Infantile spasms: A prognostic evaluation

Long-term survival and factors associated with mortality among children with infantile epileptic spasms syndrome - A retrospective cohort study

BACKGROUND AND OBJECTIVES

The existing literature indicates a higher risk of mortality among children with Infantile epileptic spasms syndrome (IESS). Our aim was to find the mortality pattern and factors that affect survival among children with IESS.

METHODS

Children with IESS who had age of onset between one month and 24 months were included. The primary outcome was survival. We used Kaplan-Meier estimates for survival analysis and Cox regression analyses to evaluate possible factors associated with mortality.

RESULTS

During the follow-up period (120 months), 19/160 children (11.9%) expired. Three children expired in the first week after initiation of ACTH. There were six deaths (3.8%; 31.6% of deaths), within two years. Clinical findings and laboratory investigations revealed the cause of death to be severe pneumonia in ten children. Three died of severe sepsis. Four died due to metabolic crisis and two children died due to probable Sudden unexpected death in epilepsy (SUDEP). On multivariable analysis, mortality was predicted by 'presence of seizures other than spasms' and an inborn error of metabolism (IEM) as the underlying cause. None of the children in the idiopathic group died.

CONCLUSION

Survival in our single center cohort with IESS was good in comparison to previous studies. Considering that pneumonia and sepsis were the most common cause of mortality that we detected, steps for prevention of sepsis might be worth considering in these children. Presence of seizures other than epileptic spasms, and an IEM should prompt the physician to let the family know that risk of mortality is high.

Heterozygous GABAA receptor β3 subunit N110D knock-in mice have epileptic spasms

OBJECTIVE

Infantile spasms is an epileptic encephalopathy of childhood, and its pathophysiology is largely unknown. We generated a heterozygous knock-in mouse with the human infantile spasms-associated de novo mutation GABRB3 (c.A328G, p.N110D) to investigate its molecular mechanisms and to establish the Gabrb3+/N110D knock-in mouse as a model of infantile spasms syndrome.

METHODS

We used electroencephalography (EEG) and video monitoring to characterize seizure types, and a suite of behavioral tests to identify neurological and behavioral impairment in Gabrb3+/N110D knock-in mice. Miniature inhibitory postsynaptic currents (mIPSCs) were recorded from layer V/VI pyramidal neurons in somatosensory cortex, and extracellular multi-unit recordings from the ventral basal nucleus of the thalamus in a horizontal thalamocortical slice were used to assess spontaneous thalamocortical oscillations.

RESULTS

The infantile spasms-associated human de novo mutation GABRB3 (c.A328G, p.N110D) caused epileptic spasms early in development and multiple seizure types in adult Gabrb3+/N110D knock-in mice. Signs of neurological impairment, anxiety, hyperactivity, social impairment, and deficits in spatial learning and memory were also observed. Gabrb3+/N110D mice had reduced cortical mIPSCs and increased duration of spontaneous oscillatory firing in the somatosensory thalamocortical circuit.

SIGNIFICANCE

The Gabrb3+/N110D knock-in mouse has epileptic spasms, seizures, and other neurological impairments that are consistent with infantile spasms syndrome in patients. Multiple seizure types and abnormal behaviors indicative of neurological impairment both early and late in development suggest that Gabrb3+/N110D mice can be used to study the pathophysiology of infantile spasms. Reduced cortical inhibition and increased duration of thalamocortical oscillatory firing suggest perturbations in thalamocortical circuits.

Long-term epilepsy control, motor function, cognition, sleep and quality of life in children with West syndrome

PURPOSE

To assess epilepsy, motor function, cognitive, sleep, and quality of life outcomes and their predictors in a follow-up cohort with West syndrome (WS) at ≥5 years of age.

