Persistent Nonconvulsive Status Epilepticus After the Control of Convulsive Status Epilepticus

Summary: Purpose: Convulsive status epilepticus (CSE) is a major medical and neurological emergency that is associated with significant morbidity and mortality. Despite this high morbidity and mortality, most acute care facilities in the United States cannot evaluate patients with EEG monitoring during or immediately after SE. The present study was initiated to determine whether control of CSE by standard treatment protocols was sufficient to terminate electrographic seizures. Methods: One hundred sixty-four prospective patients were evaluated at the Medical College of Virginia/VCU Status Epilepticus Program. Continuous EEG monitoring was performed for a minimum of 24 h after clinical control of CSE. SE and seizure types were defined as described previously. A standardized data form entry system was compiled for each patient and used to evaluate the data collected. Results: After CSE was controlled, continuous EEG monitoring demonstrated that 52% of the patients had no after-SE ictal discharges (ASIDS) and manifested EEG patterns of generalized slowing, attenuation, periodic lateralizing epileptiform discharges (PLEDS), focal slowing, and/or burst suppression. The remaining 48% demonstrated persistent electrographic seizures. More than 14% of the patients manifested nonconvulsive SE (NCSE) predominantly of the complex partial NCSE seizure (CPS) type (2). These patients were comatose and showed no overt clinical signs of convulsive activity. Clinical detection of NCSE in these patients would not have been possible with routine neurological evaluations without use of EEG monitoring. The clinical presentation, mortality, morbidity, and demographic information on this population are reported. Conclusions: Our results demonstrate that EEG monitoring after treatment of CSE is essential to recognition of persistent electrographic seizures and NCSE unresponsive to routine therapeutic management of CSE. These findings also suggest that EEG monitoring immediately after control of CSE is an important diagnostic test to guide treatment plans and to evaluate prognosis in the management of SE.     

Nonconvulsive Status Epilepticus in the Emergency Room

Purpose: The study reviewed emergent cases of nonconvulsive status epilepticus (NCSE) to evaluate causes of diagnostic and management delay and examined frequent diagnostic features suggestive of NCSE. Methods: In a retrospective study, we assessed the clinical presentation of 23 patients with one or more NCSE episodes, their medical history, EEG, and antiepileptic drug (AED) treatment. We also evaluated causes of diagnostic delay in patients referred to the emergency room (ER) in confusional states. Results: There was considerable overlap in clinical features of patients with complex partial SE (CPSE) and generalized nonconvulsive SE (GNSE). Delays in seeking medical attention were common. Diagnosis was significantly delayed in 10 patients. Three cases illustrate the possible markedly different presentations of NCSE. Conclusions: NCSE often goes unrecognized or is mistaken for behavioral or psychiatric disturbance. The pleo-morphic clinical presentation of NCSE indicates that EEG and a therapeutic trial of AEDs afford the best diagnostic measures in acute waxing and waning confusional states associated with agitation, bizarre behavior, staring, increased tone, mutism, or subtle myoclonus.     

Nonconvulsive Status Epilepticus in Adults and Children

Summary: Nonconvulsive status epilepticus (SE) accounts for approximately one-quarter of all cases of SE. The actual proportion may be higher because patients with nonconvulsive SE may go unidentified. This disorder may be divided into generalized (absence) or partial (complex partial) forms. Nonconvulsive SE may occur de novo or in patients with epilepsy. Absence SE is considered more frequent and is characterized by a continuous neurocognitive alteration. Complex partial SE may be associated with recurrent seizure activity and a cycling of the clinical states. Treatment includes antiepileptic drug(s) (AEDs) and avoidance of seizure precipitants. Electrophysiological studies are necessary to confirm the diagnosis of nonconvulsive SE and to monitor the response to AED therapy. Prompt recognition and treatment may be necessary to avoid neurological morbidity in select patients. Epilepsy with continuous spikes and waves during slow sleep (ESES) and the Landau-Kleffner syndrome are two rare childhood disorders that are difficult to classify but may be appropriate to include in a discussion of nonconvulsive SE.     

