Persistent nonconvulsive status epilepticus after the control of convulsive status epilepticus

Status epilepticus

Status epilepticus (SE) still results in significant mortality and morbidity. Whereas mortality depends mainly on the age of the patient as well as etiology, morbidity often results from a myriad of complications that occur during prolonged admission to an intensive care environment. Although SE is a clinical diagnosis in most cases (convulsant), its treatment requires support by continuous electroencephalographic recording to ensure cessation of potential nonconvulsive elements of SE. Treatment must be initiated as early as possible and consists of benzodiazepine administration and supportive measures for the airway and circulation. These initial interventions are followed by effective intravenous antiepileptic drugs. If the SE becomes refractory, more complex intensive care interventions, such as induction of barbiturate coma, need to be pursued. Data regarding the role of more recently available antiepileptic drugs in treating SE also are discussed in this review.

Seizures in the context of acute illness

PURPOSE OF REVIEW

Seizures during an acute illness demand immediate evaluation, as they indicate an acute central nervous system insult. There are three goals: identify and treat the precipitating cause; determine the need for antiepileptic drug therapy; and recognize nonconvulsive seizures. Management depends upon whether there is a primary or secondary central nervous system insult. Seizures may persist despite antiepileptic drugs if the precipitating cause is untreated.

RECENT FINDINGS

Seizures and epilepsy and children with neurodevelopmental disabilities comprise a significant percentage of acute care in children. A continuum exists from a single seizure and escalating seizures to status epilepticus. Seizure treatment is more successful when given earlier, and prognosis depends on the cause. Guidelines for the diagnostic evaluation and treatment of status epilepticus have been produced. Continuous electroencephalographic monitoring reveals frequent nonconvulsive seizures and nonconvulsive status epilepticus in the sick child.

SUMMARY

The recognition and rapid treatment of clinical and electrographic seizures is important during acute illness.

Continuous EEG monitoring: is it ready for prime time?

PURPOSE OF REVIEW

Continuous electroencephalography (cEEG) is being used more frequently in intensive care units to detect epileptic activity and ischemia. This review analyzes clinical applications and limitations of cEEG as a routine neuromonitoring tool.

RECENT FINDINGS

cEEG is primarily used to detect nonconvulsive seizures, which are frequent and possibly associated with harm. Cerebral ischemia, such as that from vasospasm after subarachnoid hemorrhage, can be detected earlier by EEG and quantitative EEG (qEEG). Highly skilled technicians and subspecialty-trained physicians are needed to generate good quality EEG and to interpret these data. qEEG allows more efficient interpretation of large amounts of EEG and may trigger prespecified alarms. Currently, there is little high-quality data on cEEG to define indications, cost-saving potential, and impact on outcome. A few studies have demonstrated how cEEG can be integrated into multimodality brain monitoring of severely brain-injured patients.

SUMMARY

cEEG should be considered as an integral part of multimodality monitoring of the injured brain, particularly in patients at risk for nonconvulsive seizure or ischemia. Automated alarms may help establish cEEG monitoring as an integral part of brain monitoring. All neurological ICUs that routinely care for patients with refractory status epilepticus should have the capability to perform cEEG monitoring. Further research determining the impact on outcome and making EEG monitoring more user friendly may help move this technique out of the subspecialized ICU setting into the general ICU environment. In the future, it may be possible to use specific EEG parameters as endpoints for therapeutic interventions.

Nonconvulsive status epilepticus and coma

Nonconvulsive status epilepticus (NCSE) in a comatose patient cannot be diagnosed without electroencephalography (EEG). In many advanced coma stages, the EEG exhibits continuous or periodic EEG abnormalities, but their causal role in coma remains unclear in many cases. To date there is no consensus on whether to treat NCSE in a comatose patient in order to improve the outcome or to retract from treatment, as these EEG patterns might reflect the end stages of a dying brain. On the basis of EEG, NCSE in comatose patients may be classified as generalized or lateralized. This review aims to summarize the ongoing debate of NCSE and coma and to critically reassess the available literature on coma with epileptiform EEG pattern and its prognostic and therapeutic implications. The authors suggest distinguishing NCSE proper and comatose NCSE, which includes coma with continuous lateralized discharges or generalized epileptiform discharges (coma-LED, coma-GED). Although NCSE proper is accompanied by clinical symptoms suggestive of status epilepticus and mild impairment of consciousness, such as in absence status or complex focal status epilepticus, coma-LED and coma-GED represent deep coma of various etiology without any clinical motor signs of status epilepticus but with characteristic epileptiform EEG pattern. Hence coma-LED and coma-GED can be diagnosed with EEG only. Subtle or stuporous status epilepticus and epilepsia partialis continua-like symptoms in severe acute central nervous system (CNS) disorders represent the borderland in this biologic continuum between NCSE proper and comatose NCSE (coma-LED/GED). This pragmatic differentiation could act as a starting point to solve terminologic and factual confusion.