METHODS

Cross-sectional evaluation in a follow-up cohort of WS (aged 5-14 years), between July 2018 and December 2019, was performed at a tertiary-care referral center in Northern India. 164 children were assessed in-person for epilepsy severity, functional status (gross motor and hand function), social quotient, behavioral comorbidities, sleep problems, and quality of life (QoL) using Early Childhood Epilepsy Severity Scale, Gross Motor Function Classification System, Manual Ability Classification System, Vineland Social Maturity Scale, Diagnostic and Statistical Manual of Mental disorders-5 criteria, Children's Sleep Habits Questionnaire, and PedsQL-Epilepsy module respectively. Furthermore, 238 children with the inability to visit the hospital were assessed through telephonic interview along with retrospective case record review for epilepsy control, gross and fine motor measures.

RESULTS

402 children with WS (75 % boys) with regular follow-up were studied and the majority (80 %) had underlying structural etiology. The median age (interquartile range) of the cohort was 92 (78-107) months. Of these, 60 % had evolved to Lennox-Gastaut syndrome (LGS). The following long-term outcomes were observed: ongoing epilepsy (261/402), unfavorable motor status (130/402), moderate to profound intellectual disability (111/164), autistic spectrum disorder (42/164), attention-deficit hyperactivity disorder (18/164), poor sleep (135/164), and impaired QoL (115/164). Non-structural etiology (odds ratio [OR] = 3.8, 95 % confidence interval [CI]: 2.1-5.5, p=<0·0001) and older age (>5 months) at the onset of epileptic spasms (OR = 2·9, 95 % CI: 1.5-5.0, p=<0·0001) were associated with enduring seizure freedom for more than two years.

CONCLUSION

The present study revealed a preponderance of structural etiology and a high rate of transition to LGS. Early age at onset of spasms (before five months) and structural etiology were the predictors of unfavorable long-term epilepsy outcome. QoL was impaired in more than two-thirds of patients and it correlated significantly with cognitive, sleep, motor, and behavioral outcomes. However, the results of our study should be interpreted in the context of significant attrition of the original cohort.

Investigation of the association between imbalance of the intestinal flora and infantile spasms: a pilot case-control study

BACKGROUND

The intestinal flora (IF) regulates brain function via the neuroendocrine and neuroimmune systems and influences the development of several neuropsychiatric diseases, including epilepsy. Here, we investigated the specific relationship between the IF and infantile spasms (IS), a specific form of epilepsy.

METHODS

Twenty-three children suffering from IS were recruited from the Chinese PLA General Hospital. According to patient response to adrenocorticotropic hormone (ACTH) treatment, the cohort was subdivided into 2 groups: an ACTH-response group and an ACTH-no response (NR) group. A total of 21 healthy children were recruited as a control group (healthy controls: HCs) during the same time period. Fecal samples were collected from infants in the IS and HC groups, and the population of fecal microorganisms was analyzed by 16s ribosomal DNA sequencing. The α and β diversity of the fecal microflora was determined, and the relative abundance of each species was classified. Tax4Fun2 was used to analyze the metabolic pathways utilized by the microflora, and the Kyoto Encyclopedia of Genes and Genomes database was used to analyze differentially expressed genes and pathways.

RESULTS

No significant differences existed in α or β diversity when compared between the IS and HC groups, nor between the ACTH-response and ACTH-NR groups which were separated before and after ACTH treatment. Although there was no significant difference between the ACTH-response and ACTH-NR groups with respect to α diversity, there was a significant difference in β diversity. Compared with that of the HCs, the IF of the IS group featured lower proportions of Lactobacillus, Roseburia, and Lachnospira, and a higher proportion of Clostridium. In the IS group, the proportion of Staphylococcus in the IF was higher before treatment than after treatment. Compared with the ACTH-NR group, the ACTH-response group had reduced populations of Odoribacter, Phascolarctobacterium, Anaerotruncus, Mitsuakella, and Robinsoniella. However, an increase was observed in the population of Bifidobacterium. A significant difference was also identified between the IS and HC groups with regard to the expression levels of genes associated with lipoic acid synthesis.

