A risk-benefit assessment of treatments for infantile spasms

Treatment modalities for infantile spasms: current considerations and evolving strategies in clinical practice

Infantile spasms, newly classified as infantile epileptic spasm syndrome (IESS), occur in children under 2 years of age and present as an occur as brief, symmetrical, contractions of the musculature of the neck, trunk, and extremities. When infantile spasms occur with a concomitant hypsarrhythmia on electroencephalogram (EEG) and developmental regression, it is known as West Syndrome. There is no universally accepted mainstay of treatment for this condition, but some options include synthetic adrenocorticotropic hormone (ACTH), repository corticotropin injection (RCI/Acthar Gel), corticosteroids, valproic acid, vigabatrin, and surgery. Without effective treatment, infantile spasms can cause an impairment of psychomotor development and/or cognitive and behavioral functions. The first-line treatment in the USA is ACTH related to high efficacy for cessation of infantile spasms long-term and low-cost profile. Acthar Gel is a repository corticotropin intramuscular injection that became FDA-approved for the treatment of IESS in 2010. Though it is believed that ACTH, Acthar Gel, and corticosteroids all work via a negative feedback pathway to decrease corticotropin-releasing hormone (CRH) release, their safety and efficacy profiles all vary. Vigabatrin and valproic acid are both anti-seizure medications that work by increasing GABA concentrations in the CNS and decreasing excitatory activity. Acthar Gel has been shown to have superior efficacy and a diminished side effect profile when compared with other treatment modalities.

A case-control evaluation of Spasm control and Tolerability of the Modified Atkins diet versus classic ketogenic diet in Chinese Children with infantile epileptic spasms syndrome

OBJECTIVE

This study was conducted to compare the efficacy, tolerability and safety of the modified Atkins diet (MAD) and the classic ketogenic diet (KD) in Chinese children with infantile epileptic spasms syndrome.

METHODS

We retrospectively recruited and analyzed 56 children with infantile epileptic spasms syndrome started on the MAD (n = 21) and classic KD (n = 35) at our institution from June 2016 to July 2022.

RESULTS

The MAD group had exhibited comparable rates of spasm reduction (>50%) as the classic KD group at the time point of 3 months (66.7% for MAD, 75% for KD; p = 0.510), 6 months (75% for MAD, 82.6% for KD; p = 0.694), and 12 months (84.6% for MAD, 90.9% for KD; p = 1.000). The probability of patients remaining on the MAD was higher (p = 0.048) than those consuming the classic KD. By analyzing discontinuation reasons, we found that the MAD patients had a lower rate of poor compliance than the classic KD patients (p = 0.014). Response to the diet at 1 month and fewer anti-seizure medicines (ASMs) had tried before KD initiation were possible factors in regard to likelihood of spasm-free response to the diet therapy at 3 months (p = 0.001 and p = 0.014, respectively).

CONCLUSIONS

The efficacy of spasm control was similar in the MAD, with better tolerability and higher compliance compared to the classic KD. Therefore, MAD could be the primary treatment for children in China with- infantile epileptic spasms syndrome. Additionally, an earlier beginning of the diet treatment may have significant advantages.

A Randomized Controlled Trial on the Study of Effectiveness and Safety of Hormonal (ACTH) Treatment Alone versus Hormonal (ACTH) with Levetiracetam for Epileptic Spasms

Background West's syndrome (WS) is a triad of epileptic spasms (ESs), psychomotor delay, and hypsarrhythmia. The treatment of ESs is still controversial. Hence, we designed a randomized controlled trial (RCT) to compare the outcomes in children with WS treated with adrenocorticotropic hormone (ACTH) alone versus ACTH and levetiracetam (LEV).

Objectives To compare the treatment outcomes and side effects in children treated with ACTH alone versus ACTH and LEV.

Methods This prospective randomized controlled trial was conducted from December 2017 to May 2019 in tertiary care center, Bangaluru. Children from 2 months to 5 years of age, diagnosed with WS were included. Fifty children in each group were analyzed for efficacy and side effects.

