHODS

22 consecutive patients with single, previously undiagnosed and untreated tonic-clonic seizures were studied. Serum and CSF samples were collected within 24 h after seizure. 18 serum and CSF samples were measured from a control group.

RESULTS

The mean CSF NSE was 8.9 ng/ml (range 0-28 ng/ml) and s-NSE 8.2 ng/ml (range 5-15 ng/ml) in the patient group. The mean concentrations in the control group were 13.1 ng/ml (range 3-24 ng/ml) and 8.0 ng/ml (range 5-12 ng/ml) respectively. The mean CSF S-100 was 3.17 microg/l (range 1.45-7.02 microg/l) and serum S-100 0.05 microg/l (range 0-0.32 microg/l), and in controls 3.19 microg/l (range 1.52-5.13 microg/l) and 0.08 microg/l (range 0-0.28 microg/l).

CONCLUSION

There were no significant differences between the mean concentrations of NSE or S-100 in CSF and serum between the epileptic group and controls. These results do not confirm the previous observation of elevated NSE-levels after tonic-clonic seizures, which argues against neuronal or glial damage after uncomplicated tonic-clonic seizures in unmedicated patients.

Typical absence status in adults: diagnostic and syndromic considerations

PURPOSE

To study the electroclinical features of typical absence status (TAS) in adults with syndromes of idiopathic generalized epilepsies (IGEs).

METHODS

Twenty-one patients with one or more spells of TAS were identified among 136 consecutive adult patients with IGEs. All patients with TAS had comprehensive electroclinical investigations and EEG or video-EEG recorded absences.

RESULTS

TAS occurred in 24.4% of 86 patients who had IGEs with typical absences alone or in combination with other seizures presisting in adult life. The prevalence of TAS appeared to be syndrome related, ranging from as high as 57.1% in perioral myoclonia with absences and 46.2% in "phantom" absences with GTCS to as low as 6.7% in juvenile myoclonic epilepsy. A varying degree of impairment of cognition was the cardinal clinical symptom shared in all TAS, but corresponding syndromes of IGE were often betrayed by other symptoms such as eyelid or perioral myoclonia. In phantom absences with GTCS, TAS was more numerous (p < or = 0.05) and more frequently the first overt seizure type (p = 0.006) than in any other IGE. Only in the syndrome of eyelid myoclonia with absences, TAS was always situation related, mainly as a result of antiepileptic drug discontinuation.

CONCLUSIONS

The clinical EEG semiology and prevalence of TAS appear to be syndrome related with the highest prevalence in the syndromes of perioral myoclonia with absences and phantom absences with GTCS (p = 0.0024).

Non-convulsive status epilepticus in a patient with hypocalcemia

Non-convulsive status epilepticus (NCSE), a neurological emergency, is reported to account for approximately 25% of patients presenting in status epilepticus. Diagnosis of NCSE can be delayed or missed because of its often subtle presentation. Hypocalcemia has rarely been reported as a precipitator of NCSE and thus should be considered in the differential. We report the case of a 46-year-old man with idiopathic hypoparathyroidism who presented in NCSE secondary to hypocalcemia. As in patients with convulsive status epilepticus, rapid diagnosis and treatment of patients in NCSE is critical to prevent permanent neurological damage.

Serum neuron-specific enolase is a marker for neuronal damage following status epilepticus in the rat

We determined the serum concentrations of neuron-specific enolase (s-NSE) in rat pups of 1, 2, 3, and 4 weeks of age and in adult rats that were subjected to lithium-pilocarpine status epilepticus (SE). Damage to brain regions was rated on a scale of 0 (no damage) to 5 (> 50% cell loss). Rat pups of 1-2 weeks of age had a higher baseline s-NSE than the adults. Following SE, 1 week old rat pups had no elevation of s-NSE and no histologic evidence of damage. At older ages the increases in NSE ranged from 18.9 +/- 0.8 ng/ml in the 2 week old (vs. 11.5 +/- 0.5 control) to 35.8 +/- 2.1 ng/ml in the 3 week old (vs. 12.1 +/- 0.8 control). In the adult rats s-NSE increased from 5.4 +/- 0.4 in the control animals to 30.4 +/- 1.3 after SE. The different brain regions examined had distinctive ontogenic profiles for SE-induced damage. Elevation of s-NSE after SE correlated with overall histologic evidence for damage.