CONCLUSIONS

Our analysis demonstrated that imbalance of the IF may be involved in the pathogenesis of IS and is related to response to ACTH. Regulating the composition of the IF may pave the way to developing a potential adjuvant therapy for patients with IS.

Management practices for West syndrome in South Asia: A survey study and meta-analysis

OBJECTIVES

Considering the dearth of literature on West syndrome (WS) from South Asian countries, this study aimed to evaluate the management practices in South Asia by an online survey and meta-analysis.

METHODS

An online questionnaire was sent to 223 pediatric neurologists/pediatricians in India, Pakistan, Myanmar, Sri Lanka, Bhutan, Nepal, and Bangladesh. Their responses were evaluated and supplemented by a meta-analysis.

RESULTS

Of 125 responses received (response rate: 56%), around 60% of responders observed male preponderance and an approximate lead-time-to-treatment (LTTT) of 4-12 weeks. The commonest etiology observed was a static structural insult (88.6% of responders). Most commonly used first-line drug (country-wise) was as follows: India-adrenocorticotropin hormone (ACTH, 50%); Pakistan-oral steroids (45.5%); Myanmar, Sri Lanka, and Nepal-oral steroids (94.4%); Bangladesh-ACTH (2/2); Bhutan-vigabatrin (3/5). ACTH and vigabatrin are not available in Myanmar and Nepal. The most commonly used regime for ACTH was maximal-dose-at-initiation-regime in India, Sri Lanka, and Bangladesh and gradually escalating-regime in Pakistan. Maximum dose of prednisolone was variable-most common response from India: 3-4 mg/kg/d; Pakistan, Bhutan, and Bangladesh: 2 mg/kg/d; Sri Lanka, Nepal, and Myanmar: 5-8 mg/kg/d or 60 mg/d. The total duration of hormonal therapy (including tapering) ranged from 4 to 12 weeks (67/91). Most responders considered cessation of spasms for four weeks as complete response (54/111) and advised electroencephalography (EEG; 104/123) to check for hypsarrhythmia resolution. Difficult access to pediatric EEG in Bhutan and Nepal is concerning. More than 95% of responders felt a need for more awareness. The meta-analysis supported the preponderance of male gender (68%; confidence interval [CI]: 64%-73%), structural etiology(80%; CI 73%-86%), longer LTTT (2.4 months; CI 2.1-2.6 months), and low response rate to hormonal therapy(18% and 28% for ACTH and oral steroids respectively) in WS in South Asia.

SIGNIFICANCE

This study highlights the practices and challenges in the management of WS in South Asia. These include a preponderance of male gender and structural etiology, a longer LTTT, difficult access to pediatric EEG, nonavailability of ACTH and vigabatrin in some countries, and low effectiveness of hormonal therapy in this region.

Modeling epileptic spasms during infancy: Are we heading for the treatment yet?

Infantile spasms (IS or epileptic spasms during infancy) were first described by Dr. William James West (aka West syndrome) in his own son in 1841. While rare by definition (occurring in 1 per 3200-3400 live births), IS represent a major social and treatment burden. The etiology of IS varies - there are many (>200) different known pathologies resulting in IS and still in about one third of cases there is no obvious reason. With the advancement of genetic analysis, role of certain genes (such as ARX or CDKL5 and others) in IS appears to be important. Current treatment strategies with incomplete efficacy and serious potential adverse effects include adrenocorticotropin (ACTH), corticosteroids (prednisone, prednisolone) and vigabatrin, more recently also a combination of hormones and vigabatrin. Second line treatments include pyridoxine (vitamin B6) and ketogenic diet. Additional treatment approaches use rapamycin, cannabidiol, valproic acid and other anti-seizure medications. Efficacy of these second line medications is variable but usually inferior to hormonal treatments and vigabatrin. Thus, new and effective models of this devastating condition are required for the search of additional treatment options as well as for better understanding the mechanisms of IS. Currently, eight models of IS are reviewed along with the ideas and mechanisms behind these models, drugs tested using the models and their efficacy and usefulness. Etiological variety of IS is somewhat reflected in the variety of the models. However, it seems that for finding precise personalized approaches, this variety is necessary as there is no "one-size-fits-all" approach possible for both IS in particular and epilepsy in general.

