Time to Onset of Cannabidiol (CBD) Treatment Effect and Resolution of Adverse Events in Tuberous Sclerosis Complex: Post Hoc Analysis of Randomized Controlled Phase 3 Trial GWPCARE6

Objective

To estimate the timing of cannabidiol (CBD) treatment effect (seizure reduction and adverse events [AEs]) onset, we conducted a post hoc analysis of GWPCARE6 (NCT02544763), a randomized, placebo‐controlled, phase 3 trial in patients with drug‐resistant epilepsy associated with tuberous sclerosis complex (TSC).

Methods

Patients received plant‐derived pharmaceutical formulation of highly purified CBD (Epidiolex; 100 mg/ml oral solution) at 25 mg/kg/day (CBD25) or 50 mg/kg/day (CBD50) or placebo for 16 weeks (4‐week titration, 12‐week maintenance). Treatment started at 5 mg/kg/day for all groups and reached 25 mg/kg/day on Day 9 and 50 mg/kg/day on Day 29. Percentage change from baseline in TSC‐associated seizure (countable focal or generalized) count was calculated by cumulative day (i.e., including all previous days). Time to onset and resolution of AEs were evaluated.

Results

Of 224 patients, 75 were randomized to CBD25, 73 to CBD50, and 76 to placebo. Median (range) age was 11.3 (1.1–56.8) years. Patients had discontinued a median (range) of 4 (0–15) antiseizure medications and were currently taking 3 (0–5). Difference in seizure reduction between CBD and placebo emerged on Day 6 (titrated dose, 15 mg/kg/day) and became nominally significant (p < .049) by Day 10. Separation between placebo and CBD in ≥50% responder rate also emerged by Day 10. Onset of AEs occurred during the first 2 weeks of the titration period in 61% of patients (CBD25, 61%; CBD50, 67%; placebo, 54%). In patients with an AE, resolution occurred within 4 weeks of onset in 42% of placebo and 27% of CBD patients and by end of trial in 78% of placebo and 51% of CBD patients.

Significance

Onset of treatment effect occurred within 6–10 days. AEs lasted longer for CBD than placebo, but the most common (diarrhea, decreased appetite, and somnolence) resolved during the 16‐week trial in most patients.

Management of status epilepticus: a narrative review

Status epilepticus causes prolonged or repetitive seizures that, if left untreated, can lead to neuronal injury, severe disability, coma and death in paediatric and adult populations. While convulsive status epilepticus can be diagnosed using clinical features alone, non-convulsive status epilepticus requires confirmation by electroencephalogram. Early seizure control remains key in preventing the complications of status epilepticus. This is especially true for convulsive status epilepticus, which has stronger evidence supporting the benefit of treatment on outcomes. When status epilepticus becomes refractory, often due to gamma-aminobutyric acid and N-methyl-D-aspartate receptor modulation, anaesthetic drugs are needed to suppress seizure activity, of which there is limited evidence regarding the selection, dose or duration of their use. Seizure monitoring with electroencephalogram is often needed when patients do not return to baseline or during anaesthetic wean; however, it is resource-intensive, costly, only available in highly specialised centres and has not been shown to improve functional outcomes. Thus, the treatment goals and aggressiveness of therapy remain under debate, especially for non-convulsive status epilepticus, where prolonged therapeutic coma can lead to severe complications. This review presents an evidence-based, clinically-oriented and comprehensive review of status epilepticus and its definitions, aetiologies, treatments, outcomes and prognosis at different stages of the patient's journey.

Patterns of benzodiazepine underdosing in the Established Status Epilepticus Treatment Trial

OBJECTIVE

This study was undertaken to describe patterns of benzodiazepine use as first-line treatment of status epilepticus (SE) and test the association of benzodiazepine doses with response to second-line agents in patients enrolled in the Established Status Epilepticus Treatment Trial (ESETT).

METHODS

Patients refractory to an adequate dose of benzodiazepines for the treatment of SE were enrolled in ESETT. Choice of benzodiazepine, doses given prior to administration of second-line agent, route of administration, setting, and patient weight were characterized. These were compared with guideline-recommended dosing. Logistic regression was used to determine the association of the first dose of benzodiazepine and the cumulative benzodiazepine dose with the response to second-line agent.

RESULTS

Four hundred sixty patients were administered 1170 doses of benzodiazepines (669 lorazepam, 398 midazolam, 103 diazepam). Lorazepam was most frequently administered intravenously in the emergency department, midazolam intramuscularly or intravenously by the emergency medical services personnel, and diazepam rectally prior to ambulance arrival. The first dose of the first benzodiazepine (N = 460) was lower than guideline recommendations in 76% of midazolam administrations and 81% of lorazepam administrations. Among all administrations, >85% of midazolam and >76% of lorazepam administrations were lower than recommended. Higher first or cumulative benzodiazepine doses were not associated with better outcomes or clinical seizure cessation in response to second-line medications in these benzodiazepine-refractory seizures.

SIGNIFICANCE

Benzodiazepines as first-line treatment of SE, particularly midazolam and lorazepam, are frequently underdosed throughout the United States. This broad and generalizable cohort confirms prior single site reports that underdosing is both pervasive and difficult to remediate. (ESETT ClinicalTrials.gov identifier: NCT01960075.).