Results There was no difference in the baseline characteristics in both groups. There was no difference in spasms response at the end of 2 weeks between the groups (88 vs. 82%) with p-value of 0.813. The relapse rates were less in ACTH and LEV group (20%) compared with ACTH alone (22%) but statistically not significant (p > 0.1). There was no difference observed in subsequent epilepsy rates (18%) in ACTH versus 19% in ACTH with LEV group (p > 0.1) and side effects. There was improvement in milestones 48% in ACTH with LEV group versus 37% in ACTH alone however statistically not significant (p > 0.1).

Conclusion There was no difference in children treated with ACTH alone versus ACTH and LEV in terms of control of spasms and subsequent epilepsy rates. The relapse rate is less, and developmental outcome is better in ACTH with LEV group but statistically not significant.

The patterns of response of 11 regimens for infantile spasms

Infantile spasms (ISs) is a devastating form of an early infantile epileptic encephalopathy. The patterns of response of multiple regimens, and the difference in response rates for the cases who receive first-line therapies on time versus those who receive them after non-first-line therapies are unknown. We performed a study involving 314 ISs cases aiming to investigate the patterns of response of 11 regimens, and the difference in response rates for the cases received first-line therapies as first two regimens versus those who received other drugs prior to first-line options. As a result, the efficacy of each regimen was: the foremost two regimens; 36.99%, third; 10.27%, fourth; 6.16%, fifth; 5.48%, and from the sixth regimen onwards, each additional regimen added ≤ 2% probability of seizure freedom. There was a statistically significant difference in seizure freedom rates between cases received first-line therapies as first or second regimen versus those who received them later. Our study revealed for the first time that in ISs cases, seizure freedom is likely to be observed within the first five regimens, and an early administration of first-line therapies is superior to non-first-line options. These results will aid in management of ISs cases.

Infantile Spasms: An Update on Pre-Clinical Models and EEG Mechanisms

Infantile spasms (IS) is an epileptic encephalopathy with unique clinical and electrographic features, which affects children in the middle of the first year of life. The pathophysiology of IS remains incompletely understood, despite the heterogeneity of IS etiologies, more than 200 of which are known. In particular, the neurobiological basis of why multiple etiologies converge to a relatively similar clinical presentation has defied explanation. Treatment options for this form of epilepsy, which has been described as “catastrophic” because of the poor cognitive, developmental, and epileptic prognosis, are limited and not fully effective. Until the pathophysiology of IS is better clarified, novel treatments will not be forthcoming, and preclinical (animal) models are essential for advancing this knowledge. Here, we review preclinical IS models, update information regarding already existing models, describe some novel models, and discuss exciting new data that promises to advance understanding of the cellular mechanisms underlying the specific EEG changes seen in IS—interictal hypsarrhythmia and ictal electrodecrement.

How can methylprednisolone work on epileptic spasms with malformation of cortical development?

Although steroids are suggested as the treatment of choice for infantile spasms, the mechanism of action is still unclear. Using a rat model of malformation of cortical development with refractory infantile spasms, we evaluated the efficacy of methylprednisolone on spasms susceptibility and behaviors. Additionally, we investigated the in vivo electrophysiological and neurochemical changes of the brain after methylprednisolone treatment. Infant rats with prenatal exposure of methylazoxymethanol at gestational day 15 were used. After a single dose of methylprednisolone or three different doses of methylprednisolone for 3 days, spasms were triggered by intraperitoneal injection of N-methyl-d-aspartic acid. In rats with 3 days of methylprednisolone pretreatment and their controls, behavioral testing was performed at postnatal day 15. In vivo magnetic resonance imaging was conducted at postnatal day 15 after 3 days of methylprednisolone treatment. The rats with single methylprednisolone pretreatment showed significantly delayed onset of spasms and multiple doses of methylprednisolone significantly suppressed the development of spasms in a dose-dependent manner. After multiple methylprednisolone pretreatment and a cluster of N-methyl-d-aspartic acid-induced spasms, the rats showed significantly increased freezing behaviors to conditioned stimuli. Glutamate-weighted chemical exchange saturation transfer revealed significant elevation of glutamate concentration in the cortices of the rats with multiple methylprednisolone pretreatments. Methylprednisolone pretreatment could attenuate N-methyl-d-aspartic acid-induced spasms with in vivo neurochemical and electrophysiological changes, which indicates this steroid's action on the brain and in epilepsy.

