A prospective, population-based epidemiologic study of status epilepticus in Richmond, Virginia

This report presents the initial analysis of a prospective, population-based study of status epilepticus (SE) in the city of Richmond, Virginia. The incidence of SE was 41 patients per year per 100,000 population. The frequency of total SE episodes was 50 per year per 100,000 population. The mortality rate for the population was 22%, 3% for children and 26% for adults. Evaluation of the seizure types for adult and pediatric patients demonstrated that both partial and generalized SE occur with a high frequency in these populations. Based on the incidence of SE actually determined in Richmond, Virginia, we project 126,000 to 195,000 SE events with 22,200 to 42,000 deaths per year in the United States. The majority of SE patients had no history of epilepsy. These results indicate that SE is a common neurologic emergency.

Refractory status epilepticus: frequency, risk factors, and impact on outcome

BACKGROUND

Refractory status epilepticus (RSE) is a life-threatening condition in which seizures do not respond to first- and second-line anticonvulsant drug therapy. How often RSE occurs, risk factors that predispose to this condition, and the effect of failure to control seizures on clinical outcome are poorly defined.

OBJECTIVE

To determine the frequency, risk factors, and impact on outcome of RSE.

DESIGN

Retrospective cohort study.

SETTING

Large academic teaching hospital.

PATIENTS

Consecutive sample of 83 episodes of status epilepticus in 74 patients (mean age, 63 years).

MAIN OUTCOME MEASURES

Refractory status epilepticus was defined as seizures lasting longer than 60 minutes despite treatment with a benzodiazepine and an adequate loading dose of a standard intravenous anticonvulsant drug. Factors associated with RSE were identified using univariate and backward stepwiselogistic regression analyses.

RESULTS

In 57 episodes (69%), seizures occurred after treatment with a benzodiazepine, and in 26 (31%), seizures occurred after treatment with a second-line anticonvulsant drug (usually phenytoin), fulfilling our criteria for RSE. Nonconvulsive SE (P=.03) and focal motor seizures at onset (P=.04) were identified as independent risk factors for RSE. Eleven (42%) of 26 patients with RSE had seizures after receiving a third-line agent (usually phenobarbital). Although mortality was not increased (17% overall), RSE was associated with prolonged hospital length of stay (P<.001) and more frequent functional deterioration at discharge (P=.02).

CONCLUSIONS

Refractory status epilepticus occurs in approximately 30% of patients with SE and is associated with increased hospital length of stay and functional disability. Nonconvulsive SE and focal motor seizures at onset are risk factors for RSE. Randomized controlled trials are needed to define the optimal treatment of RSE.

Determinants of mortality in status epilepticus

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 approximately 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 > or = 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.

Incidence, cause, and short-term outcome of convulsive status epilepticus in childhood: prospective population-based study

BACKGROUND

Convulsive status epilepticus is the most common childhood medical neurological emergency, and is associated with significant morbidity and mortality. Most data for this disorder are from mainly adult populations and might not be relevant to childhood. Thus we undertook the North London Status Epilepticus in Childhood Surveillance Study (NLSTEPSS): a prospective, population-based study of convulsive status epilepticus in childhood, to obtain a uniquely paediatric perspective.

METHODS

Clinical and demographic data for episodes of childhood convulsive status epilepticus that took place in north London were obtained through a clinical network that covered the target population. We obtained these data from anonymised copies of a standardised admission proforma; accident and emergency, nursing, ambulance, and intensive-care unit notes; and interviews with parents, medical, nursing, and paramedic staff. We investigated ascertainment using capture-recapture modelling.

FINDINGS

Of 226 children enrolled, 176 had a first ever episode of convulsive status epilepticus. We estimated that ascertainment was between 62% and 84%. The ascertainment-adjusted incidence was between 17 and 23 episodes per 100,000 per year. 98 (56%, 95% CI 48-63) children were neurologically healthy before their first ever episode and 56 (57%, 47-66) of those children had a prolonged febrile seizure. 11 (12%, 6-18) of children with first ever febrile convulsive status epilepticus had acute bacterial meningitis. Conservative estimation of 1-year recurrence of convulsive status epilepticus was 16% (10-24%). Case fatality was 3% (2-7%).