Acute confusional state in type 2 diabetic patient: non-convulsive status epilepticus

The etiology of acute confusional state in elderly patients with type 2 diabetes mellitus is broad, including hypoglycemia or hyperglycemia, electrolyte imbalance as hyponatremia or hypercalcemia, cerebrovascular disease and drug intoxication among others. Herein, we present an 80-year-old female type 2 diabetic patient in an acute confusional state due to non-convulsive status epilepticus (NCSE). Timely electroencephalogram at an emergency department when available is the only tool for the diagnosis of NCSE when clinically suspected. All clinicians must consider the possibility of NCSE in the differential diagnosis of acute confusional patients when diagnosis is uncertain.

Continuous electroencephalogram monitoring in the intensive care unit

Because of recent technical advances, it is now possible to record and monitor the continuous digital electroencephalogram (EEG) of many critically ill patients simultaneously. Continuous EEG monitoring (cEEG) provides dynamic information about brain function that permits early detection of changes in neurologic status, which is especially useful when the clinical examination is limited. Nonconvulsive seizures are common in comatose critically ill patients and can have multiple negative effects on the injured brain. The majority of seizures in these patients cannot be detected without cEEG. cEEG monitoring is most commonly used to detect and guide treatment of nonconvulsive seizures, including after convulsive status epilepticus. In addition, cEEG is used to guide management of pharmacological coma for treatment of increased intracranial pressure. An emerging application for cEEG is to detect new or worsening brain ischemia in patients at high risk, especially those with subarachnoid hemorrhage. Improving quantitative EEG software is helping to make it feasible for cEEG (using full scalp coverage) to provide continuous information about changes in brain function in real time at the bedside and to alert clinicians to any acute brain event, including seizures, ischemia, increasing intracranial pressure, hemorrhage, and even systemic abnormalities affecting the brain, such as hypoxia, hypotension, acidosis, and others. Monitoring using only a few electrodes or using full scalp coverage, but without expert review of the raw EEG, must be done with extreme caution as false positives and false negatives are common. Intracranial EEG recording is being performed in a few centers to better detect seizures, ischemia, and peri-injury depolarizations, all of which may contribute to secondary injury. When cEEG is combined with individualized, physiologically driven decision making via multimodality brain monitoring, intensivists can identify when the brain is at risk for injury or when neuronal injury is already occurring and intervene before there is permanent damage. The exact role and cost-effectiveness of cEEG at the current time remains unclear, but we believe it has significant potential to improve neurologic outcomes in a variety of settings.

Electroencephalographic monitoring during hypothermia after pediatric cardiac arrest

BACKGROUND

Hypoxic ischemic brain injury secondary to pediatric cardiac arrest (CA) may result in acute symptomatic seizures. A high proportion of seizures may be nonconvulsive, so accurate diagnosis requires continuous EEG monitoring. We aimed to determine the safety and feasibility of long-term EEG monitoring, to describe electroencephalographic background and seizure characteristics, and to identify background features predictive of seizures in children undergoing therapeutic hypothermia (TH) after CA.

METHODS

Nineteen children underwent TH after CA. Continuous EEG monitoring was performed during hypothermia (24 hours), rewarming (12-24 hours), and then an additional 24 hours of normothermia. The tolerability of these prolonged studies and the EEG background classification and seizure characteristics were described in a standardized manner.

RESULTS

No complications of EEG monitoring were reported or observed. Electrographic seizures occurred in 47% (9/19), and 32% (6/19) developed status epilepticus. Seizures were nonconvulsive in 67% (6/9) and electrographically generalized in 78% (7/9). Seizures commenced during the late hypothermic or rewarming periods (8/9). Factors predictive of electrographic seizures were burst suppression or excessively discontinuous EEG background patterns, interictal epileptiform discharges, or an absence of the expected pharmacologically induced beta activity. Background features evolved over time. Patients with slowing and attenuation tended to improve, whereas those with burst suppression tended to worsen.