Efficacy of Treatments for Infantile Spasms: A Systematic Review

OBJECTIVES

West syndrome (also known as infantile spasm because of its main seizure type) is a rare form of epilepsy that begins during early infancy. Recent guidelines and reviews on West syndrome recommend the use of adrenocorticotropic hormone steroids, or vigabatrin, as the first-line treatment. However, West syndrome remains to be one of the most challenging epilepsies to treat. Here, we systematically reviewed the current literature obtained during the previous decade. This article provides an overview of the current treatment of infantile spasms.

METHODS

PubMed and EMBASE were searched to retrieve studies on human published during 2005-2015 and to identify patients with clinical diagnosis of infantile spasms. Drug or diet treatments were used as interventions and comparators.

RESULTS

We included 55 studies, of which 1 study was a meta-analysis, 9 were randomized controlled trials, 21 were prospective studies, and 24 were retrospective studies. Topiramate, levetiracetam, zonisamide, and sodium valproate with benzodiazepine (clonazepam or nitrazepam) were found to be potential drugs for treating West syndrome besides adrenocorticotropic hormone, steroids, and vigabatrin. Ketogenic diet and modified Atkins diet were also found to be effective.

CONCLUSIONS

To date, data regarding the efficacy of treatments of West syndrome still remain limited. Some treatments, including topiramate and ketogenic diet, seem promising besides adrenocorticotropic hormone, steroids, and vigabatrin. Well-designed trials are warranted to validate the findings.

Pathogenesis and new candidate treatments for infantile spasms and early life epileptic encephalopathies: A view from preclinical studies

Early onset and infantile epileptic encephalopathies (EIEEs) are usually associated with medically intractable or difficult to treat epileptic seizures and prominent cognitive, neurodevelopmental and behavioral consequences. EIEEs have numerous etiologies that contribute to the inter- and intra-syndromic phenotypic variability. Etiologies include structural and metabolic or genetic etiologies although a significant percentage is of unknown cause. The need to better understand their pathogenic mechanisms and identify better therapies has driven the development of animal models of EIEEs. Several rodent models of infantile spasms have emerged that recapitulate various aspects of the disease. The acute models manifest epileptic spasms after induction and include the NMDA rat model, the NMDA model with prior prenatal betamethasone or perinatal stress exposure, and the γ-butyrolactone induced spasms in a mouse model of Down syndrome. The chronic models include the tetrodotoxin rat model, the aristaless related homeobox X-linked (Arx) mouse models and the multiple-hit rat model of infantile spasms. We will discuss the main features and findings from these models on target mechanisms and emerging therapies. Genetic models have also provided interesting data on the pathogenesis of Dravet syndrome and proposed new therapies for testing. The genetic associations of many of the EIEEs have also been tested in rodent models as to their pathogenicity. Finally, several models have tested the impact of subclinical epileptiform discharges on brain function. The impact of these advances in animal modeling for therapy development will be discussed.

Relationship between initial electroencephalographic characteristics and seizure outcomes in children with non-lesional West syndrome

BACKGROUND

To characterize the initial interictal electroencephalography (EEG) activities associated with seizure outcomes in children with non-lesional West syndrome (WS), and their worth in the prediction of seizure-free (SF) vs no seizure-free (No-SF) outcomes.

METHODS

We retrospectively reviewed the initial scalp EEGs for at least a 40-min duration, and the medical records of 66 children who were diagnosed as WS with normal MRI, and who were followed-up with for 4.5 ± 2.1 years. We assessed the following clinical and EEG findings: onset of seizures, development, underlying etiologies, initial interictal EEGs, and seizure evolution. These variables were compared between two groups: SF vs No-SF groups.

