Infantile spasms: modern practical aspects

Prenatal corticosteroids modify glutamatergic and GABAergic synapse genomic fabric: insights from a novel animal model of infantile spasms

Prenatal exposure to corticosteroids has long-term postnatal somatic and neurodevelopmental consequences. Animal studies indicate that corticosteroid exposure-associated alterations in the nervous system include hypothalamic function. Infants with infantile spasms, a devastating epileptic syndrome of infancy with characteristic spastic seizures, chaotic irregular waves on interictal electroencephalogram (hypsarhythmia) and mental deterioration, have decreased concentrations of adrenocorticotrophic hormone (ACTH) and cortisol in cerebrospinal fluid, strongly suggesting hypothalamic dysfunction. We have exploited this feature to develop a model of human infantile spasms by using repeated prenatal exposure to betamethasone and a postnatal trigger of developmentally relevant spasms with NMDA. The spasms triggered in prenatally primed rats are more severe compared to prenatally saline-injected ones and respond to ACTH, a treatment of choice for infantile spasms in humans. Using autoradiography and immunohistochemistry, we have identified a link between the spasms in our model and the hypothalamus, especially the arcuate nucleus. Transcriptomic analysis of the arcuate nucleus after prenatal priming with betamethasone but before trigger of spasms indicates that prenatal betamethasone exposure down-regulates genes encoding several important proteins participating in glutamatergic and GABAergic transmission. Interestingly, there were significant sex-specific alterations after prenatal betamethasone in synapse-related gene expression but no such sex differences were found in prenatally saline-injected controls. A pairwise relevance analysis revealed that, although the synapse gene expression in controls was independent of sex, these genes form topologically distinct gene fabrics in males and females and these fabrics are altered by betamethasone in a sex-specific manner. These findings may explain the sex differences with respect to both normal behaviour and the occurrence and severity of infantile spasms. Changes in transcript expression and their coordination may contribute to a molecular substrate of permanent neurodevelopmental changes (including infantile spasms) found after prenatal exposure to corticosteroids.

Long-term weekly ACTH therapy for relapsed West syndrome

Adrenocorticotrophic hormone (ACTH) therapy is an established treatment for West syndrome. However, some patients may relapse after this therapy, for whom there is no established treatment. We describe 3 patients with symptomatic West syndrome and multiple, poor prognostic factors who relapsed after initial ACTH therapy. They were treated with a second round of ACTH therapy, i.e., daily intramuscular injection for 2-3 weeks and subsequent withdrawal, alternative days for 1 or 2 weeks, every 3 days for 1 or 2 weeks, followed by weekly or biweekly for >/=1 year. Clinical seizures and hypsarrhythmia resolved in all 3 patients within 4 weeks, and these clinical improvements continued through a second round of ACTH therapy. Two patients developed other types of seizures and aggravation of paroxysms on electroencephalography, but no hypsarrhythmia, soon after termination of ACTH therapy. In the other patient, although electroencephalographic findings remained normal during weekly ACTH therapy, focal sharp waves with irregular slow waves appeared after the injection interval became biweekly. After a second round of ACTH therapy, all patients exhibited developmental progress, particularly in gross motor development and visual functions. No serious adverse events occurred during treatment. Long-term weekly ACTH therapy is a potentially effective treatment option for relapsed West syndrome.

ACTH therapy for Taiwanese children with West syndrome -- efficacy and impact on long-term prognosis