CONCLUSIONS

EEG monitoring in children undergoing therapeutic hypothermia after cardiac arrest is safe and feasible. Electrographic seizures and status epilepticus are common in this setting but are often not detectable by clinical observation alone. The EEG background often evolves over time, with milder abnormalities improving and more severe abnormalities worsening.

Coma

Coma is a state of unarousable unconsciousness due to dysfunction of the brain's ascending reticular activating system (ARAS), which is responsible for arousal and the maintenance of wakefulness. Anatomically and physiologically the ARAS has a redundancy of pathways and neurotransmitters; this may explain why coma is usually transient (seldom lasting more than 3 weeks). Emergence from coma is succeeded by outcomes ranging from the vegetative state to complete recovery, depending on the severity of damage to the cerebral cortex, the thalamus, and their integrated function. The clinical and laboratory assessments of the comatose patient are reviewed here, along with an analysis of how various conditions (structural brain lesions, metabolic and toxic disorders, trauma, infections, seizures, hypothermia, and hyperthermia) produce coma. Management issues include the determination of the cause and reversibility (prognosis) of neurological impairment, support of the patient, definitive treatment when possible, and the ethical considerations for those situations where marked disability is predicted with certainty.

Cortical regional hyperperfusion in nonconvulsive status epilepticus measured by dynamic brain perfusion CT

BACKGROUND AND PURPOSE

Nonconvulsive status epilepticus (NCSE) is associated with a mortality rate of up to 18%, therefore requiring prompt diagnosis and treatment. Our aim was to evaluate the diagnostic value of perfusion CT (PCT) in the differential diagnosis of NCSE versus postictal states in patients presenting with persistent altered mental states after a preceding epileptic seizure. We hypothesized that regional cortical hyperperfusion can be measured by PCT in patients with NCSE, whereas it is not present in postictal states.

MATERIALS AND METHODS

Nineteen patients with persistent altered mental status after a preceding epileptic seizure underwent PCT and electroencephalography (EEG). Patients were stratified as presenting with NCSE (n = 9) or a postictal state (n = 10) on the basis of clinical history and EEG data. Quantitative and visual analysis of the perfusion maps was performed.

RESULTS

Patients during NCSE had significantly increased regional cerebral blood flow (P > .0001), increased regional cerebral blood volume (P > .001), and decreased (P > .001) mean transit time compared with the postictal state. Regional cortical hyperperfusion was depicted in 7/9 of patients with NCSE by ad hoc analysis of parametric perfusion maps during emergency conditions but was not a feature of postictal states. The areas of hyperperfusion were concordant with transient clinical symptoms and EEG topography in all cases.

CONCLUSIONS

Visual analysis of perfusion maps detected regional hyperperfusion in NCSE with a sensitivity of 78%. The broad availability and short processing time of PCT in an emergency situation is a benefit compared with EEG. Consequently, the use of PCT in epilepsy may accelerate the diagnosis of NCSE. PCT may qualify as a complementary diagnostic tool to EEG in patients with persistent altered mental state after a preceding seizure.

Intravenous lacosamide as successful treatment for nonconvulsive status epilepticus after failure of first-line therapy

Treatment of status epilepticus usually requires intravenous anticonvulsant therapy. Lacosamide is a novel anticonvulsant drug that is available as infusion solution. We describe a patient with nonconvulsive status epilepticus who was successfully treated with intravenous lacosamide.

Non-convulsive status epilepticus; the rate of occurrence in a general hospital

BACKGROUND

Non-convulsive status epilepticus (NCSE) has been increasingly recognized as a cause of impaired level of consciousness in the ICU and emergency rooms. The diagnosis can be easily missed without an electroencephalogram (EEG) given the paucity of overt clinical signs in this condition. Recently few published data estimated the prevalence to be between 3% and 8%.

OBJECTIVE

To assess the rate of occurrence of NCSE among patients with various degrees of impaired consciousness referred to the Neurophysiology Laboratory at Vancouver General Hospital.

METHOD

We conducted a retrospective analysis of 451 adult patients (>16 years of age) with a question of NCSE or with an unknown cause of impaired level of consciousness between the years 2002 and 2004. NCSE was defined according to the Young's criteria of electrographic status epilepticus. NCSE was categorized into focal and generalized epileptic activity based on the continuous EEG monitoring (CEEG). Further analysis of age, gender and etiology was performed.