RESULTS

In total, 36 (54.5%) children had SF outcomes and 30 (45.5%) had No-SF outcomes during long-term follow-up (4.4 ± 2.3 vs 4.6 ± 2.0 years, p = 0.7644). The mean age at seizure onset was similar in the SF and No-SF groups (6.0 ± 3.0 vs 6.9 ± 3.2 months, p = 0.2443). Delayed development before the onset of spasms was similarly observed in both groups (13.9% vs 13.3%). Initial EEG findings significantly differed with typical hypsarrhythmia (41.7% vs 73.3%, p = 0.0098), multiple independent spike foci (MISF) (55.6% vs 83.3%, p = 0.0158), frontal-dominant MISF (0.0% vs 40.0%, p < 0.0001), and frontal-dominant generalized epileptiform discharges (EDs) (0.0% vs 16.7%, p=0.0108) being involved more infrequently in the SF group than in the No-SF group, respectively. Patients in the SF group showed no frontal-dominant MISF or frontal-dominant generalized EDs, and a more often normal to borderline sleep-spindle (83.3% vs 40.0%, p = 0.0002) than the No-SF group.

CONCLUSION

Patients with SF outcomes more frequently showed the posterior-dominant generalized EDs and normal to borderline sleep-spindle, and the No-SF group more often had typical hypsarrhythmia, frontal-dominant MISF, frontal-dominant generalized EDs, and no normal sleep-spindle. Initial interictal EEG findings may predict seizure outcomes in patients with non-lesional WS.

Balancing clinical benefits of vigabatrin with its associated risk of vision loss

Vigabatrin is an effective and well-tolerated antiepileptic drug (AED) for the treatment of refractory complex partial seizures (rCPS) and infantile spasms (IS), but its benefits must be evaluated in conjunction with its risk of retinopathy with the development of peripheral visual field defects (pVFDs). Vigabatrin should be considered for rCPS if a patient has failed appropriate trials of other AEDs or is not a suitable candidate for other AEDs, is not an optimal surgical candidate, and continues to experience debilitating effects from seizures. Vigabatrin is indicated as monotherapy for pediatric patients with IS. Its efficacy in achieving improved seizure control should be apparent within 12 weeks in patients with rCPS and within 2-4 weeks after attaining appropriate dosage for patients with IS. Because 12 weeks is well less than the known time of onset of visual defects, the risk of developing pVFDs may be minimized by discontinuing vigabatrin early during the course of therapy for patients with inadequate response. Appropriate vision screening is recommended at baseline, every 3 months during continued vigabatrin treatment, and at 3-6 months after discontinuation (if therapy has spanned more than a few months). If a pVFD is detected at any point and the decision is made to discontinue therapy, the pVFD is not likely to progress after discontinuation of vigabatrin. Although some patients will be at risk of retinopathy, vigabatrin is an appropriate treatment option for patients who achieve substantial clinical benefit, especially given the severe consequences of rCPS and uncontrolled IS. While retinopathy with the development of pVFDs is a serious adverse event, it is not life-threatening and its risk can be effectively managed.

Paediatric post-marketing pharmacovigilance: comparison of the adverse event profile of vigabatrin prescribed to children and adults

PURPOSE

Post-marketing pharmacovigilance is a cornerstone of monitoring and evaluating the safety of medicines in children and adults. However the methods may require modification to detect paediatric signals. The aim of this study was to compare the adverse event (AE) profile of children and adults taking vigabatrin, using modified signal detection methods (SDMs).

METHODS

Data from the vigabatrin prescription-event monitoring study an observational cohort study (cohort 10,177 patients), stratified into one paediatric (0-17 years) and one adult (≥ 18 years) age group were examined using summary statistics for adverse drug reactions (ADRs), reasons for stopping and deaths. Incidence densities of AEs in children and adults in the first month of treatment were compared to months two to six to examine whether the AE rate was different in these two periods. AE rates in children were compared to those in adults (proportional reporting rates; PRRs and incidence rate ratios), to compare the AE profile between these age groups.

