A methodological perspective on the cognitive outcome of epilepsy surgery in children and adolescents.

PURPOSE: The purpose of the study was to explore the impact of timing and test specificity of cognitive outcome measures after pediatric epilepsy surgery. METHODS: A consecutive national cohort of 114 children with medically resistant epilepsy having had resective epilepsy surgery were screened for children tested with a complete age-appropriate Wechsler Intelligence test at two or three time-points. This provided 43 children for analyses. Composite subscale scores were assessed in comparison to index and intelligence quotient (IQ) scores. RESULTS: We found a main effect of time in seizure-free children for full-scale IQ (FSIQ); F(2, 42) = 6.49 with higher T2 measures compared with T1 (MDiff = 5.46, p = .006). There was a difference in FSIQ scores between seizure-free and nonseizure-free children at T2; M = 7.31, 95% confidence interval (CI) [0.05 to 14.57], t(38) = 2.04, p = .049, favoring seizure-free children. A statistical difference between composite scale scores and index scores was found with medium to large effect. The correlation of medical treatment (anti-epileptic drug (AED)) change and score differences in FSIQ outcome was significant (p = .041), with less AED correlated with a higher FSIQ. All children with left-temporal surgery had a stable or improved verbal comprehension composite subscale score outcome at T2 regardless of seizure status. CONCLUSION: Our results correspond to some longitudinal studies with outcome measures >2 years, in contrast to short-term studies ≤2 years with a stable outcome. Our study supports the fact that the specificity of the used tests and the timing of assessments after pediatric epilepsy surgery are essential factors for the clinical validity of outcome measures. However, there are further needs of extensive longitudinal studies to provide a better understanding of life-long cognitive development and impact after childhood epilepsy surgery.

Infections seem to be more frequent before onset of pediatric multiple sclerosis: A Danish nationwide nested case-control study.

BACKGROUND: Infections are suspected environmental triggers for multiple sclerosis (MS). The relationship between the timing and cumulative number of childhood infections regarding pediatric MS risk is uninvestigated. OBJECTIVES: To investigate whether childhood infections contribute to pediatric MS. METHODS: A nationwide nested case-control study with detailed MS case ascertainment including chart review was undertaken. For each MS case, we selected five control children using density sampling from the entire Danish population, matching controls to children with MS by sex and birthdate. We analyzed data with the cumulative number of childhood infections as exposure and MS as outcome. Hazard ratios (HRs) including 95% confidence intervals (CIs) were estimated using Cox regression. RESULTS: We identified 212 children with MS and 1,060 controls. Median age at MS onset was 15.3 years (range: 7.6-17.8 years); 72% were girls. Each infection during the preceding 3 years increased the hazard for MS by 11% (95% CI = 1.01-1.22, p = 0.04); having 5+ infections compared with 0-4 infections in the preceding 3 years doubled the hazard for MS (HR: 2.18; 95% CI = 1.12-4.30, p = 0.02). CONCLUSION: Children with MS appeared to have more infections in the 3 years preceding MS clinical onset; accordingly, immune response to infections may influence MS pathogenesis.

Pediatric-onset multiple sclerosis and other acquired demyelinating syndromes of the central nervous system in Denmark during 1977-2015: A nationwide population-based incidence study.

BACKGROUND: The incidence of acquired demyelinating syndromes (ADS) including multiple sclerosis (MS) has never been investigated in a Danish pediatric population. OBJECTIVES: We estimated the nationwide age- and sex-specific incidence of pediatric ADS including MS. METHODS: Data were sourced from the Danish Multiple Sclerosis Registry, providing cases of pediatric MS for 1977-2015, and the National Patient Register, providing cases of ADS during 2008-2015. All medical records were reviewed to validate the register-based diagnoses. RESULTS: We identified 364 cases of pediatric MS occurring during 1977-2015 (incidence rate = 0.79 per 100,000 person-years). MS was exceptionally rare before puberty, but the incidence rose considerably from 9 years in girls and 11 years in boys. The female-to-male ratio was 2.5; the median age at onset was 16 years (range = 7-17 years). The MS incidence rate was relatively stable through the study period. During 2008-2015, we identified 219 ADS cases. The incidence was 2.29 per 100,000 person-years with considerable differences in the age peaks for the separate ADS. CONCLUSION: The incidence rates of MS and other ADS in Denmark were higher than those reported for some other European countries. Referral bias and classification differences may account for this disparity, in particular the age-intervals and the definition of onset.

Current state of hemispherectomy and callosotomy for pediatric refractory epilepsy in Denmark.