RESULTS

Of 451 patients, EEG demonstrated electrographic status epilepticus with no overt clinical signs in 42 patients (9.3%). Median age was 61.8 years (range 21-94). According to etiology, 38.1% of patients with NCSE had hypoxic-anoxic injury, 19% had intracerebral hemorrhage (including trauma), 11.9% had the diagnosis of idiopathic or cryptogenic epilepsy, 7.1% had ischemic stroke, 4.8% were secondary to tumors and 4.8% to viral encephalitis.

CONCLUSION

The rate of occurrence of NCSE in patients with decreased level of consciousness was 9.3%. The cohort represented a group of patients who were comatose and required assisted ventilation or had altered level of consciousness. Hypoxic brain injury was the most responsible etiology of NCSE in the cohort studied.

Status epilepticus

Status epilepticus (SE) in adults is a state of continuous seizures lasting more than 5 minutes, or rapidly recurrent seizures without regaining consciousness. The overall US and European estimated crude incidence rate of SE ranges from 6.8 to 41/100,000/yr. The etiologies of SE include primary central nervous system pathologies and systemic disorders. The two basic mechanisms involved in the genesis of SE are an excess of excitatory activity and a loss of normal inhibitory neurotransmission. Mortality associated with SE can be as high as 26% for the average adult. Early recognition and treatment are important for improving the chances for a good outcome. The first line of treatment is an intravenous benzodiazepine, with lorazepam being the current preferred agent. All patients with SE who remain with altered awareness 20 to 30 minutes after cessation of clinical seizures should undergo electroencephalographic studies, because up to 20% of patients without clinical evidence of seizures after initial treatment can have nonconvulsive SE.

[Clinical characteristics of status epilepticus in an emergency hospital: importance of nonconvulsive status epilepticus]

Although nonconvulsive status epilepticus (NCSE) is a major neurological emergency, its frequency and clinical course are not well clarified. We investigated the clinical characteristics of status epilepticus focusing on the significance of NCSE. One thousand seven hundred twenty-three patients were admitted as neurological emergency cases in our hospital between October 2003 and September 2006. Of these cases, 94 (5.5%) were diagnosed as status epilepticus of which, 24 (25.5%) were diagnosed with NCSE on admission. Moreover, 8 patients who presented with convulsive status epilepticus on admission had episodes of NCSE during hospitalization. Thus, 32 patients (34.0%) suffered from NCSE during their clinical course. We analyzed the prognostic factors of status epilepticus using the Glasgow Outcome Scale. Poor outcome was significantly correlated with NCSE (p = 0.003) and acute cerebrovascular disease (p = 0.010), independent of age, sex, history of epilepsy, and other etiologies. Our study revealed that NCSE is not a rare condition and results in a poor outcome. Careful EEG evaluation of patients with consciousness disturbance might increase the diagnostic accuracy of NCSE, and aggressive treatment of patients with NCSE should be necessary to improve the prognosis of NCSE.

Seizures and status epilepticus in the critically ill

Seizures represent stereotypic electroencephalographic (EEG) and behavioral paroxysms as a consequence of electrical neurologic derangement. Seizures are usually described as focal or generalized motor convulsions; however, nonconvulsive seizures that occur in the absence of motor activity may escape clinical detection. Because of the admission diagnoses and dramatic physiologic and metabolic derangements common to critically ill patients, the entire spectrum of seizure disorders may be encountered in the ICU. Seizures in the ICU are attributable to primary neurologic pathology or secondary to critical illness and clinical management. For optimal treatment, early diagnosis of the seizure type and its cause is important to ensure appropriate therapy. Convulsive status epilepticus requires emergent treatment before irreversible brain injury and severe metabolic disturbances occur.

Treatment of acute seizures and status epilepticus

Overt status epilepticus and persistent obtundation after a witnessed clinical seizure are neurologic emergencies. Early recognition and intervention in the electroclinical syndrome of status epilepticus reduces morbidity, although treatment of the underlying etiology is also critical. This review outlines key concepts related to status epilepticus, delineates an approach to the early management of status epilepticus, and highlights novel but practical approaches in the evaluation and treatment of refractory status epilepticus, emphasizing the use of a treatment algorithm. This review is written from the perspective of the intensive care unit clinician, and the approach and opinions expressed stem from clinical experience and review of the current literature. Particular attention is given to an overall approach to the management of convulsive status epilepticus in adults and older children as well as exploring novel approaches and diagnostic tools that may prove useful in difficult-to-control status epilepticus.

Propofol and barbiturates for the anesthesia of refractory convulsive status epilepticus: pros and cons

OBJECTIVE

To discuss mainly the use of propofol and barbiturates in the anesthesia of refractory status epilepticus (RSE).