Focal Status Epilepticus: Clinical Features and Significance of Different EEG Patterns

PURPOSE: Focal status epilepticus is typically diagnosed by the observation of continuous jerking motor activity, but many other manifestations have been described. EEG evidence of focal status may take several forms, and their interpretation is controversial. We detailed the clinical spectrum of focal status in patients diagnosed by both clinical deficit and EEG criteria and contrasted clinical manifestations in patients with different EEG patterns. METHODS: Patients were diagnosed with a neurologic deficit and discrete recurrent focal electrographic seizures or rapid, continuous focal epileptiform discharges on EEG. Clinical findings were determined by chart review. RESULTS: Of 41 patients with focal status, acute vascular disease was the cause in 21; 10 of 41 had exacerbations of prior epilepsy. A variety of clinical seizure types occurred, both before and after the EEG diagnosis, but the diagnosis was not expected in 28 patients before the EEG. Three had no obvious clinical seizures. Focal motor seizures and an abnormal mental status were the most common manifestations at the time of the EEG. With antiepileptic drugs, almost all had control of clinical seizures, and most improved in mental status. Patients with rapid continuous focal epileptiform discharges were nearly identical in presentation, likelihood of diagnosis, subsequent seizures, response to medication, and outcome to those with discrete seizures on EEG. CONCLUSIONS: Focal status epilepticus may be seen with a wide variety of clinical seizure types or without obvious clinical seizures. The diagnosis is often delayed or missed and should be considered after strokes or clinical seizures when patients do not stabilize or improve as expected. The diagnosis should be made equally whether patients have discrete electrographic seizures or continuous rapid focal epileptiform discharges on the EEG, and the same response to medications and outcome should be anticipated for the two groups.     

Two Patients with Juvenile Myoclonic Epilepsy and Nonconvulsive Status Epilepticus

We report 2 girls, aged 10 and 13 years, with juvenile myoclonic epilepsy (JME) who had episodes of nonconvulsive status epilepticus (NCSE). Symptoms included only mild lethargy, slow responses, and trembling of the eyelids. There was no ataxia or myoclonus of the limbs or body, and they were always able to respond. Electroencephalograms during these episodes showed almost continuous generalized polyspike-waves in both patients. Patients with JME can develop NCSE, which may be overlooked because of the subtle clinical symptoms.     

Neurosurgical Treatment of Refractory Status Epilepticus

Refractory status epilepticus (RSE) is defined as status epilepticus that continues despite aggressive treatment. A 9.8-year-old boy with a past history of daily left focal motor seizures was transferred to University of California at Los Angeles (UCLA) Hospital in pentobarbital coma after 4 days in RSE. The RSE was treated with very high doses of all appropriate antiepileptic drugs (AEDs), alone and in combination. The pentobarbital was titrated to burst suppression on EEG, but whenever pentobarbital was decreased, the seizures recurred. An ictal positron tomography scan of glucose metabolism demonstrated a right frontal area of hypermetabolism corresponding to an epileptic focus on EEG and magnetic resonance lesion. Eight days after the boy was admitted to UCLA, the right frontal focus was surgically removed, with immediate control of the status epilepticus. Whereas before onset of RSE, he had daily focal seizures, the boy has been seizure-free postoperatively for greater than 1 year. Operative treatment should be considered in patients with RSE in whom a focus of seizure onset can be demonstrated and who are reasonably considered surgical candidates.     

Nonconvulsive Status Epilepticus in Adults: Thirty-Two Consecutive Patients from a General Hospital Population

We studied all adult patients who between 1984 and 1989 were initially diagnosed at our hospital as having nonconvulsive status epilepticus. Thirty-two patients fulfilled the criteria, which included ictal EEG recordings. The annual incidence was 1.5 in 100,000 inhabitants. The median age at onset of status was 51 years. Ten patients had status as their first epileptic manifestation, but most patients had a previous history of epilepsy. Median duration of epilepsy at onset of status was 4 years. Fourteen patients had focal ictal seizure activity on EEG and thus met the criteria for complex partial status. Eighteen patients had generalized seizure activity on EEG, but only 6 of these had a history of absence epilepsy or juvenile myoclonic epilepsy. None had Lennox-Gastaut syndrome. The clinical features of status in the remaining 12 patients were in some respects similar to those of the patients with complex partial status. We hypothesize that the EEG seizure activity in these patients may have been generalized from an initial focus.     

In Nonconvulsive Status Epilepticus (NCSE), Treat to Burst-Suppression: Pro and Con

Summary:  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.     

Nonconvulsive Status Epilepticus in Two Patients Receiving Tiagabine Treatment

Summary: In the course of an open study on the add-on treatment of tiagabine (TGB) in patients with localization-related epilepsy syndromes, 2 of 9 patients developed nonconvulsive status epilepticus (NCSE) with electroclinical features consistent with those of atypical absence seizures. One patient had never had atypical absence seizures before. In both cases, immediate discontinuation of TGB was followed by complete and sustained electroclinical remission; we suggest a possible causative role of TGB. This observation may be consistent with a paradoxical effect of TGB in selected cases. Possible risk factors and a pathophysiological hypothesis are discussed.     

