Managing severe epilepsy syndromes of early childhood

Sodium-glucose cotransporter 2 inhibitors and neurological disorders: a scoping review

Background

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are a group of antidiabetic medications with a favourable cardiovascular, renal and overall safety profile. Given the limited treatment options available for neurological disorders, it is important to determine whether the pleiotropic effects of SGLT2i can be utilised in their prevention and management.

Methods

All articles published before 20 March 2021 were systematically searched in MEDLINE, EMBASE, Scopus, Web of Science, APA PsycINFO and ClinicalTrials.gov. Overall, 1395 titles were screened, ultimately resulting in 160 articles being included in the qualitative analysis. Screening and data extraction were conducted by two independent authors and studies were excluded if they were not an original research study.

Findings

Of the 160 studies, 134 addressed stroke, 19 cognitive impairment, 4 epilepsy and 4 movement disorders, encompassing a range from systematic reviews and randomised controlled trials to bioinformatic and animal studies. Most animal studies demonstrated significant improvements in behavioural and neurological deficits, which were reflected in beneficial changes in neurovascular units, synaptogenesis, neurotransmitter levels and target receptors' docking energies. The evidence from the minority clinical literature was conflicting and many studies did not reach statistical significance.

Interpretation

SGLT2i may exert neurological benefits through three mechanisms: reduction in cardiovascular risk factors, augmentation of ketogenesis and anti-inflammatory pathways. Most clinical studies were observational, meaning that a causal relationship could not be established, while randomised controlled trials were heterogeneous and powered to detect cardiovascular or renal outcomes. We suggest that a longitudinal study should be conducted and specifically powered to detect neurological outcomes.

Dravet Syndrome: A Review of Current Management

Dravet syndrome is a debilitating epileptic encephalopathy of childhood with few treatment options available in the United States before 2018. In the modern era, new genetic testing options will allow diagnosis closer to disease onset. Three new medicines-stiripentol, cannabidiol, and fenfluramine-have documented efficacy and safety as adjunctive therapies for treating pharmacoresistant Dravet syndrome. Early diagnosis resulting in earlier treatment with these and other medications may improve prognosis of long-term outcomes, including less severity of cognitive, motor, and behavioral impairments. New rescue medication formulations can now manage acute seizures and help prevent status epilepticus via intranasal, buccal, and intramuscular routes as opposed to rectal administration. Preventing status epilepticus and generalized tonic-clonic seizures could potentially lower the risk of sudden unexpected death in epilepsy. With this changing landscape in diagnostic and treatment options comes questions and controversies for the practicing clinician, especially as diagnostic techniques outpace clinical treatment strategies. Critical decision points include when to start treatment, what pharmacotherapy combinations to try first, which rescue medication to recommend, and how to advise parents on controversial topics (e.g., immunizations). Given that most patients require polypharmacy, clinicians must be cognizant of drug-drug interactions between new medicines, existing anti-epileptic drugs, and other medications to manage comorbidities and must have an understanding of available therapeutic drug monitoring strategies and pharmacokinetic parameters. This review places new diagnostic, treatment and acute care options into the modern era and provides an overview of the challenges and opportunities facing the pediatric epileptologist in this rapidly changing landscape.

Vagus Nerve Stimulation in Intractable Epilepsy Associated With SCN1A Gene Abnormalities

Mutations in the SCN1A gene cause a spectrum of epilepsy syndromes. There are 2 syndromes that are on the severe end of this spectrum. The classic severe form, Dravet syndrome, is an epileptic encephalopathy of childhood, causing cognitive decline as well as intractable seizures. Severe Myoclonic Epilepsy of Infancy-Borderline (SMEIB) is a term used to include cases with similar severities as those with Dravet syndrome, but lacking a single feature of classic severe myoclonic epilepsy of infancy. Vagus nerve stimulation is a nonpharmacologic treatment for intractable epilepsy. A retrospective review was conducted of patients with deleterious SCN1A mutations who had vagus nerve stimulation placement for treatment of their intractable epilepsy. These children had onset of their epilepsy between 3 and 29 months of age. Seizure control was assessed 6 months after implantation. Twenty patients are included in the study, with 12 implanted at our institution. Nine of the 12 patients implanted at our institution, who had confirmed pre- and post-implantation seizure assessments, showed improvement in seizure control, which was defined as >50% reduction in generalized tonic-clonic seizures, and 4 of those 12 reported improvement in cognitive or speech development. Seven of the 8 patients not implanted at our institution reported subjective benefit, with 4 relating "marked improvement" or seizure freedom. Vagus nerve stimulation appears to impart a benefit to children with deleterious SCN1A gene abnormalities associated with intractable epilepsy.