Early Exposure of Fosphenytoin, Levetiracetam, and Valproic Acid After High-Dose Intravenous Administration in Young Children With Benzodiazepine-Refractory Status Epilepticus

Fosphenytoin (FOS) and its active form, phenytoin (PHT), levetiracetam (LEV), and valproic acid (VPA) are commonly used second-line treatments of status epilepticus. However, limited information is available regarding LEV and VPA concentrations following high intravenous doses, particularly in young children. The Established Status Epilepticus Treatment Trial, a blinded, comparative effectiveness study of FOS, LEV, and VPA for benzodiazepine-refractory status epilepticus provided an opportunity to investigate early drug concentrations. Patients aged ≥2 years who continued to seizure despite receiving adequate doses of benzodiazepines were randomly assigned to FOS, LEV, or VPA infused over 10 minutes. A sparse blood-sampling approach was used, with up to 2 samples collected per patient within 2 hours following drug administration. The objective of this work was to report early drug exposure of PHT, LEV, and VPA and plasma protein binding of PHT and VPA. Twenty-seven children with median (interquartile range) age of 4 (2.5-6.5) years were enrolled. The total plasma concentrations ranged from 69 to 151.3 μg/mL for LEV, 11.3 to 26.7 μg/mL for PHT and 126 to 223 μg/mL for VPA. Free fraction ranged from 4% to 19% for PHT and 17% to 51% for VPA. This is the first report in young children of LEV concentrations with convulsive status epilepticus as well as VPA concentrations after a 40 mg/kg dose. Several challenges limited patient enrollment and blood sampling. Additional studies with a larger sample size are required to evaluate the exposure-response relationships in this emergent condition.

The association of patient weight and dose of fosphenytoin, levetiracetam, and valproic acid with treatment success in status epilepticus

The Established Status Epilepticus Treatment Trial was a blinded, comparative-effectiveness study of fosphenytoin, levetiracetam, and valproic acid in benzodiazepine-refractory status epilepticus. The primary outcome was clinical seizure cessation and increased responsiveness without additional anticonvulsant medications. Weight-based dosing was capped at 75 kg. Hence, patients weighing >75 kg received a lower mg/kg dose. Logistic regression models were developed in 235 adults to determine the association of weight (≤ or >75 kg, ≤ or >90 kg), sex, treatment, and weight-normalized dose with the primary outcome and solely seizure cessation. The primary outcome was achieved in 45.1% and 42.5% of those ≤75 kg and >75 kg, respectively. Using univariate analyses, the likelihood of success for those >75 kg (odds ratio [OR] = 0.9, 95% confidence interval [CI] = 0.54-1.51) or >90 kg (OR = 0.85, 95% CI = 0.42-1.66) was not statistically different compared with those ≤75 kg or ≤90 kg, respectively. Similarly, other predictors were not significantly associated with primary outcome or clinical seizure cessation. Our findings suggest that doses, capped at 75 kg, likely resulted in concentrations greater than those needed for outcome. Studies that include drug concentrations and heavier individuals are needed to confirm these findings.

Lessons from the Established Status Epilepticus Treatment Trial

Convulsive status epilepticus (SE) is a relatively common emergency condition affecting individuals of all ages. The primary goal of treatment is prompt termination of seizures. Where first-line treatment with benzodiazepine has failed to achieve this, a condition known as established SE (ESE), there is uncertainty about which agent to use next. The Established Status Epilepticus Treatment Trial (ESETT) is a 3-arm (valproate (VPA), fosphenytoin (FOS), levetiracetam (LEV)), phase III, double-blind randomized comparative effectiveness study in patients aged 2 years and above with established convulsive SE. Enrollment was completed in January 2019, and the results are expected later this year. We discuss lessons learnt during the conduct of the study in relation to the following: ethical considerations; trial design and practical implementation in emergency settings, including pediatric and adult populations; quality assurance; and outcome determination where treating emergency clinicians may lack specialist expertise. We consider that the ESETT is already informing both clinical practice and future trial design. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures".

Medical management of status epilepticus: Emergency room to intensive care unit

In convulsive status epilepticus (SE), achieving seizure control within the first 1-2 hours after onset is a significant determinant of outcome. Treatment is also more likely to work and be cost effective the earlier it is given. Initial first aid measures should be accompanied by establishing intravenous access if possible and administering thiamine and glucose if required. Calling for help will support efficient management, and also the potential for video-recording the events. This can be done as a best interests investigation to inform later management, provided adequate steps to protect data are taken. There is high quality evidence supporting the use of benzodiazepines for initial treatment. Midazolam (buccal, intranasal or intramuscular) has the most evidence where there is no intravenous access, with the practical advantages of administration outweighing the slightly slower onset of action. Either lorazepam or diazepam are suitable IV agents. Speed of administration and adequate initial dosing are probably more important than choice of drug. Although only phenytoin (and its prodrug fosphenytoin) and phenobarbitone are licensed for established SE, a now considerable body of evidence and international consensus supports the utility of both levetiracetam and valproate as options in established status. Both also have the advantage of being well tolerated as maintenance treatment, and possibly a lower risk of serious adverse events. Two adequately powered randomized open studies in children have recently reported, supporting the use of levetiracetam as an alterantive to phenytoin. The results of a large double blind study also including valproate are also imminent, and together likely to change practice in benzodiazepine-resistant SE.

Implementing clinical guidelines

Clinical guidelines that support practice and improve care are essential in this era of evidence-based medicine. However, implementing this guidance often falls short in practice. Sharing knowledge and auditing practice are important, but not sufficient to implement change. This article brings together evidence from the study of behaviour, education and clinical practice and offers practical tips on how practising neurologists might bring about change in the healthcare environment. Common themes include the importance of team working, multidisciplinary engagement, taking time to identify who and what needs changing, and selecting the most appropriate tool(s) for the job. Engaging with the challenge is generally more rewarding than resisting and is important for the effective provision of care.

Hiding in Plain Sight: Functional Neurological Disorders in the News

OBJECTIVE

Functional movement and seizure disorders are still widely misunderstood and receive little public and academic attention. This is in stark contrast to their high prevalence and levels of associated disability. In an exploratory observational study, the authors examined whether the relative lack of media coverage of functional neurological disorders is in part due to misidentification in "human interest" news stories.