INTERPRETATION

Convulsive status epilepticus in childhood is more common, has a different range of causes, and a lower risk of death than that in adults. These paediatric data will help inform management of convulsive status epilepticus and appropriate allocation of resources to reduce the effects of this disorder in childhood.

Incidence of status epilepticus in adults in Germany: a prospective, population-based study

PURPOSE

To determine the incidence and case-fatality rate of status epilepticus (SE) in adults in Hessen, Germany, we performed a prospective, population-based study from July 1997 through June 1999.

METHODS

All adult patients residing within the zip-code area 35 (area-35) with SE were included. Area-35 had 743.285 adult inhabitants, including 123.353 adult inhabitants of the primary service area of the University Hospital Marburg (PS-area). Patients were reported by 16 hospitals in the area and were prospectively identified and carefully reviewed within 5 days by one of the authors. Based on the crude annual incidence of SE and a rate of underascertainment of 10% determined for the PS-area, the corrected, age-adjusted incidence of SE in area 35, more representative of the population of Germany, was calculated.

RESULTS

The crude annual incidence in the PS-area was 15.8/100,000 [95% confidence interval (CI), 11.2-21.6]. The calculated, corrected, age-adjusted incidence of SE in area 35 was 17.1/100,000. It was higher for men compared with women (26.1 vs. 13.7) and for those aged 60 years and older (54.5 vs. 4.2/100,000, p < 0.0001). The etiology was mainly remote symptomatic due to cerebrovascular disease. Epilepsy was previously diagnosed in only 50% of the patients. The case-fatality rate was 9.3%.

CONCLUSIONS

Based on our data, at least 14,000 patients would be affected by SE in Germany, associated with approximately 1,300 deaths annually. The incidence of SE in Germany is similar to that found in the white United States population. Furthermore, this study confirms the higher incidence of SE in male patients and in the elderly population. This may be due to a higher incidence of cerebrovascular disease in these subpopulations.

Incidence of status epilepticus in Rochester, Minnesota, 1965-1984

We determined the incidence of status epilepticus (SE) by ascertaining all first episodes of SE in Rochester, Minnesota through the Rochester Epidemiology Project's records-linkage system between January 1, 1965 and December 31, 1984. Information was collected on age, gender, duration, seizure type, and etiology. The age-adjusted incidence of SE was 18.3 per 100,000 population. SE incidence was U-shaped, peaking under 1 year and over 60 years of age. The incidence of SE was greater for males than for females, for acute symptomatic etiology than any other etiology, and for partial SE that did not generalize than any other seizure type. Status of long duration (at least 2 hours) occurred more frequently among infants and the elderly than among persons aged 1 to 65 years. Cumulative incidence was 4 per 1,000 to age 75 and showed the greatest increase after age 60. Given the aging of the population, SE will become an increasingly important public health problem.

Electrographic seizures and periodic discharges after intracerebral hemorrhage

OBJECTIVE

To determine the frequency and significance of electrographic seizures and other EEG findings in patients with intracerebral hemorrhage (ICH).

METHODS

We reviewed 102 consecutive patients with ICH who underwent continuous electroencephalographic monitoring (cEEG). Demographic, clinical, radiographic, and cEEG findings were recorded. Using multivariate logistic regression analysis, we determined factors associated with 1) electrographic seizures, 2) periodic epileptiform discharges (PEDs), and 3) poor outcome (death, vegetative or minimally conscious state) at hospital discharge.

RESULTS

Seizures occurred in 31% (n = 32) of patients with ICH, prior to cEEG in 19 patients. Eighteen percent (n = 18) of patients had electrographic seizures; only one of these patients also had clinical seizures while on cEEG. After controlling for demographic and clinical predictors, only an increase in ICH volume of 30% or more between admission and 24-hour follow-up CT scan was associated with electrographic seizures (33% vs 15%; OR 9.5, 95% CI 1.7 to 53.8). PEDs were less frequently seen in those with hemorrhages located at least 1 mm from the cortex (8% vs 29%; OR 0.2, 95% CI 0.1 to 0.7). PEDs were independently associated with poor outcome (65% vs 17%; OR 7.6, 95% CI 2.1 to 27.3). In patients with electrographic seizures, the first seizure was detected within the first hour of cEEG monitoring in 56% and within 48 hours in 94%.

