Randomized dose-controlled study of topiramate as first-line therapy in epilepsy.

OBJECTIVES: To evaluate the efficacy and tolerability of topiramate as monotherapy, using a dose-controlled study design. MATERIALS AND METHODS: We conducted a multinational, randomized, double-blind trial in adults and children (> or =6 years old) with epilepsy that was not being treated when randomized to 400 or 50 mg/day topiramate as target maintenance dosages. In addition to > or =2 lifetime unprovoked seizures, patients had to have one or two partial-onset seizures or generalized-onset tonic-clonic seizures in the 3-month retrospective baseline. The primary efficacy end point was time to first seizure; a secondary efficacy measure was the seizure-free rate at 6 months and 1 year. Double-blind treatment continued until 6 months after the last patient was randomized. RESULTS: Kaplan-Meier survival analyses for time to first seizure (intent-to-treat, n = 470) favored 400 mg/day over 50 mg/day (P = 0.0002) as a target maintenance dosage. The first evaluation point with a significant difference (P = 0.046) favoring the higher dose was at day 14 when patients were receiving 100 or 25 mg/day. The probability of being seizure-free at 6 months was 83% in patients randomized to 400 mg/day and 71% in those randomized to 50 mg/day (P = 0.005). Seizure-free rates at 12 months were 76% and 59%, respectively (P = 0.001). Differences favoring the higher dose were significant in patients with partial-onset seizures (P = 0.009) and in those with generalized-onset tonic-clonic seizures (P = 0.005). The most common dose-related adverse events were paresthesia, weight loss, and decreased appetite. Discontinuations due to cognitive-related adverse events were 2% in the 50-mg group and 7% in the 400-mg group. Overall, 7% and 19%, respectively, discontinued with adverse events during the median treatment duration of 9 months. CONCLUSION: Topiramate is effective as monotherapy in adults and children. Because a therapeutic effect emerges during titration, clinicians should adjust dosages in step-wise fashion with intermediate stopping points, e.g., 100 mg/day, to evaluate patient response and achieve the optimal maintenance dosage.

Ganaxolone for treating intractable infantile spasms: a multicenter, open-label, add-on trial.

This is a multicenter, open-label, add-on trial, investigating the safety and efficacy of ganaxolone (GNX) in a population of children with refractory infantile spasms, or with continuing seizures after a prior history of infantile spasms. A total of 20 children aged 7 months to 7 years were enrolled in this dose-escalation study, after baseline seizure frequencies were established. Concomitant antiepilepsy drugs were maintained throughout the study period. The dose of GNX was progressively increased to 36 mg/kg/d (or to the maximally tolerated dose) over a period of 4 weeks, then maintained for 8 weeks before tapering and discontinuation. Seizure diaries were maintained by the families, and spasm frequency was compared with the baseline period. The occurrence of adverse events was clinically monitored, and global evaluations of seizure severity and response to treatment were obtained. A total of 16 of the 20 subjects completed the study, 15 of whom had refractory infantile spasms at the time of study enrollment. Spasm frequency was reduced by at least 50% in 33% of these subjects, with an additional 33% experiencing some improvement (25-50% reduction in spasm frequency). Ganaxolone was well tolerated, and adverse events attributed to GNX were generally mild. Ganaxolone was safe and effective in treating this group of refractory infantile spasms patients in an open-label, add-on trial. Further investigation with randomized, controlled study design is warranted.

Transparahippocampal selective amygdalohippocampectomy in children and adolescents: efficacy of the procedure and cognitive morbidity in patients.