METHODS

Thirteen recent news stories from high-impact English-language media outlets that portrayed patients with complex symptoms either attributed to other diagnoses or presented as medical mysteries were identified using online keyword searches. All selected news stories contained video or still images displaying relevant symptoms. Cases were categorized into movement disorders or seizure disorders and were then independently assessed by 10 respective expert raters. For each category, one story of a patient whose symptoms were due to a well-recognized neurological disease was also included. Both the diagnostic category and the respective confidence level were reported by each rater for each case. The interrater agreement was calculated for each group of disorders.

RESULTS

The raters confirmed almost unanimously that all presented news stories except the negative control cases portrayed misidentified functional movement or seizure disorders. The interrater agreement and average diagnostic confidence were high.

CONCLUSIONS

Functional neurological disorders are often wrongly considered a rare medical curiosity of the past. However, these findings suggest that, while they are largely absent from public discourse, they often appear in the news incognito, hiding in plain sight.

Functional neurological disorders: acute presentations and management

Functional neurological disorders (FND) are common and associated with significant morbidity and healthcare costs. Patients with FND often present acutely, particularly with dissociative seizures (resembling epilepsy) or persistent weakness resembling a stroke. History and careful observation and examination are critical to diagnosis, as investigations will often be normal or non-contributory. The nature of convulsive movements in dissociative seizures often differs from that in epilepsy, and long duration of individual events, waxing and waning, closed eyes and high reported frequency in an apparently well individual are all suggestive. In those with stroke-like episodes, demonstration of normal power even briefly (eg Hoover's sign, 'give way' weakness) together with distractability are positive physical features indicating a functional disorder. A positive diagnosis and clear non-judgemental explanation, backed up by reliable information sources associated with prompt onward referral to a neurologist can greatly reduce distress and ultimately improve outcomes.

Diagnoses and referral pattern at a first seizure clinic in London

Background. Epilepsy is among the most frequent neurological conditions and it is estimated that approximately 8% of the population experience a seizure at some time in their lives.

Aim. To examine the characteristics of patients referred to a First Seizure Clinic (FSC) at a University Hospital in South-West London.

Methods. All subjects referred to the FSC at St George’s University Hospitals between January and December 2015 were included in this audit.

Results. From a total of 257 patients, males 49.5%, age range 16–90, 30% referred by General Practices (GPs), 59.1% by the Accident & Emergency Department (A&E) and 10.9% by other hospital wards, 24.5% did not attend (DNA) the clinical appointment. Females who did not attend were significantly older than males (49.8 years old vs 39.7; p = 0.007). Among those who attended the clinical appointment, 17% were diagnosed first unprovoked seizure, 12.4% acute symptomatic seizure and 28.9% epilepsy. These patients were referred mainly by A&E while GPs referred seizure mimics especially non-epileptic attack disorder (NEAD) and syncope. Patients with NEAD were significantly younger than those with seizures (29.4 years old vs 44.2; p < 0.001) and had a previous psychiatric history (72.7% vs 16.8%; p < 0.001). The proportion of seizure mimics was similar in the older sample group (> 65 years). Regarding acute symptomatic seizures, 33.3% were alcohol-related, 20.8% acute brain insults and 12.5% drug-related (always overdose).

Conclusions. 1 in 4 patients referred to a FSC does not attend the clinical appointment, especially older females. More than 1 in 3 cases represent seizure mimics and are referred mainly by GPs.

Vitamin D supplementation

Vitamin D testing and supplementation is of great interest to neurologists and their patients. Recommended nutritional intakes of vitamin D in the UK remain focused on bone health, despite increasing evidence for a role outside this area. Here we discuss how neurologists might approach vitamin D testing and supplementation, focusing on two conditions associated with vitamin D deficiency that have an increased risk of downstream complications resulting from these: multiple sclerosis and epilepsy. We set out a rationale for testing serum 25-hydroxyvitamin D concentrations and discuss our personal practice in terms of supplementation, with evidence where available.

The effect of depression and side effects of antiepileptic drugs on injuries in patients with epilepsy

BACKGROUND AND PURPOSE

People with epilepsy are at increased risk of accidents and injuries but, despite several studies on this subject, data regarding preventable causes are still contradictory. The aim of this study was to investigate the relationship between injuries, side effects of antiepileptic drugs (AEDs) and depression.

METHODS

Data from a consecutive sample of adult patients with epilepsy attending the outpatient clinics at St George's University Hospital in London were included. All patients were asked if they had had any injury since the last clinic appointment and completed the Liverpool Adverse Event Profile (LAEP) and Neurological Disorders Depression Inventory for Epilepsy.

RESULTS

Among 407 patients (243 females, mean age 43.1 years), 71 (17.4%) reported injuries since the last appointment. A two-step cluster analysis revealed two clusters with the major cluster (53.5% of the injured group) showing a total score for LAEP ≥45, a positive Neurological Disorders Depression Inventory for Epilepsy screening and presence of AED polytherapy. A total score for LAEP ≥45 was the most important predictor.

CONCLUSIONS

Antiepileptic drug treatment should be reviewed in patients reporting injuries in order to evaluate the potential contribution and burden of AED side effects.

Non-hyperammonaemic valproate encephalopathy after 20 years of treatment

Sodium valproate is a commonly used antiseizure drug with broad indications for different seizuretypes and epilepsy syndromes. Well-recognised side effects include weight gain, tremor, dizziness, and unsteadiness. Non-hyperammonaemic parkinsonism, with or without cognitive impairment, is a rare adverse effect of sodium valproate. We present the case of a sixty year-old lady with a generalized seizure disorder, treated with phenytoin, valproate, lamotrigine and clonazepam. Following withdrawal of phenytoin she developed an akinetic-rigid syndrome, with ataxia and marked cognitive impairment. Extensive investigation failed to identify a cause. Serum ammonia and valproate levels were normal. Hypothesizing this might be valproate encephalopathy, valproate was rapidly substituted with levetiracetam. Her severe motor symptoms resolved within two weeks and cognitive impairment markedly improved. Valproate-induced encephalopathy, with or without hyperammonaemia and liver toxicity are typically recognizable for their temporal relation between the start of therapy with valproate and emergence of the clinical syndrome. Reversible disorders of motor function and cognition attributable to valproate are well described, but few cases have been reported presenting years after starting treatment. Given the insidious progression, delayed onset, lack of association with drug levels or presence of hyperammonaemia, a high index of suspicion is needed to make the diagnosis.

