Catherine Chiron

Randomized trial comparing vigabatrin and hydrocortisone in infantile spasms due to tuberous sclerosis

Vigabatrin has been shown to be efficient in infants with infantile spasms and tuberous sclerosis, in open studies. In order to compare vigabatrin to oral steroids, a prospective randomized multicenter study was implemented using both drugs as monotherapy in newly diagnosed patients with infantile spasms and tuberous sclerosis. Eleven infants received vigabatrin (150 mg/kg per day) and 11 hydrocortisone (15 mg/kg per day) for 1 month. Spasm free patients continued vigabatrin or progressively stopped hydrocortisone in 1 month, non-responders were crossed to the other drug for a new 2 month-period. All vigabatrin patients (11/11) were spasm-free versus 5/11 hydrocortisone infants (P < 0.01). Seven patients were crossed to vigabatrin (six for inefficacy, one for adverse events) and became also totally controlled. Mean time to disappearance of infantile spasms was 3.5 days on vigabatrin versus 13 days on hydrocortisone (P < 0.01). Five patients exhibited side effects on vigabatrin but nine on hydrocortisone (P = 0.006). Vigabatrin should therefore be considered as the first choice treatment for infantile spasms due to tuberous sclerosis.

Spectrum of SCN1A mutations in severe myoclonic epilepsy of infancy

Objectives: SCN1A mutations were recently reported in several patients with severe myoclonic epilepsy in infancy (SMEI). The authors analyzed SCN1A mutations in 93 patients with SMEI and made genotype-phenotype correlation to clarify the role of this gene in the etiology of SMEI. Methods: All patients fulfilled the criteria for SMEI. The authors analyzed all patients for SCN1A mutations using denaturing high performance liquid chromatography. If a patient’s chromatogram was abnormal, the authors sequenced the gene in the patient and both parents. Results: SCN1A mutations were identified in 33 patients (35%). Most mutations were de novo, but were inherited in three patients. Parents carrying the inherited mutations had either no symptoms or a milder form of epilepsy. A greater frequency of unilateral motor seizures was the only clinical difference between patients with SCN1A mutations and those without. Truncating mutations were more frequently associated with such seizures than were missense mutations. The percentage of cases with family history of epilepsy was significantly higher in patients with SCN1A mutations. Conclusions: Unilateral motor seizures may be a specific clinical characteristic of SMEI caused by SCN1A mutations. Ten percent of SCN1A mutations are inherited from an asymptomatic or mildly affected parent, suggesting that SMEI is genetically heterogeneous. The increased frequency of familial epilepsy indicates that other genetic factors may contribute to this disorder.

Therapeutic Trial of Vigabatrin in Refractory Infantile Spasms

Infantile spasms usually start during the first year of life and constitute one of the most difficult types of epilepsy to treat. They carry a very poor prognosis for both epilepsy and mental development. Seventy children, including 47 infants, with intractable infantile spasms were entered into an open study with vigabatrin as add-on therapy to the usual anticonvulsant treatment. All were resistant to previous treatments, including corticosteroids (43 patients), carbamazepine, benzodiazepines, and sodium valproate. Two children withdrew from the study because of intolerance to vigabatrin (hypotonia or hypertonia) before evaluation of efficacy could be made. Of the remaining 68 children, 29 (43%) showed complete suppression of spasms. Forty-six children had a greater than 50% reduction in spasms. The best response was observed in those with tuberous sclerosis (12/14 compared with 12/18 with symptomatic infantile spasms of other origin and 22/36 with cryptogenic infantile spasms). Following the initial response to treatment of these patients (n = 68), a long-term response was confirmed in 75% of children with symptomatic infantile spasms and 36% of children with cryptogenic infantile spasms. In eight children, all other anticonvulsant medication could be definitively withdrawn. Tolerability appeared excellent, with 52 of 70 patients reporting no side effects. Somnolence, hypotonia, weight gain, excitation, and insomnia were the most common problems at the beginning of the study and were usually transient. Given the poor prognosis of this type of childhood epilepsy, vigabatrin appears to be a very interesting advance in the management of drug-resistant infantile spasms. (J Child Neurol 1991;6(Suppl):2S52-2S59).