To study the efficacy of adrenocorticotrophic hormone (ACTH) in treating Taiwanese children with West syndrome (WS) and the impact on long-term prognosis, 66 patients with WS (54 symptomatic and 12 cryptogenic) were collected from 1987 to 1998 in a medical center in Taiwan. A total of 53 patients were enrolled in this study and treated with ACTH at the dosage of 2.5IU/kg daily for 2 weeks with gradual tapering in subsequent 6 weeks. Immediate responses, side effects of ACTH and long-term outcomes of the patients including seizure and developmental status were evaluated during the average follow-up period of 35.6 months. The spasm-free percentage after one or two courses of ACTH treatment was 77.4%. Nine (17%) patients encountered severe side effects such as major infections, which prompted us to stop ACTH. At the end of follow-up, 22 (41.5%) patients had intractable seizures but 25 (47.2%) patients remained seizure free with or without anticonvulsants. The ACTH-responders had a better chance of remaining seizure free (P<0.05). Regarding the long-term developmental outcome, 12 (22.6%) patients had normal or borderline development; two thirds of them belonged to the crytpogenic group. Six (11.3%) patients expired and 24 (45.3%) were severely retarded; all but one of them belonged to the symptomatic group. The prognosis of WS heavily relies on whether a patient is cryptogenic or symptomatic (P<0.001). Good response to therapy or short treatment lag did not favorably affect the developmental outcomes of the symptomatic cases. We conclude that the long-term outcomes of WS in Taiwan were generally poor despite of treatment. Only cryptogenic patients had favorable prognosis. For symptomatic patients, ACTH therapy may be used to control the spasms and decrease the incidence of subsequent epilepsy, but it will not improve developmental outcome. Considering a high percentage of severe side effects in our study, a lower dosage of ACTH with adequate therapeutic efficacy but less side effects should be considered for treating Taiwanese children with WS.

Infantile spasms in Down syndrome--effects of delayed anticonvulsive treatment

To investigate the impact of treatment lag in infantile spasms (IS) on treatment response, occurrence of later epilepsy, and long-term cognition and behavior in patients with one single etiological entity, we examined 18 patients with Down syndrome (DS) and earlier IS retrospectively (follow-up period of 32-180 months with a mean of 85.1 months), and determined their history and present condition, in terms of previously mentioned items. There was a statistically significant correlation between treatment lag and lag to cessation of spasms (R=0.55, P=0.02), developmental quotient (DQ) (R=-0.75, P=0.003), and score of autistic features (AF) (R=0.57, P=0.04). Moreover we found that the later the response to treatment of IS, the lower was the DQ (R=-0.86, P=0.001) and the higher was the score of autistic features (R=0.5, P=0.06). A long duration of spasms also determined a low DQ (R=-0.93, P<0.0001) and a high score of autistic features (R=0.66, P<0.01). All patients with persistent epilepsy (n=5) had had a treatment lag of over 2 months. Conversely, for all children treated within 2 months (n=8) spasms ceased within 3 months of treatment and none of them had later epilepsy. This group of patients with a treatment lag of less than 2 months had earlier treatment response (P=0.002), higher DQ (P=0.004) and lower score of autistic features (P=0.006). The data stress the importance of a short treatment lag in view of mental development and prevention of later epilepsy and autistic features, and raise the question of antiepileptogenic effect in this specific condition.

Treatment of infantile spasms: an evidence-based approach

The object of this work was to subject established empirical medical treatment regimens for infantile spasms to evidence-based medicine analysis in order to determine the current best practice for the treatment of infantile spasms in children. Clinical studies of infantile spasms reported during the presteroid era were reviewed critically to define the natural history of the disorder. Treatment trials of infantile spasms conducted since 1958 were rigorously assessed using MEDLINE and hand searches of the English language literature. Inclusion criteria were the documented presence of infantile spasms and hypsarrhythmia. Outcome measures included complete cessation of spasms, resolution of hypsarrhythmia, relapse rate, developmental outcome, the presence or absence of epilepsy, and/or an epileptiform electroencephalogram. Evidence was defined as class I, II, or III, and practice parameter recommendations were made using the framework devised by the American Academy of Neurology. Class I and III evidence support a standard of practice recommendation for the use of vigabatrin in the treatment of infantile spasms in children with tuberous sclerosis. Class I and III evidence support a guidelines recommendation for the use of either ACTH or vigabatrin in infantile spasms in nontuberous sclerosis patients. There is no strong evidence that successful treatment of infantile spasms improves the long-term prognosis for cognitive outcome or decreases the incidence of later epilepsy. A practice option recommendation for the use of oral corticosteroids in the treatment of infantile spasms is supported by limited and inconclusive class I and III data. Based on the evidence, no recommendation can be made for the use of pyridoxine, benzodiazepines, or the newer antiepileptic drugs in the treatment of infantile spasms. ACTH and vigabatrin are the most effective agents in the treatment of infantile spasms, but concerns remain about the risk/benefit profiles of these drugs.