CONCLUSIONS

Seizures occurred in one third of patients with intracerebral hemorrhage (ICH) and over half were purely electrographic. Electrographic seizures were associated with expanding hemorrhages, and periodic discharges with cortical ICH and poor outcome. Further research is needed to determine if treating or preventing seizures or PEDs might lead to improved outcome after ICH.

Status epilepticus. Causes, clinical features and consequences in 98 patients

The etiology, clinical features and outcome of generalized major motor status epilepticus in 98 patients over the age of 14 years have been reviewed. Approximately half of the patients had not had previous seizures. The most common single cause of the status was noncompliance with anticonvulsant drug regimens and this accounted for the status in 53 percent of the patients with previous seizures and in 28 percent of all the patients in our series. The other causes in our series were alcohol-withdrawal, cerebrovascular disease, cerebral tumors or trauma (involving especially the frontal lobe), intracranial infection, metabolic disorders, drug overdose and cardiac arrest. In 15 percent of the patients, however, no specific cause could be found. Status was never the initial manifestation of primary (constitutional) generalized epilepsy in our experience. The etiology of the status was sometime multifactorial, so patients must be screened as fully as possible even when a likely cause is readily apparent. The motor manifestations of the convulsions were frequently restricted in distribution (62 percent of the cases). Focal or lateralized convulsive activity, especially during the course of continued seizure activity, did not necessarily indicate that localized structural pathology was responsible for the status. The seizures were of the tonic variety in a few of our patients and in such circumstances were usually associated with cerebral anoxia. We found that a poor outcome of the status was more likely as its duration increased, and the morbidity rate from the status itself was 12.5 percent among our patients, with a mortality rate of 2.5 percent. The episode of status was usually accompanied by hyperthermia, and often by a brisk peripheral leukocytosis, and in some of our patients a status-induced cerebrospinal fluid pleocytosis also developed. These features may lead to diagnostic confusion if their basis is not recognized. In most of our patients a systemic acidosis developed during the course of the status, but this did not appear to greatly influence the outcome.

Predictors and prognosis of refractory status epilepticus treated in a neurological intensive care unit

OBJECTIVE

To assess risk factors and prognosis in patients with refractory status epilepticus (RSE).

METHODS

We retrospectively analysed all episodes of status epilepticus (SE) treated between 1993 and 2002 on the neurological intensive care unit (NICU) of the Charite-Universitatsmedizin Berlin. The predictive and prognostic features of RSE were compared with non-RSE (NRSE). All patients with "de novo" SE were followed up to identify the possible development of post-SE symptomatic epilepsy.

RESULTS

A total of 83 episodes fulfilled our criteria of SE. Of these 43% were refractory to first line anticonvulsants. The mean age of patients with SE was 53.3 (SD 19) years, with only two patients younger than 18 years. Encephalitis was significantly more often the primary cause in RSE (p<0.05), whereas low levels of antiepileptic drugs were significantly more often associated with NRSE (p<0.001). Hyponatraemia within the first 24 hours after onset of status activity was significantly more often associated with RSE (p<0.05). In RSE, compared with NRSE, significantly longer duration of seizure activity (p<0.001), more frequent recurrence of epileptic activity within the first 24 hours after the end of seizure activity (p<0.001), longer stay in the NICU and in hospital (p<0.001 and p<0.01, respectively), and more frequent development of symptomatic epilepsy (p<0.05) were seen.

CONCLUSIONS

SE treated in the NICU is frequently refractory to first line anticonvulsant drugs. Encephalitis is a predictor for RSE, which is associated with markedly poor outcome, in particular, the development of post-SE symptomatic epilepsy. Thus prevention of this most severe form of SE should be the primary target of treatment of SE.

Incidence of status epilepticus in French-speaking Switzerland: (EPISTAR)

BACKGROUND

To determine the incidence, risk factors, and case fatality rate of status epilepticus (SE) in the French-speaking part of Switzerland.