RESULTS

Abnormal behaviour (PRR 5.3) and hyperactivity (PRR 4.5) were more frequently reported in children; confusion (PRR 25.0) and psychosis (PRR 12.5) more frequently in adults. In children 11.8% of ADRs were reported to the regulatory authority compared to 27.3% in adults. A higher proportion of children stopped treatment due to lack of effectiveness (57.7% vs. 47.5%). No deaths were attributed to vigabatrin.

CONCLUSION

This study demonstrated that modified SDMs can be used to detect differences in the AE profiles between children and adults taking a medicinal product, and also to identify drug safety signals.

ACTH receptor (MC2R) promoter variants associated with infantile spasms modulate MC2R expression and responsiveness to ACTH

OBJECTIVE

Adrenocorticotropin hormone (ACTH) has been the standard treatment to infantile spasms (IS). However, the mechanism of ACTH therapy is still unclear. ACTH exerts the function via melanocortin 2 receptor (MC2R). Our previous study showed a common 4-single nucleotide polymorphism (SNP) haplotype TCCT at the MC2R promoter was strongly associated with responsiveness to ACTH therapy, where these 4 SNPs [rs1893219, rs1893220, rs2186944, and a novel SNP (T>C)] were mapped at position -853, -759, -7, and -2 bp based on the transcription start site of the MC2R gene. In this study, we further elucidated functional significances of the TCCT haplotype.

METHODS

To evaluate whether the TCCT haplotype influences MC2R transcription levels, the luciferase reporter vector was used by a transient transfection. Expression of rat MC2R cDNA driven by the TCCT-carrying or TCCC-carrying promoter was detected by the real-time quantitative reverse transcription-PCR. These assays were performed on cell lines cultured in absence or presence of ACTH.

RESULTS

In the baseline, the light intensity of the luciferase reporter assay driven by the TCCT promoter was four times higher than that by the TCCC promoter. The intensity was dramatically increased in the pGL3-TCCT after ACTH stimulation, compared to that in the pGL3-TCCC. MC2R expression assay showed a 5-fold increase in the TCCT promoter in presence of ACTH, compared with that in absence of ACTH.

CONCLUSION

The results showed that the haplotype TCCT in MC2R promoter significantly led to increased MC2R expression and strong responses to ACTH, providing evidence of the molecular mechanism of ACTH therapy in IS.

The dilemma on treatment of the EEG: a justified perspective

Electroencephalography is an important, noninvasive, and useful technique for identifying an epileptogenic region. Electroencephalogram (EEG)-identified interictal epileptiform discharges (IEDs) have been found to correlate well with local metabolic changes in the brain as studied by neuroradiological examinations. In-depth studies on IEDs have revealed not only their multidimensional influence on neural functioning, but also a potential damaging effect on neurons signifying their nonbenign nature. Yet, the issue of treatment of the EEG has remained a topic of intense debate. In this brief article an attempt is made to justify the significance of treatment of the EEG and its impact on the overall prognostic outcome and quality of life of patients with abnormal EEGs.

Vigabatrin but not valproate prevents development of age-specific flexion seizures induced by N-methyl-D-aspartate (NMDA) in immature rats

In immature rats, N-methyl-D-aspartate (NMDA) induces several seizure types: flexion seizures (FS; in rats younger than 3 weeks), clonic seizures (in animals older than 3 weeks), and clonic-tonic seizures (CTS; in rats of all ages). FS represent a model of human infantile spasms. Effects of vigabatrin and valproate against all types of NMDA-induced seizures were studied in rats at postnatal days 12 (P12) and 25 (P25). NMDA (60 or 300 mg/kg) was injected to animals pretreated with vigabatrin (300-1,200 mg/kg; 24 h before NMDA) or valproate (100-400 mg/kg; 15 min before NMDA). Vigabatrin suppressed FS in P12 rats, but was ineffective against CTS in both age groups. Valproate suppressed CTS in P12, but not in P25 rats. Clonic seizures were rare in NMDA-treated P25 rats, but valproate pretreatment increased their incidence significantly. Neither drug decreased NMDA-induced mortality, which occurred within approximately 15 min after NMDA administration and reached almost 100% in all groups.

