Mortality and recovery from refractory status epilepticus in the intensive care unit: A 7-year observational study

Can anesthetic treatment worsen outcome in status epilepticus?

Status epilepticus refractory to first-line and second-line antiepileptic treatments challenges neurologists and intensivists as mortality increases with treatment refractoriness and seizure duration. International guidelines advocate anesthetic drugs, such as continuously administered high-dose midazolam, propofol, and barbiturates, for the induction of therapeutic coma in patients with treatment-refractory status epilepticus. The seizure-suppressing effect of anesthetic drugs is believed to be so strong that some experts recommend using them after benzodiazepines have failed. Although the rationale for the use of anesthetic drugs in patients with treatment-refractory status epilepticus seems clear, the recommendation of their use in treating status epilepticus is based on expert opinions rather than on strong evidence. Randomized trials in this context are lacking, and recent studies provide disturbing results, as the administration of anesthetics was associated with poor outcome independent of possible confounders. This calls for caution in the straightforward use of anesthetics in treating status epilepticus. However, there are still more questions than answers, and current evidence for the adverse effects of anesthetic drugs in patients with status epilepticus remains too limited to advocate a change of treatment algorithms. In this overview, the rationale and the conflicting clinical implications of anesthetic drugs in patients with treatment-refractory status epilepticus are discussed, and remaining questions are elaborated. This article is part of a Special Issue entitled "Status Epilepticus".

Factors associated with poor discharge status in patients with status epilepticus at Khon Kaen Hospital

BACKGROUND

Status epilepticus (SE) is a serious neurological condition and has high a mortality rate. Data on importance of factors associated with poor outcomes in Asian or Thai populations are limited.

METHODS

Adult patients diagnosed as SE at Khon Kaen Hospital, Thailand from October 1, 2010 to September 30, 2012 were enrolled. Patients were categorized as good or poor outcomes at discharge. Good outcomes were defined by improvement at discharge and absence of neurological deficits, while poor outcomes were defined by: not being improved at discharge; being discharged against advice; death; or presence of a neurological deficit. Clinical factors were compared between both groups.

RESULTS

During the study period, there were 211 patients diagnosed as SE. Of those, 130 patients were male (61.61%). The mean age of all patients was 53.28 years. Acute stroke was the most common cause of SE in 33 patients (15.64%). At discharge, there were 91 patients (43.13%) who had poor outcomes. Only initial plasma glucose levels were significantly associated with poor outcomes with an adjusted odds ratio of 1.012 (95% confidence interval of 1.003 and 1.021).

CONCLUSION

Initial plasma glucose is associated with poor discharge status in patients with SE.

Activation of calcineurin underlies altered trafficking of α2 subunit containing GABAA receptors during prolonged epileptiform activity

Fast inhibitory signalling in the mammalian brain is mediated by gamma-aminobutyric acid type A receptors (GABAARs), which are targets for anti-epileptic therapy such as benzodiazepines. GABAARs undergo tightly regulated trafficking processes that are essential for maintenance and physiological modulation of inhibitory strength. The trafficking of GABAARs to and from the membrane is altered during prolonged seizures such as in Status Epilepticus (SE) and has been suggested to contribute to benzodiazepine pharmacoresistance in patients with SE. However, the intracellular signalling mechanisms that cause this modification in GABAAR trafficking remain poorly understood. In this study, we investigate the surface stability of GABAARs during SE utilising the low Mg(2+) model in hippocampal rat neurons. Live-cell imaging of super ecliptic pHluorin (SEP)-tagged α2 subunit containing GABAARs during low Mg(2+) conditions reveals that the somatic surface receptor pool undergoes down-regulation dependent on N-methyl-d-aspartate receptor (NMDAR) activity. Analysis of the intracellular Ca(2+) signal during low Mg(2+) using the Ca(2+)-indicator Fluo4 shows that this reduction of surface GABAARs correlates well with the timeline of intracellular Ca(2+) changes. Furthermore, we show that the activation of the phosphatase calcineurin was required for the decrease in surface GABAARs in neurons undergoing epileptiform activity. These results indicate that somatic modulation of GABAAR trafficking during epileptiform activity in vitro is mediated by calcineurin activation which is linked to changes in intracellular Ca(2+) concentrations. These mechanisms could account for benzodiazepine pharmacoresistance and the maintenance of recurrent seizure activity, and reveal potential novel targets for the treatment of SE.

