How should children with West syndrome be efficiently and accurately investigated? Results from the National Infantile Spasms Consortium

New insights into epileptic spasm generation and treatment from the TTX animal model

Currently, we have an incomplete understanding of the mechanisms underlying infantile epileptic spasms syndrome (IESS). However, over the past decade, significant efforts have been made to develop IESS animal models to provide much-needed mechanistic information for therapy development. Our laboratory has focused on the TTX model and in this paper, we review some of our findings. To induce spasms, tetrodotoxin (TTX) is infused into the neocortex of infant rats. TTX produces a lesion at its infusion site and thus mimics IESS resulting from acquired structural brain abnormalities. Subsequent electrophysiological studies showed that the epileptic spasms originate from neocortical layer V pyramidal cells. Importantly, experimental maneuvers that increase the excitability of these cells produce focal seizures in non-epileptic control animals but never produce them in TTX-infused epileptic rats; instead, epileptic spasms are produced in epileptic rats, indicating a significant transformation in the operations of neocortical networks. At the molecular level, studies showed that the expression of insulin-like growth factor 1 was markedly reduced in the cortex and this corresponded with a loss of presynaptic GABAergic nerve terminals. Very similar observations were made in surgically resected tissue from IESS patients with a history of perinatal strokes. Other experiments in conditional knockout mice indicated that IGF-1 plays a critical role in the maturation of neocortical inhibitory connectivity. This finding led to our hypothesis that the loss of IGF-1 in epileptic animals impairs inhibitory interneuron synaptogenesis and is responsible for spasms. To test this idea, we treated epileptic rats with the IGF-1-derived tripeptide (1-3)IGF-1, which was shown to act through IGF-1's receptor. (1-3)IGF-1 rescued inhibitory interneuron connectivity, restored IGF-1 levels, and abolished spasms. Thus, (1-3)IGF-1 or its analogs are potential novel treatments for IESS following perinatal brain injury. We conclude by discussing our findings in the broader context of the often-debated final common pathway hypothesis for IESS. PLAIN LANGUAGE SUMMARY: We review findings from the TTX animal model of infantile epileptic spasms syndrome, which show that these seizures come from an area of the brain called the neocortex. In this area, the amount of an important growth factor called IGF-1 is reduced, as is the number of inhibitory synapses that play an important role in preventing seizures. Other results indicate that the loss of IGF-1 prevents the normal development of these inhibitory synapses. Treatment of epileptic animals with (1-3)IGF-1 restored IGF-1 levels and inhibitory synapses and abolished spasms. Thus, (1-3)IGF-1 or an analog is a potential new therapy for epileptic spasms.

Infantile Epileptic Spasms Syndrome Due to Neonatal Hypoglycemic Brain Injury: A Retrospective Audit

In this retrospective audit of 56 children with infantile epileptic spasms syndrome (IESS), neonatal hypoglycemic brain injury (NHBI) was the leading etiology (35.71%), followed by hypoxic ischemic encephalopathy (HIE) (25%). Other causes accounted for 30.3% cases. Hypotonia, visual concerns, and microcephaly were more prominent in NHBI-related IESS compared to HIE.

Pulsatile Dexamethasone in Patients with Infantile Spasms: A Retrospective Analysis of a Unique Therapy Regime

OBJECTIVE

 Infantile spasms (IS) are an age-specific epilepsy syndrome associated with poor outcomes. Sustained and early spasm control remains the main goal of therapy. We aimed to evaluate a unique pulsatile dexamethasone therapy regime in children with IS.

METHODS

 Children with IS were treated with oral pulsatile-applied dexamethasone in the Children's Hospital Jena between 2002 and 2021, regardless of duration since IS onset or previous therapy (except ACTH). A prolonged initial pulse was given in case of insufficient response (standard: 5-7 days, prolonged: 10-14 days). We analyzed spasm reduction, electroencephalographic response, adverse reactions, neurodevelopmental status, and epileptic disorders at the last follow-up.

RESULTS

 Included were 26 patients with a median age of 5.5 months (interquartile range 4-8) at IS onset and a mean follow-up of 6.2 years (standard deviation [SD] 3.99). Fifty percent had an unknown etiology. Patients received on average 10.8 pulses (SD 6.0); 69.2% achieved initial seizure freedom, however, 38.9% relapsed. Seventeen patients had an initial prolonged pulse, of those, 14 got initially seizure-free (82.4%). Sixty-four percent of the cases had a sustained spasm cessation after the third pulse. At the last follow-up, half of the patients had no persisting epileptic disorder; 22.2% had a favorable neurocognitive development. Patients with unknown etiology were more likely to achieve seizure freedom during therapy (p = 0.025), had a more favorable neurocognitive outcome (p = 0.049), and were less likely to suffer from epileptic disorders (p = 0.037). No serious adverse effects were observed.

CONCLUSION

 Our results show that our treatment is safe and leads to outcomes comparable to usually applied hormonal therapy regimes. Etiology remains the most influential factor.

Disparities in the utilization of genetic testing for non-acquired infantile epileptic spasms syndrome in a single healthcare center in North Carolina

OBJECTIVE

To investigate disparities in the utilization of genetic sequencing among children with Infantile Epileptic Spasms Syndrome (IESS), a severe early-onset epilepsy where timely diagnosis and treatment are crucial for improving neurodevelopmental outcomes, previous studies have highlighted disparities in the evaluation and management of IESS. Genetic sequencing has emerged as a crucial tool in diagnosing unexplained epilepsies, offering precise etiological insights that can guide management. Despite guidelines recommending genetic sequencing for all unexplained epilepsies, little is known about how demographic and clinical factors influence the utilization of genetic sequencing in children with IESS.

METHODS

Retrospective cross-sectional cohort study, of 121 children diagnosed with IESS (2015-2020) within a single healthcare system. The primary outcome was the association between the utilization of genetic sequencing and demographic factors (race, ethnicity, language, rurality, and insurance status). Secondary outcomes included the utilization of genetic sequencing and its association with healthcare providers or clinical characteristics.

RESULTS

Genetic sequencing was performed in 64% (n = 74) of the patients with IESS. Race was significantly associated with the utilization of genetic sequencing, with non-Hispanic Black/African American children having significantly lower odds of undergoing genetic testing (OR = 0.19, 95% CI = 0.04-0.74, p = 0.02). No significant associations were found between language, rurality, or insurance status and the utilization of genetic sequencing. Notably, a low number of patients were from small towns and rural areas (7%). Clinical measures of seizure severity, including the presence of additional seizure types (p = 0.039) and the use of interventions in addition to standard IESS treatments (p = 0.01), were associated with higher rates of genetic sequencing.

SIGNIFICANCE

Non-Hispanic Black/African American children with IESS were less likely to undergo genetic sequencing. These findings underscore the need for evidence-based solutions addressing genetic sequencing utilization that may disproportionately impact children with IESS from medically underserved groups.

PLAIN LANGUAGE SUMMARY

This study looked at how genetic testing is used in children with Infantile Epileptic Spasms Syndrome (IESS), a serious type of epilepsy. The results showed that Black/African American children were much less likely to receive genetic testing compared to children of other racial groups, even though this testing is important for diagnosing and treating IESS. The study also found that only 7% of children in the study came from small towns or rural areas, suggesting that children in these areas may not have the same access to healthcare. These findings show the need for more research to understand and address gaps in genetic testing for children with IESS.

Clinical Features and Predictors of Unfavorable Outcomes in Infantile Epileptic Spasms Syndrome: Results from a Multiancestry Cohort

Background: Infantile epileptic spasms syndrome is an epileptic encephalopathy with poor prognosis. Objective: To describe clinical features and predictors of unfavorable outcomes of infantile epileptic spasms syndrome in a multiancestry cohort. Methods: Retrospective cross-sectional chart review analysis at a single tertiary pediatric hospital in 56 patients with infantile epileptic spasms syndrome. Results: Fifty-nine percent were males. Most patients (57%) were from the Middle East North African region. The mean age at onset of spasms was 6.6 months (±3.5 mo). At presentation, 80% of patients had a preexisting neurologic disorder, an abnormal development (66%), and/or an abnormal neurologic examination (73%). Hypsarrhythmia on electroencephalography (EEG) was reported in 55% of patients. Etiology was identified in 75%. Abnormalities on neuroimaging were common (70%), and 54% had abnormal genetic testing. The preferred first-line treatment was vigabatrin (66%) followed by high-dose oral steroids (16%). Only a minority (∼30%) experienced complete resolution of their epileptic spasms/hypsarrhythmia by 2 weeks. At the last follow-up, 84% of patients had an abnormal development and 40% were still on antiseizure medications. Comorbidities were common (75%). The majority of patients had unfavorable outcomes, including abnormal development (84%) and/or drug-resistant epilepsy (45%). Preexisting abnormal development/neurologic examination or neurologic conditions, perinatal risk factors, neuroimaging abnormalities, and an identified etiology were associated with increased odds ratios for unfavorable developmental outcomes or drug-resistant epilepsy. Significance: Clinical features and outcomes of infantile epileptic spasms syndrome in this multiancestry cohort confirms findings of previous epidemiologic studies, recognizes some differences, and highlights risk factors that can be used for early identification of patients with predicted unfavorable outcomes.

Interictal paroxysmal fast activity and functional connectivity in steroid responsive and non-responsive Lennox-Gastaut syndrome

OBJECTIVE

The aim of this study was to investigate the changes in interictal paroxysmal fast activity and functional connectivity before and after steroid pulse therapy in patients with Lennox-Gastaut syndrome (LGS).