Report from a Survey of Parents Regarding the Use of Cannabidiol (Medicinal cannabis) in Mexican Children with Refractory Epilepsy

Structured online surveys were used to explore the experiences of the parents of children with refractory epilepsy using medicinal cannabis in Mexico during September 2016. The surveys, which were completed in full, were reviewed, and 53 cases of children aged between 9 months and 18 years were identified. Of these, 43 cases (82%) were from Mexico and 10 (18%) were from Latin American countries. Of the 43 Mexican cases, the diagnoses were as follows: 20 cases (47%) had Lennox-Gastaut syndrome (LGS); 13 cases (30%) had unspecified refractory epilepsy (URE); 8 cases (19%) had West syndrome (WS); 1 case (2%) had Doose syndrome (DS); and 1 case (2%) had Ohtahara syndrome (OS). In total, 47.1% of cases had previously been treated with 9 or more anticonvulsant therapies. The parents reported a decrease in convulsions when cannabidiol was used in 81.3% of the cases; a moderate to significant decrease occurred in 51% of cases, and 16% of cases were free from seizure. The number of antiepileptic drugs being used was reduced in 9/43 (20.9%) cases. No serious adverse effects were reported, with only some mild adverse effects, such as increased appetite or changes in sleep patterns, reported in 42% of cases.

Cannabidiol as potential treatment in refractory pediatric epilepsy

In recent years there has been great scientific and public interest focused on the therapeutic potential of compounds derived from cannabis for the treatment of refractory epilepsy in children. From in vitro and in vivo studies on animal models, cannabidiol (CBD) appears to be a promising anticonvulsant drug with a favorable side-effect profile. In humans, CBD efficacy and safety is not supported by well-designed trials and its use has been described by anecdotal reports. It will be necessary to investigate CBD safety, pharmacokinetics and interaction with other anti-epileptic drugs (AEDs) alongside performing double-blinded placebo-controlled trials in order to obtain conclusive data on its efficacy and safety in children.

Ketogenic diet therapy can improve ACTH-resistant West syndrome in Japan

PURPOSE

Ketogenic diet therapy (KD) has been used to treat children with refractory generalized epilepsy. We herein reported the efficacy of KD for West syndrome (WS) resistant to ACTH therapy.

SUBJECTS

SUBJECTS, consisting of 6 patients (3 boys, 3 girls) with WS who continued to have epileptic spasms (ES) and hypsarrhythmia, received KD because other treatments including ACTH therapy failed to control WS.

METHODS

We retrospectively studied the clinical details of these patients and the efficacy of KD.

RESULTS

The mean age at the onset of epilepsy was 4 months (0-15 months). The underlying etiology consisted of lissencephaly, Down's syndrome, and focal cortical dysplasia. Hypsarrhythmia disappeared 1 month after the introduction of KD in 5 patients. The disappearance of ES was achieved in 2 patients, the frequency of ES episodes was 80% less in 3, and no change was observed in 1. Psychomotor development was promoted in 5 patients, along with improvements in ES and EEG. Gastrointestinal complications and lethargy, presumably caused by rapid ketosis, were reported as side effects in 3 patients during the first week of KD. Side effects including lethargy, anorexia, and unfavorable weight gain continued thereafter in these patients in spite of tolerance to KD.

CONCLUSION

KD was effective for WS resistant to ACTH therapy, although gastrointestinal side effects should be considered when introducing KD to milk-fed infants.