OBJECTIVE: To evaluate outcomes from hemispherectomy and callosotomy related to the need for anti-seizure medication (ASM), seizure frequency, and cognition. METHODS: A review of the medical charts of all Danish pediatric patients who underwent hemispherectomy or callosotomy from January 1996 to December 2019 for preoperative and postoperative ASM use, seizure frequency, and cognitive data. RESULTS: The median age of epilepsy onset was two years (interquartile range (IQR): 0.0-5.3) for the hemispherectomy patients (n = 16) and one year (IQR: 0.6-1.7) for callosotomy patients (n = 5). Median time from onset to final surgery was 3.4 years for hemispherectomy and 10.2 years for callosotomy, while the median follow-up time was 6.9 years and 9.0 years, respectively. Preoperatively, all patients had daily seizures and were treated with ≥ 2 ASM. Hemispherectomy resulted in a reduction in seizure frequency in 87.5 % of patients, with 78.6 % achieving seizure freedom. Furthermore, 81.3 % experienced a reduction in ASM use and 56.3 % stopped all ASM. Median IQ/developmental quotient (IQ/DQ) was low preoperatively (44.0 [IQR: 40.0-55.0]) and remained unchanged postoperatively (IQ change: 0.0 [IQR: -10.0-+4.0]). Callosotomy resulted in a seizure reduction of 86-99 % in four patients, and ASM could be reduced in three patients. Median IQ/DQ was 20.0 preoperatively (IQR: 20.0-30.0) and remained unchanged postoperatively (IQ change: 0.0 [IQR: 0.0]). CONCLUSION: Hemispherectomy and callosotomy result in a substantial reduction in seizure frequency and ASM use without deterioration of IQ. Extensive epilepsy surgery should be considered early in children with drug-resistant epilepsy.

School performance and psychiatric comorbidity in childhood absence epilepsy: A Danish cohort study.

The aim was to determine school performance and psychiatric comorbidity in children with childhood absence epilepsy (CAE). We reviewed the medical records in children with ICD-10 codes for idiopathic generalized epilepsy before 18 years of age, and pediatric neurologists confirmed the International League Against Epilepsy criteria for CAE were met. Control groups were the general pediatric population or children with non-neurological chronic disease. Outcomes were from nationwide and population-based registers on school performance and psychiatric comorbidity. We compared the mean grade point average using linear regression and estimated hazard ratios (HR) using Cox regression for the other outcomes. Analyses were adjusted for the child's sex, and year of birth, and parental highest education, receipt of cash benefits or early disability pension. We included 114 children with CAE with a median age at onset of 5.9 years (interquartile range = 4.5-7.3 years). Compared with both population controls and non-neurological chronically ill children, children with CAE had increased hazard of special needs education (HR = 2.7, 95% confidence interval (CI) = 1.8-4.1, p < 0.0001), lower grade point average at 9th grade by 1.7 grade points (95% CI = -2.5 to -1.0, p < 0.001), increased ADHD medicine use (HR = 4.4, 95% CI = 2.7-7.2, p < 0.001), increased sleep medicine use (HR = 2.7, 95% CI = 1.7-4.3, p < 0.001), and increased psychiatry visits (HR = 2.1, 95% CI = 1.1-4.0, p = 0.03). In conclusion, children with CAE have increased psychiatric comorbidity and a considerable proportion of these children receive special needs education in primary/secondary school, albeit insufficient to normalize their considerably lower grade point average in the 9th grade.

Epilepsy-Related Mortality in Children and Young Adults in Denmark: A Nationwide Cohort Study.