METHODS

The medical records of patients who visited the pediatric neurology clinics with LGS as their primary complaint and completed intravenous methylprednisolone therapy were reviewed. Effects of steroid therapy on clinical seizures and scalp EEG were analyzed. Generalized paroxysmal fast activity (GPFA) burden were detected and compared before and after treatment. As a measure of global functional connectivity, we calculated mutual information (MI) between all channels, which was then used to assess network topology.

RESULTS

Steroid pulse therapy improved seizure control in 20 (27 %) patients. Fourteen (18.9 %) children became complete seizure-free, but 8 patients experienced relapses subsequently. The later age of disease onset, shorter duration of epilepsy, and definite cerebral structural etiology were found to advantageous for hormone response. A significant correlation was observed between GPFA burden and diary seizure number. Patients with higher GPFA burdens and higher MI values exhibited a poor response to steroid treatment. Patients who respond positively to steroids therapy demonstrated longer characteristic path length, higher modularity and lower global efficiency in high beta and gamma bands.

CONCLUSION

Add-on steroid therapy can be considered as an optional adjunct for LGS. GPFA could be utilized as a parameter to predict treatment effects and prognosis for LGS. The group that responded to steroids showed a high level of local clustering and low long-range network connectivity. This study provides real-world evidence regarding the effectiveness of steroid in refractory LGS.

What is the impact of etiology, lead time to treatment, and parental awareness on outcomes in infantile epileptic spasm syndrome?

OBJECTIVE

Infantile epileptic spasm syndrome (IESS) is a kind of developmental epileptic encephalopathy that can lead to severe outcomes, including drug-resistant epilepsy and impaired neurodevelopment. The underlying etiology, early diagnosis, and adequate treatment impact the outcome. Our study focused on examining the factors that influence the prognosis and the level of knowledge among families regarding IESS.

METHODS

In the Department of Pediatric Neurology at Gazi University Hospital, we examined 62 IESS children's demographics, neuroimaging, metabolic and genetic findings, seizure characteristics, treatment choices, and long-term outcomes. Our study examined family awareness of seizures, lead time to treatment(LTT), and their impact on prognosis.

RESULTS

Forty-two (67.8 %) patients presented with a symptomatic cause, with over half experiencing intraventricular hemorrhage and/or periventricular leukomalacia attributable to prematurity. The hormonal therapy (tetracosactide or oral prednisolone) was the preferred treatment. Treatment was effective for two-thirds of the patients. Nevertheless, hardly 50 % of the families acknowledged the "event" as a seizure. However, 34 (61 %) individuals had sought medical advice from a doctor during the first seven days. The mean time from the start of seizures to seeking medical care was 9.2 ± 5.7 days.

CONCLUSION

Our research revealed that the etiology was the most significant factor influencing the long-term outcomes of IESS. Additionally, we demonstrated that the clinicians who initially encountered the patients promptly referred them to pediatric neurology departments, despite the fact that the families' seizure awareness was poor. To help prevent this circumstance, it is important to provide information about infantile spasms to the families of high-risk infants.

Etiology-specific subgroup analysis of initial pharmacotherapy in infantile epileptic spasm syndrome: A single-center cohort study

AIM

To evaluate the efficacy of initial pharmacotherapy for infantile epileptic spasm syndrome (IESS) with electro-clinical outcome characteristics.

METHOD

A retrospective comparative cohort study with 280 IESS patients was designed; I. vigabatrin monotherapy (n = 129, 46 %); II. hormonotherapy (ACTH/oral prednisolone) (n = 73, 26 %); and III. vigabatrin plus early initiation of hormonotherapy in the first 14 days (n = 78, 28 %). Two types of outcomes were defined: (1) short-term outcome with spasm cessation time ≤42 days and resolution of hypsarrhythmia on the EEG on ≤3 months and (2) long-term outcome with spasm relapse rate or evolution to a new epileptic syndrome.

RESULTS

The etiology-specific diagnoses of the IESS cohort were defined according to the ILAE classification: structural (n = 131, 46.8 %), genetic (n = 28, 10 %), metabolic (n = 13, 4.6 %), immune-infectious (n = 10, 3.6 %), and unknown (n = 98, 35 %). Each treatment modalities had similar short- and long-term outcome characteristics. However, hormonotherapy with steroids (ACTH/oral prednisolone) provided "early IESS resolution" with spasm cessation and resolution of hypsarrhythmia (p = 0.042). The relapse rates of IESS were significantly higher in the etiology well-defined group compared to the unknown group (p = 0.005). The genetic-etiology specific group was more likely to have evolved to a new electro-clinical syndrome with a rate of 83.3 % than the others (p = 0.039).

CONCLUSION

We observed that the early initiation of hormonotherapy with VGB (sequential therapy) should be investigated in etiology well-defined subgroup with short- and long-term outcome characteristics.

Diagnostic yields of genetic testing and related benefits in infantile epileptic spasms syndrome: A systematic review and meta-analysis

BACKGROUND

Diagnostic yields for infantile epileptic spasms syndrome (IESS) are notably heterogeneous across different testing modalities and studies. To investigate the proportion of individuals with IESS harboring causative/pathogenic genetic variants identified using whole-exome sequencing (WES), multi-gene panels (MGPs), and chromosomal microarray (CMA), thereby providing evidence to inform guidelines for genetic testing strategies.

METHODS

The study team searched PubMed, Embase, and Cochrane Central Register of Controlled Trials between January 2012- October2023. Data were extracted and synthesized by two investigators following the preferred reporting items for systematic reviews and meta-analyses guideline. The primary outcome was the pooled diagnostic rate of individual WES, MGPs, and CMA across studies. Subgroup analyses were performed based on the inclusion of cases with tuberous sclerosis complex and the number of genes included on MGPs.

RESULTS

Our study included 30 studies, involving 2 738 participants. The diagnostic rates in IESS for WES (13 studies, n = 799), MGPs (13 studies, n = 1 117), and CMA (13 studies, n = 629) were 26 % (95 % CI = 21 %-31 %), 20 % (95 % CI = 15 %-27 %), and 14 % (95 % CI = 11 %-16 %), respectively. WES and MGPs showed comparable diagnostic yields (P = 0.34). Our results indicated that 61.6 % of individuals with genetic IESS may potentially benefit from genetic diagnosis in terms of clinical management.

CONCLUSIONS

Our results showed that WES and MGPs exhibited comparable genetic diagnostic yields. Therefore, either method could be equally recommended as a first-tier testing approach for IESS cases with suspected genetic or unknown etiologies, especially considering the potential clinical benefits derived from genetic diagnosis.

A Multicenter Retrospective Observational Cohort Study of Seizure Freedom before Lennox-Gastaut Syndrome (the "Gap"). Opportunities for Prevention

Objective

Lennox-Gastaut Syndrome (LGS) is a severe, often treatment-resistant epilepsy syndrome typically diagnosed in early childhood. Many have seizures before diagnosis. Some have periods of seizure freedom before treatment resistance, i.e., a "gap." Review of these gaps may identify early candidate biomarkers of LGS and/or highlight opportunities for intervention.

Methods

We reviewed charts of children diagnosed with LGS born in 2008-2010 and diagnosed with LGS by 2014 at five academic medical centers in New York City using the RENYC (Rare Epilepsies in New York City) database. We collected dates of events of potential biomarkers by chart abstraction, including onset of slow spike-and-wave (SSW) and onset and offset of seizure freedom. Seizure-free periods ("gaps") were defined as greater than 30 days without unprovoked seizures.

Results

Thirty-three children had LGS (52% male; etiology 33% structural-acquired, 6% structural-congenital, 3% genetic-structural, 24% genetic, 33% unknown). Twenty-two (67%) had a gap before diagnosis. Eight of these twenty-two (36%) had SSW described before the gap, five (23%) during the gap, and six (27%) after the gap. A history of infantile epileptic spasms syndrome (IESS), age at seizure onset, and age of tonic seizure onset were not different between those with and without a gap. Of 20 (61%) with a history of IESS, 10 (30% of the full cohort) had not received recommended therapy (i.e., ACTH, prednisolone, or vigabatrin) as first-line treatment.

Conclusions

The appearance of SSW, even in seizure-free children, may herald the development of LGS in high-risk children. Further studies on its predictive value are warranted. Our findings also highlight use of recommended first-line therapy for infantile spasms as a potentially modifiable treatment gap in children who subsequently develop LGS.

Therapeutic implications of etiology-specific diagnosis of early-onset developmental and epileptic encephalopathies (EO-DEEs): A nationwide Turkish cohort study

OBJECTIVE

To evaluate the etiology-specific diagnosis of early-onset developmental epileptic encephalopathies (EO-DEEs) in a nationwide Turkish cohort to determine the implications for therapeutic management.

METHODS

The cohort comprised 1450 patients who underwent EO-DEE. The utility of genetic testing was assessed with respect to the initial phases of next generation sequencing (NGS) (2005-2013) and the current NGS era (2014-2022). A predefined four-stepwise diagnostic model was evaluated using cost-effectiveness analysis. The diagnostic and potential therapeutic yields of the genetic tests were subsequently determined.