Justification of vigabatrin administration in West syndrome patients? Warranting a re-consideration for improvement in their quality of life

West syndrome (WS) or infantile spasms (IS) is a severe epileptic syndrome associated with poor prognosis and increased morbidity. The exact etio-pathogenesis of the disorder still remains elusive ant therefore the management continues to pose a challenge to the clinicians. Currently, adreno-corticotrophic hormone (ACTH), steroids and vigabatrin (VGB) form the mainstay of its treatment. However, the recent detection of an irreversible visual field defect observed in as high as 30-50% of children treated with vigabatrin has raised concern over the drug's usage. This brief paper is intended to highlight the significance of the irreversible visual toxicity in an already existent mentally challenged state in WS patients, which can lead to a worsening in the disability status of such patients. Therefore, based on the enhancement of handicap by VGB administration it is recommended that a comprehensive review be performed on its continuation in WS patients in order to prevent further deterioration of their quality of life (QOL).

Current trends in the treatment of infantile spasms

Infantile spasms are an epilepsy syndrome with distinctive features, including age onset during infancy, characteristic epileptic spasms, and specific electroencephalographic patterns (interictal hypsarrhythmia and ictal voltage suppression). Adrenocorticotropic hormone (ACTH) was first employed to treat infantile spasms in 1958, and since then it has been tried in prospective and retrospective studies for infantile spasms. Oral corticosteroids were also used in a few studies for infantile spasms. Variable success in cessation of infantile spasms and normalization of electroencephalograms was demonstrated. However, frequent significant adverse effects are associated with ACTH and oral corticosteroids. Vigabatrin has been used since the 1990s, and shown to be successful in resolution of infantile spasms, especially for infantile spasms associated with tuberous sclerosis. It is associated with visual field constriction, which is often asymptomatic and requires perimetric visual field study to identify. When ACTH, oral corticosteroids, and vigabatrin fail to induce cessation of infantile spasms, other alternative treatments include valproic acid, nitrazepam, pyridoxine, topiramate, zonisamide, lamotrigine, levetiracetam, felbamate, ganaxolone, liposteroid, thyrotropin-releasing hormone, intravenous immunoglobulin and a ketogenic diet. Rarely, infantile spasms in association with biotinidase deficiency, phenylketonuria, and pyridoxine-dependent seizures are successfully treated with biotin, a low phenylalanine diet, and pyridoxine, respectively. For medically intractable infantile spasms, some properly selected patients may have complete cessation of infantile spasms with appropriate surgical treatments.

Current role of vigabatrin in infantile spasms

Vigabatrin (VGB), a selective irreversible inhibitor of gamma-aminobutyric acid transaminase, has proved to be effective against cryptogenic and symptomatic infantile spasms (IS). Unfortunately, reports of serious visual field defects have led to a drastic reduction in the use of the drug. This review is based on a systematic search in the literature for evidence regarding efficacy and safety of VGB in IS. Based on a specific mechanism of action, there is a solid evidence of clinical efficacy of VGB in children with Tuberous Sclerosis. Similarly, VGB could represent a potential effective therapy also for spasms due to focal cortical dysplasia. In infants with spasms due to other causes, the risk of ophthalmologic toxicity should be carefully weighted against the benefit of controlling spasms.

Regional cerebral blood flow and developmental outcome in cryptogenic West syndrome

PURPOSE

To elucidate the relation between alterations of regional cerebral blood flow (rCBF) by adrenocorticotropic hormone (ACTH) therapy and developmental outcomes of cryptogenic West syndrome.

METHODS

Quantitative measurement of rCBF, with autoradiography method using N-isopropyl-((123)I) p-iodoamphetamine single photon emission computed tomography before and after ACTH therapy, was performed on 17 infants with cryptogenic West syndrome. Regions of interest for rCBF were placed bilaterally in the cerebellum, the thalamus, the caudate nucleus, and the frontal, temporal, and occipital cortices. RCBFs and the alteration ratios calculated from rCBFs before and after ACTH therapy were compared between two groups: the normal and delayed groups, which were divided by developmental outcome at 2 years old.