Indomethacin can downregulate the levels of inflammatory mediators in the hippocampus of rats submitted to pilocarpine-induced status epilepticus

OBJECTIVE

Refractory status epilepticus is one of the most life-threatening neurological emergencies and is characterized by high morbidity and mortality. Additionally, the use of anti-inflammatory drugs during this period is very controversial. Thus, this study has been designed to analyze the effect of a low dose of indomethacin (a COX inhibitor) on the expression of inflammatory molecules.

METHOD

The hippocampus of rats submitted to pilocarpine-induced long-lasting status epilepticus was analyzed to determine the expression of inflammatory molecules with RT-PCR and immunohistochemistry.

RESULTS

Compared with controls, reduced levels of the kinin B2 receptors IL1β and TNFα were found in the hippocampus of rats submitted to long-lasting status epilepticus and treated with indomethacin.

CONCLUSIONS

These data show that low doses of indomethacin could be employed to minimize inflammation during long-lasting status epilepticus.

Determinants and predictors of outcome in super refractory status epilepticus--a developing country perspective

IMPORTANCE

Super refractory status epilepticus (SRSE) is a recent entity. There is limited information about the etiology and outcome of SRSE from developing countries.

OBJECTIVE

We evaluated determinants and predictors of outcome in patients with convulsive SRSE in Indian population.

METHODS

In this open cohort study, data of patients with convulsive SE admitted in neurointensive care unit (NICU) from 2005 to 2013 was retrospectively analyzed. Regression and survival analysis was done for outcome of patients divided into non refractory SE (NRSE), refractory SE (RSE), and SRSE groups.

MAIN OUTCOME MEASURE

The primary outcome for analysis was in hospital mortality. Also functional outcome at 6 months was graded according to the Glasgow outcome scale (GOS), and classified as good (GOS 4 and 5) and poor (GOS 1, 2 and 3) outcome groups.

RESULTS

Out of 177 patients with SE, 105 (59.3%) had NRSE; 72 (40.7%) had RSE of which 30 (16.9% of 177) were sub-classified as SRSE. SRSE was frequent (39%) in children (p<0.01), elderly (21.7%; p<0.003), and in incident SE (82.1%, p=0.05). Encephalitis was the commonest etiology in RSE (30.9%, p=0.015), SRSE (66.7%, p<0.001) than NRSE (12.3%). Encephalitis (β=8.250 (1.8-37.82); p=0.007) was the determinant of the progression of SE to SRSE. Overall mortality was 19.2%, highest in SRSE (40.0%) followed by RSE (35.7%), both significantly (p<0.001) higher than NRSE (6.7%). Mortality was high in patients with encephalitis than other etiologies (39.1% vs. 12.1%; p=0.001). Acidosis predicted mortality in the entire cohort (β=7.313 (1.6-32.58); p=0.009); however none of the variables predicted mortality in SRSE patients. At 6 months follow up only 33.3% of patients with SRSE were in GOS good outcome group when compared to RSE (33.3% vs. 57.1%; p=0.055), and NRSE (33.3% vs. 79.1%; p<0.0001).

CONCLUSIONS AND RELEVANCE

SRSE is common in children, elderly, and incident SE. Encephalitis was the determinant of progression of SE to SRSE. None of the variables predicted mortality in SRSE patients. Sixty percent of patients with SRSE survived and one third had good outcome. Therefore one should continue the care inspite of weeks of SE.

Early predictors of refractory status epilepticus: an international two-center study

BACKGROUND AND PURPOSE

Status epilepticus (SE) refractory to first- and second-line antiepileptic drugs carries high mortality. Little is known on early prediction of refractory SE (RSE)—an essential tool for planning appropriate therapy. Our aim was to identify and validate independent early RSE predictors in adults.

METHODS

Clinical and laboratory data on consecutive intensive care unit patients with SE from two academic care centers (a derivation data set from a Swiss center and a validation data set from a US center) were assessed. Multivariable analysis was performed with the derivation set to identify RSE predictors at SE onset. Their external validity was evaluated with an independent validation set. Measures of calibration and discrimination were assessed.

RESULTS

In all, 302 patients were analyzed (138 with and 164 without RSE), 171 in the derivation data set and 131 in the validation data set. Acute SE etiology, coma/stupor and serum albumin <35 g/l at SE onset were independent predictors for RSE in the derivation data set [odds ratio (OR) 2.02, 95% confidence interval (CI) 1.01-4.07; OR 4.83, 95% CI 2.42-9.68; OR 2.45, 95% CI 1.16-5.16]. The prediction model showed good measures of calibration (Hosmer-Lemesow goodness-of-fit test P = 0.99) and discrimination (area under the receiver operating characteristic curve 0.8) on the derivation data set—results that were similar in the validation data set (Hosmer-Lemeshow P = 0.24; area under the receiver operating characteristic curve 0.73).