RESULTS

Gene-related EO-DEEs were identified in 48.3 % (n = 701) of the cohort: non-structural genetic (62.6 %), metabolic genetic (15.1 %), and structural genetic (14.1 %). The most common nonstructural genetic variants were SCN1A (n = 132, 18.8 %), CDKL5 (n = 30, 4.2 %), STXBP1 (n = 21, 2.9 %), KCNQ2 (n = 21, 2.9 %), and PCDH19 (n = 17, 2.4 %). The rate of ultra-rare variants (< 0.5 %) was higher in the NGS era (52 %) than that in the initial phase (36 %). The potential therapeutic yields with precision therapy and antiseizure drug modification were defined in 34.5 % and 56.2 % in genetic-EO-DEEs, respectively. The diagnostic model provided an etiology-specific diagnosis at a rate of 78.7 %: structural (nongenetic) (31.4 %), genetic (38.5 %), metabolic (6.1 %), and immune-infectious (2.8 %). Based on a cost-effectiveness analysis, the presented diagnostic model indicated the early implementation of whole-exome sequencing for EO-DEEs.

SIGNIFICANCE

In the present cohort, the higher rate (48.3 %) of gene-related EO-DEE diagnoses in the NGS era provides a potential therapeutic management plan for more patients.

Clinical signatures of genetic epilepsies precede diagnosis in electronic medical records of 32,000 individuals

PURPOSE

An early genetic diagnosis can guide the time-sensitive treatment of individuals with genetic epilepsies. However, most genetic diagnoses occur long after disease onset. We aimed to identify early clinical features suggestive of genetic diagnoses in individuals with epilepsy through large-scale analysis of full-text electronic medical records.

METHODS

We extracted 89 million time-stamped standardized clinical annotations using Natural Language Processing from 4,572,783 clinical notes from 32,112 individuals with childhood epilepsy, including 1925 individuals with known or presumed genetic epilepsies. We applied these features to train random forest models to predict SCN1A-related disorders and any genetic diagnosis.

RESULTS

We identified 47,774 age-dependent associations of clinical features with genetic etiologies a median of 3.6 years before molecular diagnosis. Across all 710 genetic etiologies identified in our cohort, neurodevelopmental differences between 6 to 9 months increased the likelihood of a later molecular diagnosis 5-fold (P < .0001, 95% CI = 3.55-7.42). A later diagnosis of SCN1A-related disorders (area under the curve [AUC] = 0.91) or an overall positive genetic diagnosis (AUC = 0.82) could be reliably predicted using random forest models.

CONCLUSION

Clinical features predictive of genetic epilepsies precede molecular diagnoses by up to several years in conditions with known precision treatments. An earlier diagnosis facilitated by automated electronic medical records analysis has the potential for earlier targeted therapeutic strategies in the genetic epilepsies.

Effectiveness of vigabatrin for infantile epileptic spasm syndrome categorized by etiologies

PURPOSE

We aimed to assess the effectiveness of vigabatrin (VGB) in patients diagnosed with infantile epileptic spasm syndrome (IESS) and categorize these patients based on their etiologies.

METHODS

This retrospective study included patients diagnosed with IESS who exhibited epileptic spasms before the age of 2 years between January 1, 2015, and October 31, 2023 at Saitama Children's Medical Center. Patients with tuberous sclerosis as the identified etiology were excluded. The effectiveness of VGB was assessed based on the resolution of ES for three months with the absence of hypsarrhythmia on interictal electroencephalogram.

RESULTS

This study analyzed 41 patients (26 boys). The etiologies included genetic, congenital structural, acquired structural, and unknown in 12, 11, 10, and 8 patients, respectively. Patient characteristics did not significantly differ among the four groups. The overall effectiveness of VGB for IESS was 39.0 % (16/41). Categorized based on etiology, VGB was effective in 41.7 % (5/12), 9.1 % (1/11), 50 % (5/10), and 75 % (6/8) in the genetic, congenital structural, acquired structural, and unknown groups, respectively. Statistical analysis revealed a significant difference in effectiveness among the four groups (p = 0.03). Categorized based on diseases, VGB was effective in 28.6 % (2/7) and 50 % (4/8) in trisomy 21 and perinatal brain injury, respectively.

CONCLUSION

The effectiveness of VGB in patients with IESS varied with etiology. Further investigations into the effectiveness of VGB in etiological subtypes of IESS could facilitate the development of tailored treatment algorithms for each etiology, representing valuable guidelines for future medical practice.

Diagnostic evaluation of patients with epileptic spasms in the era of next-generation sequencing

OBJECTIVE

Epileptic spasms (ES) can be caused by a variety of etiologies. However, in almost half of cases, the etiology is unidentified. With the advent of next-generation sequencing (NGS), the recognition of genetic etiologies has increased.

METHODS

We retrospectively reviewed the medical records of patients with ES who were evaluated in the comprehensive epilepsy program at King Fahad Specialist Hospital Dammam between 2009 and 2022.

RESULTS

Our data show that in 57.7% of patients with ES, the etiology was unidentified after a standard clinical evaluation and neuroimaging. Of these patients, n = 25 (35.2%) received a genetic diagnosis after some form of genetic testing, and 3.1% of patients from specialized metabolic work indicated the need for genetic testing to confirm the diagnosis. Karyotyping led to a diagnosis in 3.6% of patients, and chromosomal microarray led to a diagnosis in 7.1%. An NGS epilepsy gene panel (EP) was done for 45 patients, leading to a diagnosis in 24.4% (n = 11). Exome sequencing was done for 27 patients, including n = 14 with non-diagnostic panel testing; it led to a diagnosis in 37.3% (n = 10). Exome sequencing led to a diagnosis in 61.5% of patients without a previous panel test and in only two patients who had previously had a negative panel testing.

SIGNIFICANCE

In this article, we present the diagnostic evaluations of ES for a cohort of 123 patients and discuss the yield and priority of NGS for evaluating ES. Our findings suggest that exome sequencing has a higher diagnostic yield for determining the etiology of ES in patients for whom the etiology is still unclear after an appropriate clinical assessment and a brain MRI.

Copy Number Variation and Epilepsy: State of the Art in the Era of High-Throughput Sequencing-A Multicenter Cohort Study

BACKGROUND

Genetic epilepsy diagnosis is increasing due to technological advancements. Although the use of molecular diagnosis is increasing, chromosomal microarray analysis (CMA) remains an important diagnostic tool for many patients. We aim to explore the role and indications of CMA in epilepsy, given the current genomic advances.

METHODS

We obtained data from 378 epileptic described patients, who underwent CMA between 2015 and 2021. Different types of syndromic or nonsyndromic epilepsy were represented.

RESULTS

After excluding patients who were undertreated or had missing data, we included 250 patients with treated epilepsy and relevant clinical information. These patients mostly had focal epilepsy or developmental and epileptic encephalopathy, with a median start age of 2 years. Ninety percent of the patients had intellectual disability, more than two thirds had normal head size, and 60% had an abnormal magnetic resonance imaging. We also included 10 patients with epilepsy without comorbidities. In our cohort, we identified 35 pathogenic copy number variations (CNVs) explaining epilepsy with nine recurrent CNVs enriched in patients with epilepsy, 12 CNVs related to neurodevelopmental disorder phenotype with possible epilepsy, five CNVs including a gene already known in epilepsy, and nine CNVs based on size combined with de novo occurrence. The diagnosis rate in our study reached 14% (35 of 250) with first-line CMA, as previously reported. Although targeted gene panel sequencing could potentially diagnose some of the reported epilepsy CNVs (34% [12 of 35]).

CONCLUSIONS

CMA remains a viable option as the first-line genetic test in cases where other genetic tests are not available and as a second-line diagnostic technique if gene panel or exome sequencing yields negative results.

The Utility of Genetic Testing in Infantile Epileptic Spasms Syndrome: A Step-Based Approach in the Next-Generation Sequencing Era

BACKGROUND

To evaluate the utility of genetic testing for etiology-specific diagnosis (ESD) in infantile epileptic spasms syndrome (IESS) with a step-based diagnostic approach in the next-generation sequencing (NGS) era.

METHODS

The study cohort consisted of 314 patients with IESS, followed by the Pediatric Neurology Division of Ege University Hospital between 2005 and 2021. The ESD was evaluated using a step-based approach: step I (clinical phenomenology), step II (neuroimaging), step III (metabolic screening), and step IV (genetic testing). The diagnostic utility of genetic testing was evaluated to compare the early-NGS period (2005 to 2013, n = 183) and the NGS era (2014 to 2021, n = 131).

RESULTS

An ESD was established in 221 of 314 (70.4%) infants with IESS: structural, 40.8%; genetic, 17.2%; metabolic, 8.3%; immune-infectious, 4.1%. The diagnostic yield of genetic testing increased from 8.9% to 41.7% in the cohort during the four follow-up periods. The rate of unknown etiology decreased from 34.9% to 22.1% during the follow-up periods. The genetic ESD was established as 27.4% with genetic testing in the NGS era. The genetic testing in the NGS era increased dramatically in subgroups with unknown and structural etiologies. The diagnostic yields of the epilepsy panels increased from 7.6% to 19.2%. However, the diagnostic yield of whole exome sequencing remained at similar levels during the early-NGS period at 54.5% and in the NGS era at 59%.

CONCLUSIONS

The more genetic ESD (27.4%) was defined for IESS in the NGS era with the implication of precision therapy (37.7%).

Clinical features and underlying etiology of children with Lennox-Gastaut syndrome

OBJECTIVE

Lennox-Gastaut Syndrome (LGS) is characterized by the presence of multiple seizure types and encompasses a heterogenous group of etiologies. The aim of our study was to evaluate the etiological profile of LGS and investigate seizure outcomes based on different clinical variables.

METHODS

The clinical features, neuroimaging findings, genetic testing and other testing results of LGS patients were systematically reviewed. The identifiable etiology was categorized as either acquired or nonacquired. Univariate and multivariate regression analyses were performed to explore the association between clinical variables and seizure outcome at the last follow-up.