METHODS

Between October 1, 1997 and September 30, 1998 all cases of SE referred to all the hospitals in the six cantons of the French-speaking part of Switzerland were identified by physicians working in emergency rooms, intensive care units, and electroencephalography departments; neurologists; and pediatricians from all hospitals in the area. Each case was validated and classified according to seizure type and etiology.

RESULTS

Over 1 year, 172 cases were identified, of whom 74 had a history of epilepsy (42.4%). The crude and standardized annual incidence rate were 9.9/100,000 (95% CI, 8.4 to 11.4) and 10.3/100,000 (95% CI, 8.7 to 11.9). The incidence rate was higher among children < 1 year of age and adults > 65 years, and among men than women. There were 108 cases of acute symptomatic SE (incidence: 6.2 per 1000), 49 cases of remote symptomatic SE, and 15 cases of unknown etiology. Case fatality rate was 7.6%.

CONCLUSIONS

The standardized incidence rate of SE in the French-speaking part of Switzerland was lower than that reported in Rochester, MN (18.3/100,000) and in the white population of Richmond, VA (20/100,000). The discrepancy may stem from the lack of a homogeneous, rigorous, and pragmatic definition of SE and the efficient management of acute repetitive seizures in this area.

Status epilepticus at an urban public hospital in the 1980s

We retrospectively reviewed the clinical course of adult patients treated for generalized status epilepticus (SE) at the San Francisco General Hospital (SFGH) from 1980 to 1989. The review was designed to determine whether the etiologies of SE at our hospital have changed over the last two decades, and to investigate the relationships between etiology, response to anticonvulsant therapy, and short-term clinical outcome. Of 154 patients reviewed, the four leading etiologies for SE were anticonvulsant drug withdrawal (39), alcohol-related (39), drug toxicity (14), and CNS infection (12). This pattern was essentially unchanged from observations made at SFGH in the 1970s. Sixty percent of all patients responded to first-line drug treatment (usually phenytoin +/- diazepam), and the remainder required an additional agent (usually phenobarbital) for control of SE. The best response to anticonvulsants occurred in patients with SE related to tumor, anticonvulsant drug withdrawal, or refractory epilepsy, and the poor responders had anoxia, drug toxicity, CNS infection, or other metabolic abnormalities. Seventy-six percent of the patients had good outcomes. Of the 22 patients who died, SE was a likely cause of death in only two (ie, 1.3% of the entire study group). Metabolic abnormalities, stroke, and anoxia were associated with particularly poor outcomes compared with other etiologies. These observations show that the etiologies of SE have remained similar over two successive decades, and that the etiology of SE may help predict both the initial response to drug therapy and the short-term outcome.

Prognosis of status epilepticus: role of aetiology, age, and consciousness impairment at presentation

BACKGROUND

Identification of outcome-predictive factors could lower risk of under- or over-treatment in status epilepticus (SE). Older age and acute symptomatic aetiology have been shown to predict mortality, but other variables are controversial and level of consciousness has received relatively little attention. The objective of this study was to assess variables predictive of mortality, particularly those available at presentation.

METHODS

The discharge database (1997-2004) of two university hospitals was screened for adult patients with EEG confirmed SE, excluding cerebral anoxia. Outcome at discharge (mortality, return to baseline clinical conditions) was analysed in relation to demographics, clinical features, and aetiology. Aetiologies were also classified based on whether or not they were potentially fatal independently of SE.

RESULTS

Mortality was 15.6% among 96 patients with a first SE episode, 10 of whom also experienced recurrent SE during the study period. Eleven other patients had only recurrent SE. Mortality was 4.8% among these 21 patients with recurrent SE. Return to baseline condition was more frequent after recurrent than incident SE (p=0.02). For the first SE episode, death was associated with potentially fatal aetiology (p=0.01), age>or=65 (p=0.02), and stupor or coma at presentation (p=0.04), but not with gender, history of epilepsy, SE type, or time to treatment>or=1 h.

CONCLUSIONS

At initial evaluation, older age and marked impairment of consciousness are predictive of death. Surviving a first SE episode could lower the mortality and morbidity of subsequent episodes, suggesting that underlying aetiology, rather than SE per se, is the major determinant of outcome.