CONCLUSIONS

This study confirms the independent prognostic value of readily available parameters for early RSE prediction. Prospective studies are needed to identify additional robust predictors, which could be added to the proposed model for further optimization towards a reliable prediction scoring system.

Effect of perampanel, a novel AMPA antagonist, on benzodiazepine-resistant status epilepticus in a lithium-pilocarpine rat model

This study assessed the efficacy of diazepam, and the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor antagonists perampanel and GYKI52466 in a lithium-pilocarpine status epilepticus (SE) model. SE was induced in rats using lithium chloride, scopolamine methyl bromide, and pilocarpine. Diazepam 10, 20, or 40 mg kg⁻¹, or perampanel 1, 2.5, 5, or 8 mg kg⁻¹ were administered intravenously at 10 or 30 min after seizure onset, and GYKI52466 50 mg kg⁻¹, or combinations of diazepam 2.5–5 mg kg⁻¹ and perampanel 0.5–1 mg kg⁻¹, were administered intravenously at 30 min after seizure onset. Diazepam 20 mg kg⁻¹ terminated seizures (based on electroencephalography and assessment of behavioral seizures) in 2/6 rats at 10 min and 0/6 rats at 30 min (ED₅₀: 10 min, 30 mg kg⁻¹; 30 min, not determined). Perampanel 8 mg kg⁻¹ terminated seizures in 6/6 rats at both 10 and 30 min (ED₅₀: 10 min 1.7 mg kg⁻¹; 30 min, 5.1 mg kg⁻¹). GYKI52466 50 mg kg⁻¹ terminated seizures in 2/4 rats at 30 min. Co-administration of diazepam 5 mg kg⁻¹ and perampanel 1 mg kg⁻¹ terminated seizures in 9/9 rats at 30 min. In conclusion, perampanel and GYKI52466 provided efficacy in a lithium-pilocarpine SE model at 30 min after seizure onset, when SE was refractory to diazepam, supporting the therapeutic potential of AMPA receptor antagonists for refractory SE. The perampanel dose required to terminate seizures was reduced by combination with diazepam, suggesting synergy.

Refractory status epilepticus treated with trigeminal nerve stimulation

Refractory status epilepticus (RSE) is a neurologic emergency associated with significant morbidity and mortality. Alternative therapies are needed for patients who do not respond to more traditional therapies for RSE. We report on a patient with RSE treated with external trigeminal nerve stimulation (eTNS). On admission, the patient was experiencing consecutive focal dyscognitive seizures with secondary generalization without recovery in between. His seizures remained refractory to multiple therapies, including IV lorazepam, valproic acid, levetiracetam, phenobarbital, and midazolam. Although a burst suppression pattern was achieved with a continuous pentobarbital infusion, seizures returned following attempts to taper it. Given his beneficial response to eTNS during a previous clinical trial, eTNS was initiated. Four days after starting eTNS, the pentobarbital infusion was finally weaned, and his EEG revealed no further seizures. The patient's mental status improved and he was ultimately discharged with only moderately severe disability. Our case demonstrates that eTNS may have antiseizure effects in RSE. Given our patient's quick response, such benefit may have arisen from EEG-desynchronization. If confirmed in larger studies, eTNS could one day be considered along with other adjuvant treatments for RSE.

SGE-102: a novel therapy for refractory status epilepticus

Refractory status epilepticus (SE) has a mortality rate of up to 35%. Current treatment protocols for the treatment of SE begin with benzodiazepines and then proceed to conventional anticonvulsants. If seizures continue, SE is considered refractory (RSE) and treatment with anesthetic agents in undertaken. Twenty-four h to 48 h after initiation of anesthesia with midazolam, pentobarbital or thiopental, or propofol, an attempt is made to wean the anesthetic. If this fails and seizures recur, SE is considered highly refractory (HRSE) and repeated attempts are undertaken. No randomized trial data are available to guide the choice of anesthetic agent in either RSE or HRSE status. Medication resistance in established SE is thought to result, in part, from internalization of synaptic γ-aminobutyric acid (GABA) receptors, making them unavailable for modulation. Neurosteroids act on both synaptic and extrasynaptic GABAA receptors, which are not internalized, and are therefore hypothesized to have a role in the treatment of RSE. SGE-102 is a neurosteroid metabolite of progesterone with demonstrated anticonvulsant properties in animal seizure models. A randomized double-blind placebo-controlled adjunctive trial of SGE will include subjects randomized at the time that initial treatment with anesthesia is initiated. Subjects will receive midazolam and either SGE-102 or placebo. Midazolam will be tapered and discontinued between hours 24 and 48. SGE-102 or placebo will be continued through hour 120. The primary end point will be the difference in proportion of subjects from each arm who remain seizure free through hour 120. Secondary end points will include the proportion of subjects who are seizure free at hour 168, 2 days after discontinuation of the experimental agent. The study will be powered to have a 90% chance of detecting a clinically meaningful reduction in seizure recurrence at 120 h. Comprehensive safety and pharmacokinetic data will also be obtained during the course of the trial.