RESULTS

We enrolled 156 patients diagnosed with LGS, of whom 66% were male. The mean age of patients was 34.2 months and the median follow-up duration was 29.5 months (interquartile range = 14-56.25 months). The initial seizure type was epileptic spasm in 61 patients, among which 33 of them met the criteria for infantile epileptic spasm syndrome. All patients underwent neuroimaging test, with 25% falling into the acquired structural category. Etiology could be identified in 84 individuals, including pathogenetic variants found in 34 out of 117 patients with nonacquired etiology. CHD2 mutations were most frequently observed among these pathogenetic variants. At the last follow-up, favorable outcomes were observed in 27 patients. The identification of etiology emerged as a significant determinant influencing LGS outcome; specifically, patients with unknown etiology had a higher likelihood of experiencing favorable outcomes compared to those with known cause (p = 0.041). Early onset age and longer epilepsy duration significantly increased the odds of an unfavorable outcome (p = 0.006 and 0.024).

SIGNIFICANCE

We present novel data on the clinical and etiological spectrum of LGS, with determined etiology observed in over half of the patients. Epileptic spasms were found to be more prevalent than tonic seizures as seizure onset types in LGS. The presence of a known etiology, earlier age at onset, and longer duration of epilepsy were associated with a poorer long-term epileptological outcome.

Novel copy number variations and phenotypes of infantile epileptic spasms syndrome

We summarize the copy number variations (CNVs) and phenotype spectrum of infantile epileptic spasms syndrome (IESS) in a Chinese cohort. The CNVs were identified by genomic copy number variation sequencing. The CNVs and clinical data were analyzed. 74 IESS children with CNVs were enrolled. 35 kinds of CNVs were identified. There were 11 deletions and 5 duplications not reported previously in IESS, including 2 CNVs not reported in epilepsy. 87.8% were de novo, 9.5% were inherited from mother and 2.7% from father. Mosaicism occurred in one patient with Xq21.31q25 duplication. 16.2% (12/74) were 1p36 deletion, and 20.3% (15/74) were 15q11-q13 duplication. The age of seizure onset ranged from 17 days to 24 months. Seizure types included epileptic spasms, focal seizures, tonic seizures, and myoclonic seizures. All patients displayed developmental delay. Additional features included craniofacial anomaly, microcephaly, congenital heart defects, and hemangioma. 29.7% of patients were seizure-free for more than 12 months, and 70.3% still had seizures after trying 2 or more anti-seizure medications. In conclusion, CNVs is a prominent etiology of IESS. 1p36 deletion and 15q duplication occurred most frequently. CNV detection should be performed in patients with IESS of unknown causes, especially in children with craniofacial anomalies and microcephaly.

Three Patients of the Early Onset Epileptic Spasms without Hypsarrhythmia

Epileptic spasms without hypsarrhythmia occur when patients do not display hypsarrhythmia on electroencephalogram (EEG) at the onset and throughout the clinical course. We report three patients of epileptic spasms in patients with early onset, all of whom experienced other types of seizures.We detail three patients (two boys and one girl) of epileptic spasms without hypsarrhythmia, occurring between 1 and 3 months of age, with no abnormalities detected on neurometabolic analysis and brain magnetic resonance imaging. Long-term video-EEG monitoring revealed epileptic spasms with focal onset seizures in two patients, and epileptic spasms followed by generalized tonic-clonic seizures in one patient. Hypsarrhythmia was never observed in repeated EEG examinations. Two patients achieved seizure freedom and improved development through treatment with topiramate alone or in combination with valproate, without requiring hormonal therapies or vigabatrin. The remaining patient achieved seizure freedom following administration of antiseizure medications, including topiramate, after a trial of adrenocorticotropic hormone therapy.We report the cases of three patients with early onset epileptic spasms without hypsarrhythmia. All patients achieved seizure freedom after topiramate treatment. Topiramate may be considered as a relatively effective antiseizure medication for early onset epileptic spasms without hypsarrhythmia.

Exhaustive clinical examination of etiology and initial response to first-line treatment in 577 children with infantile epileptic spasm syndrome children: A 5-year retrospective observational study

OBJECTIVE

Employing whole-exome sequencing (WES) technology to investigate the etiology of infantile epileptic spasm syndrome (IESS), and determining whether different etiologies exhibit phenotypic variations, while elucidating the potential associated factors, might improve short-term responses to first-line treatment.

METHODS

We retrospectively evaluated patients with IESS admitted for treatment between January 2018 and June 2023. Clinical phenotypic differences among etiological classifications and clinical manifestations were analyzed. Variable selection using the best subset method was performed, followed by logistic regression analysis to identify the factors influencing treatment response.

RESULTS

A total of 577 patients were included; 412 completed trio-WES. Magnetic resonance imaging abnormalities were detected in 387 patients (67.1%). Patients with etiology as structural abnormalities were likelier to have non-spasms at the initial seizure onset. A total of 532 patients completed the first-line treatment; 273 patients received it for the first time at our hospital (initial response rates: 30.1% and 42.1%, respectively). The response group had a lower proportion of early-onset seizures (≤3 months) than the no-response group (11.3% vs. 23.7%, p < 0.01 and 11.3% vs. 21.5%, p = 0.03, respectively). Logistic regression analysis indicated that earlier initiation of first-line treatment was associated with a higher likelihood of an initial response. However, the etiological classification did not have a significant impact on the initial response.

INTERPRETATION

IESS patients with structural abnormalities are more likely to present with non-spasm seizures at initial onset. Early initiation of first-line treatment is crucial; however, initial responses may be less favorable when seizures occur in early infancy.

Identification and treatment of surgically-remediable causes of infantile epileptic spasms syndrome

INTRODUCTION

Infantile epileptic spasms syndrome (IESS) is a common developmental and epileptic encephalopathy with poor long-term outcomes. A substantial proportion of patients with IESS have a potentially surgically remediable etiology. Despite this, epilepsy surgery is underutilized in this patient group. Some surgically remediable etiologies, such as focal cortical dysplasia and malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE), are under-diagnosed in infants and young children. Even when a surgically remediable etiology is recognised, for example, tuberous sclerosis or focal encephalomalacia, epilepsy surgery may be delayed or not considered due to diffuse EEG changes, unclear surgical boundaries, or concerns about operating in this age group.

AREAS COVERED

In this review, the authors discuss the common surgically remediable etiologies of IESS, their clinical and EEG features, and the imaging techniques that can aid in their diagnosis. They then describe the surgical approaches used in this patient group, and the beneficial impact that early epilepsy surgery can have on developing brain networks.

EXPERT OPINION

Epilepsy surgery remains underutilized even when a potentially surgically remediable cause is recognized. Overcoming the barriers that result in under-recognition of surgical candidates and underutilization of epilepsy surgery in IESS will improve long-term seizure and developmental outcomes.

Interictal EEG features as computational biomarkers of West syndrome

BACKGROUND

West syndrome (WS) is a devastating epileptic encephalopathy with onset in infancy and early childhood. It is characterized by clustered epileptic spasms, developmental arrest, and interictal hypsarrhythmia on electroencephalogram (EEG). Hypsarrhythmia is considered the hallmark of WS, but its visual assessment is challenging due to its wide variability and lack of a quantifiable definition. This study aims to analyze the EEG patterns in WS and identify computational diagnostic biomarkers of the disease.

METHOD

Linear and non-linear features derived from EEG recordings of 31 WS patients and 20 age-matched controls were compared. Subsequently, the correlation of the identified features with structural and genetic abnormalities was investigated.

RESULTS

WS patients showed significantly elevated alpha-band activity (0.2516 vs. 0.1914, p < 0.001) and decreased delta-band activity (0.5117 vs. 0.5479, p < 0.001), particularly in the occipital region, as well as globally strengthened theta-band activity (0.2145 vs. 0.1655, p < 0.001) in power spectrum analysis. Moreover, wavelet-bicoherence analysis revealed significantly attenuated cross-frequency coupling in WS patients. Additionally, bi-channel coherence analysis indicated minor connectivity alterations in WS patients. Among the four non-linear characteristics of the EEG data (i.e., approximate entropy, sample entropy, permutation entropy, and wavelet entropy), permutation entropy showed the most prominent global reduction in the EEG of WS patients compared to controls (1.4411 vs. 1.5544, p < 0.001). Multivariate regression results suggested that genetic etiologies could influence the EEG profiles of WS, whereas structural factors could not.

SIGNIFICANCE

A combined global strengthening of theta activity and global reduction of permutation entropy can serve as computational EEG biomarkers for WS. Implementing these biomarkers in clinical practice may expedite diagnosis and treatment in WS, thereby improving long-term outcomes.

Metabolic etiologies in children with infantile epileptic spasm syndrome: Experience at a tertiary pediatric neurology center

OBJECTIVE

Infantile epileptic spasm syndrome (IESS), including West syndrome (WS) and infantile spasm (IS), causes a challenging prognosis, particularly when associated with metabolic etiologies.

METHODS

This study, conducted at a tertiary pediatric neurology center, explored the prevalence and clinical features of inborn errors of metabolism in 112 children with IESS over 10 years.