Screening of anxiety and quality of life in people with epilepsy

PURPOSE

Up to 60% of people with epilepsy (PwE) have psychiatric comorbidity including anxiety. Anxiety remains under recognized in PwE. This study investigates if screening tools validated for depression could be used to detect anxiety disorders in PWE. Additionally it analyses the effect of anxiety on QoL.

METHOD

261 participants with a confirmed diagnosis of epilepsy were included. Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) and Emotional Thermometers (ET), both validated to screen for depression were used. Hospital Anxiety and Depression Scale-Anxiety (HADS-A) with a cut off for moderate and severe anxiety was used as the reference standard. QoL was measured with EQ5-D. Sensitivity, specificity, positive and negative predictive value and ROC analysis as well as multivariate regression analysis were performed.

RESULTS

Patients with depression (n=46) were excluded as multivariate regression analysis showed that depression was the only significant determinant of having anxiety in the group. Against HADS-A, NDDI-E and ET-7 showed highest level of accuracy in recognizing anxiety with ET7 being the most effective tool. QoL was significantly reduced in PwE and anxiety.

CONCLUSION

Our study showed that reliable screening for moderate to severe anxiety in PwE without co-morbid depression is feasible with screening tools for depression. The cut off values for anxiety are different from those for depression in ET7 but very similar in NDDI-E. ET7 can be applied to screen simultaneously for depression and "pure" anxiety. Anxiety reduces significantly QoL. We recommend screening as an initial first step to rule out patients who are unlikely to have anxiety.

Stress and epilepsy: fact or fiction, and what can we do about it?

People with epilepsy report that stress is their most common trigger for seizures and some believe it caused their epilepsy in the first place. The extensive preclinical, epidemiological and clinical studies examining the link between stress and epilepsy have given confusing results; the clinical studies in particular are fraught with confounders. However stress is clearly bad for health, and we now have substantial preclinical evidence suggesting that chronic stress worsens epilepsy; in selected cases it may even be a causal factor for epilepsy. Healthcare professionals working with people with epilepsy should pay more attention to stress in clinical practice. This review includes some practical advice and guidance for stress screening and management.

Different attachment styles correlate with mood disorders in adults with epilepsy or migraine

PURPOSE

Interpersonal relationships are viewed as important contexts within which psychopathology emerges and persists or desists. Attachment theory describes the dynamics of long-term relationships between humans especially in families and lifelong friendships. The present study was aimed at investigating attachment styles in adult patients with epilepsy as compared to subjects with migraine and their potential correlates with a history of mood disorders.

METHODS

A consecutive sample of 219 adult outpatients with epilepsy (117) or migraine (102) was assessed with the Attachment Style Questionnaire (ASQ).

RESULTS

Patients with epilepsy and a lifetime history of mood disorders presented elevated scores for Need for approval (p<0.001) and Preoccupation with relationships (p<0.001). Age correlated with the Relationships as secondary (r=0.322; p<0.001) and Need for approval (r=0.217; p=0.019) subscales while age at onset correlated only with Relationships as secondary (r=0.225; p=0.015). Seizure-free patients presented lower scores for Need for approval (p=0.003). Patients with migraine and a lifetime history of mood disorders presented lower scores in Confidence (p=0.002) and higher scores in Discomfort with closeness (p=0.026).

CONCLUSIONS

An anxious-preoccupied attachment correlated with mood disorders in epilepsy while it was an avoidant pattern in migraine. Our results bring further data on the role of psychological variables in mood disorders in epilepsy. Further studies will allow early identification of patients at risk and the development of preventive strategies.

Screening for depression in epilepsy: a model of an enhanced screening tool

OBJECTIVE

Depression is common but frequently underdiagnosed in people with epilepsy. Screening tools help to identify depression in an outpatient setting. We have published validation of the NDDI-E and Emotional Thermometers (ET) as screening tools for depression (Rampling et al., 2012). In the current study, we describe a model of an optimized screening tool with higher accuracy.

METHODS

Data from 250 consecutive patients in a busy UK outpatient epilepsy clinic were prospectively collected. Logistic regression models and recursive partitioning techniques (classification trees, random forests) were applied to identify an optimal subset from 13 items (NDDI-E and ET) and provide a framework for the prediction of class membership probabilities for the DSM-IV-based depression classification.

RESULTS

Both logistic regression models and classification trees (random forests) suggested the same choice of items for classification (NDDI-E item 4, NDDI-E item 5, ET-Distress, ET-Anxiety, ET-Depression). The most useful regression model includes all 5 mentioned variables and outperforms the NDDI-E as well as the ET with respect to AUC (NDDI-E: 0.903; ET7: 0.889; logistic regression: 0.943). A model developed using random forests, grown by restricting the possible splitting of variables to these 5 items using only subsets of the original data for single classification, performed similarly (AUC: 0.949).

CONCLUSIONS

For the first time, we have created a model of a screening tool for depression containing both verbal and visual analog scales, with characteristics supporting that this will be more precise than previous tools. Collection of a new data sample to assess out-of-sample performance is necessary for confirmation of the predictive performance.

Which symptoms are indicative of depression in epilepsy settings? An analysis of the diagnostic significance of somatic and non-somatic symptoms

BACKGROUND

Depression is a common psychiatric co-morbidity in epilepsy. However, there have been no previous studies which have investigated the validity of individual symptoms for comorbid depression in epilepsy, in particular the diagnostic value of somatic and non-somatic symptoms.