癫痫持续状态的定义演变

癫痫持续状态是神经内科常见的急危重症。对癫痫持续状态概念的界定是进行临床诊疗 和科学研究的基础,随着癫痫持续状态病理生理机制研究的深入,其定义也在不断地修订与完善, 由抽象到具体,由惊厥到非惊厥,癫痫发作持续时间逐渐严谨且更加强调难治性的概念。本文着重 回顾癫痫持续状态的定义演变历程。     

Physiologic Consequences of Status Epilepticus

Summary: Prolonged seizures produce central nervous system damage. Physiologic consequences of status epilepticus may exacerbate this damage or may mislead the physician into making inappropriate therapeutic decisions. Status results in an elevation of body temperature, an increase in the peripheral white cell count, and often a transient pleocytosis in the spinal fluid. A marked metabolic acidosis occurs routinely. Prominent elevations in plasma hormonal concentrations occur as well. Epinephrine levels are in the arrhythmogenic range and could play a role in sudden death. Transient but marked pressure responses occur in the systemic and pulmonary circulations. Pulmonary edema may result from these pressure transients.     

Generalized Convulsive Status Epilepticus in the Adult

Summary: Status epilepticus (SE) is denned as recurrent epileptic seizures without full recovery of consciousness before the next seizure begins, or more-or-less continuous clinical and/or electrical seizure activity lasting for more than 30 min whether or not consciousness is impaired. Three presentations of SE are now recognized: recurrent generalized tonic and/or clonic seizures without full recovery of consciousness between attacks, nonconvulsive status where the patient appears to be in a prolonged "epileptic twilight state," and continuous/repetitive focal seizure activity without alteration of consciousness. Generalized convulsive status epilepticus (GCSE) encompasses a broad spectrum of clinical presentations from repeated overt generalized tonic-clonic seizures to subtle convulsive movements in a profoundly comatose patient. Thus, GCSE is a dynamic state that is characterized by paroxysmal or continuous tonic and/or clonic motor activity, which may be symmetrical or asymmetrical and overt or subtle but which is associated with a marked impairment of consciousness and with bilateral (although frequently asymmetrical) ictal discharges on the EEG. Just as there is a progression from overt to increasingly subtle clinical manifestations of GCSE, there is also a predictable sequence of progressive EEG changes during untreated GCSE. A sequence of five patterns of ictal discharges has been observed: discrete electrographic seizures, waxing and waning, continuous, continuous with flat periods, and periodic epileptiform discharges on a relatively flat background. A patient actively having seizures or comatose who exhibits any of these patterns on EEG should be considered to be in GCSE and should be treated aggressively to stop all clinical and electrical seizure activity to prevent further neurological morbidity and mortality.     

Oculoclonic Status Epilepticus

Continuous oculoclonic status epilepticus occurred for 90 min in a 4-year-old girl. The seizure consisted of continuous contralateral horizontal nystagmus concurrent with left occipital spike discharges, occasional vomiting and no loss of consciousness. Oculoclonic status epilepticus may be a variant form of versive status epilepticus.     

Short-Term Mortality After a First Episode of Status Epilepticus

Summary: Purpose: Studies evaluating short-term mortality among people who experience status epilepticus (SE) have produced conflicting results. Most studies are derived from clinical series with results affected by unspecified follow-up period and select referral of cases. This study was planned to evaluate short-term mortality after a first episode of SE. Methods: We performed a population-based retrospective cohort study to determine the short-term mortality following a first episode of SE. Between January 1,1965 and December 31, 1984, we studied all first episodes of a febrile SE who received medical attention in Rochester, Minnesota. Cases were followed until death or end of the study (February 1996). Results: Mortality within the first 30 days was 19% (38 deaths out of 201 incident SE). Thirty-four deaths (89%) occurred among those with non febrile acute symptomatic SE, while 4 deaths (11%) occurred among those with unprovoked SE. Within the acute symptomatic group, after adjusting for age, there was a decreased risk of death in women (RR = 0.4; 95% CI: 0.2–0.9). No effect of duration or seizure type was shown after adjusting for other risk factors. Conclusions: One out of 5 subjects with SE died within the first 30 days. Short-term mortality is associated with the presence of an underlying acute etiology. Among acute symptomatic cases, women had a decreased risk of dying.     

De Novo Aphasic Status Epilepticus

: The literature contains only a handful of reports of patients with aphasia as the principal or only obvious manifestation of partial status epilepticus. Even fewer patients of this type have been well documented both clinically and by ictal EEG monitoring. We studied an otherwise healthy woman with abrupt onset of aphasia initially thought to be the result of an infarct of the left temporoparietal area. We were able to document partial status epilepticus involving the left temporoparieta1 area with EEG/video monitoring and showed rapid reversal of the aphasic disorder with antiepileptic drug (AED) treatment. The case is presented with a review of previous reports to underscore the importance of considering this diagnosis in patients with abrupt onset of aphasia.     