A risk-benefit assessment of treatments for infantile spasms

Infantile spasms are a devastating epileptic encephalopathy of the young child. The continuing spasms and hypsarrhythmia have a deleterious effect on brain maturation and further cognitive development. Corticotropin (adrenocorticotropic hormone) or corticosteroids have been the gold standard treatment for the last 40 years, but there is little agreement on the best agent to use, or the dosage and duration of the treatment. Despite this empirical approach, corticotropin or corticosteroids are effective in controlling spasms and normalising electroencephalograms in about 60% of cases. The major concern with this treatment is the occurrence of frequent and severe adverse effects. The introduction of vigabatrin in the 1990s improved the outcome of infantile spasms. Vigabatrin shows an efficacy at least equal to that of corticosteroids, and even higher in specific groups such as those with tuberous sclerosis. The major advantages of vigabatrin are the ability to initiate treatment at the full dosage. rapid efficacy, suitability for outpatient treatment and particularly good tolerability with only minor adverse effects. Recently, however, the safety of vigabatrin has caused concern since a specific visual field loss has been reported in treated adults. The current problem is determining the risk-benefit ratio of vigabatrin and corticosteroids/corticotropin in children with infantile spasms, and to specify the groups where their use could be optimal. Visual field loss is usually asymptomatic and can be detected only by perimetric visual field studies. In children, especially in the young or disabled, it is difficult if not impossible to detect the visual field loss and it is not yet known if children are at higher or lower risk for this adverse effect. Until a clear answer about the occurrence of this adverse effect in children has been established through randomised study, vigabatrin may still be considered first-line therapy in infantile spasms. Children who do not achieve a good response to vigabatrin should be switched to corticotropin/corticosteroid therapy. Despite the efficacy of corticosteroids and vigabatrin, the use of the conventional antiepileptic drugs, the newly developed antiepileptic drugs and some promising results with ketogenic diet, 25 to 30% of patients with infantile spasms continue to have spasms and experience psychomotor regression. These drug-resistant patients could be candidates for surgery.

Treatment of infantile spasms

OBJECTIVE

To summarize and evaluate the literature regarding the clinical features, epidemiology, etiology, pathophysiology, and treatment of infantile spasms.

DATA SOURCES

A literature search of articles from January 1966 to July 1993 using MEDLINE, EM-Base, and Current Concepts/Life Sciences, as well as bibliographies of relevant articles.

STUDY SELECTION

All identified original and review publications regarding the clinical features, epidemiology, etiology, pathophysiology, and treatment of infantile spasms were reviewed. Emphasis was placed on original studies published since 1975.

DATA EXTRACTION

Data from published research were extracted and evaluated according to study design, sample size, dosing regimen, outcome measures, and treatment efficacy and safety.

DATA SYNTHESIS

Infantile spasms constitute a rare epileptic syndrome with a poor long-term prognosis for normal intellectual development. The spasms are characterized by a brief symmetric contraction of the muscles of the neck, trunk, and/or extremities, often occurring in a series of 2 to more than 100 spasms during a single episode. The disorder is age-specific, with the peak onset of symptoms occurring between 2 and 8 months of age. Spasms of no identifiable cause in infants with normal development prior to the onset of infantile spasms are classified as cryptogenic or idiopathic, whereas those with an identifiable cause are classified as symptomatic. Long-term prognosis is best in cryptogenic cases, with 30-70 percent attaining normal intellect compared with 5-19 percent in symptomatic cases. The etiology and pathophysiology are not well understood. Recent theory postulates that infantile spasms may be caused by an excess of corticotropin-releasing hormone activity during infancy. The suspected association between the whole-cell pertussis vaccine and infantile spasms is coincidental. Few well-designed, prospective, controlled clinical trials for the treatment of infantile spasms have been conducted.