OBJECT: Unilateral resection of the hippocampus and amygdala can be used to treat medically intractable mesial temporal lobe seizures. To date seizure outcome and the extent of cognitive morbidity have been unknown in children following the transparahippocampal variation of selective amygdalohippocampectomy (TSA), which prompted the present prospective study. METHODS: Preoperative examinations and outcomes in 22 consecutive children and adolescents who underwent TSA were studied. Cognitive and psychological morbidity were assessed using standard neuropsychological instruments. The authors evaluated relationships between seizure control and cognitive morbidity and 13 and nine clinical variables, respectively. Seizure control was achieved in 11 (65%) of 17 patients (>2 years follow up). Among 13 clinical variables, the only preoperative finding that had a significant bearing on seizure control was the presence of unilateral hypometabolism, which could be observed on [18F]fluorodeoxyglucose-positron emission tomography scans (p<0.001). Patients with seizure control showed significant improvements in verbal and full scale intelligence quotients (both p = 0.05). Patients with longer preoperative durations of seizures exhibited more cognitive impairment that persisted postoperatively. Cognitive outcome analysis based on nine clinical factors revealed no significant difference in cognitive parameters postoperatively, except that significant improvement occurred in rote verbal memory scores among patients who underwent right-sided TSA (p = 0.01). Individually, 81% of the children achieved significant improvement in at least one of seven cognitive parameters, and 52% had stable or improved scores in all parameters. CONCLUSIONS: The results indicate that TSA is a safe effective approach for the treatment of medically intractable mesial temporal lobe seizures in children with minimum effect on cognitive morbidity. Given that the literature suggests that children suffer progressive cognitive morbidity from persistent seizures, the results of this study support early surgical intervention for this group of children.

Subtemporal transparahippocampal amygdalohippocampectomy for surgical treatment of mesial temporal lobe epilepsy. Technical note.

Amygdalohippocampectomy (AH) is an accepted surgical option for treatment of medically refractory mesial temporal lobe epilepsy. Operative approaches to the amygdala and hippocampus that previously have been reported include: the sylvian fissure, the superior temporal sulcus, the middle temporal gyrus, and the fusiform gyrus. Regardless of the approach, AH permits not only extirpation of an epileptogenic focus in the amygdala and anterior hippocampus, but interruption of pathways of seizure spread via the entorhinal cortex and the parahippocampal gyrus. The authors report a modification of a surgical technique for AH via the parahippocampal gyrus, in which excision is limited to the anterior hippocampus, amygdala and parahippocampal gyrus while preserving the fusiform gyrus and the rest of the temporal lobe. Because transparahippocampal AH avoids injury to the fusiform gyrus and the lateral temporal lobe, it can be performed without intracarotid sodium amobarbital testing of language dominance and language mapping. Thus the operation would be particularly suitable for pediatric patients in whom intraoperative language mapping before resection is difficult.

Epilepsy in children.

Childhood epilepsies comprise a broad range of disorders which vary from benign to progressive and disabling. Accurate diagnosis of epilepsy type and determination of aetiology, when possible, are essential for appropriate treatment. The most common seizure type encountered in children is febrile seizures. These represent a benign condition which is not, in fact, epilepsy and usually does not require antiepileptic medication. When partial seizures occur in childhood, benign syndromes with spontaneous remission, such as rolandic epilepsy, must be distinguished from symptomatic epilepsies which may be refractory to medical management. Complex partial seizures in young children may appear different than in adults. The adverse effect profiles and dosing regimens of antiepileptic drugs in children are also different than in adults, and influence the choice of treatment. Epilepsy surgery should be considered for some children with intractible partial seizures. Generalized epilepsies also have a broader spectrum in children. The idiopathic generalized absence epilepsies are usually easy to control with medication. They range from childhood absence epilepsy which tends to remit in adolescence to juvenile myoclonic epilepsy which is a lifelong condition. In contrast, the seizures of West syndrome and Lennox-Gastaut syndrome are difficult to control, and treatment involves therapeutic modalities rarely used in adults such as ACTH and the ketogenic diet. Many childhood epilepsy syndromes have a familial predisposition, and the genetic bases for several disorders have been described.

Pharmacology and therapeutic aspects of antiepileptic drugs in pediatrics.