Cannabis and Endocannabinoid Signaling in Epilepsy

The antiepileptic potential of Cannabis sativa preparations has been historically recognized. Recent changes in legal restrictions and new well-documented cases reporting remarkably strong beneficial effects have triggered an upsurge in exploiting medical marijuana in patients with refractory epilepsy. Parallel research efforts in the last decade have uncovered the fundamental role of the endogenous cannabinoid system in controlling neuronal network excitability raising hopes for cannabinoid-based therapeutic approaches. However, emerging data show that patient responsiveness varies substantially, and that cannabis administration may sometimes even exacerbate seizures. Qualitative and quantitative chemical variability in cannabis products and personal differences in the etiology of seizures, or in the pathological reorganization of epileptic networks, can all contribute to divergent patient responses. Thus, the consensus view in the neurologist community is that drugs modifying the activity of the endocannabinoid system should first be tested in clinical trials to establish efficacy, safety, dosing, and proper indication in specific forms of epilepsies. To support translation from anecdote-based practice to evidence-based therapy, the present review first introduces current preclinical and clinical efforts for cannabinoid- or endocannabinoid-based epilepsy treatments. Next, recent advances in our knowledge of how endocannabinoid signaling limits abnormal network activity as a central component of the synaptic circuit-breaker system will be reviewed to provide a framework for the underlying neurobiological mechanisms of the beneficial and adverse effects. Finally, accumulating evidence demonstrating robust synapse-specific pathophysiological plasticity of endocannabinoid signaling in epileptic networks will be summarized to gain better understanding of how and when pharmacological interventions may have therapeutic relevance.

Report of a parent survey of cannabidiol-enriched cannabis use in pediatric treatment-resistant epilepsy

Severe childhood epilepsies are characterized by frequent seizures, neurodevelopmental delays, and impaired quality of life. In these treatment-resistant epilepsies, families often seek alternative treatments. This survey explored the use of cannabidiol-enriched cannabis in children with treatment-resistant epilepsy. The survey was presented to parents belonging to a Facebook group dedicated to sharing information about the use of cannabidiol-enriched cannabis to treat their child's seizures. Nineteen responses met the following inclusion criteria for the study: a diagnosis of epilepsy and current use of cannabidiol-enriched cannabis. Thirteen children had Dravet syndrome, four had Doose syndrome, and one each had Lennox-Gastaut syndrome and idiopathic epilepsy. The average number of antiepileptic drugs (AEDs) tried before using cannabidiol-enriched cannabis was 12. Sixteen (84%) of the 19 parents reported a reduction in their child's seizure frequency while taking cannabidiol-enriched cannabis. Of these, two (11%) reported complete seizure freedom, eight (42%) reported a greater than 80% reduction in seizure frequency, and six (32%) reported a 25-60% seizure reduction. Other beneficial effects included increased alertness, better mood, and improved sleep. Side effects included drowsiness and fatigue. Our survey shows that parents are using cannabidiol-enriched cannabis as a treatment for their children with treatment-resistant epilepsy. Because of the increasing number of states that allow access to medical cannabis, its use will likely be a growing concern for the epilepsy community. Safety and tolerability data for cannabidiol-enriched cannabis use among children are not available. Objective measurements of a standardized preparation of pure cannabidiol are needed to determine whether it is safe, well tolerated, and efficacious at controlling seizures in this pediatric population with difficult-to-treat seizures.

Critical review of palliative surgical techniques for intractable epilepsy

Approximately one third of epilepsy patients are not adequately treatable by antiepileptic medication. Curative resective epilepsy surgery can be performed in only a subgroup of these pharmacoresistent patients in whom the epileptogenic focus is localizable and does not overlap with eloquent brain areas. To the remaining patients (with bilateral or multiple epileptogenic foci, with epilepsy onset in eloquent areas, or with no identifiable epileptogenic focus) palliative epilepsy surgery can be offered if they suffer from disabling seizures. Standard palliative procedures currently comprise corpus callosotomy, multiple subpial transections, and vagus nerve stimulation. New approaches such as focus distant deep brain stimulation or direct stimulation of the hippocampus have gained the most interest. Feasibility studies, small pilot studies, and, recently, larger multicenter trials showed that direct brain stimulation shall be considered a potential helpful procedure in the field of palliative surgery. Moreover, with the increasing use of stereo-EEG in invasive video-EEG monitoring, stereo-EEG-guided thermocoagulation has the potential for a promising new treatment option in patients not amenable to resective epilepsy surgery. There is no general consensus on which palliative procedure is most effective in patients with difficult-to-treat epilepsy syndromes. The decision must be based on individual factors of a given patient. This review summarizes experience with palliative approaches collected in adult and pediatric patient series over the past decades and may help to thoroughly balance beneficial effects and risks of each procedure.