RESULTS

RCBFs before the therapy were not different statistically between the normal and delayed groups, and between those groups and the control group also. RCBFs after ACTH therapy of the occipital, thalamic and cerebellar regions were different between the normal and delayed groups (p < 0.05). Alteration ratios were different between the normal and delayed groups, in all of the regions but the frontal region (p < 0.05).

CONCLUSIONS

This study showed the differences of rCBF response by ACTH therapy between the normal and delayed groups of cryptogenic West syndrome. The difference of rCBF alteration might be associated with maturation of the cerebrovascular system, or influence of corticotropin-releasing hormone regarding the brain-adrenal-axis.

Developmental outcomes of cryptogenic West syndrome

OBJECTIVE

To elucidate factors affecting the developmental outcome of cryptogenic West syndrome.

STUDY DESIGN

Medical records of 32 patients, who were followed-up regularly for more than 1 year, were reviewed for clinical features: treatment lag, electroencephalography findings, and seizure evolution. Those features were compared between the normal outcome group (12 patients) and the delayed outcome group (20 patients). The outcomes were determined at the average age of 8.6 +/- 4.7 years.

RESULTS

The duration from onset to any treatment of the delayed group was longer than that of the normal group (P < .05). Evolution of electroencephalographic findings showed that paroxysmal discharges reappeared in frontal regions more frequently in the delayed group than in the normal group (P < .05). In the delayed group, other types of seizure except for spasms occurred more commonly than in the normal group (P < .05). More patients of the delayed group evolved to focal epilepsy than those of the normal group (P < .05).

CONCLUSIONS

Shorter treatment lag might be associated with a favorable outcome in cryptogenic West syndrome. Reappearance of paroxysmal discharges in the frontal regions and evolution to other types of seizure may be associated with undetectable lesions in the frontal regions.

Vigabatrin

Refractory epilepsies such as infantile spasms (IS) and complex partial seizures (CPS) can have a severe negative impact on the neurological integrity and quality of life of affected patients, in addition to drastically increasing their risk of premature mortality. Early identification of potentially effective pharmacotherapy agents is important. Vigabatrin has been shown to be a generally well tolerated and effective antiepileptic drug (AED) in a wide variety of seizure types affecting both children and adults, particularly those with IS and CPS. A bilateral, concentric constriction of the peripheral visual field characterizes the visual field defect (VFD) associated with vigabatrin, well characterized by numerous studies. This peripheral VFD presents in 30-50% of patients with exposure of several years; however, most of these patients are asymptomatic. In well-controlled studies, the earliest onset in patients with CPS is 11 months and at 5 months in infants, with average onsets being more than 5 years and 1 year, respectively. Patients with a peripheral VFD retain an average 65 degrees of lateral vision (normal, 90 degrees). The fact that many patients never develop the vigabatrin-related peripheral VFD, despite long-term exposure at high doses, may support the hypothesis that the injury is an idiosyncratic adverse drug reaction (as opposed to a strict dose- or duration-dependent toxicity). Effective testing methods are available to aid in the early detection and management of the peripheral VFD. This article discusses issues of importance to clinical decision-making in the use of vigabatrin to assist the physician and patient in assessing the benefits of vigabatrin therapy and understanding the potential risks of the VFD and uncontrolled seizures.