Progression of spontaneous seizures after status epilepticus is associated with mossy fibre sprouting and extensive bilateral loss of hilar parvalbumin and somatostatin-immunoreactive neurons

The development of spontaneous limbic seizures was investigated in a rat model in which electrical tetanic stimulation of the angular bundle was applied for up to 90 min. This stimulation produced behavioural and electrographic seizures that led to a status epilepticus (SE) in most rats (71%). Long-term EEG monitoring showed that the majority of the rats (67%) that underwent SE, displayed a progressive increase of seizure activity once the first seizure was recorded after a latent period of about 1 week. The other SE rats (33%) did not show this progression of seizure activity. We investigated whether these different patterns of evolution of spontaneous seizures could be related to differences in cellular or structural changes in the hippocampus. This was the case regarding the following changes. (i) Cell loss in the hilar region: in progressive SE rats this was extensive and bilateral whereas in nonprogressive SE rats it was mainly unilateral. (ii) Parvalbumin and somatostatin-immunoreactive neurons: in the hilar region these were almost completely eliminated in progressive SE rats but were still largely present unilaterally in nonprogressive SE rats. (iii) Mossy fibre sprouting: in progressive SE rats, extensive mossy fibre sprouting was prominent in the inner molecular layer. In nonprogressive SE rats, mossy fibre sprouting was also present but less prominent than in progressive SE rats. Although mossy fibre sprouting has been proposed to be a prerequisite for chronic seizure activity in experimental temporal lobe epilepsy, the extent of hilar cell death also appears to be an important factor that differentiates between whether or not seizure progression will occur.

A new model of chronic temporal lobe epilepsy induced by electrical stimulation of the amygdala in rat

Spontaneous seizures are the hallmark of human epilepsy but they do not occur in most of the epilepsy models that are used to investigate the mechanisms of epilepsy or to test new antiepileptic compounds. This study was designed to develop a new focal epilepsy model that mimics different aspects of human temporal lobe epilepsy (TLE), including the occurrence of spontaneous seizures. Self-sustained status epilepticus (SSSE) lasting for 6-20 h was induced by a 20-30 min stimulation of the lateral nucleus of the amygdala (100 ms train of 1 ms, 60 Hz bipolar pulses, 400 microA, every 0.5 s). Stimulated rats (n = 16) were monitored with a video-EEG recording system every other day (24 h/day) for 6 months, and every other video-EEG recording was analyzed. Spontaneous epileptic seizures (total number 3698) were detected in 13 of the 15 animals (88%) after a latency period of 6 to 85 days (median 33 days). Four animals (31%) had frequent (697-1317) seizures and 9 animals (69%) had occasional seizures (1-107) during the 6-months follow-up period. Fifty-seven percent of the seizures occurred during daytime (lights on 07:00-19:00 h). At the end of the follow-up period, epileptic animals demonstrated impaired spatial memory in the Morris water-maze. Histologic analysis indicated neuronal loss in the amygdala, hippocampus, and surrounding cortical areas, and mossy fiber sprouting in the dentate gyrus. The present data indicate that focal stimulation of the amygdala initiates a cascade of events that lead to the development of spontaneous seizures in rats. This model provides a new tool to better mimic different aspects of human TLE for investigation of the pathogenesis of TLE or the effects of new antiepileptic compounds on status epilepticus, epileptogenesis, and spontaneous seizures.

Incidence and mortality of generalized convulsive status epilepticus in California

BACKGROUND

Few population-based studies of status epilepticus have been performed in the United States.

OBJECTIVE

To determine the incidence, case fatality, and demographics of generalized convulsive status epilepticus (GCSE) in the state of California.

METHODS

Using a state-wide hospital discharge database, the authors identified all hospitalizations from 1991 through 1998 with a discharge diagnosis of convulsive status epilepticus. They identified the first admission for each individual to estimate the incidence of GCSE. In-hospital case fatality rates were calculated, and multivariate analysis was performed to determine predictors of death during hospitalization. Secondary diagnoses were analyzed by retrieving all discharge diagnoses accompanying the diagnosis of GCSE.