Mental and behavioural outcome of infantile epilepsy treated by vigabatrin in tuberous sclerosis patients

Vigabatrin (VGB) has demonstrated high efficacy in infantile spasms (IS) due to tuberous sclerosis. Our first objective was to evaluate the cognitive long term effect outcome of children whose refractory spasms definitely disappeared when VGB was given as an add on drug. Our second objective was to determine the response of generalized epilepsy (infantile spasms) compared to partial epilepsy on cognitive impairment. A non selected series of 13 children underwent psychometric and behavioural evaluation before VGB initiation at a mean of 3 years on VGB treatment. Eight of them could perform detailed neuropsychological tests at follow-up. Seven had infantile spasms (Group I), they all were spasm free before 2 years of age and five remained with rare partial seizures (mean age, 5.5 years). Six others had partial epilepsy without spasms (Group II) and five remained with rare seizures (mean age, 7.5 years). Patients of Group I experienced dramatic changes. Developmental quotient (DQ) significantly rose in six out of seven by ten to more than 45 points (P = 0.03) and autistic behaviour disappeared in five out of the six who presented with. The four tested children had normal verbal level after 5 years and could integrate at school but they remained with marked visuospatial disabilities. By contrast, patients of Group II remained with an unchanged DQ of about 60 so that both groups had similar DQ levels on follow-up. The cessation of spasms with VGB is therefore associated with significant improvement of cognition and behaviour in children with tuberous sclerosis. Controlling secondary generalization induced by infantile spasms seems to be a key factor for mental development.

FDG-PET improves surgical outcome in negative MRI Taylor-type focal cortical dysplasias

Objective: To determine the diagnostic accuracy and prognostic value of 18FDG-PET in a recent series of patients operated for intractable partial epilepsy associated with histologically proven Taylor-type focal cortical dysplasia (TTFCD) and negative MRI. Methods: Of 23 consecutive patients (12 male, 7–38 years old) with negative 1.5-Tesla MRI, 10 exhibited subtle nonspecific abnormalities (e.g., unusual sulcus depth or gyral pattern) and the 13 others had strictly normal MRI. FDG-PET was analyzed both visually after coregistration on MRI and using SPM5 software. Metabolic data were compared with the epileptogenic zone (EZ) determined by stereo-EEG (SEEG) and surgical outcome. Results: Visual PET analysis disclosed a focal or regional hypometabolism in 18 cases (78%) corresponding to a single gyrus (n = 9) or a larger cortical region (n = 9). PET/MRI coregistration detected a partially hypometabolic gyrus in 4 additional cases. SPM5 PET analysis (n = 18) was concordant with visual analysis in 13 cases. Location of PET abnormalities was extratemporal in all cases, involving eloquent cortex in 15 (65%). Correlations between SEEG, PET/MRI, and histologic findings (n = 20) demonstrated that single hypometabolic gyri (n = 11) corresponded to EZ and TTFCD, which was localized at the bottom of the sulcus. Larger hypometabolic areas (n = 9) also included the EZ and the dysplastic cortex but were more extensive. Following limited cortical resection (mean follow-up 4 years), seizure freedom without permanent motor deficit was obtained in 20/23 patients (87%). Conclusions: 18FDG-PET coregistered with MRI is highly sensitive to detect TTFCD and greatly improves diagnosis and surgical prognosis of patients with negative MRI.