In the past year, several new antiepileptic drugs have emerged that have potential benefits for children with epilepsy. The spectrum of adverse effects is the principal feature that differentiates among the older drugs used to treat partial and related seizures, including simple partial, complex partial, and partial secondarily generalized seizures. Based on studies in adults with refractory seizures, the new or investigational compounds felbamate, gabapentin, lamotrigine, and vigabatrin should be active against these types of seizures in children, but none of them have been subjected to pediatric randomized controlled trials, and no studies have been done that compare new and old drugs in this category. Thus, the new drugs hold promise in children with these types of seizures, but their role relative to old drugs has not been elucidated. Several of the new drugs are active against myoclonic and generalized tonic-clonic seizures, but thus far, none have been proven to possess antiabsence activity in children. Open-label investigations suggest that lamotrigine may be helpful in Lennox-Gastaut syndrome, and vigabatrin in infantile spasms. Only felbamate has been evaluated in a randomized controlled study in children, in which it has proven beneficial against astatic and generalized tonic-clonic seizures in children with Lennox-Gastaut syndrome. Whereas investigations of these and other novel drugs are ongoing, this is an active and exciting period in pediatric antiepileptic drug development.

Course and outcome of acute cerebellar ataxia.

We report a study of 73 consecutive children with acute cerebellar ataxia, representing all of the children evaluated at St. Louis Children's Hospital during a 23-year-period to whom this diagnosis could appropriately be assigned. Twenty-six percent had chickenpox, 52% had other illnesses that were presumed to be viral, and in 3% the ataxia was related to immunization. Nineteen percent had no definite prodrome. Sixty children were followed for 4 months or longer after onset of their ataxia (mean, 7.4 +/- 6.0 years). Ninety-one percent (55/60) of these, including all children with chickenpox, recovered completely from ataxia. Eighty-nine percent (39/44) of the children with non-varicella-related ataxia recovered completely from the ataxia, a much better rate of recovery than what was found in prior large studies. One fifth of the children followed for more than 4 months experienced transient behavioral or intellectual difficulties, but only 5 of the 60 children demonstrated sustained learning problems. This study represents the largest reported series of acute cerebellar ataxia and the most complete characterization of the clinical features and outcome of this illness.

Felbamate in the treatment of Lennox-Gastaut syndrome: results of a 12-month open-label study following a randomized clinical trial.

Felbamate (FBM) is a new antiepileptic drug (AED) that has been evaluated in partial seizures and in the Lennox-Gastaut syndrome (LGS). When tested against placebo in an add-on, randomized, double-blind trial in 73 children with LGS, FBM significantly reduced the frequencies of astatic (atonic) seizures and generalized tonic-clonic seizures plus total seizure counts. In addition, FBM-treated subjects improved significantly on a parent-rated global evaluation and had fewer injuries. Overall, approximately 50% of subjects experienced a 50% or greater reduction in total seizure frequency and a dose-response relationship was apparent. The improvement that occurred in the double-blind study has been sustained for at least 12 months in subsequent open-label follow-up studies. In the first month of FBM treatment, 62% of the subjects who had previously received placebo had a reduction in total seizure frequency of > 50%. By the 12-month follow-up point, approximately half of the patients had a 50% reduction in total seizure count. Astatic seizures responded even better, with two-thirds of patients having a reduction of > 50% in astatic seizure frequency after 12 months of treatment. Based on adverse experience reports thus far, FBM appears to be well tolerated. FBM is the first drug to be shown effective in the LGS in randomized controlled trials. Although few subjects with LGS became seizure free, the frequency of the most severe seizure types decreased and the patients' global functioning improved.

Early childhood hepatocerebral degeneration misdiagnosed as valproate hepatotoxicity.