METHODS

Patients with epilepsy diagnosed in a specialist epilepsy clinic were approached and completed several self-reported mood scales, prior to or immediately after their neurology outpatient consultations. Symptoms of depression were elicited using PHQ-9, BDI-II and HADS scales, comprising a total of 44 self report questions. 266 patients returned complete questionnaires of whom 18.0% met criteria for DSM-IV major depression according to the WHO Major Depression Inventory.

RESULTS

Against DSM-IV major depressive disorder (MDD), both somatic and non-somatic symptoms were valuable. The top five most useful questions relating to a diagnosis of MDD in epilepsy were "Moving or speaking so slowly that other people could have noticed" "Little interest or pleasure in doing things" "Feeling down depressed or hopeless" "Trouble concentrating on things such as reading" and "Feeling tired or having little energy." Four of these symptoms were rated as excellent initial screening questions for depression namely, "Moving or speaking so slowly that other people could have noticed" "Little interest or pleasure in doing things" "Feeling down depressed or hopeless" "Trouble concentrating on things such as reading." The item "Moving or speaking so slowly that other people could have noticed" from the PHQ9 was endorsed in about 90% of depressed patients with epilepsy but only about 6% of non-depressed patients.

CONCLUSION

These findings suggest that both somatic and non-somatic symptoms can be valuable when diagnosing depression in epilepsy and should be considered when designing scales for depression in epilepsy. Specific psychological symptoms and specific somatic symptoms are indicative of depression in epilepsy.

Established status epilepticus treatment trial (ESETT)

Phenytoin (PHT) has been the standard treatment for convulsive status epilepticus (SE) where initial benzodiazepines have failed for many years, despite that it has many limitations in the emergency situation. Valproate (VPA) and levetiracetam (LEV) are emerging as potentially superior alternatives, and there is an urgent need for an adequately powered comparative randomized controlled trial (RCT). An international group, having not succeeded in obtaining funding from the United Kingdom in 2010, is now preparing a revised proposal for submission to the National Institute of Neurological Disorders and Stroke (NINDS) to undertake a blinded comparative RCT using an adaptive design. This will be necessarily international and multicenter, requiring up to 1,500 patients from over 50 centers, and if successful will commence recruiting in 2012. The primary outcome, agreed from the 2009 SE workshop as pragmatic, generalizable, and clinically meaningful, will be cessation of seizures without need for other drug or sedation, and without serious adverse events, maintained for at least 2 h.

Administration of Levetiracetam after prolonged status epilepticus does not protect from mitochondrial dysfunction in a rodent model

Neuronal death and dysfunction occur after status epilepticus (SE), and is associated with mitochondrial enzyme damage. We previously showed, using the rat perforant pathway stimulation model, that levetiracetam administration (LEV; 1000 mg/kg intraperitoneal) during established SE reduces seizure severity and prevents mitochondrial dysfunction. We now show that administration of the same dose of LEV after 5h SE, does not protect from mitochondrial dysfunction.

Antiepileptic effect of gap-junction blockers in a rat model of refractory focal cortical epilepsy

PURPOSE

Epilepsy is the most common serious neurologic disease, and current treatments are ineffective for <or=30% of patients. Gap junctions have been implicated in seizure generation and propagation, and as such, may represent a novel therapeutic target but have been little investigated in vivo. We set out to assess the efficacy and tolerability of gap-junction blockers delivered to the seizure focus in a well-characterized model of refractory cortical epilepsy in rats.

METHODS

A chronic epilepsy focus was induced in the cortex of rats by using tetanus toxin, and subsequent studies were conducted in freely moving unanesthetized animals with frequent spontaneous seizures, as we previously described. Carbenoxolone, meclofenamic acid, and saline were applied directly to the seizure focus. EEG, electromyogram (EMG), and behavioral parameters were measured for >or=1 h before drug infusion and for >or=3 h afterward. No ill effects were observed.

RESULTS

An immediate and marked reduction in percentage of seizure time was seen in rats receiving carbenoxolone (baseline, 69.4%+/- 7.0% (SEM); maximum effect, 9.3%+/- 3.5%, p <or=0.001) and meclofenamic acid (baseline, 58.3%+/- 3.7%; maximum effect, 0.92%+/- 0.92%, p < 0.001). No effect was seen after saline infusion.

CONCLUSIONS

Gap-junction blockers applied focally are effective at suppressing seizures and, as such, represent a potential new treatment for epilepsy. Development of focal treatment strategies is essential in this regard.

Levetiracetam: antiepileptic properties and protective effects on mitochondrial dysfunction in experimental status epilepticus

PURPOSE

To assess the anticonvulsant activity of the novel antiepileptic drug, levetiracetam (LEV) in a model of self-sustaining limbic status epilepticus, and to measure the consequence of LEV treatment on the pattern of mitochondrial dysfunction known to occur after status epilepticus (SE).

METHODS

The rat perforant pathway was stimulated for 2 h to induce self-sustaining status epilepticus (SSSE). Stimulated rats were assigned to one of three treatment groups, receiving intraperitoneal injections of saline, 200 mg/kg LEV, or 1,000 mg/kg LEV, 15 min into SSSE and at 3 times over the next 44-h period. All animals received diazepam after 3-h SSSE to terminate seizures. Forty-four hours later, the hippocampi were extracted and prepared for electrochemical high-performance liquid chromatography (HPLC), to measure reduced glutathione levels, and for spectrophotometric assays to measure activities of mitochondrial enzymes (aconitase, alpha-ketoglutarate dehydrogenase, citrate synthase, complex I, and complex II/III). These parameters were compared between treatment groups and with sham-operated rats.

RESULTS

LEV administration did not terminate seizures or have any significant effect on spike frequency, although rats that received 1,000 mg/kg LEV did exhibit improved behavioral seizure parameters. Significant biochemical changes occurred in saline-treated stimulated rats compared with shams: with reductions in glutathione, alpha-ketoglutarate dehydrogenase, aconitase, citrate synthase, and complex I activities. Complex II/III activities were unchanged throughout. Rats that received 1,000 mg/kg LEV had significantly improved biochemical parameters, in many instances, comparable to sham control levels.