Devastating epileptic encephalopathy in school-aged children (DESC): A pseudo encephalitis

PURPOSE To describe the characteristics of a previously overlooked devastating epileptic encephalopathy that presents as intractable bilateral perisylvian epilepsy starting with prolonged status epilepticus (SE) in normally developing school-aged children. METHODS Retrospective study over 7 years of all normally developing children admitted in our institution for a prolonged SE following non-specific febrile illness with at least one seizure recorded on EEG. RESULTS Fourteen children were included at a median age of 7.5 years (4-11) (median follow-up of 4 years (1-7)). Intractable SE lasted 4-60 days (median 30). CSF cell count was normal in five cases and moderately increased in the others. During SE, seizures were recorded in 11 patients and involved temporal lobes in 7; the other 4 patients exhibited perisylvian clinical features with secondary generalization. Intractable epilepsy followed SE in all cases without any latent period. Persisting seizures were recorded in 10 patients and involved temporo-perisylvian regions in 8, frontal regions in 2; 3 others had perisylvian ictal semiology. Spiking was bilateral in 10 cases. MRI showed bilateral hippocampal hypersignal and/or atrophy in 10 cases (extended to the neocortex in 3). All children had major cognitive sequelae. When feasible (six patients), detailed neuropsychology suggested fronto-temporal impairment. CONCLUSIONS Among so called grey matter encephalitis patients, we identified a recognizable pattern we propose to call Devastating Epileptic encephalopathy in School-age Children (DESC) that begins with prolonged SE triggered by fever of unknown cause, and persists as intractable perisylvian epilepsy with severe cognitive deterioration.

Guidelines for imaging infants and children with recent-onset epilepsy

The International League Against Epilepsy (ILAE) Subcommittee for Pediatric Neuroimaging examined the usefulness of, and indications for, neuroimaging in the evaluation of children with newly diagnosed epilepsy. The retrospective and prospective published series with n ≥30 utilizing computed tomography (CT) and magnetic resonance imaging (MRI) (1.5 T) that evaluated children with new‐onset seizure(s) were reviewed. Nearly 50% of individual imaging studies in children with localization‐related new‐onset seizure(s) were reported to be abnormal; 15–20% of imaging studies provided useful information on etiology or and seizure focus, and 2–4% provided information that potentially altered immediate medical management. A significant imaging abnormality in the absence of a history of a localization‐related seizure, abnormal neurologic examination, or focal electroencephalography (EEG) is rare. Imaging studies in childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy, and benign childhood epilepsy with centrotemporal spikes (BECTS) do not identify significant structural abnormalities. Imaging provides important contributions to establishing etiology, providing prognostic information, and directing treatment in children with recently diagnosed epilepsy. Imaging is recommended when localization‐related epilepsy is known or suspected, when the epilepsy classification is in doubt, or when an epilepsy syndrome with remote symptomatic cause is suspected. When available, MRI is preferred to CT because of its superior resolution, versatility, and lack of radiation.

Acute encephalopathy with inflammation-mediated status epilepticus

Fever-induced refractory epileptic encephalopathy in school-aged children (FIRES), and idiopathic hemiconvulsion-hemiplegia syndrome (IHHS) are both triggered by fever, although evidence for a causal microorganism or an autoimmune phenomenon is lacking. FIRES begins in school age with status epilepticus lasting several weeks, involves perisylvian areas including mesial temporal structures, and is followed by pharmacoresistant epilepsy with major cognitive deterioration. IHHS begins in infancy with unilateral clonic status epilepticus and is followed by hemiplegia with pharmacoresistant epilepsy. The aetiology of FIRES and IHHS remains unknown, although clinical features and experimental models point to a likely vicious cycle involving inflammation and seizure activity that depends on the stage of brain maturation. We therefore propose to group these conditions under the concept of acute encephalopathy with inflammation-mediated status epilepticus. In addition to preliminary but encouraging clinical observations, there are theoretical reasons to consider the ketogenic diet as an early means to control both seizures and inflammation.

The three stages of epilepsy in patients with CDKL5 mutations.

Mutations in the X‐linked cyclin‐dependent kinase‐like 5 (CDKL5) gene are responsible for a severe encephalopathy with early epilepsy. So far, the electroclinical phenotype remains largely unknown and no clear genotype–phenotype correlations have been established.

Severe myoclonic epilepsy in infancy: a systematic review and a meta-analysis of individual patient data.

Severe myoclonic epilepsy in infancy (SMEI) is a rare, but severe disorder with seizures typically resistant to conventional antiepileptic drugs. The objective of the present study was to systematically review the literature on the available treatments for SMEI.