Considerations in prophylaxis for tumor-associated epilepsy: prevention of status epilepticus and tolerability of newer generation AEDs

OBJECTIVE

To identify risk factors for the development of tumor-associated epilepsy (TAE) and potential benefit of newer generation AEDs in seizure prevention.

METHODS

We performed an IRB approved retrospective study of newly diagnosed GBM patients at the University of Rochester between 1/1/05 and 5/13/11. Records were reviewed to describe demographics, seizure incidence, occurrence of status epilepticus, and AED use and toxicity.

RESULTS

172 patients with newly diagnosed GBM were included in the study. 53.4% developed TAE. 31.4% had seizure prior to diagnosis. 118 patients were seizure-free at diagnosis: 32.2% developed post-diagnosis TIE (PostTAE) and 60.2% remained seizure-free. 70 seizure-free patients received an AED peri-operatively. 36 were weaned off AEDs and 31 were continued. Incidence of PostTAE and time to first seizure were comparable in AED-treated and untreated patients. 4 PostTAE patients presented with status epilepticus (SE), all were not AED treated. AEDs were withdrawn in 10 patients due to toxicity: 9 from phenytoin and 1 from levetiracetam.

CONCLUSION

There is a high incidence of PostTAE in GBM. Prophylactic AED therapy did not reduce PostTAE but may have prevented SE. Minimal toxicity was observed on 2nd generation AEDs. The high burden of epilepsy in this population and tolerability of newer AEDS suggest that AAN guidelines should be revisited.

Outcome predictors for status epilepticus--what really counts

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

Safety and efficacy of intravenous lacosamide for adjunctive treatment of refractory status epilepticus: a comparative cohort study

BACKGROUND

Refractory status epilepticus (RSE) is an emergency with high mortality requiring neurointensive care. Treatment paradigms include first-generation antiepileptic drugs (AEDs) and anesthetics. Lacosamide (LCM) is a new AED, holding promise as a potent treatment option for RSE. High-level evidence regarding safety and efficacy in the treatment of RSE is lacking.

OBJECTIVE

The objective of the study was to evaluate the safety profile and efficacy of intravenous (i.v.) LCM as an add-on treatment in adult RSE patients.

METHODS

All consecutive RSE patients treated in the intensive care units (ICUs) of an academic tertiary care center between 2005 and 2011 were included. Severity of status epilepticus (SE) was graded by the SE Severity Scale (STESS), and SE etiology was categorized according to the guidelines of the International League Against Epilepsy (ILAE). Outcomes were seizure control, RSE duration, and death.

RESULTS

Of 111 RSE patients, 53 % were treated with LCM. Twenty-five patients with hypoxic-ischemic encephalopathy were excluded. Mortality was 30 %. Mean number of AEDs, duration, severity, and etiology of SE, as well as critical medical conditions did not differ between patients with and without LCM. While age tended to be higher, critical interventions, such as the use of anesthetics and mechanical ventilation, tended to be less frequent in patients with LCM. Seizure control tended to be achieved more frequently in patients with LCM (odds ratio, OR 2.34, 95 % CI 0.5-10.1, p = 0.252). Among patients with LCM, 51 % received LCM as the last AED (including hypoxic-ischemic encephalopathy), allowing the reasonable assumption that LCM was responsible for seizure control, which was achieved in 91 %. Multivariable analysis revealed a decreased mortality in patients with LCM (OR 0.34, 95 % CI 0.1-0.9, p = 0.035). A possible confounder in this context was the implementation of continuous video-electroencephalography (EEG) monitoring 6 months prior to the first use of i.v. LCM. There were no serious LCM-related adverse events.

CONCLUSION

LCM had a favorable safety profile as adjunctive treatment for RSE. Its use was associated with decreased mortality of RSE-a finding that might have been confounded by the implementation of continuous video-EEG monitoring in the ICU prior to the use of i.v. LCM, leading to heightened awareness as well as earlier diagnosis and treatment of SE. Randomized trials are warranted to further strengthen the evidence of efficacy of LCM for RSE treatment.