METHODS

Review of literature.

RESULTS

There are no prospective, randomized works comparing the effects of anesthetics in the treatment of RSE. Recently, the use of propofol has increased in the treatment of RSE. Propofol terminates both clinical and electric seizures quickly, but the maintenance of burst-suppression EEG pattern requires repetitive titration of doses. Relapses of seizures have occurred in 19-33% of patients, especially when tapering of dose. The advantages of barbiturates are lower frequency of short-term treatment failures, breakthrough seizures and changes to a different anesthetic agent. On the other hand, prolonged recovery leads to prolonged duration of mechanical ventilation, intensive care and hospital stay.

DISCUSSION

The use of propofol, barbiturates or midazolam in the anesthesia of RSE can be justified. When using propofol, the duration of high doses should be limited to 48 hours and the risk of propofol infusion syndrome should be kept in mind. High doses of barbiturates terminate effectively seizures but recovery from anesthesia prolongs ventilator treatment and intensive care.

Ictal neuropsychological findings in focal nonconvulsive status epilepticus

OBJECTIVE

This study was intended to describe the neuropsychological phenomenology of focal nonconvulsive status epilepticus (NCSE).

METHODS

Ictal, postictal, and interictal neuropsychological testing (NPT) was performed on six patients who developed NCSE during video/electroencephalographic monitoring in the context of presurgical evaluation.

RESULTS

Neuropsychological impairments were marked in four of six and discrete in two of six patients. The majority of patients had selective rather than global neuropsychological deficits. The most important deficits involved consciousness, speech, praxis, cognitive functions, and affect. Impairment of consciousness was characterized by reduced vigilance, reactivity, and orientation. Some patients exhibited combined deficits of several higher cognitive functions (apraxia, acalculia, alexia, and aphasia with or without additional memory disturbance). Several patients had relatively subtle expressive or receptive aphasia. More severe language deficits were associated with reduced vigilance. Speech deficits may have caused poor performance in other areas evaluated with NPT.

CONCLUSION

NPT demonstrated that focal NCSE can be associated with pleomorphic but often discrete neuropsychological deficits.

Multimodality monitoring in neurocritical care

Multimodality monitoring of cerebral physiology encompasses the application of different monitoring techniques and integration of several measured physiologic and biochemical variables into assessment of brain metabolism, structure, perfusion, and oxygenation status. Novel monitoring techniques include transcranial Doppler ultrasonography, neuroimaging, intracranial pressure, cerebral perfusion, and cerebral blood flow monitors, brain tissue oxygen tension monitoring, microdialysis, evoked potentials, and continuous electroencephalogram. Multimodality monitoring enables immediate detection and prevention of acute neurologic injury as well as appropriate intervention based on patients' individual disease states in the neurocritical care unit. Real-time analysis of cerebral physiologic, metabolic, and cardiovascular parameters simultaneously has broadened knowledge about complex brain pathophysiology and cerebral hemodynamics. Integration of this information allows for more precise diagnosis and optimization of management of patients with brain injury.

Rhythmic diffuse delta frequency activity presenting as an unusual EEG correlate of nonconvulsive status epilepticus: three case studies

We report three cases of nonconvulsive status epilepticus (NCSE) in which electroencephalograms (EEGs) were dominated by rhythmic or semirhythmic, high-voltage, diffuse, delta activity. These recordings initially contained little or no clear epileptiform activity. Two of these patients had prolonged episodes of NCSE, which were recorded with continuous long-term EEGs. These recordings revealed focal epileptiform discharges as well as persistent generalized epileptiform patterns. Rhythmic or semirhythmic, diffuse, delta activity with little or no clear epileptiform components has only rarely been reported with NCSE. Diffuse delta slowing is commonly seen in many toxic-metabolic encephalopathies, and this activity may occasionally appear rhythmic. EEG and clinical characteristics that may help distinguish these conditions are discussed.

Outcomes in 140 critically ill patients with status epilepticus

OBJECTIVE

Despite recent management guidelines, no recent study has evaluated outcomes in ICU patients with status epilepticus (SE).

DESIGN AND SETTING

An 8-year retrospective study.

SUBJECTS AND INTERVENTION

Observational study in 140 ICU patients with SE, including 81 (58%) with continuous SE and 59 (42%) with intermittent SE (repeated seizures without interictal recovery).