CONCLUSIONS

Standard anticonvulsants such as phenytoin, the barbiturates, carbamazepine, and the succinimides have been ineffective. Of the anticonvulsants, only the benzodiazepines, valproic acid, and vigabatrin have shown efficacy in reducing spasm frequency and severity. Hormonal therapy with adrenocorticotropic hormone (ACTH) and/or prednisone has been the most frequently studied treatment modality and appears to be the most effective. Hormonal therapy achieves complete spasm control in 50-75 percent of infants within four weeks of initiation. Opinions differ regarding the relative efficacy between ACTH and prednisone, the need for early initiation of hormonal treatment, and the benefits of high dosages of ACTH (> 40 units/d). No treatment has been shown conclusively to improve the long-term intellectual development of these infants. Neurosurgery may be the treatment of choice in select cases when a localized central nervous system abnormality can be demonstrated. Well-designed, blind, prospective clinical trials are needed to answer definitively many lingering questions regarding the treatment of infantile spasms.

Treatment of infantile spasms with high-dosage vitamin B6

High-dose vitamin B6 (pyridoxine-HCl, 300 mg/kg/day orally) was introduced as the initial treatment of recently manifested infantile spasms in 17 children (13 symptomatic cases with identified brain lesion and 4 cryptogenic cases). 5 of 17 children (2 cryptogenic, 2 with severe pre/perinatal brain damage and one with Sturge-Weber syndrome) were classified as responders to high-dose vitamin B6. In all 5 cases the response to vitamin B6 occurred within the first 2 weeks of treatment and within 4 weeks all patients were free of seizures. Two patients developed other seizures (partial seizures, etiologically unclear blinking attacks), but no relapse of infantile spasms was observed among the five responders to vitamin B6. No serious adverse reactions were noted. Side effects were mainly gastrointestinal symptoms, which were reversible after reduction of the dosage. Considering the life-threatening side effects of treatment with ACTH/corticosteroids or valproate, a controlled clinical trial with high-dose vitamin B6 would appear justified to either prove or disprove efficacy.

Non-verbal communication skills of surgically treated children with infantile spasms

The authors present preliminary findings on the effects of surgery on the development of early non-verbal social communication skills in eight children with intractable infantile spasms. After a mean follow-up of 15.2 months, there was no statistically significant change in the post-surgical non-verbal communication behavior of these children beyond the expected developmental change. Implications of these findings for the developmental impairment associated with infantile spasms are discussed.

Combination treatment of high-dose pyridoxal phosphate and low-dose ACTH in children with West syndrome and related disorders

Combination therapy of high-dose pyridoxal phosphate (PAL-P, 40-50 mg/kg/day) and low-dose ACTH beta 1-24-Z (tetracosactide acetate-Zn, Cortrosyn Z, 0.01 mg/kg/day) was instituted in 26 children suffering from West syndrome and related disorders--pretreated without success with high-dose PAL-P alone; 18 with West syndrome (14 with symptomatic and 4 with cryptogenic types), 2 with symptomatic Lennox-Gastaut syndrome, 5 with cerebral palsy with hypsarhythmia or diffuse slow spike-waves and one with myoclonic seizures (secondary generalized epilepsy). Clinical, electroencephalographic and neurochemical investigations were carried out. The results were summarized as follows. 1) Only one of 27 children with West syndrome and related disorders pretreated using high-dose PAL-P alone before ACTH showed a clinically excellent response. 2) Clinical seizures were completely suppressed in 19 of 21 children who initially had seizures (90%) after this combination therapy. 3) Twenty-one of the total 26 children (80%) had disappearance of hypsarhythmia or diffuse slow spike-waves in EEG after this therapy. 4) During PAL-P treatment alone transient increases in liver enzymes occurred in 37 percent. The brain shrinkage of CT and the significant rise in CSF NSE were seen in 95% and 78% after ACTH, respectively. 5) Twenty-three children have been followed for one to 29 months after tapering off of ACTH. No relapses were experienced in 11 of 18 who initially had seizures (61%) and 13 of 23 with hypsarhythmia or diffuse slow spike-waves (57%). 6) Postictal PRL elevations were suppressed during high-dose PAL-P. 7) No significant changes in the CSF levels of HVA and 5-HIAA were seen during this combination therapy. The CSF levels of HVA were significantly lower than the controls. 8) Daily ACTH therapy transiently suppressed the secretion of anterior pituitary hormones (GH, TSH, PRL, LH and FSH) and thyroid hormones (T3 free T3, T4 and free T4). It is recommended that the combination therapy of high-dose PAL-P and low-dose ACTH is a promising new method and should be tried in children with West syndrome and related disorders. The mechanism of action of this combination therapy remains obscure although some information has been obtained from our investigations.

