J. Nicholas Brenton

Antibody-Mediated Autoimmune Encephalitis in Childhood

BACKGROUND The differential diagnosis of encephalitis in childhood is vast, and evaluation for an etiology is often unrevealing. Encephalitis by way of autoimmunity has long been suspected, as in cases of acute disseminated encephalomyelitis; however, researchers have only recently reported evidence of antibody-mediated immune dysregulation resulting in clinical encephalitis. MAIN FINDINGS These pathologic autoantibodies, aimed at specific neuronal targets, can result in a broad spectrum of symptoms including psychosis, catatonia, behavioral changes, memory loss, autonomic dysregulation, seizures, and abnormal movements. Autoimmune encephalitis in childhood is often quite different from adult-onset autoimmune encephalitis in clinical presentation, frequency of tumor association, and ultimate prognosis. As many of the autoimmune encephalitides are sensitive to immunotherapy, prompt diagnosis and initiation of appropriate treatment are paramount. CONCLUSIONS Here we review the currently recognized antibody-mediated encephalitides of childhood and will provide a framework for diagnosis and treatment considerations.

Approach to the Management of Pediatric-Onset Anti-N-Methyl-d-Aspartate (Anti-NMDA) Receptor Encephalitis: A Case Series.

Anti-N-methyl-d-aspartate (anti-NMDA) receptor encephalitis is a treatable cause of autoimmune encephalitis. It remains unclear if the natural history of this disease is altered by choice of acute therapy or the employment of chronic immunotherapy. Chart review was undertaken for pediatric patients diagnosed with anti-NMDA receptor encephalitis. Data obtained included patient demographics, disease manifestations, treatment course, and clinical outcomes. Ten patients with anti-NMDA receptor encephalitis were identified. All patients were treated with immunotherapy in the acute period, and all patients experienced good recovery. Neurologic relapse did not occur in any patient. All patients received varied forms of chronic immunosuppression to prevent relapses. Complications of chronic immunotherapy occurred in 50% of patients. The benefits of chronic immunotherapy and the duration of use should be carefully weighed against the risks. Complications from immunotherapy are not uncommon and can be serious. Clinical trials assessing the benefit of long-term immunotherapy in this population are needed.

A study of dietary modification: Perceptions and attitudes of patients with multiple sclerosis

BACKGROUND Modifiable risk factors for multiple sclerosis (MS), including obesity and the gut microbiome, have been studied and have been found to be potentially relevant. Given this, there is a growing interest in diet modification as a means of impacting MS risk and disease course. OBJECTIVES The aim of this study was to determine the current behaviors, level of interest, and relevant factors surrounding modification of diet in MS patients. METHODS A total of 601 MS patients were mailed a dietary modification survey containing questions regarding subject demographics, disease course, and diet-related questions. RESULTS Of the 199 survey responders, 17% admitted to currently attempting a diet for their MS and 91.5% were interested in diet modification as a means of benefiting their disease. Willingness to attempt diet therapy was not affected by demographic features or an individuals disease course. Over 85% of these patients were willing to attempt diet therapy for 3 months or longer. CONCLUSIONS The majority of survey responders expressed interest in diet modification in attempts to improve or treat their MS. Our data demonstrate the feasibility of patient recruitment for future studies assessing therapeutic intervention by way of diet modification for MS disease.

Vitamin D status and age of onset of demyelinating disease

OBJECTIVE To evaluate the prevalence of and associated factors impacting vitamin D insufficiency and deficiency in childhood versus adult-onset demyelinating disease. METHODS We conducted a retrospective, cross-sectional, chart-review, cohort study on geographically-similar pediatric, young adult, and adult patients with a diagnosis of demyelinating disease identified at the University of Virginia from 2008 to 2013. Group prevalence of vitamin D insufficiency and deficiency as well as relevant factors associated with vitamin D status was analyzed and compared. RESULTS We identified 24 childhood-onset (CO), 33 young adult-onset (Y-AO), and 59 adult-onset (AO) cases. There was no difference in the prevalence of vitamin D insufficiency or deficiency between the cohorts. Non-Caucasian race and elevated body mass index were significantly associated with low vitamin D levels, regardless of age of onset. In regression models, race and obesity were independent predictors of vitamin D status. The prevalence of obesity was significantly higher in the childhood-onset cohort (CO=58.5%; Y-AO=31%; AO=34%; p=0.02). CONCLUSIONS Our findings demonstrate no difference in the prevalence of vitamin D insufficiency/deficiency between childhood and adult-onset demyelinating disease, suggesting age at disease onset is irrelevant to vitamin D status in demyelinating disease. Both race and obesity are independent factors associated with vitamin D insufficiency/deficiency, regardless of age of disease onset. Obesity, independent of gender, is significantly higher in children compared to adult patients diagnosed with multiple sclerosis and may have a role in the development of childhood-onset demyelinating disease.

Late-onset nonketotic hyperglycinemia with a heterozygous novel point mutation of the GLDC gene.