MEASUREMENTS AND RESULTS

The 95 men and 45 women had a median age of 49 years (IQR 24-71). Median seizure time was 60 min (IQR 20-180), and 58 patients had seizures longer than 30 min. The SE was nonconvulsive in 16 (11%) patients and convulsive in 124 (89%), including 89 (64%) with tonic-clonic generalized seizures, 27 (19%) with partial seizures, 7 (5%) with myoclonic seizures, and 1 with tonic seizures. The most common causes of SE were cerebral insult in 53% and anticonvulsant drug withdrawal in 20% of patients. No cause was identified in 35% of patients. Median time from SE to treatment was 5 min (IQR 0-71). The SE was refractory in 35 (25%) patients. Mechanical ventilation was needed in 106 patients. Hospital mortality was 21%. By multivariate analysis, independent predictors of 30-day mortality were age (OR 1.03/year; 95% CI 1.00-1.06), GCS at scene (OR 0.84/point; 95% CI 0.72-0.98), continuous SE (OR 3.17; 95% CI 1.15-8.77), symptomatic SE (OR 4.08; 95% CI 1.49-11.10), and refractory SE (OR 2.83; 95% CI 1.06-7.54).

CONCLUSION

Mortality in SE patients remains high and chiefly determined by seizure severity. Further studies are needed to evaluate the possible impact of early maximal anticonvulsant treatment on outcomes.

Predicting neurological outcome following cardiac arrest

Because a large number of patients will suffer cardiac arrest each year, physicians must place attention on improving care for patients in the post-resuscitative setting. Part of this effort requires setting realistic goals based on patients' potential for recovery. Recovery from cardiac arrest often depends on the extent of anoxic brain injury, and for this reason primary teams consult neurologists to offer insight into potential for awakening from post-arrest coma. In doing so, neurologists inform a decision with legal, social and ethical implications. Though inapplicable without preparation at the time of cardiac arrest, the four principles of medical ethics have a direct impact on decision making during the post-resuscitative period. A review of the literature reveals that physical examination, electrophysiology, radiology, and biochemical markers can prove useful in estimating a patient's chances for neurological recovery from cardiac arrest. These factors most reliably predict poor outcome, but do so with high specificity. However, the role of the neurology consultant must change to include guidance on strategies of neuroprotection. Aggressive efforts directed towards neuroprotection may change predictions for outcomes after cardiac arrest in the future.

Nonconvulsive status epilepticus in a pediatric intensive care unit

We aimed to describe nonconvulsive status epilepticus in terms of patient age, etiology, initial presentation, and electroencephalogram and neuroimaging findings. Twenty children with nonconvulsive status epilepticus were identified by a retrospective review of children who underwent long-term electroencephalogram monitoring in a pediatric intensive care unit. Age ranged from 2 months to 18 years, and in 30% of patients, the age was <1 year. Nonconvulsive status epilepticus occurred most commonly in children with prior epilepsy (35%) or congenital heart disease (25%). Prior to nonconvulsive status epilepticus, most had experienced isolated seizures (55%) or convulsive status epilepticus (20%), but some had only preceding mental-status change (25%). The most common etiologies were exacerbation of epilepsy (35%) and ischemic stroke (25%). No children aged <1 year had preexisting epilepsy. Electroencephalograms confirmed nonconvulsive status epilepticus immediately in 65%. Nonconvulsive status epilepticus lasted up to 8 days, and neuroimaging was abnormal in 82% of patients. Nonconvulsive status epilepticus occurs in a heterogeneous group of children, results from acute symptomatic etiologies in children aged <1 year, most frequently follows isolated convulsions but can occur with only preceding mental status change, and is often prolonged. These findings suggest that a high level of suspicion for nonconvulsive status epilepticus must be maintained, and long-term electroencephalogram monitoring may be indicated in a large number of patients.

Diagnosis and management of nonconvulsive status epilepticus in children

Nonconvulsive status epilepticus (NCSE) encompasses a wide range of diagnoses with variable outcomes and treatment recommendations. In children, NCSE can be observed in various conditions, including acute neurological injuries, specific childhood epilepsy syndromes and other neurological conditions, and can also be observed in individuals with learning difficulties. NCSE in children is thought to be under-recognized, and further studies examining the electrographic characteristics of very young children in NCSE would aid the prompt recognition of additional patients. Some subtypes of NCSE are probably more harmful than others, and long-term prospective studies are needed to evaluate the damaging potential of NCSE itself as opposed to that of the underlying circumstances in which it occurs. Specific data in childhood are clearly lacking, but extrapolation from adult studies indicates that aggressive treatment is most warranted in comatose patients. By contrast, a cautious approach seems to be indicated for absence status epilepticus, complex partial status epilepticus and electrical status epilepticus during sleep.