Four unrelated children were thought to have valproate-associated hepatotoxicity. They presented with recurrent partial secondarily generalized status epilepticus and epilepsia partialis continua followed by mental and motor regression. Despite treatment with multiple antiepileptic medications, they continued to have seizures. After initiation of valproic acid (VPA), all 4 manifested liver failure within 3 months. Two of these children each had 1 sibling who was not exposed to VPA, but who developed the same clinical picture including liver failure. At the time of autopsy, all 6 children had similar neuropathological findings with focal areas of spongiosis and neuronal loss, diffuse gliosis, and Alzheimer type II cells. One VPA-treated patient underwent a successful liver transplantation only to die from relentlessly progressive neurological deterioration. We propose that many of the reported patients with VPA-associated hepatotoxicity represent undiagnosed patients with early childhood hepatocerebral degeneration, the Huttenlocher variant of Alpers' syndrome. This disease manifests by obstinate partial seizures, recurrent partial secondarily generalized status epilepticus, epilepsia partialis continua, psychomotor deterioration, and hepatic dysfunction that is exacerbated by VPA administration. The accelerated demise from liver failure in the nontransplanted patients before the central nervous system pathology fully evolves makes the diagnosis of this rare condition difficult. The occurrence of disease in the unexposed siblings suggests recessive inheritance.

Cytochrome c oxidase-associated Leigh syndrome: phenotypic features and pathogenetic speculations.

Fourteen new cases of cytochrome oxidase (COX)-associated Leigh syndrome (LS) are combined with 20 reported cases to describe the clinical, laboratory, and radiological features of this devastating metabolic condition. Three clinical stages are identified. Most patients have normal neurological development during the first 8-12 months (stage I). Somatic complaints are common, including chronic diarrhea, recurrent vomiting, anorexia, and decelerating body and head growth. The second stage evolves during late infancy and early childhood when motor regression becomes evident. Eye signs, altered breathing patterns, pyramidal, extrapyramidal, and cerebellar signs emerge and sudden clinical deterioration occurs during intercurrent infectious or metabolic stress. The last stage may extend from 2 to 10 years and is manifested by extreme hypotonia, swallowing difficulties and undernutrition. Feeding assistance is necessary and seizures may occur. The CSF lactate concentration is consistently elevated and MRI abnormalities are seen in the subcortical structures. COX deficiency affects most tissues, but is not always generalized. For example, 3 patients with a cardiomyopathy had normal COX activity in cultured skin fibroblasts. Nearly normal amounts of cross-reacting material are present by ELISA and immunoblot analyses. Parental consanguinity has been found in several families, the hereditary pattern is recessive and males are affected more commonly (2:1). The biomolecular abnormality causing COX deficiency in LS is unknown, but the available evidence implicates a nuclear-encoded protein that affects the structure or the stability of the holoenzyme complex.

Combined deficiency of beta-galactosidase and neuraminidase: natural history of the disease in the first 18 years of an American patient with late infantile onset form.

We describe the clinical findings over the first 18 years of a patient with a novel phenotype for galactosialidosis, the storage disease produced by the combined deficiency of beta-galactosidase and neuraminidase. Clinical findings in the first few months included somewhat unusual appearance and hepatosplenomegaly. Dysostosis multiplex was evident by age 2 1/2 years. Mitral and aortic valvular disease appeared over the next few years and cardiac disease has become the most important clinical problem. Foam cells were present in the bone marrow, and vacuolated lymphocytes were present in the peripheral blood smear. The patient had no neurological symptoms, cherry red spots, or intellectual deterioration during the first 18 years. Evidence presented elsewhere indicates that the basic defect in this late infantile form of galactosialidosis (as is thought to be true for the other forms of galactosialidosis) is a reduced amount of the 32 kDa phosphoglycoprotein which associates with beta-galactosidase and alpha-neuraminidase in lysosomes.

Immunochromatographic measurement of phenobarbital in whole blood with a non-instrumented assay.

We tested the precision and accuracy of the AccuLevel Phenobarbital Test, which reports whole-blood (fingerstick) results in plasma equivalent values, and compared these values with plasma results obtained using established methods. We conclude that the assay is precise, reliable, accurate for single tests, and is appropriate for use in offices, outpatient settings, and emergency rooms.