The EEG and Prognosis in Status Epilepticus

Summary: Purpose: To examine the relation between specific EEG features and clinical outcome, determine whether a predictable sequence of EEG patterns exists during status epilepticus (SE), and examine the relation between periodic epileptiform discharges (PEDs) and SE.
Methods: EEG records of 50 patients with SE admitted to Graduate Hospital between January 1990 and July 1995 were reviewed. Ictal EEGs were available in 72%; 28% had only postictal EEGs. Poor outcome was defined as death or persistent vegetative state, and good outcome as all others. Fisher's Exact test, x², and t tests were performed for data analysis.
Results: Of 50 patients, 72% had a good outcome and 28%, a poor outcome. If PEDs were present at any time during or after SE, outcome tended to be worse (p = 0.053). With PEDs, eight (44%) of 18 had a poor outcome; without PEDs, six (19%) of 32 had a poor outcome. Etiologies for SE did not substantially differ in patients with or without PEDs, and structural abnormalities were not more associated with the presence of PEDs. PEDs were seen both early and late, during and after SE. Other EEG characteristics (lateralized vs. bilateral symmetric ictal EEG, discrete vs. continuous ictal activity, and postictal focal slowing) did not relate to outcome. No predictable sequence of EEG changes was found during SE.
Conclusions: PEDs are the only EEG feature related to outcome in SE and are associated with poor outcome independent of etiology.     

Determinants of Mortality in Status Epilepticus

Summary: Using univariate and multivariate regression analysis, we studied seizure duration, seizure type, age, etiologies, other clinical features, and mortality among 253 adults with status epilepticus (SE) admitted to the Medical College of Virginia. Cerebral vascular disease and discontinuation of antiepileptic drugs (AEDs) were the most prominent causes of SE, each accounting for ∼22% of all patients in the series. The other principle etiologies were alcohol withdrawal, idiopathic, anoxia, metabolic disorders, hemorrhage, infection, tumor, drug overdose, and trauma. When the patients were divided into two groups, the group with SE lasting < 1 h had a lower mortality as compared with seizure duration ≥ 1 h. Low mortality rates were noted in alcohol and AED discontinuation etiologies. Anoxia and increasing age were significantly correlated with higher mortality. The mortality rates of partial and generalized SE were not significantly different. Race and sex did not affect mortality significantly. Our findings represent the first multivariate analysis of predictive indicators of mortality in SE and demonstrate that specific factors influence mortality rate in SE.     

Nonconvulsive Status Epilepticus: High Incidence of Complex Partial Status

Nonconvulsive status epilepticus may be subdivided into generalized (absence) status and complex partial status. The latter is regarded as a rarity, whereas the former constitutes the dominant part of the hitherto reported cases. We report 10 consecutive cases of adult patients with nonconvulsive status epilepticus, all documented by ictal electroencephalographic (EEG) recordings. Five had a complex partial status; the origin of the complex partial status appeared to be frontal in four of these patients. Three had recurrent complex partial seizures with incomplete recovery between seizures, and two had more continuous symptoms. One of the latter exhibited neither motor phenomena nor automatisms. The effect of diazepam or clonazepam was immediate in all 10 cases though transient in eight. A lasting control of the status was not achieved in six patients until i.v. phenytoin was added. The difficulties in the differentiation between complex partial status and absence status despite ictal EEG recordings are discussed, illustrated by a case with seizure discharges of a focal onset which rapidly generalized. The study indicates that complex partial status may be more common and the clinical expressions of absence status more variable than hitherto recognized.     

Age-Dependent Consequences of Status Epilepticus: Animal Models

Summary:  Status epilepticus (SE) is a significant neurological emergency that occurs most commonly in children. Although SE has been associated with an elevated risk of brain injury, it is unclear from clinical studies in whom and under what circumstances brain injury will occur. The purpose of this review is to evaluate the effects of age on the consequences of SE. In this review, we focus mainly on the animal data that describe the consequences of a single episode of SE induced in the adult and immature rat brain. The experimental data suggest that the risk of developing SE-induced brain damage, subsequent epilepsy and cognitive deficits in large part depends on the age in which the SE occurs. Younger rats are more resistant to seizure-induced brain damage than older rats; however, when SE occurs in immature rats with abnormal brains, there is an increase in the severity of seizure-induced brain injury. Better understanding of the pathophysiologic mechanisms underlying the age-specific alterations to the brain induced by SE will lead to the development of novel and effective strategies to improve the deleterious consequences.