Emergent EEG in clinical practice

OBJECTIVE

Emergency situations require a rapid and precise diagnostic approach. However, the exact role and value of the electroencephalogram (EEG) in emergent conditions have yet to be clearly defined. Our objective was to determine why clinicians order an emergency EEG, to assess to what extent it helps establish a correct diagnosis and to evaluate the result it has on subsequent patient management.

METHODS

We studied all successive emergency EEGs ordered during a 3-month period in our institution. We analyzed the reasons why each EEG was ordered and interviewed the prescribing clinicians in order to determine the impact the result of the EEG had on the diagnosis and subsequent therapeutic management.

RESULTS

We prospectively studied a total of 111 consecutive recordings. The main reasons for ordering an emergent EEG were: suspected cerebral death (21%), non-convulsive status epilepticus (19.7%), subtle status epilepticus (14%) and follow-up of convulsive status epilepticus (11.2%). In 77.5% of the cases the clinicians considered that the EEG contributed to making the diagnosis and that it helped confirm a clinically-suspected diagnosis in 36% of the cases. When subtle status epilepticus (SSE) or non-convulsive status epilepticus (NCSE) was suspected, the diagnosis was confirmed in 45% and 43.3% of the cases, respectively. In 22.2% of the requests involving follow-up of convulsive status epilepticus after initial treatment, the EEG demonstrated persistent status epilepticus. It resulted in a change in patient treatment in 37.8% of all the cases. When the EEG helped establish the diagnosis, patient treatment was subsequently modified in 46.6% of the cases.

CONCLUSIONS

This prospective study confirms the value of an emergent EEG in certain specific clinical contexts: the management of convulsive status epilepticus following initial treatment or to rule out subtle status epilepticus. An emergent EEG can also be ordered if one suspects the existence of non-convulsive status epilepticus when a patient presents with mental confusion or altered wakefulness after first looking for the specific signs suggesting this diagnostic hypothesis.

SIGNIFICANCE

After 50 years of development and use in daily practice, the EEG remains a dependable, inexpensive and useful diagnostic tool in a number of clearly-defined emergency situations.

Convulsive status epilepticus: clinical profile in a developing country

PURPOSE

In developing countries optimal care of status epilepticus (SE) is associated with major barriers, particularly transportation.

METHODS

A prospective study of SE was performed between 1994 and 1996 to determine the clinical profile, response to treatment and outcome, Glasgow Outcome Scale (GOS).

RESULTS

Of the 85 patients admitted, the mean age was 33 years (8-75 years), 16% <16 years of age. The mean duration of SE before admission was 18.02 h (1-72 h). Only 23 (28%) patients, all locals, presented within <3 h of onset. Etiology included acute symptomatic (54%), remote symptomatic (7%), cryptogenic (19%), and established epilepsy (20%). Central nervous system infections accounted for 24 (28%) of the etiologies. Seventy-five (88%) patients responded to first-line drugs and 10 (12%) required second-line drugs. The mean duration of SE was significantly long in nonresponders (Mean +/- SD: 32.6 +/- 20.11 vs. 15.2 +/- 18.32, p < 0.006). Duration (p < 0.01; OR 1.04, 95% CI 1.01-1.07) and acute symptomatic etiology (p < 0.038; OR 10.38, 95% CI 1.13-95.09) were the independent predictors of no-response to first-line drugs. Of the nine deaths (10.5%), eight were in acute symptomatic group. Predictors of mortality included female sex (p < 0.017, OR 13.41, 95% CI 1.59-115.38) and lack of response to first-line drugs (p < 0.0001, OR 230.27, 95% CI 8.78-6037.19). Longer duration was associated with poor GOS 1-4 (p = 0.001). Of the 37 patients with <6 h, 81% had GOC5 outcome.

CONCLUSION

This study suggests that longer duration of SE and acute symptomatic etiology are independent predictors of lack of response to first-line drugs. Failure to respond to first-line drugs and duration predict the outcome.