CONCLUSIONS

Despite continuing seizures, administration of LEV (1,000 mg/kg) protects against mitochondrial dysfunction, indicating that in addition to its antiepileptic actions, LEV may have neuroprotective effects.

An audit of electroencephalography requests: Use and misuse

OBJECTIVE

To investigate whether electroencephalogram (EEG) requests at St George's Hospital (SGH) are being made according to clinical guideline recommendations.

METHODS

A retrospective audit at a regional neurology and neurosurgery referral centre, also serving a district population. All adult National Health Service patients undergoing standard EEG between 1st November 2003 and 31st January 2004, for whom the request originated within the hospital, were identified. Data was collected from each subject's case notes, request form and EEG report and compared to predetermined criteria.

RESULTS

Fifty sets of notes from ninety patients meeting the inclusion criteria were available for review. Twenty-six percent of requests were considered 'inappropriate', with respect to clinical guidelines, of which 92% were for 'funny turns' where there appeared to be insufficient clinical evidence to justify the request. The EEG contributed to diagnosis or management in only 22% of cases, all of which had been appropriately requested. Neurologists/epileptologists appeared better than non-specialists in terms of appropriateness of referrals, though the numbers were too small to reach significance (p = 0.173, Fisher's exact). Forty-two percent of all patients, and less than 10% of outpatients, had their EEG within the guideline target wait of 4 weeks.

CONCLUSIONS

Over a quarter of EEG referrals are not being made in accordance with guidelines, mainly because of the misconception that an EEG can confirm or exclude a diagnosis of epilepsy in patients with "funny turns". In addition, less than 10% of out patient requests are being met within 4 weeks. Strategies to maximise service utilisation are discussed.

The antioxidant N-acetyl-L-cysteine does not prevent hippocampal glutathione loss or mitochondrial dysfunction associated with status epilepticus

Hippocampal reduced glutathione (GSH) levels diminish after status epilepticus (SE), which precedes damage to mitochondrial enzymes, which is associated with cell death. The rat perforant pathway stimulation model was used to assess whether intraperitoneal administration of the GSH precursor N-acetyl-L-cysteine (NAC) protected against these changes. NAC (300 mg/kg) treated animals exhibited the same GSH decrease post SE as vehicle treated. Furthermore, NAC treatment had no protective effects on mitochondrial dysfunction.

The -1021C->T DBH gene variant is not associated with epilepsy or antiepileptic drug response

Dopamine beta-hydroxylase (DBH) catalyzes the conversion of dopamine to norepinephrine (NE). Animal studies show that genes in the NE pathway are candidates for susceptibility to epilepsy and antiepileptic drug (AED) response. The authors genotyped the -1021C-->T major functional polymorphism in the DBH gene in 675 patients with epilepsy and 1,087 controls. The authors found no association with epilepsy, several epilepsy subtypes, or AED response. The results suggest that the -1021C-->T variant does not contribute to epilepsy.

Depletion of reduced glutathione precedes inactivation of mitochondrial enzymes following limbic status epilepticus in the rat hippocampus

The time course and critical determinants of mitochondrial dysfunction and oxidative stress following limbic status epilepticus (SE) were investigated in hippocampal sub-regions of an electrical stimulation model in rats, at time points 4-44h after status. Mitochondrial and cytosolic enzyme activities were measured spectrophotometrically, and reduced glutathione (GSH) concentrations by HPLC, and compared to results from sham controls. The earliest change in any sub-region was a fall in GSH, appearing as early as 4h in CA3 (-13%, p<0.05), and persisting at all time points. This was followed by a transient fall in complex I activity (CA3, 16h, -13%, p<0.05), and later changes in aconitase (CA1,-18% and CA3, -22% at 44h, p<0.05). The activity of the cytosolic enzyme glyceraldehyde-3-phosphate-dehydrogenase was unaffected at all time points. It is known that GSH levels are dependent both on redox status, and on the availability of the precursor cysteine, in turn dependent on the cysteine/glutamate antiporter, for which extracellular glutamate concentrations are rate limiting. Both mechanisms are likely to contribute indirectly to GSH depletion following seizures. That a relative deficiency in GSH precedes later changes in the activities of complex I and aconitase in vulnerable hippocampal sub-regions, occurring within a clinically relevant therapeutic time window, suggests that strategies to boost GSH levels and/or otherwise reduce oxidative stress following seizures, deserve further study, both in terms of preventing the biochemical consequences of SE and the neuronal dysfunction and clinical consequences.

Characterization of the tetanus toxin model of refractory focal neocortical epilepsy in the rat

PURPOSE

To characterize in detail a model of focal neocortical epilepsy.

METHODS

Chronic focal epilepsy was induced by injecting 25-50 ng of tetanus toxin or vehicle alone (controls) into the motor neocortex of rats. EEG activity was recorded from electrodes implanted at the injection site, along with facial muscle electromyographic (EMG) activity and behavioral monitoring intermittently for up to 5 months in some animals. Drug responsiveness was assessed by using the antiepileptic drugs (AEDs) diazepam (DZP) and phenytoin (PHT) delivered systemically, while 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide (NBQX), a competitive antagonist at AMPA receptors, was administered directly to the brain to investigate the potential benefits of focal drug delivery.

RESULTS

Tetanus toxin induced mild behavioral seizures that persisted indefinitely in all animals. EEG spiking activity, occurring up to 80% of the time, correlated with clinical seizures consisting of interrupted behavioral activity, rhythmic bilateral facial twitching, and periods of abrupt motor arrest. Seizures were refractory to systemic administration of DZP and PHT. However, focal delivery of NBQX to the seizure site reversibly reduced EEG and behavioral seizure activity without detectable side effects.

