lennox-Gastaut syndrome: an updateon treatment

Long-term Outcome of Resective Epilepsy Surgery in Patients With Lennox-Gastaut Syndrome

OBJECTIVE

We aimed to evaluate the long-term outcome of resective epilepsy surgery in patients with Lennox-Gastaut syndrome (LGS).

METHODS

We reviewed the case reports of 90 patients with LGS who had undergone resective surgery between 2003 and 2014 at the Severance Children's Hospital and managed them for a minimum period of 2 years.

RESULTS

At the time of surgery, the patients were between 3.0 and 23.5 years old (mean ± SD: 9.3 ± 4.4). The time from seizure onset to surgery ranged from 0.7 to 20.1 years (7.2 ± 4.3). On postoperative follow-up for an average period of 6.1 ± 2.2 years (range: 2.1-11.4 years), 45 patients (50.0%) had no seizures, and 15 (16.7%) reported infrequent seizures. Seizure-free outcomes were achieved in 15 of the 21 (71.4%) hemispherectomies, 23 of the 51 (45.1%) multilobar resections, and 7 of the 18 (38.9%) single lobar resections. On high-resolution MRIs, 20 patients (22.2%) had negative findings, 8 of whom (40.0%) became seizure-free after resective surgery. Malformation of cortical development was the most common pathologic finding and was noted in 57 patients (63.3%). Seizure-free patients achieved better adaptive behavior and social competence than did patients with persistent seizures at the second (2-3 years after surgery) and third (4-6 years after surgery) follow-ups, as indicated by social quotients (P < .05).

CONCLUSIONS

Resective surgery is a viable option in some patients to treat seizures that are associated with LGS, with a high probability of seizure control and better adaptive function.

Early Diagnosis and Treatment of Lennox-Gastaut Syndrome

Lennox-Gastaut syndrome (LGS) is a severe form of childhood-onset epilepsy associated with high morbidity and mortality. The peak period for manifestations of Lennox-Gastaut syndrome is between ages 3 and 5 years, a time of critical brain development and corresponding vulnerability to the electroclinical dysfunction arising from Lennox-Gastaut syndrome. Diagnosis is based on a triad of symptoms: multiple seizure types, cognitive impairment, and slow spike-and-wave pattern on electroencephalography. In practice, Lennox-Gastaut syndrome presentation is diverse, and there may be a delay between initial symptoms and emergence of the full triad of clinical features. Additionally, differential diagnosis is complicated by the resemblance of Lennox-Gastaut syndrome to other forms of epilepsy and by the need for varied diagnostic techniques requiring specific clinical skills. Because diagnosis is complex and early intervention may lead to improved outcomes, clinicians should consider treatment when Lennox-Gastaut syndrome symptoms are present, even in the absence of a formal diagnosis.

Safety and pharmacokinetic profile of rufinamide in pediatric patients aged less than 4 years with Lennox-Gastaut syndrome: An interim analysis from a multicenter, randomized, active-controlled, open-label study

OBJECTIVE

A good knowledge of safety and age group-specific pharmacokinetics (PK) of antiepileptic drugs (AEDs) in young pediatric patients is of great importance in clinical practice. This paper presents 6-month interim safety and PK from an ongoing 2-year open-label study (Study 303) of adjunctive rufinamide treatment in pediatric subjects ≥ 1 to < 4 years with inadequately controlled epilepsies of the Lennox-Gastaut syndrome (LGS) spectrum.

METHODS

Subjects (N = 37) were randomized to either rufinamide or any other approved AED chosen by the investigator as adjunctive therapy to the subject's existing regimen of 1-3 AEDs.