Deleterious effects of drugs on the developing nervous system.

In the past two decades, several categories of drugs have emerged as serious neuroteratogens. These include vitamin A congeners, isotretinoin and etretinate, certain antiepileptic drugs, especially trimethadione, and valproic acid. Other antiepileptic drugs have low teratogenic potential and variably affect the developing CNS. When multiple antiepileptics are administered during pregnancy, however, the risk to the fetus increases considerably.

Medical treatment and pharmacology of antiepileptic drugs.

Antiepileptic drugs are effective even when metabolic, infectious, or structural lesions are present. Therefore, the underlying cause should be sought, and not just the seizure treated. After this is done, the drug therapy can be directed to controlling the seizure.

Cerebrospinal fluid IgG in childhood: the establishment of reference values.

A retrospective analysis of quantitative and qualitative immunoglobulin G (IgG) results from 253 children who were either medically and neurologically normal or highly unlikely to have abnormalities of CSF IgG is reported. Normal values in this reference population vary with age for CSF/albumin IgG ratio and CSF/serum IgG index and are significantly different from the adult reference values. The rate of false positivity is lower for quantitative values than for qualitative IgG determinations (oligoclonal bands).

Aspects of antiepileptic treatment in children.

About 75% of patients with epilepsy have seizures during childhood, often requiring antiepileptic therapy. Children possess all the drug-specific pharmacokinetic features of adults (e.g., nonlinearity of phenytoin elimination and autoinduction of carbamazepine metabolism), plus other factors (e.g., age, intercurrent illness, comedication) that influence dosage. Kinetic differences are maximal in newborns and infants, with limited drug elimination in premature and full-term babies, soon followed by accelerated elimination during infancy and childhood, before lower adult elimination rates develop during late childhood or early adolescence. Most children with epilepsy require two- to fourfold larger doses relative to bodyweight than adults, to achieve comparable drug levels and therapeutic effects. Although rapid growth may require increased dosage, the need is limited as relative clearance declines with age. Children of any age, but particularly premature and newborn babies, show greater individual variability in drug handling and therefore in dose requirements than adults. Clinical response and antiepileptic drug concentrations should both be monitored carefully in children.

Phenytoin and carbamazepine, alone and in combination: anticonvulsant and neurotoxic effects.

Comedication with phenytoin and carbamazepine is frequently used in patients with refractory seizures, although the benefit of this strategy has not been established. To assess whether the combination is a rational anticonvulsant treatment, we determined the therapeutic index (toxicity:efficacy ratio) for the drugs, alone and together, in mice, The individual agents were virtually identical in anticonvulsant and neurotoxic activity, and combined use had no additional therapeutic advantage. Analysis of drug concentrations in brain showed an additive pharmacodynamic interaction for phenytoin and carbamazepine, indicating that the combination is unlikely to be superior to either drug alone. Thus, we find no experimental justification for the simultaneous use of phenytoin and carbamazepine in the treatment of epilepsy.

Carbamazepine efficacy and utilization in children.

Carbamazepine is effective for preventing partial and generalized tonic-clonic seizures in children. Although absence epilepsies are more common in children than adults, an estimated 80% of children with epilepsy have seizure types or epilepsies that are potentially responsive to carbamazepine. The differential diagnosis of ictal staring is an especially important issue in children because absence and atypical absence seizures are more prevalent in children than adults. Age-related pharmaco-kinetic differences and drug interactions are major considerations in children. On average, children have higher clearance rates of carbamazepine, shorter half-lives, and higher ratios of carbamazepine-10, 11-epoxide to carbamazepine than adults. In addition, children with severe epilepsy are more likely to require multiple-drug therapy, which can lead to complex drug interactions. When carbamazepine is administered along with valproate, drug protein binding interactions can cause intermittent side effects.