CONCLUSIONS

This study provides a long-term detailed characterisation of the tetanus toxin model. Spontaneous, almost continuous, well-tolerated seizures occur and persist, resembling those seen in neocortical epilepsy, including cortical myoclonus and epilepsia partialis continua. The seizures appear to be similarly resistant to conventional AEDs. The consistency, frequency, and clinical similarity of the seizures to refractory epilepsy in humans make this an ideal model for investigation of both mechanisms of seizure activity and new therapeutic approaches.

Synergism between Topiramate and Budipine in Refractory Status Epilepticus in the Rat

PURPOSE

To evaluate the antiepileptic and neuroprotective properties of topiramate (TPM) alone and with coadministration of the N-methyl-D-aspartate (NMDA)-receptor antagonist budipine in a rat model of refractory status epilepticus.

METHODS

Male Sprague-Dawley rats had electrodes implanted into the perforant path and dentate granule cell layer of the hippocampus under halothane anesthesia. Approximately 1 week after surgery, the perforant path of each animal was electrically stimulated for 2 h to induce self-sustaining status epilepticus. Successfully stimulated rats were given intraperitoneally vehicle (n = 6), TPM (20-320 mg/kg; n = 28), budipine (10 mg/kg; n = 5), or budipine (10 mg/kg) and TPM (80 mg/kg; n = 6) 10 min after the end of the stimulation and monitored behaviorally and electroencephalographically for a further 3 h. The animals were killed 14 days later, and histopathology was assessed.

RESULTS

Neither budipine alone nor TPM at any dose terminated status epilepticus. Despite this, TPM resulted in various degrees of neuroprotection at doses between 40 and 320 mg/kg. Coadministration of budipine with TPM terminated the status epilepticus in all rats. This combination also significantly improved the behavioral profile and prevented status-induced cell death compared with control.

CONCLUSIONS

Budipine and TPM are an effective drug combination in stopping self-sustained status epilepticus, and TPM alone was neuroprotective, despite the continuation of seizure activity.

Focal treatment for refractory epilepsy: hope for the future?

Despite advances in anti-epileptic drug therapy and epilepsy surgery in recent years, intractable epilepsy remains a large clinical problem. Surgical resection, which can have an excellent outcome, is appropriate for only a minority of patients in whom an identifiable focus in non-eloquent brain can be identified. Systemic drug delivery is inevitably limited by the potential for unwanted side effects, due to actions both outside the CNS and in non-epileptic brain regions. Thus for a substantial number of patients novel treatment approaches are urgently needed. Both focal drug delivery and neuronal stem cell grafting have been evaluated in a variety of experimental epilepsy models in recent years, targeting either the seizure focus or key propagation pathways. The literature in this field is critically reviewed and considered in a clinical context. Studies in both areas are hampered by the limitations of available animal models, and by uncertainties in discerning which changes in the epileptic brain directly promote seizures, and which are compensatory. However, in many cases promising, though short-term, results have been obtained. Before such studies could be considered in humans further investigations that include long-term seizure and behavioural outcomes, in clinically relevant experimental models, are required. However, the current literature does provide proof in principle for a focal treatment approach, which may offer hope for many currently intractable patients for whom drug developments and surgical advances have proved disappointing.

Advances in epilepsy

Advances in understanding of both the causes and consequences of epilepsy have been paralleled by a number of recent reports and clinical guidelines highlighting the complexities involved in both diagnosing and treating epilepsy. We review recent developments, including comments on the evolution of clinical guidelines, anti-epileptic drugs, epilepsy surgery and new treatment approaches in development. Epilepsy genetics and emerging evidence on mechanisms of drug resistance in epilepsy will also be discussed. Issues with respect to pregnancy and epilepsy are considered, together with more recently identified dilemmas including bone health in epilepsy and whether seizures themselves cause brain damage. Imaging in epilepsy has recently been reviewed elsewhere, and will not be discussed.

The role of mitochondria and oxidative stress in neuronal damage after brief and prolonged seizures

Studies in vitro and in other disease states where excitotoxicity is believed to be important have demonstrated that mitochondrial function is a critical determinant of cell death, reflecting key roles in intracellular calcium homeostasis, energy production and oxidative stress. Central to this is the process of mitochondrial permeability transition, for which there are numerous influencing factors, although many, if not all, may specifically act though effects on the redox state of the cell and oxidative stress. Mitochondrial function in relation to seizure-induced cell death has been little studied until recently, but there is now accumulating evidence that similar mechanisms operate, certainly in cell death, following prolonged seizures. To what extent these same mechanisms might contribute to non-fatal but pathologically significant functional cellular changes in epilepsy, and the significance of reported free radical production after brief seizures is as yet uncertain. However, with the wide range of established techniques available to study mitochondrial function and oxidative stress, and those currently under development, these questions are undoubtedly answerable in the near future. Increased understanding of the mechanisms involved in seizure-induced cellular damage is an essential basis for the development of rational neuroprotective strategies.

A comparison of lorazepam and diazepam as initial therapy in convulsive status epilepticus

BACKGROUND

Previous trials have suggested lorazepam may be superior to diazepam as first-line treatment of convulsive status epilepticus (CSE), with improved seizure outcome, and a lower incidence of side-effects. Many published guidelines however still recommend diazepam.

AIM

To compare the efficacy, safety and cost of lorazepam compared to diazepam, in adults with CSE.

DESIGN

Retrospective case note audit.

METHODS

Cases of CSE were retrospectively identified over two 18-month periods either side of the introduction of a new management protocol in May 1997, in which lorazepam 4 mg i.v. was substituted for diazepam 10 mg i.v. as first-line treatment for CSE. Diagnostic codes for all admissions and casualty presentations of patients over 16 years of age were examined for primary or secondary codes including 'epilepsy', 'fits' or 'status epilepticus'. Medical records and casualty notes were reviewed to identify CSE cases. Treatment groups were compared using ANOVA and a Tukey post hoc analysis. Treatment success was defined as cessation of seizures without recurrence in the subsequent 12 h.