RESULTS

The incidence rate of GCSE was 6.2/100,000 population and fell by 42% between the years 1991 and 1998 from 8.5 to 4.9/100,000. The rate of GCSE was highest among children under the age of 5 (7.5/100,000) and among the elderly (22.3/100,000). Blacks also demonstrated a relatively high incidence of GCSE (13.4/100,000). The case fatality for incident admissions was 10.7%, with increasing age being the only significant predictor in multivariate analysis. Case fatality was highest in patients who also carried a diagnosis of anoxia, CNS infection, or stroke.

CONCLUSIONS

The incidence of GCSE requiring hospitalization has fallen over the last decade and is lower than that reported in previous studies. The case fatality is also lower than that reported previously. Further studies are needed to determine the cause of this decline in incidence and mortality of GCSE.

Environment matters: synaptic properties of neurons born in the epileptic adult brain develop to reduce excitability

Neural progenitors in the adult dentate gyrus continuously produce new functional granule cells. Here we used whole-cell patch-clamp recordings to explore whether a pathological environment influences synaptic properties of new granule cells labeled with a GFP-retroviral vector. Rats were exposed to a physiological stimulus, i.e., running, or a brain insult, i.e., status epilepticus, which gave rise to neuronal death, inflammation, and chronic seizures. Granule cells formed after these stimuli exhibited similar intrinsic membrane properties. However, the new neurons born into the pathological environment differed with respect to synaptic drive and short-term plasticity of both excitatory and inhibitory afferents. The new granule cells formed in the epileptic brain exhibited functional connectivity consistent with reduced excitability. We demonstrate a high degree of plasticity in synaptic inputs to adult-born new neurons, which could act to mitigate pathological brain function.

Seizure recurrence after a first unprovoked seizure

We studied 244 patients (of all ages) who presented with a first unprovoked seizure and were followed for a median of 22 months in order to ascertain the risk of subsequent seizures. The cumulative risks of recurrence were 16 per cent at 12 months, 21 per cent at 24 months, and 27 per cent at 36 months after the initial seizure. The risk of recurrence in patients with a history of prior neurologic insult was 34 per cent; all recurrences in this group were observed within the first 20 months. Only 17 per cent of patients without such a history (classified as idiopathic) had a recurrence by 20 months; recurrence in this group was 26 per cent by 36 months. Patients with no recurrence for 36 months did not have a recurrence after that time. Among idiopathic cases the risk of recurrence was increased in patients with generalized spike-wave electroencephalograms (50 per cent at 18 months) and in those who had a sibling with seizures (35 per cent at four months). Age at first seizure, sex, seizure type, onset with status epilepticus, or abnormality on neurologic examination did not affect the risk of recurrence.

Outcome from coma after cardiopulmonary resuscitation: relation to seizures and myoclonus

We studied the effect of seizures and myoclonus following cardiopulmonary resuscitation (CPR) on the outcome of all comatose adult survivors of CPR over an 8-year period. Either seizures or myoclonus occurred in 50 of 114 patients (44%): seizures in 41 patients (36%) and myoclonus in 40 (35%). Status epilepticus or status myoclonus occurred in 36 patients (32%), and 19 (17%) had myoclonic status epilepticus (MSE). Seizures and myoclonus per se were not significantly related to outcome, but status epilepticus, status myoclonus, and, particularly, MSE were predictive of poor outcome as judged by survival and recovery of consciousness.

Prevalence and predictors of early seizure and status epilepticus after first stroke

BACKGROUND

Early seizure (ES) has been reported in 2% to 6% of strokes and is a predictor of recurrent seizures. Acute stroke has been reported to cause 22% of all cases of status epilepticus in adults. The determinants of ES and status epilepticus (SE) after stroke, however, are not well understood.

METHODS

An incidence study was conducted to identify all cases of first stroke in adult residents of northern Manhattan. Cases of ES and SE within 7 days of stroke were identified through medical record review. Statistical analyses were performed using univariate and multivariate logistic regression models.