Computerized tomography of brain in infantile spasms (West syndrome)

Computerized tomographic scanning of the brain was performed in 26 infants with Infantile spasms. Majority of the patients, 18 (69%) had some abnormality. Changes noted were cerebral atrophy in 12, calcifications in 5 and dysgenesis of the corpus callosum in 3 patients. One infant each had porencephaly, hydrocephalus and cavum septum pellucidum. Five patients had more than one abnormality simultaneously. Three infants had progressively worsening atrophy on ACTH therapy. Patients with infantile spasms, without any physical or neurological abnormality, are unlikely to have any abnormalities on brain CT scanning (p = less than 0.005).

Epidermal nevus syndrome: case report and review of clinical manifestations

The epidermal nevus syndrome is a disorder characterized by epidermal nevi and associated neurologic, skeletal, and other abnormalities. We cared for a 3-month-old male with multiple epidermal nevi and severe central nervous system involvement.

Improvement of modern treatment and outcome in childhood epilepsy in Asia

Epilepsy and epileptic syndromes are one of the major pediatric neurological diseases in Taiwan, R.O.C. In 1984 we investigated 38 elementary schools in Taichung city, in the middle-west part of Taiwan. Among 57,944 school-aged children, 388 had suffered from at least two episodes of afebrile seizures occurring separately over a two-week period. The period prevalence rate was 0.67%. In our clinic, once seizures are diagnosed, the seizure types are then classified as well as possible, in order to develop a rational approach to treatment. We commonly use carbamazepine for partial seizures and some generalized seizures, low dose ACTH (10 I.U.) for infantile spasms, valproic acid for absence seizures and myoclonic seizures, clonazepam for atonic-akinetic and myoclonic seizures, and phenobarbital for young children with generalized seizures. In the last three years, we have used a ketogenic diet for akinetic-atonic seizures and Lennox-Gastaut syndrome; we have also used temporal lobectomy for complex partial seizures since 1981. Owing to the marked increase in the medical understanding of epileptic seizures and syndromes, and models of treatment, there is no question that children with seizure disorders are better off today than they were ten years ago.

[Myoclonic epilepsy with non-progressive encephalopathy]

We report 6 cases of particular type of myoclonic epilepsy with non-progressive encephalopathy. It consists of a syndrome characterized by an onset of seizures in the first year of life, frequent myoclonic status, generalized spikes and waves on EEG and an unfavourable outcome with encephalopathy. At the beginning, the diagnosis is difficult, the symptomatology later suggests a progressive encephalopathy. In the present study, a detailed analysis of the early electroencephalographic aspects and of the arguments in favour of a non-progressive encephalopathy is proposed. Hypothesis of perinatal vascular lesions mainly involving the central areas is forwarded.