RESULTS

Most patients presented with seizures, primarily flexor spasms, and the median age at onset was 5 months. Comprehensive clinical evaluation and neuroimaging revealed structural-acquired causes as the most common etiology. Notably, inborn errors of metabolism were identified in 5.4 % of cases, with six distinct diagnoses including nonketotic hyperglycinemia, pyridoxine-dependent epilepsy, primary coenzyme Q10 deficiency 7, congenital disorder of glycosylation type IIM, 6-pyruvoyl tetrahydrobiopterin synthase deficiency, and argininosuccinate lyase deficiency. The prevalence of inborn errors of metabolism in this cohort was consistent with global variations reported in the literature. Genetic testing, including karyotype analysis and whole exome sequencing, was performed in a subset of cases with no clear diagnosis, revealing abnormalities in approximately 50 % of cases. Adrenocorticotropic hormone emerged as the most frequently prescribed antiseizure medication.

CONCLUSION

This study provides insight into the diagnostic challenges associated with IESS and highlights the importance of metabolic investigations, especially in cases without a clear etiology. The findings emphasize the need for further genetic and metabolic studies to enhance prognostic accuracy and guide potential treatment options for children with IESS, particularly in populations with high rates of consanguinity.

Diagnosis and management of infantile epileptic spasms syndrome (IESS) in Gulf Cooperation Council (GCC) countries: Expert consensus statement

Despite the availability of international recommendations for the management of Infantile Epileptic Spasms Syndrome (IESS), there is a lack of recommendations adapted to the local context of clinical practice of pediatric neurology in the Gulf Cooperation Council (GCC) countries. By an initiative from the Saudi Pediatric Neurology Society (SPNS), a literature review was performed and an expert panel comprised of 13 pediatric neurologists from all GCC countries (Saudi Arabia, Kuwait, Bahrain, Oman, Qatar, and the United Arab Emirates) was subsequently convened to discuss all issues related to the management and diagnosis practices of IESS in the GCC. The overall aim of this consensus document was to develop practical recommendations to support the care of patients with IESS in the GCC and to reflect on how clinical management approaches compare with those adopted internationally.

Quantification of Hypsarrhythmia in Infantile Spasmatic EEG: A Large Cohort Study

Infantile spasms (IS) is a neurological disorder causing mental and/or developmental retardation in many infants. Hypsarrhythmia is a typical symptom in the electroencephalography (EEG) signals with IS. Long-term EEG/video monitoring is most frequently employed in clinical practice for IS diagnosis, from which manual screening of hypsarrhythmia is time consuming and lack of sufficient reliability. This study aims to identify potential biomarkers for automatic IS diagnosis by quantitative analysis of the EEG signals. A large cohort of 101 IS patients and 155 healthy controls (HC) were involved. Typical hypsarrhythmia and non-hypsarrhythmia EEG signals were annotated, and normal EEG were randomly picked from the HC. Root mean square (RMS), teager energy (TE), mean frequency, sample entropy (SamEn), multi-channel SamEn, multi-scale SamEn, and nonlinear correlation coefficient were computed in each sub-band of the three EEG signals, and then compared using either a one-way ANOVA or a Kruskal-Wallis test (based on their distribution) and the receiver operating characteristic (ROC) curves. The effects of infant age on these features were also investigated. For most of the employed features, significant ( ) differences were observed between hypsarrhythmia EEG and non-hypsarrhythmia EEG or HC, which seem to increase with increased infant age. RMS and TE produce the best classification in the delta and theta bands, while entropy features yields the best performance in the gamma band. Our study suggests RMS and TE (delta and theta bands) and entropy features (gamma band) to be promising biomarkers for automatic detection of hypsarrhythmia in long-term EEG monitoring. The findings of our study indicate the feasibility of automated IS diagnosis using artificial intelligence.

Clinical and electroencephalographic characteristics of 34 infant with onset of epileptic spasms before three months of age

Epileptic spasms (ES) occur mostly between age 3 months and 24 months. ES beginning before 3 months of age were called early-onset ES in previous studies. The aim of this study was to identify clinical and electroencephalographic characteristics of patients with ES onset before 3 months of age. In total, 34 ES patients were retrospectively identified at Children's Hospital of Chongqing Medical University from January 1, 2020 to October 1, 2022. Our patients had diverse etiologies, including genetic (32.3 %), genetic-structural (11.8 %), structural-acquired (11.8 %), structural-congenital (8.8 %), and metabolic (5.9 %), with 29.4 % of patients having unknown etiology. Some patients experienced ES in clusters (either symmetrical or flexional) that occurred most often during awakening after sleep, and a minority of ES were characterized as isolated or asymmetrical, occurred during sleep, and could also manifest as relatively subtle. Approximately 35.3 % of patients also experienced other seizure types concurrently, including 10 focal seizures and 2 generalized seizures, and only half of the focal seizures had structural causes. The other seizure types occurred alone or sequentially with ES. Interictal electroencephalography revealed hypsarrhythmia or its variants, multifocal discharge, or burst suppression. 18 patients had no seizures lasting for more than 2 months, however, at the last follow-up visit, 5 of them had relapsed. All patients had different degrees of psychomotor retardation.

Landscape of genetic infantile epileptic spasms syndrome-A multicenter cohort of 124 children from India

OBJECTIVE

Literature on the genotypic spectrum of Infantile Epileptic Spasms Syndrome (IESS) in children is scarce in developing countries. This multicentre collaboration evaluated the genotypic and phenotypic landscape of genetic IESS in Indian children.

METHODS

Between January 2021 and June 2022, this cross-sectional study was conducted at six centers in India. Children with genetically confirmed IESS, without definite structural-genetic and structural-metabolic etiology, were recruited and underwent detailed in-person assessment for phenotypic characterization. The multicentric data on the genotypic and phenotypic characteristics of genetic IESS were collated and analyzed.

RESULTS

Of 124 probands (60% boys, history of consanguinity in 15%) with genetic IESS, 105 had single gene disorders (104 nuclear and one mitochondrial), including one with concurrent triple repeat disorder (fragile X syndrome), and 19 had chromosomal disorders. Of 105 single gene disorders, 51 individual genes (92 variants including 25 novel) were identified. Nearly 85% of children with monogenic nuclear disorders had autosomal inheritance (dominant-55.2%, recessive-14.2%), while the rest had X-linked inheritance. Underlying chromosomal disorders included trisomy 21 (n = 14), Xq28 duplication (n = 2), and others (n = 3). Trisomy 21 (n = 14), ALDH7A1 (n = 10), SCN2A (n = 7), CDKL5 (n = 6), ALG13 (n = 5), KCNQ2 (n = 4), STXBP1 (n = 4), SCN1A (n = 4), NTRK2 (n = 4), and WWOX (n = 4) were the dominant single gene causes of genetic IESS. The median age at the onset of epileptic spasms (ES) and establishment of genetic diagnosis was 5 and 12 months, respectively. Pre-existing developmental delay (94.3%), early age at onset of ES (<6 months; 86.2%), central hypotonia (81.4%), facial dysmorphism (70.1%), microcephaly (77.4%), movement disorders (45.9%) and autistic features (42.7%) were remarkable clinical findings. Seizures other than epileptic spasms were observed in 83 children (66.9%). Pre-existing epilepsy syndrome was identified in 21 (16.9%). Nearly 60% had an initial response to hormonal therapy.

SIGNIFICANCE

Our study highlights a heterogenous genetic landscape and phenotypic pleiotropy in children with genetic IESS.

Clinical and biochemical footprints of inherited metabolic diseases. XV. Epilepsies

We provide a comprehensive overview of inherited metabolic disorders (IMDs) in which epilepsy is a prominent manifestation. Our unique database search has identified 256 IMDs associated with various types of epilepsies, which we classified according to the classic pathophysiology-based classification of IMDs, and according to selected seizure-related factors (neonatal seizures, infantile spasms, myoclonic seizures, and characteristic EEG patterns) and treatability for the underlying metabolic defect. Our findings indicate that inherited metabolic epilepsies are more likely to present in the neonatal period, with infantile spasms or myoclonic seizures. Additionally, the ∼20% of treatable inherited metabolic epilepsies found by our search were mainly associated with the IMD groups of "cofactor and mineral metabolism" and "Intermediary nutrient metabolism." The information provided by this study, including a comprehensive list of IMDs with epilepsy stratified according to age of onset, and seizure type and characteristics, along with an overview of the key clinical features and proposed diagnostic and therapeutic approaches, may benefit any epileptologist and healthcare provider caring for individuals with metabolic conditions.

The Effect of Smartphone Video on Lead Time to Diagnosis of Infantile Spasms

OBJECTIVE

To assess whether access to smartphone video capture of infantile spasms at initial presentation is associated with improved time to diagnosis and treatment.

METHODS

We conducted a collaborative retrospective cohort study of 80 consecutive infants with confirmed infantile epileptic spasms syndrome initially presenting from 2015 to 2021 at 2 US pediatric centers. Statistical methods used included Mann-Whitney U test to assess the difference in lead times to electroencephalogram (EEG), diagnosis, and treatment between groups with and without video capture. A χ2 analysis was used to assess differences in demographics, clinical characteristics, and treatment outcomes between groups. Multivariate regression analysis was used to account for etiology types and infantile spasms capture on EEG.

RESULTS

Patients with smartphone video infantile spasms capture initially presented a median of 9 days earlier (P = .02), had their first EEG 16 days earlier (P = .007), and were diagnosed and started treatment 17 days earlier (P = .006 and P = .008, respectively) compared with the nonvideo group. The video group had a 25% greater response to initial standard treatment (P = .02) and a 21% greater freedom from infantile spasms at long-term follow-up (P = .03), although this long-term outcome lost statistical significance after adjustment for etiology type (P = .07) and EEG capture of infantile spasms (P = .059).