RESULTS

The cohort consisted of 904 patients; ES occurred in 37 (4.1%). The frequency of ES by stroke subtype and location was deep infarct 0.6% (2/356), lobar infarct 5.9% (20/341), deep intracerebral hemorrhage (ICH) 4.0% (4/101), lobar ICH 14.3% (7/49), and subarachnoid hemorrhage 8.0% (4/50). SE occurred in 10 patients (1.1%), representing 27.0% of patients with ES. Diabetes, hypertension, current smoking, alcohol use, age, gender, and race/ethnicity were not significant determinants of ES. In a subgroup of patients who had an NIH stroke scale (NIHSS) score recorded, NIHSS score was not an independent predictor of ES in multivariate analysis. After accounting for stroke severity, ES was not a predictor of 30-day case fatality.

CONCLUSIONS

Lesion location and stroke subtype are strong determinants of ES risk, even after adjusting for stroke severity. ES does not predict 30-day mortality. SE occurs in more than one-quarter of patients with ES.

Frequency and timing of nonconvulsive status epilepticus in comatose post-cardiac arrest subjects treated with hypothermia

BACKGROUND

Therapeutic hypothermia (TH) improves outcomes in comatose patients resuscitated from cardiac arrest. However, nonconvulsive status epilepticus (NCSE) may cause persistent coma. The frequency and timing of NCSE after cardiac arrest is unknown.

METHODS

Review of consecutive subjects treated with TH and receiving continuous EEG (cEEG) monitoring between 8/1/2009 and 11/16/2010. Demographic data, survival, and functional outcome were prospectively recorded. Each cEEG file was analyzed using standard definitions to define NCSE. Data were analyzed using descriptive and nonparametric statistics.

RESULTS

Mean age of the 101 subjects was 57 years (SD 15) with most subjects being male (N = 55, 54%) and experiencing out-of-hospital cardiac arrest (N = 78; 77%). Ventricular fibrillation was the initial cardiac rhythm in 39 (38%). All subjects received TH. Thirty subjects (30%) awoke at a median of 41 h (IQR 30, 61) after cardiac arrest. A total of 29/30 (97%) subjects surviving to hospital discharge were awake. Median interval from arrest to placement of cEEG was 9 h (IQR 6, 12), at which time the mean temperature was 33.9°C. NCSE occurred in 12 (12%) subjects. In 3/12 (25%) subjects, NCSE was present when the cEEG recording began. In 4 subjects, NCSE occurred within 8 h of cEEG recording. One (8%) subject with NCSE survived in a vegetative state.

CONCLUSIONS

NCSE is common in comatose post-cardiac arrest subjects receiving TH. Most seizures occur within the first 8 h of cEEG recording and within the first 12 h after resuscitation from cardiac arrest. Outcomes are poor in those who experience NCSE.

A systematic review of the epidemiology of status epilepticus

Population-based data on the incidence, aetiology, and mortality associated with status epilepticus (SE) are required to develop preventative strategies for SE. Through a systematic review, we aimed to assess the methodological quality as well as similarities, and differences between available population based studies in order to arrive at conclusions on the epidemiology of SE. All population-based studies where primary outcome was incidence, aetiology or mortality of SE were identified through a systematic search and synthesized. Methodological quality of studies were independently rated by two examiners using a unique scoring system. Seven population-based projects on SE yielding nine published reports and five abstracts were reviewed. Quality scores were in the range of 19-34 with a possible maximum of 40 (kappa scores 0.67-1.0). The incidence of SE has a bimodal distribution with peaks in children aged less than a year and the elderly. Most SE were acute symptomatic. Short-term mortality was 7.6-22% and long-term mortality was 43%. Age and aetiology were the major determinants of mortality. There are few population-based studies on SE but most are of good quality. Most studies are primarily or exclusively based on adult populations. There is limited information on the association of ethnicity and socio-economic status and SE.

Status epilepticus: An independent outcome predictor after cerebral anoxia

BACKGROUND

Prognosis of status epilepticus (SE) depends on its cause, but there is uncertainty as to whether SE represents an independent outcome predictor for a given etiology. Cerebral anoxia is a relatively homogenous severe encephalopathy. Postanoxic SE is associated to a nearly 100% mortality in this setting; however, it is still unclear whether this is a severity marker of the underlying encephalopathy, or an independent factor influencing outcome. The goal of this study was to assess if postanoxic SE is independently associated with mortality after cerebral anoxia.