BACKGROUND AND OBJECTIVES: Mortality is increased in epilepsy, but the important issue is that a proportion of epilepsy-related death is potentially preventable by optimized therapy and therefore needs to be identified. A new systematic classification of epilepsy-related mortality has been suggested to identify these preventable deaths. We applied this classification to an analysis of premature mortality in persons with epilepsy who were <50 years of age. METHODS: The study was a population-based retrospective cohort of all Danish citizens with and without epilepsy 1 to 49 years of age during 2007 to 2009. Information on all deaths was retrieved from the Danish Cause of Death Registry, autopsy reports, death certificates, and the Danish National Patient Registry. The primary cause of death in persons with epilepsy was evaluated independently by 3 neurologist, 1 neuro-pediatrician, and 2 cardiologists. In case of uncertainty, a pathologist was consulted. All deaths were classified as either epilepsy related or not epilepsy related, and the underlying causes or modes of death were compared between persons with and without epilepsy. RESULTS: During the study period, 700 deaths were identified in persons with epilepsy, and 440 (62.9%) of these were epilepsy related, 169 (38%) directly related to seizures and 181 (41%) due to an underlying neurologic disease. Sudden unexpected death in epilepsy accounted for 80% of deaths directly related to epilepsy. Aspiration pneumonia was the cause of death in 80% of cases indirectly related to epilepsy. Compared with the background population, persons with epilepsy had a nearly 4-fold increased all-cause mortality (adjusted mortality hazard ratio 3.95 [95% confidence interval [CI] 3.64-4.27], p < 0.0001) and a higher risk of dying of various underlying causes, including alcohol-related conditions (hazard ratio 2.91 [95% CI 2.23-3.80], p < 0.0001) and suicide (hazard ratio 2.10 [95% CI 1.18-3.73], p = 0.01). DISCUSSION: The newly proposed classification for mortality in persons with epilepsy was useful in an unselected nationwide cohort. It helped in classifying unnatural causes of death as epilepsy related or not and in identifying potentially preventable deaths. The leading causes of premature mortality in persons <50 years of age were related to epilepsy and were thus potentially preventable by good seizure control.

Validation of Pediatric Idiopathic Generalized Epilepsy Diagnoses from the Danish National Patient Register During 1994‒2019.

Objective: To identify pediatric idiopathic generalized epilepsy (IGE) during 1994-2019 using ICD-10 codes in the Danish National Patient Register and anti-seizure prescriptions in the Danish Prescription Database. Study Design and Setting: We reviewed the medical records in children with ICD-10 codes for IGE before 18 years of age, and pediatric neurologists confirmed that the International League Against Epilepsy criteria were met. We estimated positive predictive values (PPV) and sensitivity for ICD-10 alone, including combinations of codes, anti-seizure prescription, and age at first code registration using medical record-validated diagnoses as gold standard. Results: We validated the medical record in 969 children with an ICD-10 code of IGE, and 431 children had IGE (115 childhood absence epilepsy, 97 juvenile absence epilepsy, 192 juvenile myoclonic epilepsy, 27 generalized tonic-clonic seizures alone). By combining ICD-10 codes with antiseizure prescription and age at epilepsy code registration, we found a PPV for childhood absence epilepsy at 44% (95% confidence interval [CI]=34%‒54%) and for juvenile absence epilepsy at 44% (95% CI=36%-52%). However, ethosuximide prescription, age at ethosuximide code registration before age 8 years and a combination of ICD-10 codes yielded a PPV of 59% (95% CI=42%‒75%) for childhood absence epilepsy but the sensitivity was only 17% (20/115 children identified). For juvenile myoclonic epilepsy the highest PPV was 68% (95% CI=62%‒74%) using the code G40.3F plus antiseizure prescription and age at epilepsy code registration after age 8 years, with sensitivity of 85% (164/192 children identified). For generalized tonic-clonic seizures alone the highest PPV was 31% (95% CI=15%‒51%) using G40.3G during 2006-2019 plus antiseizure prescription and age at code registration after age 5 years. Conclusion: The Danish National Patient Register and the Danish Prescription Database are not suitable for identifying children with IGE subtypes, except for juvenile myoclonic epilepsy which can be identified with caution.

School performance and psychiatric comorbidity in juvenile absence epilepsy and juvenile myoclonic epilepsy: a Danish population-based cohort study.

BACKGROUND: We aimed to determine school performance and psychiatric comorbidity in juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), and generalized tonic-clonic seizures (GTCS) alone. METHODS: All children (< 18 years) fulfilled International League Against Epilepsy criteria after review of their medical records. Control groups were the pediatric background population or children with non-neurological chronic disease. Outcomes were on school performance and psychiatric comorbidity. We compared mean grade point averages using linear regression and estimated hazard ratios using Cox regression in the remaining analyses. We adjusted for the child's sex, age, and year of birth; and parental highest education, receipt of cash benefits or early retirement. RESULTS: We included 92 JAE, 190 JME, 27 GTCS alone, 15,084 non-neurological chronic disease controls, and population controls. JAE had two times increased hazard for special needs education compared with age-matched population controls (hazard ratio 2.2, 95% CI = 1.1‒4.6, p = 0.03); this was not seen in JME. Compared with population controls, both JAE and JME had lower grade point average in secondary and high school (JME: 9th grade: - 0.5 points, 95% CI = -0.9 to -0.06, p = 0.03; high school: - 0.6 points, 95% CI = -1.3 to -0.1, p = 0.04), and 8% fewer JME and 15% fewer JAE attended high school. Both JME and JAE had higher hazard for redeeming sleep medication compared with non-neurological chronic disease; additionally, JAE had increased hazard for ADHD medicine redemptions. CONCLUSIONS: Both JAE and JME had marginally poorer school performance; performance seemed worse in JAE than in JME. Both JAE and JME had increased use of sleep medication.