CONCLUSION

Our findings suggest a benefit of smartphone video capture of infantile spasms in reduced time to diagnosis and initial standard treatment, which are associated with improved treatment response rates. Substantial differences in lead times and treatment response highlight the clinical importance of pediatricians recommending caregivers to obtain smartphone video of events concerning for infantile spasms.

The landscape of infantile epileptic spasms syndrome in South Asia: peculiarities, challenges, and way forward

Infantile Epileptic Spasms Syndrome (IESS), commonly known as West syndrome, is the most common cause of infantile-onset epileptic encephalopathy. There is a peculiar epidemiological profile of IESS in South Asia. Specific features identified were a preponderance of acquired structural aetiology, male gender dominance, a long treatment lag, limited availability of adrenocorticotropic hormone (ACTH) and vigabatrin, and use of carboxymethyl cellulose derivative of ACTH. Because of the significant disease burden and limited resources, there are distinctive challenges to the optimal care of children with IESS in the South Asian region. Also, there are unique opportunities to bridge these challenges and improve outcomes. This review provides an overview of the landscape of IESS in South Asia and highlights its peculiarities, various challenges, and way forward.

Epileptic spasms: A South African overview of aetiologies, interventions, and outcomes

AIM

To better understand the aetiologies of epileptic spasms in infants, as well as the safety and efficacy of high dose corticosteroids in tuberculosis and human immunodeficiency virus (HIV) endemic resource-limited settings.

METHOD

This was a retrospective analysis of infants with epileptic spasms managed at the tertiary referral centres in the Western Cape, South Africa.

RESULTS

Of 175 children with epileptic spasms, the median age at onset was 6 months (interquartile range 4-8 months). Structural aetiologies were most common (115 out of 175 [66%]), with two-thirds related to perinatal insults. A lead time to treatment (LTTT) of less than 1 month was more likely in the epileptic encephalopathy/developmental and epileptic encephalopathy (DEE) group: 58 out of 92 (63%), compared to 28 out of 76 (37%) of those with developmental encephalopathy (p = 0.001). Failure to recognize preceding developmental delay was common. Ninety-nine children (57%) received first line hormonal therapy such as adrenocorticotropic hormone. A total of 111 out of 172 children (65%) from the developmental encephalopathy and epileptic encephalopathy/DEE groups had clinical and/or electroencephalogram resolution of spasms within 14 days. In our population, children in whom an aetiology could not be identified were statistically more likely to have moderate to profound developmental delay at 1 year of age: 33 out of 44 (p = 0.001). Based on reported incidence of epileptic spasms, 23 to 58 cases per annum would be expected but a far smaller proportion presented to our centres.

INTERPRETATION

Whilst this is the largest cohort of infants with epileptic spasms from sub-Saharan Africa, the study size is less than expected; this may reflect misdiagnosis and failure of referral pathways. Despite a reported shorter LTTT, infants with DEE had worse developmental outcomes compared to international studies. Hormonal therapy was safe and effective in our setting, despite exposure to high levels of tuberculosis and HIV.

WHAT THIS PAPER ADDS

The number of unreferred cases of epileptic spasms in South Africa remains high. Caregivers and health care workers in primary care facilities often fail to recognize developmental delay. The burden of disease from hypoxic-ischaemic encephalopathy remains high in our resource-limited setting. Hormonal treatment (e.g. adrenocorticotropic hormone) was safe and effective despite the high prevalence of human immunodeficiency virus and tuberculosis.

The Epilepsy Surgery Experience in Children With Infantile Epileptic Spasms Syndrome at a Tertiary Care Center in Canada

BACKGROUND

Infantile epileptic spasms syndrome is an epileptic encephalopathy, characterized by spasms, hypsarrhythmia, and developmental regression. Appropriately selected patients with infantile epileptic spasms syndrome may be candidates for epilepsy surgery.

METHODS

This is a single-center retrospective case series of children 0-18 years with a current or previous diagnosis of infantile epileptic spasms syndrome with a lesion on magnetic resonance imaging (MRI) and/or positron emission tomography scan who underwent epilepsy surgery at The Hospital for Sick Children (HSC) in Toronto, Canada. The records of 223 patients seen in the infantile epileptic spasms syndrome clinic were reviewed.

RESULTS

Nineteen patients met inclusion criteria. The etiology of infantile epileptic spasms syndrome was encephalomalacia in 6 patients (32%), malformations of cortical development in 12 patients (63%), and atypical hypoglycemic injury in 1 patient (5%). Nine patients (47%) underwent hemispherectomy, and 10 patients (53%) underwent lobectomy/lesionectomy. Three patients (16%) underwent a second epilepsy surgery. Fifteen patients (79%) were considered ILAE seizure outcome class 1 (completely seizure free; no auras) at their most recent follow-up visit. The percentage of patients who were ILAE class 1 at most recent follow-up decreased with increasing duration of epilepsy prior to surgery. Developmental outcome after surgery was improved in 14 of 19 (74%) and stable in 5 of 19 (26%) patients.

CONCLUSIONS

Our study found excellent seizure freedom rates and improved developmental outcomes following epilepsy surgery in patients with a history of infantile epileptic spasms syndrome with a structural lesion detected on MRI brain. Patients who undergo surgery earlier have improved seizure freedom rates and improved developmental outcomes.

Epileptic spasms related to neuronal differentiation factor 2 (NEUROD2) mutation respond to combined vigabatrin and high dose prednisolone therapy

BACKGROUND

Epileptic spasms are a devastating form of early infantile epileptic encephalopathy (EIEE) with various etiologies. Early diagnosis and a shorter lead time to treatment are crucial to stop the seizures and optimize the neurodevelopmental outcome. Genetic testing has become an integral part of epilepsy care that directly guides management and family planning and discovers new targeted treatments. Neuronal differentiation Factor 2 (NEUROD2) variants have recently been a cause of neurodevelopmental disorders (NDDs) and EIEEs with distinctive features. However, there is limited information about the clinical and electroencephalographic response of epileptic spasm treatment in NEUROD2-related NDD syndrome.

CASE PRESENTATION

We report a female patient of Southeast Asian ethnicity with global developmental delay and epileptic spasms commencing in the first few months of life. A novel de novo heterozygous pathogenic NEUROD2 variant, p. E130Q, was subsequently identified by whole-exome sequencing. Electroencephalogram before treatment showed multifocal independent spikes predominantly in both posterior head regions and demonstrated marked improvement following combined vigabatrin and high-dose prednisolone treatment. However, multiple courses of relapse occurred after weaning off the antiseizure medication.

CONCLUSIONS

We propose that epileptic spasms related to de novo NEUROD2 pathogenic variant respond well to combined vigabatrin and high-dose prednisolone therapy. These findings may imply the benefit of using combination therapy to treat epileptic spasms in NEUROD2-related NDD syndrome.

Neurobehavioral deficits and a progressive ictogenesis in the tetrodotoxin model of epileptic spasms

OBJECTIVE

Our goal was to determine whether animals with a history of epileptic spasms have learning and memory deficits. We also used continuous (24/7) long-term electroencephalographic (EEG) recordings to evaluate the evolution of epileptiform activity in the same animals over time.

METHODS

Object recognition memory and object location memory tests were undertaken, as well as a matching to place water maze test that evaluated working memory. A retrospective analysis was undertaken of long-term video/EEG recordings from rats with epileptic spasms. The frequency and duration of the ictal events of spasms were quantified.

RESULTS

Rats with a history of epileptic spasms showed impairment on the three behavioral tests, and their scores on the object recognition memory and matching to place water maze tests indicated neocortical involvement in the observed impaired cognition. Analysis of EEG recordings unexpectedly showed that the ictal events of spasms and their accompanying behaviors progressively increased in duration over a 2-week period soon after onset, after which spasm duration plateaued. At the same time, spasm frequency remained unchanged. Soon after spasm onset, ictal events were variable in wave form but became more stereotyped as the syndrome evolved.

SIGNIFICANCE

Our EEG findings are the first to demonstrate progressive ictogenesis for epileptic spasms. Furthermore, in demonstrating cognitive deficits in the tetrodotoxin model, we have met a criterion for an animal model of West syndrome. Animal models will allow in-depth studies of spasm progression's potential role in cognitive regression and may elucidate why early treatment is considered essential for improved neurodevelopmental outcomes in children.

Successful medical treatment of west syndrome with a KCNA2 variant: a case report

Background

West syndrome is a devastating disorder characterized by a triad of epileptic spasms, abnormal electroencephalography (EEG), and developmental arrest or psychomotor delay. In addition to early diagnosis, knowing the etiology of the condition is also important for its treatment. Among various etiologies, the genetic factors, especially mutations of ion channel genes, are very common and strongly linked to West syndrome.

Case presentation

A boy who had epileptic spasms from the age of 4 months was diagnosed with West syndrome based on the clinical manifestation and EEG results in Shenzhen Children’s Hospital in June 2019. Trios whole-exome sequencing (WES) test and protein structural model prediction were performed. We also reviewed the clinical and genetic features of this syndrome and the mechanisms of action of topiramate (TPM) by literature search in databases of Online Mendelian Inheritance in Man, Clinical Genome Resource, PubMed, Chinese National Knowledge Infrastructure and Wanfang database using keywords “KCNA2” “West syndrome” and “Topiramate” by December 2020. The relationship between the effect of TPM and the pathogenesis of the KCNA2 variant was also assessed. The WES test revealed c.244C > T/p. Arg82Cys varaint of KCNA2 (NM_004974.3) in this patient, and Sanger sequencing identified this was a de novo mutation. As far as we know, this is the first report of the c.244C > T/p. Arg82Cys variant in KCNA2, which was likely a pathogenic mutation. The seizures were successfully controlled for 10 months by TPM after failure of sodium valproate, large doses of vitamin B6, and adrenocorticotropic hormone. We speculate that the therapeutic effect of TPM in this patient is partially due to the inhibition of carbonic anhydrase.