A plausible explanation for superiority of adreno-cortico-trophic hormone (ACTH) over oral corticosteroids in management of infantile spasms (West syndrome)

West syndrome (WS), an age dependent epileptic encephalopathy is identified as a triad of infantile spasms (IS), psychomotor retardation and a specific EEG pattern known as hypsarrhythmia. The exact pathophysiology still remains unclear, although a majority of cases reveal history of exposure to stress, mainly hypoxic-ischemia. The management remains empirical with a poor prognosis. Adrenocorticotrophic hormone (ACTH) and oral steroids continue to remain gold standard treatment. Vigabatrin (VGB), a newer anti-epileptic drug has emerged as an effective alternative but recent observation of a serious visual defect (constriction of peripheral field of vision that is likely to exaggerate the disability status of the WS patient) associated with its administration is gradually limiting its therapeutic usage and popularity. A number of studies have shown superiority of ACTH over oral steroids in the management of West syndrome, but the explanation for this long-standing observation is missing; however, this clinical observation has led to a wide acceptance of the implication of corticotropin releasing hormone (CRH) in causing spasms and at the same time also explaining the relief in spasms obtained by the inhibition of CRH secretion by ACTH and oral steroids. This hypothesis-article compares the negative feedback influences of ACTH and oral steroids on CRH secretion and shows that ACTH exerts a dual significantly stronger inhibitory influence on CRH secretion that far exceeds the inhibition exerted by oral steroids. Thus, this difference in feedback mechanism may be the major factor responsible for the superior therapeutic efficacy of ACTH over oral steroids in the management of West syndrome.

Profile of West syndrome in North Indian children

To study the profile of West syndrome (WS) in North Indian Children, 165 cases of WS were analyzed. Details of seizure semiology, prenatal and perinatal events, developmental milestones, treatment received, physical and neurological examination and investigations were recorded. The response of seizures to various therapeutic modalities and the final developmental status were taken as primary outcome variables. Analysis was done to find the factors influencing these outcome variables. The age of onset of infantile spasms ranged from 1 to 19 (mean 6.1 +/- 3.4) months. Age at presentation ranged from 1.5 months to 4.5 years (mean 14.7 +/- 11.4 months); 74% had flexor spasms. Other types of seizures were associated in 31 children. Antenatal problems and adverse perinatal events were reported in 26.7 and 59.4%, respectively. Developmental delay was recognized in 69.7% prior to and in 27.9% after onset of spasms. Microcephaly was seen in 72.7%. Interictal EEG showed hypsarrhythmia in 44; generalized spike and slow waves in 31% and burst suppression in 7%. Computed tomography scan done in 94 cases showed cerebral atrophy in 15%, infarcts in 8%, tubers in 7%, developmental malformations in 5%. Magnetic resonance imaging done in 77 cases showed periventricular T2WI white matter hyper intensities in 33.8% and cerebral atrophy in 21%. Prednisolone and ACTH were used in 57 and 35 cases, respectively. Complete control of seizures was seen in 49 and 46% cases. No significant difference in seizure control or developmental outcome was found in the two groups. Overall, 42.4, 30.9 and 16% children showed complete, partial and no control of seizures. After therapy, developmental improvement was seen in 55.8% and no change in 23.6% cases. The type of spasms had no correlation with the other parameters including etiology, seizure or developmental outcome. An early age of onset correlated with presence of antenatal problems (P < 0.05). Seizure control and developmental improvement correlated significantly (P < 0.005). Developmental outcome was better in cryptogenic as compared to symptomatic cases (P < 0.05). No other significant correlations were found. In India WS is often diagnosed late because of lack of awareness. Adverse perinatal events are important etiological factors. Non-affordability of ACTH and Vigabatrin prompts the use of prednisolone in most cases.

Treatment Strategies for Myoclonic Seizures and Epilepsy Syndromes with Myoclonic Seizures

Despite the availability of numerous treatment options, the diagnosis and treatment of myoclonic seizures continue to be challenging. Based on clinical experience, valproate and benzodiazepines have historically been used to treat myoclonic seizures. However, many more treatment options exist today, and the clinician must match the appropriate treatment with the patient's epilepsy syndrome and its underlying etiology. Comorbidities and other medications must also be considered when making decisions regarding treatment. Rarely, some antiepileptic drugs may exacerbate myoclonic seizures. Most epileptic myoclonus can be treated pharmacologically, but some cases respond better to surgery, the ketogenic diet, or vagus nerve stimulation. Because myoclonic seizures can be difficult to treat, clinicians should be flexible in their approach and tailor therapy to each patient.