Increase in cognitive function is seen in many single-operated pediatric patients after epilepsy surgery.

PURPOSE: The recurrent seizures of pediatric drug-resistant epilepsy (DRE) are known to impair brain development and can lead to a loss in cognitive functioning. Surgery is increasingly being used to treat children with DRE. This study investigates the pre- and postoperative cognitive function in a pediatric epilepsy surgery cohort as well as predictive determinants of change in intelligence quotient (IQ) following surgery. METHODS: A consecutive series of 91 Danish children who underwent focal resective epilepsy surgery between January 1996 and December 2016 were included. All underwent preoperative cognitive evaluation and were reevaluated at 1-year and/or 2-year follow-up. Single-operated and multi-operated patients were examined separately. RESULTS: 79 of 91 patients were single-operated. Single-operated patients received less anti-epileptic drugs (AED) and experienced a decrease in seizure frequency postoperatively, p < 0.001. IQ increased postoperatively (IQ change ± standard deviation: 3.3 ± 14.0), p < 0.05. High preoperative seizure frequency was a significant predictor for decreased IQ, p < 0.01. Multi-operated patients did not experience a reduction in AED treatment. Surgery and continued AED treatment did, however, result in significantly better seizure control, p < 0.01. IQ remained unchanged in multi-operated patients. CONCLUSION: Epilepsy surgery allowed for IQ gains in single-operated patients. Preoperative seizure frequency was a significant predictor of IQ change following surgery. Interactions between other, not included, possible predictors remain to be examined. Single-operated patients had the best cognitive outcome. The inclusion of a non-surgical control group is needed to assess the extent of the beneficial effects of surgery on cognitive ability.

Post-varicella Arterial Ischemic Stroke in Denmark 2010 to 2016.

BACKGROUND: Varicella, most often a benign disease of childhood, is associated with an increased risk of arterial ischemic stroke in children. The aim of the present study was to estimate the incidence of post-varicella arterial ischemic stroke in the Danish child population and describe clinical characteristics of children admitted with post-varicella arterial ischemic stroke. METHODS: In the Danish National Patient Register, we identified inpatients 28 days to 16 years of age with a discharge diagnosis of stroke or cerebrovascular disease from 2010 to 2016. Medical files were reviewed, and children with arterial ischemic stroke and varicella infection less than 12 months before onset of symptoms were included. RESULTS: We identified 15 children with arterial ischemic stroke and varicella less than 12 months before. In nine children, the diagnosis was confirmed by detection of varicella zoster virus DNA or varicella zoster virus immunoglobulin G in the cerebrospinal fluid. All children were previously healthy, the mean age was four years, and 67% were male. The median time from varicella rash to arterial ischemic stroke was 4.6 months. The most common location of arterial ischemic stroke was the basal ganglia, and affected vessels were most often in the anterior circulation. Fifty-three percent experienced neurological sequelae of varying degree. CONCLUSIONS: In Denmark, where varicella vaccination is not part of the childhood vaccination program, the estimated risk of post-varicella arterial ischemic stroke was one case (including possible cases) per 26,000 children with varicella.

Fever in pregnancy and offspring head circumference.

PURPOSE: To examine whether maternal fever during pregnancy is associated with reduced head circumference and risk of microcephaly at birth. METHODS: A prospective study of 86,980 live-born singletons within the Danish National Birth Cohort was carried out. Self-reported maternal fever exposure was ascertained in two interviews during pregnancy and information on head circumference at birth was extracted from the Danish Medical Birth Registry. RESULTS: Fever in pregnancy was reported by 27% of the mothers, and we identified 3370 cases of microcephaly (head circumference less than or equal to third percentile for sex and gestational age) and 1140 cases of severe microcephaly (head circumference less than or equal to first percentile for sex and gestational age). In this study, maternal fever exposure was not associated with reduced head circumference (adjusted ß = 0.03, 95% confidence intervals [CI]: 0.01-0.05), increased risk of microcephaly (odds ratio: 0.95, 95% CI: 0.88-1.03) nor severe microcephaly (odds ratio: 1.01, 95% CI: 0.88-1.15) in the offspring. These findings were consistent for increasing numbers of fever episodes, for increasing fever severity, and for exposure in both early pregnancy and midpregnancy. CONCLUSIONS: In this most comprehensive study to date, we found no indication that maternal fever in pregnancy is associated with small head size in the offspring.