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.

Comparison of the Effect of High and Low Doses of Adrenocorticotropic Hormone (ACTH) in the Management of Infantile Spasms

OBJECTIVES

Infantile spasms can have irrecoverable adverse effects on a child's brain. Adrenocorticotropic hormone (ACTH) is the most common first-line medication for the treatment of infantile spasms. However, the suitable dose and duration of treatment continue to be debated among specialists. Since high doses of ACTH, which are commonly used, can produce more side effects, lower doses are preferred. The aim of this study was to determine the effect and extent of complications caused by high and low doses of ACTH in children with infantile spasms.

MATERIALS & METHODS

This clinical trial was performed on 32 infants with infantile spasms, aged 1.5-18 months. The subjects were divided into high- and low-dose ACTH groups. Treatment continued for two months. The therapeutic effects and complications were then compared over 18 months.

RESULTS

The results indicated no significant difference between the groups in terms of the short-term prognosis of convulsions, final prognosis of patients with spasm relapse, EEG changes after treatment, and post-treatment development of hypertension. On the other hand, there was a significant difference in the frequency distribution of restlessness intensity and becoming Cushingoid, which were more frequent in the high-dose group.

CONCLUSION

The results indicated that high- and low-dose ACTH are equally effective in controlling spasms, yet the low dose causes fewer side effects.

Why West? Comparisons of clinical, genetic and molecular features of infants with and without spasms

Infantile spasms are the defining seizures of West syndrome, a severe form of early life epilepsy with poorly-understood pathophysiology. We present a novel comparative analysis of infants with spasms versus other seizure-types and identify clinical, etiological, and molecular-genetic factors preferentially predisposing to spasms. We compared ages, clinical etiologies, and associated-genes between spasms and non-spasms groups in a multicenter cohort of 509 infants (<12months) with newly-diagnosed epilepsy. Gene ontology and pathway enrichment analysis of clinical laboratory-confirmed pathogenic variant-harboring genes was performed. Pathways, functions, and cellular compartments between spasms and non-spasms groups were compared. Spasms onset age was similar in infants initially presenting with spasms (6.1 months) versus developing spasms as a later seizure type (6.9 months) but lower in the non-spasms group (4.7 months, p<0.0001). This pattern held across most etiological categories. Gestational age negatively correlated with spasms onset-age (r = -0.29, p<0.0001) but not with non-spasm seizure age. Spasms were significantly preferentially associated with broad developmental and regulatory pathways, whereas motor functions and pathways including cellular response to stimuli, cell motility and ion transport were preferentially enriched in non-spasms. Neuronal cell-body organelles preferentially associated with spasms, while, axonal, dendritic, and synaptic regions preferentially associated with other seizures. Spasms are a clinically and biologically distinct infantile seizure type. Comparative clinical-epidemiological analyses identify the middle of the first year as the time of peak expression regardless of etiology. The inverse association with gestational age suggests the preterm brain must reach a certain post-conceptional, not just chronological, neurodevelopmental stage before spasms manifest. Clear differences exist between the biological pathways leading to spasms versus other seizure types and suggest that spasms result from dysregulation of multiple developmental pathways and involve different cellular components than other seizure types. This deeper level of understanding may guide investigations into pathways most critical to target in future precision medicine efforts.

West syndrome in three patients with brain injury and a benign course

Infants with West Syndrome and underlying structural pathology typically experience persistent symptomatic focal seizures and intellectual disability. We performed a retrospective case review of 84 patients with West Syndrome evaluated at one institution between 1990 and 2013. From this group we identified three patients with West syndrome and congenital hemiplegia who later developed genetic epilepsy features and had normal intellectual development. This outcome is highly unusual and raises important questions about the relationship and possible influence of genetic epilepsy in patients with pre-existent West Syndrome and brain injury.