Indirect comparison of clobazam and other therapies for Lennox-Gastaut syndrome

OBJECTIVE

In the absence of head-to-head trials, it is not feasible to make direct comparisons of antiepileptic therapies for the treatment of Lennox-Gastaut syndrome (LGS). We conducted indirect comparisons of the relative efficacies of clobazam, felbamate, lamotrigine, topiramate, and rufinamide as adjunctive treatments for LGS.

METHODS

Clinical studies of LGS patients were identified in a 2009 Cochrane review and by electronic database search. Five randomized controlled trials were included in this systematic review, which reports findings from indirect comparisons between clobazam and other approved adjunctive LGS therapies (felbamate, lamotrigine, topiramate, rufinamide) in the United States and Europe. As outcomes were not uniformly reported across studies, the primary efficacy endpoint from each trial was transformed into Cohen's d effect size, to facilitate indirect comparisons. Typical interpretations of Cohen's d results are as follows: d < 0.2, change not detectable; 0.2 ≤ d < 0.5, small change; 0.5 ≤ d < 0.8, moderate change; and 0.8 ≤ d, large change.

RESULTS

High-dosage clobazam (1.0 mg/kg/day) was found to have the strongest treatment effect vs placebo (effect size 0.80), with moderate effects (effect sizes >0.50) for medium-dosage clobazam (0.5 mg/kg/day) and rufinamide. Felbamate, lamotrigine, and topiramate had low effect sizes. Indirect comparisons of numbers of total seizures and tonic-atonic seizures ('drop attacks') demonstrated superiority of both clobazam dosages over all comparators.

CONCLUSIONS

High- and medium-dosage clobazam was estimated to be more efficacious than other LGS treatments. Our analysis relied on published data and could not draw on direct head-to-head data of clobazam with alternatives. Further comparative research is ongoing to assess the usefulness of clobazam for LGS.

Vagus nerve stimulation vs. corpus callosotomy in the treatment of Lennox-Gastaut syndrome: a meta-analysis

PURPOSE

Lennox-Gastaut syndrome (LGS) is an epileptogenic disorder that arises in childhood and is typically characterized by multiple seizure types, slow spike-and-wave complexes on EEG and cognitive impairment. If medical treatment fails, patients can proceed to one of two palliative surgeries, vagus nerve stimulation (VNS) or corpus callosotomy (CC). Their relative seizure control rates in LGS have not been well studied. The purpose of this paper is to compare seizure reduction rates between VNS and CC in LGS using meta-analyses of published data.

METHODS

A systematic search of Pubmed, Ovidsp, and Cochrane was performed to find articles that met the following criteria: (1) prospective or retrospective study, (2) at least one patient diagnosed with Lennox-Gastaut syndrome, and (3) well-defined measure of seizure frequency reduction. Seizure reduction rates were divided into seizure subtypes, as well as total seizures, and categorized as 100%, >75%, and >50%. Patient groups were compared using chi-square tests for categorical variables and t-test for continuous measures. Pooled proportions with 95% confidence interval (95% CI) of seizure outcomes were estimated for total seizures and seizure subtypes using random effects methods.

RESULTS

17 VNS and 9 CC studies met the criteria for inclusion. CC had a significantly better outcome than VNS for >50% atonic seizure reduction (80.0% [67.0-90.0%] vs. 54.1% [32.1-75.4%], p<0.05) and for >75% atonic seizure reduction (70.0% [48.05-87.0%] vs. 26.3% [5.8-54.7%], p<0.05). All other seizure types, as well as total number of seizures, showed no statistically significant difference between VNS and CC.

CONCLUSIONS

CC may be more beneficial for LGS patients whose predominant disabling seizure type is atonic. For all other seizure types, VNS offers comparable rates to CC.

Rational Polytherapy with Antiepileptic Drugs

Approximately 30-40% of patients do not achieve seizure control with a single antiepileptic drug (AED). With the advent of multiple AEDs in the past 15 years, rational polytherapy, the goal of finding combinations of AEDs that have favorable characteristics, has become of greater importance. We review the theoretical considerations based on AED mechanism of action, animal models, human studies in this field, and the challenges in finding such optimal combinations. Several case scenarios are presented, illustrating examples of rational polytherapy.