Increased cerebrospinal fluid chitinase 3-like 1 and neurofilament light chain in pediatric acquired demyelinating syndromes.

BACKGROUND: Chitinase 3-like 1 (CHI3L1), neurofilament light chain (NFL) and oligoclonal bands (OCB) in cerebrospinal fluid are associated with central nervous system demyelination in adults. CHI3L1 and OCB are markers of central nervous system inflammation, whereas NFL is a marker of white-matter axonal injury. The aim was to examine whether CHI3L1 and NFL in cerebrospinal fluid are associated with acquired demyelinating syndromes at disease onset in a pediatric population. METHODS: Children (<18 years) referred to hospital for possible neuroinflammatory disease were retrospectively included from 2010 to 2016. Case ascertainment was by review of medical records. NFL and CHI3L1 were measured by enzyme-linked immunosorbent assays. Endpoints were differences in concentrations of cerebrospinal fluid NFL and CHI3L1. RESULTS: We included 193 children who all underwent cerebrospinal fluid OCB examination as part of their diagnostic work-up and classified these children into 5 groups: acquired demyelinating syndromes (n = 33), normal diagnostic work-up (n = 36), inflammatory neurological disease (n = 50), other neurological disease (n = 55), and systemic inflammatory diseases (n = 19). NFL and CHI3L1 in cerebrospinal fluid differed significantly between the five groups (p = 0.0001). CHI3L1 was significantly higher in acquired demyelinating syndromes than in all other groups, and NFL was significantly higher in acquired demyelinating syndromes than in the other groups except systemic inflammatory disease. Children with acute disseminated encephalomyelitis had significantly higher concentrations of CHI3L1 than did children with multiple sclerosis. CONCLUSION: We provide class II evidence that CHI3L1 and NFL are associated with pediatric acquired demyelinating syndromes. CHI3L1 may help distinguishing between acute disseminated encephalomyelitis and multiple sclerosis, but this needs further confirmation.

Psychiatric morbidity develops after onset of pediatric multiple sclerosis: A Danish nationwide population-based study.

BACKGROUND: Pediatric-onset multiple sclerosis (MS) affects life at a stage vital for social and educational achievements and psychiatric co-morbidity is common after MS onset. Few studies have examined psychiatric morbidity before MS onset. METHODS: In this nationwide study, detailed case ascertainment was performed in all children with pediatric MS, including chart review. For each MS patient, we selected five controls using density sampling from the entire Danish population, matching controls to children with MS by sex and birthdate. We analyzed data as a nested case-control study with psychiatric morbidity as exposure and MS as outcome, and a matched cohort study with MS as exposure and psychiatric co-morbidity as outcome. Hazard ratios (HR) including 95% confidence intervals (CI) were estimated using Cox regression. RESULTS: We identified 212 children with MS and 1060 controls. No association between psychiatric morbidity and the rate of MS was found before MS onset. After MS onset, children with MS had two times higher hazard for psychiatric co-morbidity compared with children without MS (HR=2.0; 95% CI=1.3-3.1; p<0.001). CONCLUSION: Psychiatric morbidity seems to commence after MS onset, making screening for neuropsychiatric conditions pertinent in newly-diagnosed children with MS.

[Cannabis is not for children or adolescents].

The Danish parliament has decided to establish a four-year pilot scheme for medical treatment with cannabis. We increasingly experience requests from parents for medical treatment with cannabis of children and have the impression that a growing number of parents treat their children with illegally acquired cannabis products for various conditions. We summarize the sparse evidence regarding effects, side effects and long-term effects of medical treatment with cannabis in children and adolescents. At present, cannabis should very rarely be considered as part of medical treatment for children and adolescents.

A child with myoclonus-dystonia (DYT11) misdiagnosed as atypical opsoclonus myoclonus syndrome.

INTRODUCTION: DYT11 is an autosomal dominant inherited movement disorder characterized by myoclonus and dystonia. CLINICAL PRESENTATION: We present a case with atypical symptoms and with episodes of ataxia and myoclonus preceded by infections. Atypical presentation of opsoclonus myoclonus syndrome was suspected and treatment with bolus steroids and immunoglobulin were initiated with some response over 28 months. A re-evaluation gave suspicion of a dyskinetic disorder and whole exome-sequencing was performed but no causal variant was identified. OUTCOME: A specific analysis of the SGCE gene was subsequently initiated, which revealed a pathogenic aberration confirming the diagnosis of DYT11. CONCLUSION: A clinical DYT11 diagnosis can be difficult to establish in early childhood without a known family history.