Conclusions

Mutations in the KCNA2 gene should be considered for patients with West syndrome. The TPM treatment is probably effective for KCNA2-associated disorders.

A Role for Insulin-like Growth Factor 1 in the Generation of Epileptic Spasms in a murine model

OBJECTIVE

Infantile spasms are associated with a wide variety of clinical conditions, including perinatal brain injuries. We have created a model in which prolonged infusion of tetrodotoxin (TTX) into the neocortex, beginning in infancy, produces a localized lesion and reproduces the behavioral spasms, electroencephalogram (EEG) abnormalities, and drug responsiveness seen clinically. Here, we undertook experiments to explore the possibility that the growth factor IGF-1 plays a role in generating epileptic spasms.

METHODS

We combined long-term video EEG recordings with quantitative immunohistochemical and biochemical analyses to unravel IGF-1's role in spasm generation. Immunohistochemistry was undertaken in surgically resected tissue from infantile spasms patients. We used viral injections in neonatal conditional IGF-1R knock-out mice to show that an IGF-1-derived tripeptide (1-3)IGF-1, acts through the IGF-1 receptor to abolish spasms.

RESULTS

Immunohistochemical methods revealed widespread loss of IGF-1 from cortical neurons, but an increase in IGF-1 in the reactive astrocytes in the TTX-induced lesion. Very similar changes were observed in the neocortex from patients with spasms. In animals, we observed reduced signaling through the IGF-1 growth pathways in areas remote from the lesion. To show the reduction in IGF-1 expression plays a role in spasm generation, epileptic rats were treated with (1-3)IGF-1. We provide 3 lines of evidence that (1-3)IGF-1 activates the IGF-1 signaling pathway by acting through the receptor for IGF-1. Treatment with (1-3)IGF-1 abolished spasms and hypsarrhythmia-like activity in the majority of animals.

INTERPRETATION

Results implicate IGF-1 in the pathogenesis of infantile spasms and IGF-1 analogues as potential novel therapies for this neurodevelopmental disorder. ANN NEUROL 2022;92:45-60.

Whole-exome sequencing and adrenocorticotropic hormone therapy in individuals with infantile spasms

AIM

To identify additional genes associated with infantile spasms using a cohort with defined infantile spasms.

METHOD

Whole-exome sequencing (WES) was performed on 21 consented individuals with infantile spasms and their unaffected parents (a trio-based study). Clinical history and imaging were reviewed. Potentially deleterious exonic variants were identified and segregated. To refine potential candidates, variants were further prioritized on the basis of evidence for relevance to disease phenotype or known associations with infantile spasms, epilepsy, or neurological disease.

RESULTS

Likely pathogenic de novo variants were identified in NR2F1, GNB1, NEUROD2, GABRA2, and NDUFAF5. Suggestive dominant and recessive candidate variants were identified in PEMT, DYNC1I1, ASXL1, RALGAPB, and STRADA; further confirmation is required to support their relevance to disease etiology.

INTERPRETATION

This study supports the utility of WES in uncovering the genetic etiology in undiagnosed individuals with infantile spasms with an overall yield of five out of 21. High-priority candidates were identified in an additional five individuals. WES provides additional support for previously described disease-associated genes and expands their already broad mutational and phenotypic spectrum.

Assessing Risk for Relapse among Children with Infantile Spasms Using the Based Score after ACTH Treatment: A Retrospective Study

Introduction

Even though adrenocorticotropic hormone (ACTH) demonstrated powerful efficacy in the initially successful treatment of infantile spasms (IS), nearly one-half of patients whose spasms were once suppressed experienced relapse. There is currently no validated method for the prediction of the risk of relapse. The Burden of Amplitudes and Epileptiform Discharges (BASED) score is an electroencephalogram (EEG) grading scale for children with infantile spasms. We sought to determine whether an association exists between the BASED score after ACTH treatment and relapse after initial response with ACTH.

Methods

Children with IS who achieved initial response after ACTH treatment were selected as the study subjects. Those who experienced relapse within 12 months after ACTH treatment were categorized as the relapse group, and those who did not were categorized as the non-relapse group. Their general clinical data and EEG data (using BASED scoring) after ACTH treatment were collected, and compared between groups. Cox proportional hazards models were fit to determine factors associated with relapse.

Results

A total of 64 children with IS were enrolled in the study, of which 37 (57.8%) experienced a relapse, and the median duration after ACTH treatment was 3 (1.5, 6) months. The BASED score was significantly higher in the relapse group than in the non-relapse group. Cox modeling demonstrated that BASED score was independently associated with relapse. The patients with a score greater than or equal to 3 showed a high rate (89.3%) of relapse. The relapse group had stronger, more stable EEG functional networks than the non-relapse group, and there were obvious correlations between BASED score and functional connectivity.

Conclusion

This study suggests the BASED score after ACTH treatment has potential value as a predictor for relapse after initial response. Children with IS who have a BASED score greater than or equal to 3 after the initial response of ACTH carry a high risk of relapse within 1 year.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-022-00347-7.

Inequities in therapy for infantile spasms: a call to action

OBJECTIVE

To determine whether selection of treatment for children with infantile spasms (IS) varies by race/ethnicity.

METHODS

The prospective US National Infantile Spasms Consortium database includes children with IS treated from 2012-2018. We examined the relationship between race/ethnicity and receipt of standard IS therapy (prednisolone, adrenocorticotropic hormone, vigabatrin), adjusting for demographic and clinical variables using logistic regression. Our primary outcome was treatment course, which considered therapy prescribed for the first and, when needed, the second IS treatment together.

RESULTS

Of 555 children, 324 (58%) were Non-Hispanic white, 55 (10%) Non-Hispanic Black, 24 (4%) Non-Hispanic Asian, 80 (14%) Hispanic, and 72 (13%) Other/Unknown. Most (398, 72%) received a standard treatment course. Insurance type, geographic location, history of prematurity, prior seizures, developmental delay or regression, abnormal head circumference, hypsarrhythmia, and IS etiologies were associated with standard therapy. In adjusted models, Non-Hispanic Black children had lower odds of receiving a standard treatment course compared with Non-Hispanic white children (OR 0.42, 95% CI 0.20-0.89, p = 0.02). Adjusted models also showed that children with public (vs. private) insurance had lower odds of receiving standard therapy for treatment 1 (OR 0.42, CI 0.21-0.84, p = 0.01).

INTERPRETATION

Non-Hispanic Black children were more often treated with non-standard IS therapies than Non-Hispanic white children. Likewise, children with public (vs. private) insurance were less likely to receive standard therapies. Investigating drivers of inequities, and understanding the impact of racism on treatment decisions, are critical next steps to improve care for patients with IS. This article is protected by copyright. All rights reserved.

Multicenter Study of the Impact of COVID-19 Shelter-In-Place on Tertiary Hospital-based Care for Pediatric Neurologic Disease

Objective

To describe changes in hospital-based care for children with neurologic diagnoses during the initial 6 weeks following regional Coronavirus 2019 Shelter-in-Place orders.

Methods

This retrospective cross-sectional study of 7 US and Canadian pediatric tertiary care institutions included emergency and inpatient encounters with a neurologic primary discharge diagnosis code in the initial 6 weeks of Shelter-in-Place (COVID-SiP), compared to the same period during the prior 3 years (Pre-COVID). Patient demographics, encounter length, and neuroimaging and electroencephalography use were extracted from the medical record.

Results

27,900 encounters over 4 years were included. Compared to Pre-COVID, there was a 54% reduction in encounters during Shelter-in-Place. COVID-SiP patients were younger (median 5 years vs 7 years). The incidence of encounters for migraine fell by 72%, and encounters for acute diagnoses of status epilepticus, infantile spasms, and traumatic brain injury dropped by 53%, 55%, and 56%, respectively. There was an increase in hospital length of stay, relative utilization of intensive care, and diagnostic testing (long-term electroencephalography, brain MRI, and head CT (all P<.01)).

Conclusion

During the initial 6 weeks of SiP, there was a significant decrease in neurologic hospital-based encounters. Those admitted required a high level of care. Hospital-based neurologic services are needed to care for acutely ill patients. Precise factors causing these shifts are unknown and raise concern for changes in care seeking of patients with serious neurologic conditions. Impacts of potentially delayed diagnosis or treatment require further investigation.

Fifteen-minute consultation: The efficient investigation of infantile and childhood epileptic encephalopathies in the era of modern genomics

The investigation of children presenting with infantile and childhood epileptic encephalopathies (ICEE) is challenging due to diverse aetiologies, overlapping phenotypes and the relatively low diagnostic yield of MRI, electroencephalography (EEG) and biochemical investigations. Careful history and thorough examination remain essential as these may identify an acquired cause or indicate more targeted investigation for a genetic disorder. Whole exome sequencing (WES) with analysis of a panel of candidate epilepsy genes has increased the diagnostic yield. Whole genome sequencing (WGS), particularly as a trio with both parents' DNA, is likely to supersede WES. Modern genomic investigation impacts on the timing and necessity of other testing. We propose a structured approach for children presenting with ICEE where there is diagnostic uncertainty, emphasising the importance of WGS or, if unavailable, WES early in the investigative process. We note the importance of expert review of all investigations, including radiology, neurophysiology and biochemistry, to confirm the technique used was appropriate as well as the results. It is essential to counsel families on the risks associated with the procedures, the yield of the procedures, findings that are difficult to interpret and implication of 'negative' results. Where children remain without a diagnosis despite comprehensive investigation, we note the importance of ongoing multidisciplinary care.