METHODS

This was a retrospective observation of consecutive comatose survivors of cardiac arrest, including subjects treated with hypothermia. On the subgroup with EEG recordings in the first hospitalization days, univariate and multivariate analyses were applied to potential determinants of in-hospital mortality, and included the following variables: age, gender, type and length of cardiac arrest, occurrence of circulatory shock, presence of therapeutic hypothermia, and electrographic SE.

RESULTS

Out of 166 postanoxic patients, 107 (64%) had an EEG (median latency from admission, 2 days); in this group, therapeutic hypothermia was administered in 59%. Death occurred in 71 (67%) patients. Postanoxic SE was associated with mortality regardless of type of acute cardiac rhythm and administration of hypothermic treatment.

CONCLUSION

In this hospital-based cohort, postanoxic status epilepticus (SE) seems to be independently related to death in cardiac arrest survivors, suggesting that SE might determine a bad prognosis for a given etiology. Confirmation of these results in a prospective assessment is needed.

Intravenous ketamine for the treatment of refractory status epilepticus: a retrospective multicenter study

PURPOSE

To examine patterns of use, efficacy, and safety of intravenous ketamine for the treatment of refractory status epilepticus (RSE).

METHODS

Multicenter retrospective review of medical records and electroencephalography (EEG) reports in 10 academic medical centers in North America and Europe, including 58 subjects, representing 60 episodes of RSE that were identified between 1999 and 2012. Seven episodes occurred after anoxic brain injury.

KEY FINDINGS

Permanent control of RSE was achieved in 57% (34 of 60) of episodes. Ketamine was felt to have contributed to permanent control ("possible" or "likely" responses) in 32% (19 of 60) including seven (12%) in which ketamine was the last drug added (likely responses). Four of the seven likely responses, but none of the 12 possible ones, occurred in patients with postanoxic brain injury. No likely responses were observed when infusion rates were lower than 0.9 mg/kg/h, when ketamine was introduced at least 8 days after SE onset, or after failure of seven or more drugs. Ketamine was discontinued due to possible adverse events in five patients. Complications were mostly attributed to concurrent drugs, especially other anesthetics. Mortality rate was 43% (26 of 60), but was lower when SE was controlled within 24 h of ketamine initiation (16% vs. 56%, p = 0.0047).

SIGNIFICANCE

Ketamine appears to be a relatively effective and safe drug for the treatment of RSE. This retrospective series provides preliminary data on effective dose and appropriate time of intervention to aid in the design of a prospective trial to further define the role of ketamine in the treatment of RSE.

Treatment of status epilepticus in children

Status epilepticus (SE) is a condition characterised by frequent and prolonged epileptic seizures which frequently develop in the immature brain. Fever, metabolic disorders and subtherapeutic concentrations of antiepileptic drugs are the most common factors precipitating SE in children. Progressive neuronal damage occurs if convulsive SE persists for more than 30 minutes, with neurological, epileptic and cognitive sequelae. Unfortunately, the immature brain is more predisposed to SE and its sequelae than the mature brain. SE may be categorised as convulsive, nonconvulsive or neonatal according to its responsiveness to antiepileptic drugs. Regardless of category, the main objective in the treatment of SE is to abort the seizures and treat the inciting condition. Treatment includes: (i) monitoring of hydration, electrolyte balance, and cardiocirculatory and pulmonary functions; and (ii) rapid intravenous administration of specific antiepileptic drugs. Benzodiazepines (usually diazepam, lorazepam or midazolam) are the most effective agents for the initial treatment of convulsive and nonconvulsive SE. In particular, midazolam infusion is an effective and well tolerated therapeutic approach for the management of childhood SE, including refractory SE. Phenytoin remains an excellent agent because of its long duration of action, but it is not active in nonconvulsive SE. Fosphenytoin, a phenytoin prodrug, represents a significant advance in the treatment of children with convulsive SE. Intravenous phenytoin and intramuscular phenobarbital (phenobarbitone) are generally used in neonatal SE; other agents are rarely used.