RESULTS

Interim safety results showed that treatment-emergent adverse events (TEAEs) were similar between the rufinamide (22 [88.0%]) and any-other-AED group (9 [81.8%]), with most events considered mild or moderate. A population PK analysis was conducted including plasma rufinamide concentrations from Study 303 and two other study populations of LGS subjects ≥ 4 years. The rufinamide PK profile was dose independent. The apparent clearance (CL/F) estimated from the PK model was 2.19 L/h; it was found to increase significantly as a function of body weight. Coadministration of valproic acid significantly decreased rufinamide CL/F. CL/F was not significantly affected by other concomitant AEDs, age, gender, race, hepatic function, or renal function. No adjustments to body weight-based rufinamide dosing in subjects ≥ 1 to < 4 years are necessary.

SIGNIFICANCE

Rufinamide was safe and well tolerated in these pediatric subjects. Results from the interim analysis demonstrate that rufinamide's safety and PK profile is comparable in subjects ≥ 1 to < 4 and ≥ 4 years with LGS.

CLINICAL TRIAL REGISTRATION

Study 303 (clinicaltrials.gov: NCT01405053).

Dietary therapy is not the best option for refractory nonsurgical epilepsy

The ketogenic diet (KD) is currently a well-established treatment for patients with medically refractory, nonsurgical epilepsy. However, despite its efficacy, the KD is highly restrictive and constitutes a treatment with serious potential adverse effects, and often with difficulties in its implementation and compliance. Patients on the KD require strict follow-up and constant supervision by a medical team highly experienced in its management in order to prevent complications. Other alternative treatments for patients with refractory epilepsy include vagus nerve stimulation (VNS), new-generation antiepileptic drugs (AEDs), corpus callosotomy (CC), and responsive focal cortical stimulation (RNS). In this review, we explain not only the difficulties of the KD as a therapeutic option for refractory epilepsy but also the benefits of other therapeutic strategies, which, in many cases, have proven to have better efficacy than the KD itself.

Lennox-Gastaut syndrome. Management update

Lennox-Gastaut syndrome (LGS) is a severe pediatric epilepsy syndrome characterized by mixed seizures, cognitive decline, and generalized slow (<3 Hz) spike wave discharges on electroencephalography. Atonic seizures result in dangerous drop attacks with risks of injury and impairment of the quality of life. The seizures are frequently resistant to multiple antiepileptic (AED) drugs. Newer AEDs, such as rufinamide, are now available. When multiple AED trials fail, non-pharmacological treatments such as the ketogenic diet, vagus nerve stimulation, and epilepsy surgery, should be considered. The aim of this review is to present an updated outline of LGS and the available treatments. Although the prognosis for complete seizure control remains poor, the addition of newer therapies provides an improved hope for some of these patients and their families. Further long term randomized controlled trials are required to compare different therapeutic interventions in terms of efficacy and tolerability.

Epileptic encephalopathies: new genes and new pathways

Epileptic encephalopathies represent a group of devastating epileptic disorders that occur early in life and are often characterized by pharmaco-resistant epilepsy, persistent severe electroencephalographic abnormalities, and cognitive dysfunction or decline. Next generation sequencing technologies have increased the speed of gene discovery tremendously. Whereas ion channel genes were long considered to be the only significant group of genes implicated in the genetic epilepsies, a growing number of non-ion-channel genes are now being identified. As a subgroup of the genetically mediated epilepsies, epileptic encephalopathies are complex and heterogeneous disorders, making diagnosis and treatment decisions difficult. Recent exome sequencing data suggest that mutations causing epileptic encephalopathies are often sporadic, typically resulting from de novo dominant mutations in a single autosomal gene, although inherited autosomal recessive and X-linked forms also exist. In this review we provide a summary of the key features of several early- and mid-childhood onset epileptic encephalopathies including Ohtahara syndrome, Dravet syndrome, Infantile spasms and Lennox Gastaut syndrome. We review the recent next generation sequencing findings that may impact treatment choices. We also describe the use of conventional and newer anti-epileptic and hormonal medications in the various syndromes based on their genetic profile. At a biological level, developments in cellular reprogramming and genome editing represent a new direction in modeling these pediatric epilepsies and could be used in the development of novel and repurposed therapies.