Etiologic Classification of 541 Infantile Spasms Cases: A Cohort Study

OBJECTIVE

To explore the etiology of infantile spasms (IS) in a large Chinese cohort based on the United States National Infantile Spasms Consortium (NISC) classification.

METHODS

In the present study, we recruited IS patients diagnosed at a single center (Xiangya Hospital, Central South University) between Jan 2010 and Aug 2019. Thereafter, we collected their clinical and genetic information retrospectively. Their underlying etiologies were classified according to the NISC classification and then compared in different scenarios to understand their distribution.

RESULTS

A total of 541 patients with IS from 18 provinces were included in this study. The underlying etiology was identified in 53.2% of the cases: structural-acquired, 25.3%; genetic, 12.9%; genetic-structural, 7.2%; structural-congenital, 5.0%; metabolic, 2.4%; infections, 0.4% and immune, 0%. Whole-exome sequencing (WES) provided the highest diagnostic yield (26.9%). In structural-acquired IS, the proportion of hypoglycemic brain injuries was significant, second only to hypoxic-ischemic encephalopathy. There was no patient discovered to have Down syndrome. STXBP1, CDKL5, TSC2, KCNQ2, IRF2BPL, and TSC1 were the most frequently implicated genes. Genetic causes were found to be the most common cause of IS in the early onset group, while structural-acquired etiologies were common in males and preterm babies. Patients with pre-spasm seizures were associated with a higher proportion of identified causes than those without. Non-acquired structural etiologies were more common in patients without hypsarrhythmia than in those with hypsarrhythmia.

SIGNIFICANCE

The most prevalent cause of IS was structural acquired followed by genetic causes. When brain MRI fails to detect the etiology, we propose WES as the next step. Structural-acquired IS and cases with genetic disorders are characteristic of the Chinese cohort, however, the etiology differs with the patient's age of onset, gestation age at birth, sex, and the presence/absence of both pre-spasm seizures, and hypsarrhythmia.

Infantile spasms: assessing the diagnostic yield of an institutional guideline and the impact of etiology on long-term treatment response

OBJECTIVE

Neuroimaging and genetic testing have been proposed for diagnostic evaluation of infantile spasms (IS), establishing etiology in ~60% of multicenter IS cohorts. A retrospective analysis of the yield of diagnostic etiology following an institutionally established guideline for investigation/treatment of IS was conducted, and the association between etiological subgroups and sustained response to standard treatment was evaluated.

METHODS

Etiology of IS, neuroimaging, and genetic results were extracted from clinical records. Etiology was categorized as acquired or non-acquired, the latter including syndromic patients, non-syndromic patients with confirmed etiology, and unknown cases. Regression analyses, using clinical variables including subtypes of etiology, were conducted to determine which factors correlated with favorable (spasms freedom at last follow-up after ≤ 2 standard treatments) versus unfavorable treatment outcome (refractory spasms despite two standard treatments or relapse).

RESULTS

We included 127 IS patients (60% males) with a follow-up of 2.4 years (range 0.6-5 years). All patients had neuroimaging, and 95% of patients in the non-acquired category (103 of 108 patients) had genetic testing. Etiology was identified in 103/127 (81%, CI-0.73-0.86). At last follow-up, 42 (33%) patients had favorable treatment outcome. No difference in treatment response was observed between acquired and non-acquired etiologies. Among patients with non-acquired etiologies, developmental delay prior to spasms onset increased the odds of unfavorable treatment outcome (p=0.014) while a clearly recognizable dysmorphic/syndromic etiology was associated with a lower risk for treatment failure (p=0.034). In non-acquired etiology without a recognizable dysmorphic/syndrome but with a genetic etiology, unfavorable treatment outcome was more likely (p=0.043).

SIGNIFICANCE

Rigorous evaluation with neuroimaging and genetic testing yields an etiological diagnosis in most patients with IS. Among patients with a non-acquired etiology, those with recognizable dysmorphic/syndromic diagnosis had a higher likelihood of a favorable treatment outcome, while the absence of such a finding, when associated with an identifiable genetic diagnosis, was associated with unfavorable treatment outcomes.

Clinical profile, treatment modalities, and outcomes in patients with infantile spasms: A retrospective study from the United Arab of Emirates (UAE)

BACKGROUND

Infantile spasms (IS) are an epileptic encephalopathy where the prognosis is generally poor, with most patients exhibiting psychomotor retardation or intractable epilepsy. However, it is claimed that early and aggressive treatment is related to better response rate and outcome, especially in patients with idiopathic IS.

OBJECTIVE

To investigate different treatment modalities and outcomes in patients with IS attending a pediatric neurology clinic at a specialized neurology center in Abu Dhabi, United Arab Emirates.

METHODS

Retrospective chart review was done for detailed history, demographic data, etiology, neuro-diagnostic workup, treatment modalities, and the outcomes for all patients diagnosed with IS from September 2014 to September 2019.

RESULTS

Three treatment modalities were identified as 1st line- Prednisolone United Kingdom Infantile Spasms Study (UKISS) (N = 15, 46.8%), Anti-Seizure Medications (ASMs) (N = 12, 37.5%), and Vigabatrin (N = 5, 15.6%). The complete response rate to Vigabatrin as a 1st line treatment showed the highest statistical significance (X² = 7.34, p = 0.007). Patients with idiopathic IS showed a comparable response to treatment to those with symptomatic IS. Additional response to 2nd line treatment with Prednisolone UKISS protocol (25%) and Vigabatrin (15%) was noted in patients who showed partial or no response to the 1st line treatment. None of our patients received Adrenocorticotropic Hormone as treatment. All patients with desirable final outcomes were with idiopathic IS and none were symptomatic.

CONCLUSION

More than a third of our patients showed poor treatment response whenever they were not offered treatment according to the current available protocols. This indicates an urgent need for having a unified treatment protocol that takes into consideration the availability of medications, professional expertise as well as diagnostic workup outside major tertiary care centers in our region.

Serum matrix metallopeptidase-9 and tissue inhibitor of metalloproteinase-1 levels may predict response to adrenocorticotropic hormone therapy in patients with infantile spasms

OBJECTIVE

To evaluate whether serum matrix metallopeptidase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) levels predict response to adrenocorticotropic hormone (ACTH) therapy in patients with infantile spasms.

METHODS

We prospectively evaluated patients with infantile spasms who were referred to Saitama Children's Medical Center from January 2011 to December 2020. We measured Q-albumin and serum MMP-9 and TIMP-1 levels before ACTH therapy. Patients were divided into three groups based on the etiology of their infantile spasms: those with an unknown etiology and normal development (unknown-normal group); those with a structural and acquired etiology (structural-acquired group); and those with a structural and congenital, genetic, metabolic, or unknown etiology with developmental delay (combined-congenital group). Responders were defined as those having complete cessation of spasms for more than 3 months with the resolution of hypsarrhythmia on electroencephalography during ACTH therapy.

RESULTS

We collected serum from 36 patients with West syndrome and five patients with infantile spasms without hypsarrhythmia before ACTH therapy. Twenty-three of 41 patients (56.1%) were responders, including 8/8 (100%) in the unknown-normal group, 6/9 (66.7%) in the structural-acquired group, and 9/24 (37.5%) in the combined-congenital group. The serum MMP-9 level and MMP-9/TIMP-1 ratio were significantly higher in responders than in nonresponders (P = 0.001 for both).

CONCLUSION

A therapeutic response to ACTH was associated with a higher serum MMP-9 level and higher MMP-9/TIMP-1 ratio in patients with infantile spasms. Therefore, these biomarkers may predict responses to ACTH therapy in this patient population.

Trends and Costs Associated With the Diagnosis and Treatment of Infantile Spasms: A 10-Year Multicenter Retrospective Review

OBJECTIVE

Early treatment of infantile spasms (IS) may be imperative for improvement of neurodevelopmental outcomes. Existing studies have led to inconclusive recommendations with variation in treatment. Our objective was to determine the national average cost, initial diagnostic workup, treatments, and hospital length of stay for patients with IS.

METHODS

This retrospective cohort study was designed to review data of patients < 2 years from 43 non-profit institutions. Data obtained included patient demographics, length of stay, admission cost, and treatments used from 2004 to 2014. Cost data were collected and adjusted to 2014 dollars, the year data were analyzed.

RESULTS

A total of 6183 patients met study criteria (n = 3382, 55% male). Three-quarters of patients (n = 4684, 76%) had an electroencephalogram, 56.4% had brain imaging (n = 3487), and 17% (n = 1050) underwent a lumbar puncture. Medication for IS was initiated during inpatient hospital stay in two-thirds of all patients (n = 4139, 67%). Most patients were initiated on corticotropin (n = 2066, 33%) or topiramate (n = 1804, 29%). Average length of stay was 5.8 days with an average adjusted cost of $18,348. Over time there was an 86.6% increase in cost from an average $12,534.54 (2004) to $23,391.20 (2014), a significant change (p < 0.01). This correlated with an increase in average length of stay.

CONCLUSIONS

Variability exists in diagnostic workup and pharmacotherapy initiated for IS, which may lead to differences in the cost of hospital stay. Further studies may help determine contributing factors to increased cost and improve health care utilization for IS patients.