RESULTS

In both premonitory and established CSE, both drugs were equally effective at terminating seizures, but significantly fewer seizure recurrences followed lorazepam, and fewer repeat doses were needed. There were no differences in reported adverse events or in drug costs.

DISCUSSION

We recommend that lorazepam be the first-line therapy in preference to diazepam in adults with CSE.

Mitochondrial dysfunction associated with neuronal death following status epilepticus in rat

Status epilepticus (SE) in humans and animal models results in significant cerebral damage and an increased risk of subsequent seizures, associated with a characteristic pattern of neuronal loss particularly affecting the hippocampus. Seizure related cell death is considered to be excitotoxic, but studies have been limited, concentrating on terminal events rather than initial mechanisms. We have studied the biochemical events in the first few days following SE. Self-sustaining limbic SE was induced in adult rats using perforant path stimulation, and animals were allowed to recover. Biochemical studies were performed at 16, 44 h and 8 days following SE, using spectrophotometric enzyme assays and HPLC on regional brain homogenates compared with those from sham-operated controls. Haematoxylin and eosin histology was also undertaken at each time point. Brain aconitase and alpha-ketoglutarate dehydrogenase (alphaKDH) activity were both significantly (P<0.05) reduced by approximately 20% in the first 16-44 h following status, but had returned to normal by 8 days. These enzymes are part of the tri-carboxylic acid (Krebbs) cycle in the mitochondrial matrix, and are known to be sensitive to free radical, especially peroxynitrite damage. There was a similar decrease in reduced glutathione levels. Histological studies confirmed evidence of acute neuronal damage up to 44 h, and neuronal loss by 8 days. This is the first in vivo demonstration of this pattern of mitochondrial dysfunction and loss of brain glutathione following SE. The pattern of abnormalities is consistent with reversible mechanisms being involved in excitotoxic cell damage. This, together with the timing of changes, suggests new avenues for therapeutic intervention.

Mitochondrial myopathies and encephalomyopathies

Defects of mitochondrial metabolism result in a wide variety of human disorders, which can present at any time from infancy to late adulthood and involve virtually any tissue either alone or in combination. Abnormalities of the electron transport and oxidative phosphorylation (OXPHOS) system are probably the most common cause of mitochondrial diseases. Thirteen of the protein subunits of OXPHOS are encoded by mitochondrial DNA (mtDNA) and mutations of this genome are important causes of OXPHOS deficiency. The link between genotype and phenotype with respect to mtDNA mutations is not clear: the same mutation may result in a variety of phenotypes, and the same phenotype may be seen with a variety of different mtDNA mutations. The pathogenesis of mtDNA mutations is unclear although OXPHOS and ATP deficiency, and free radical generation, are thought to contribute to tissue dysfunction. There is now strong evidence for mitochondrial dysfunction in neurodegenerative disorders. In some cases, e.g. Friedreich's ataxia, hereditary spastic paraplegia, this is a result of a mutation of a nuclear gene encoding a mitochondrial protein, whilst in others, e.g. Huntington's disease, amyotrophic lateral sclerosis, the OXPHOS defect is secondary to events induced by a mutation in a nuclear gene encoding a non-mitochondrial protein. In yet a third group, e.g. Parkinson's disease, Alzheimer's disease, the relationship of the mitochondrial defect to aetiology and pathogenesis is unclear.

Functional consequences of the 3460-bp mitochondrial DNA mutation associated with Leber's hereditary optic neuropathy

Complex I is the largest of the mitochondrial respiratory chain proteins, and contains subunits encoded by both mitochondrial and nuclear genomes. Leber's hereditary optic neuropathy has been clearly linked to mutations of mitochondrial DNA complex I genes, and variable complex I functional defects have been reported. We have confirmed an approximate 60% defect in mitochondrial NADH CoQ1 reductase activity in cultured fibroblasts bearing the 3460-bp G to A mutation within the ND1 gene. However complex I-linked ATP synthesis was found to be normal in these fibroblasts. A 60% rotenone-induced decrease in complex I activity was shown to reduce ATP synthesis in normal fibroblasts, indicating that this level of complex I activity was below the threshold required to affect ATP synthesis. Although 3460 LHON mitochondria were less sensitive to rotenone inhibition, this did not explain the decreased complex I activity as the rotenone insensitive activity was not increased, nor did the inhibitor diphenyleneiodonium inhibit the NADH CoQ1 reductase activity to a greater extent. Decreased NADH cytochrome c reductase activity in cybrids homoplasmic for the 3460 LHON mtDNA mutation confirmed that the decrease in complex I activity was not specific to the assay used and was not caused by inhibitory effects of ubiquinone analogues used in the NADH CoQ1 reductase assay. These findings have important implications for our understanding of complex I dysfunction in the pathogenesis of 3460 Leber's hereditary optic neuropathy.

The influence of nuclear background on the biochemical expression of 3460 Leber's hereditary optic neuropathy

The role of mitochondrial DNA (mtDNA) mutations in the pathogenesis of Leber's hereditary optic neuropathy (LHON) has yet to be characterized. Several clinical features of the disease imply that nuclear genes might also be involved in its expression. We have confirmed the presence of a severe NADH:coenzyme Q1 reductase (complex I) defect in association with the A3460G mtDNA LHON mutation in cultured fibroblasts compared with age-matched controls. This defect was not seen in clonal fibroblasts with 0% mutant mtDNA developed from a heteroplasmic A3460G LHON subject, confirming the association between the A3460G mutation and the complex I defect. Cybrids prepared from the fusion of enucleated fibroblasts homoplasmic for the A3460G mutation with 206 (osteosarcoma) cells lacking mtDNA (p0) also had a severe deficiency of complex I activity. However, in A3460G LHON fusion cybrids containing a different nuclear background, A549 p0 (lung derived), this biochemical defect was not apparent in all the clones studied. These results suggest that the nuclear environment can influence the expression of the biochemical defect in LHON patients with the A3460G mutation.