Orofacial automatisms induced by acute withdrawal from high-dose midazolam mimicking nonconvulsive status epilepticus in a child

Nonconvulsive Status Epilepticus (NCSE) is not uncommon in children, and can be challenging to diagnose and treat. Etiologies vary widely and include infection, trauma and acute withdrawal from medications such as anticonvulsants. We report a child who experienced orofacial dyskinesias concerning for NCSE after withdrawal from high dose benzodiazepines andopiates. Automonic signs typically associated with sedative withdrawal were absent and treatment with benzodiazepines did not improve his symptoms. Diagnostic testing was negative, including electroencephalogram, and resolution was complete within five days. Our case demonstrates the orofacial dyskinesias that may occur during sedative medication withdrawal, and highlights potential confusion with non-convulsive status epilepticus.

Nonconvulsive seizures: developing a rational approach to the diagnosis and management in the critically ill population

Originally described in patients with chronic epilepsy, nonconvulsive seizures (NCSs) are being recognized with increasing frequency, both in ambulatory patients with cognitive change, and even more so in the critically ill. In fact, the majority of seizures that occur in the critically ill are nonconvulsive and can only be diagnosed with EEG monitoring. The semiology of NCSs and the associated EEG findings are quite variable. There are a number of periodic, rhythmic or stimulation-related EEG patterns in the critically ill of unclear significance and even less clear treatment implications. The field struggles to develop useful diagnostic criteria for NCSs, to standardize nomenclature for the numerous equivocal patterns, and to devise studies that will help determine which patterns should be treated and how aggressively. This review surveys the evidence for and against NCSs causing neuronal injury, and attempts to develop a rational approach to the diagnosis and management of these seizures, particularly in the encephalopathic population.

The anaesthetic and intensive care of status epilepticus

PURPOSE OF REVIEW

Status epilepticus refractory to first and second-line anticonvulsants represents an outstanding challenge to the medical team. This review covers new insights into the anaesthetic and intensive care of status epilepticus.

RECENT FINDINGS

In the anaesthetic treatment of status epilepticus, barbiturates, midazolam, or propofol are the drugs of choice, but the lack of controlled prospective data as yet does not allow the recommendation of a preference for one of the substances, unequivocally. Recent observational studies reported on inhalational anaesthetics and supplementary nonanaesthetics such as levetiracetam or topiramate that may be administered if status epilepticus is not controlled by intravenous anaesthetics. Nonpharmacological approaches including resective surgery, brain stimulation, and hypothermia may be applied in selected patients, only. Psychogenic nonepileptic status epilepticus commonly mimics refractory generalized convulsive status epilepticus, and clinical features discerning the two conditions are presented. The underlying cause is the major contributor for a difficult-to-treat 'malignant' course of status epilepticus and together with age determines mortality and functional outcome.

SUMMARY

The common substances administered for the anaesthetic treatment of status epilepticus require assessment in a prospective randomized controlled trial. Alternative pharmacological or nonpharmacological approaches need further studies as well before they can be recommended as part of the therapeutic regime.

In nonconvulsive status epilepticus (NCSE), treat to burst-suppression: pro and con

Dr. Jordan (PRO) argues that when refractory NCSE is combined with acute brain injury, it produces synergistically compounded brain damage that is time dependent. Treating to EEG burst-suppression is the most rapid and effective method for stopping NCSE. The risks of burst-suppression are common to many intensive care interventions and can be minimized with expert management. Dr. Hirsch (CON) argues that treating with coma-inducing medication is highly risky and has a high mortality rate, often due to iatrogenic complications. It remains unclear if nonconvulsive seizures cause permanent neuronal injury. Nonconvulsive seizures should be diagnosed and treated as quickly as possible,but with non-coma-inducing treatments in most cases [corrected]

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.

Comparative Efficacy and Safety of Antiepileptic Drugs for the Treatment of Status Epilepticus

Status epilepticus (SE) is a medical emergency with high mortality rate. Common causes of SE include noncompliance with antiepileptic medications, drug- and alcohol-related etiologies, and central nervous system (CNS) infections. Because prolonged seizures can cause neuronal damage, treatment should be initiated promptly to avoid potential complications. Previous studies support intravenous (IV) lorazepam as first-line therapy and IV phenytoin or fosphenytoin as a second-line medication. If first-and second-line medications fail to control SE, further treatment with propofol, pentobarbital, midazolam, or other medications should be considered. Many of the drugs currently used to control SE are associated with sedation, respiratory suppression, hypotension, cardiac dysrhythmia, and anaphylactic reactions. Therefore, IV valproate or other newer antiepileptic drugs may be considered as an alternative third-line therapy for those who cannot tolerate the hypotensive effects of other anticonvulsants. This paper reviews comparative effectiveness and safety concerns among frequently used medications for SE.