Generalized epilepsy in childhood: some notes from a developmental perspective

Efforts to establish more detailed classification of childhood epilepsy have increased our knowledge in this field, but have also led to a tendency of excessive subdivision, especially in generalized forms. This paper emphasizes the need for the reconsideration of a number of basic factors that favour a more unitary physiopathogenetic and clinical interpretation: 1) the electroclinical pattern is age-related; 2) the electroclinical paroxysmal expressiveness is greatest in childhood; 3) two types of manifestations can be distinguished in the process of spread and generalization (a benzodiazepine-sensitive complex associated with a more regular and organized EEG pattern, and a corticotropin-sensitive complex associated with an irregular, unorganized EEG pattern).

Identification of infants at risk for infantile spasms by neonatal polygraphy

Reevaluation of neonatal EEGs and polygraphic tracings of 40 infants with infantile spasms and/or hypsarrhythmia resulted in the constitution of a compound score for the identification of infants at risk for infantile spasms by neonatal EEG. The score comprises 8 distinct items: 2 concern behavioral characteristics, 6 abnormality of EEG background activity and paroxysmal events. A tracing registered at conceptional age 36 to 44 weeks (eventually up to 50 weeks) presenting at least 4 of these 8 items is scored positive for the risk of evolving hypsarrhythmia. In a prospective study the polygraphic tracings of 941 newborn infants were evaluated for risk: 18 infants suffering from perinatal distress and 7 newborns with malformations of the brain were scored positive and all 25 developed infantile spasms and/or hypsarrhythmia. One infant with later infantile spasms was missed by the scoring system. None of the remaining infants scored negative manifested infantile spasms. Thus, correct positive prognostication was 100% and false negative 0.1%. By conventional EEG 5 out of 8 patients with infantile spasms were correctly predicted. The high validity of the risk-score based on polygraphic tracing between conceptional age 36 to 44 weeks may allow pre-onset treatment preventing secondary mental deterioration due to hypsarrhythmia and infantile spasms.

The prognostic value of EEG patterns in epilepsies with infantile spasms

By scoring EEG patterns (hypsarrhythmia = 10, absence of sleeping patterns = 10, focal epileptic discharge = 5, general-treatment or in whom infantile spasms never disappeared even during ACTH. A low voltage EEG did not have any ending ACTH therapy free of seizures showed lower scores compared to those infants relapsing after the end of ACTH treatment or in whom infantile spasms never disappeared even during ACTH. A low voltage EED did not have any prognostic significance. Using EEG scores it might be possible to separate non-responders and responders after 3 weeks of ACTH therapy, thus shortening ACTH treatment in non-responding infants.

New experience with Rett syndrome in France: the problem of atypical cases

Thirty-five patients with typical Rett syndrome have been observed by the authors. Fourteen patients with behavioral features suggestive of RS but who lacked some of the diagnostic criteria are reported. They were divided into 3 groups: 1) abnormal development from birth, 2) acute post-epileptic onset, and 3) encephalopathy with a known etiology different from RS. These 14 patients included 3 boys. In none of these cases was there an obvious history of acquired, progressive deterioration. The latter is essential for the diagnosis of RS.

Epilepsy and associated handicaps in a 1 year birth cohort in northern Finland

A 1 year birth cohort in the provinces of Oulu and Lapland in the Northern part of Finland consisted of 12058 live-born infants, this being 96% of all children born in 1966 in this area. Information on morbidity up to the age of 14 years was collected prospectively by means of questionnaires, special examinations and from national and regional registers of hospital admissions and social services contacts. The total number of children with epilepsy, defined as the occurrence of at least one afebrile epileptic seizure, was 208, 113 boys and 95 girls. The cumulative incidences for epilepsy up to the age of 14 years was 17.3 per 1000. Primary generalised epilepsy was present in 63% and partial seizures in 37%. At least one additional handicapping condition, such as cerebral palsy, mental retardation, and visual or auditory defect was present in 74 children (35.5%). Mental retardation was the most frequent additional handicap, being present in 28%, whereas 16% of the children had cerebral palsy. A total of 75% of the children were able to attend an ordinary school. The high frequency of epilepsy in this study, as compared to other studies, is explained by the cumulative registration of the cases and a high degree of ascertainment of cases with epilepsy.