BACKGROUND Atypical nonketotic hyperglycinemia is characterized by heterogeneous phenotypes that often include nonspecific behavioral problems, cognitive deficits, and developmental delays. PATIENT We describe a girl with late-onset nonketotic hyperglycinemia presenting at 5 years of age with hypotonia, chorea, ataxia, and alterations in consciousness in the setting of febrile illness. RESULTS Serum amino acid analysis was mildly elevated; however, urine amino acid analysis was instrumental in demonstrating marked hyperglycinuria. Mutation testing showed a heterozygous novel sequence change/point mutation in the glycine decarboxylase gene. CONCLUSIONS This patient illustrates the importance of obtaining urine amino acids in individuals whose clinical manifestations are suspicious for any form of nonketotic hyperglycinemia, because this testing may provide more prominent evidence of elevations in glycine. She also illustrates the potential for a heterozygous mutation to result in manifestations of an atypical form of nonketotic hyperglycinemia.

White Matter Changes in an Untreated, Newly Diagnosed Case of Classical Homocystinuria:

The authors report the case of a 4-year-old boy who developed progressive unilateral weakness and developmental delays prior to his diagnosis of classical homocystinuria. Magnetic resonance imaging (MRI) of the brain demonstrated diffuse white matter changes, raising the concern for a secondary diagnosis causing leukoencephalopathy, since classical homocystinuria is not typically associated with these changes. Other inborn errors of the transsulfuration pathway have been reported as causing these changes. Once begun on therapy for his homocystinuria, his neurologic deficits resolved and his delays rapidly improved. Repeat MRI performed one year after instating therapy showed resolution of his white matter abnormalities. This case illustrates the need to consider homocystinuria and other amino acidopathies in the differential diagnosis of childhood white matter diseases and lends weight to the hypothesis that hypermethioninemia may induce white matter changes.

Pediatric Multiple Sclerosis: Genes, Environment, and a Comprehensive Therapeutic Approach

BACKGROUND Pediatric multiple sclerosis is an increasingly recognized and studied disorder that accounts for 3% to 10% of all patients with multiple sclerosis. The risk for pediatric multiple sclerosis is thought to reflect a complex interplay between environmental and genetic risk factors. MAIN FINDINGS Environmental exposures, including sunlight (ultraviolet radiation, vitamin D levels), infections (Epstein-Barr virus), passive smoking, and obesity, have been identified as potential risk factors in youth. Genetic predisposition contributes to the risk of multiple sclerosis, and the major histocompatibility complex on chromosome 6 makes the single largest contribution to susceptibility to multiple sclerosis. With the use of large-scale genome-wide association studies, other non-major histocompatibility complex alleles have been identified as independent risk factors for the disease. The bridge between environment and genes likely lies in the study of epigenetic processes, which are environmentally-influenced mechanisms through which gene expression may be modified. CONCLUSIONS This article will review these topics to provide a framework for discussion of a comprehensive approach to counseling and ultimately treating the pediatric patient with multiple sclerosis.

Extreme delta brush and distinctive imaging in a pediatric patient with autoimmune GFAP astrocytopathy

Autoimmune encephalitis has been increasingly recognized within the pediatric population, and the number of implicated autoantibodies continues to grow. The identification of characteristic clinical and paraclinical features helps direct the evaluation and increases the likelihood of making a definitive diagnosis of a specific antibody-mediated encephalitis. The finding of extreme delta brush on electroencephalogram (EEG) has been suggested to serve as a clinical clue to the diagnosis of anti-NMDA-R encephalitis. Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a recently described antibody-mediated meningoencephalomyelitis, reported almost exclusively in adult patients. We report a case of autoimmune GFAP astrocytopathy in a pediatric patient with extreme delta brush pattern on EEG, negative anti-NMDA-R antibodies, and distinctive MRI findings. The findings reported herein should prompt clinicians to consider the diagnosis of autoimmune GFAP astrocytopathy in patients with suspected autoimmune encephalitis.

Platform Session – Electroencephalography/Epilepsy: Clinical characteristics and outcomes of pediatric super refractory status epilepticus

Introduction There is limited literature on pediatric super refractory status epilepticus (SRSE). We aimed to identify clinical variables associated with the occurrence of SRSE and to describe variability in SRSE treatment in a cohort of children admitted to pediatric intensive care units (ICU) with refractory status epilepticus (RSE). Methods This prospective, observational study was performed at 14 US hospitals. Inclusion criteria: (1) hospital admission between June 2011 and September 2017, (2) convulsive RSE defined as focal or generalized convulsive seizures at onset that continued after administration of at least 2 anti-seizure drugs (ASDs), including one non-benzodiazepine ASD or use of continuous infusion (CI) and (3) age 1 month to 21 years. We divided the cohort into SRSE and non-SRSE groups. SRSE was defined as continuous or intermittent seizures lasting ⩾ 24 h following initiation of CI. We used Fisher’s exact test and Wilcoxon rank sum test in the univariate analysis. Results The initial cohort included 264 patients with a median (p25–p75) age of 4 (1.23–9.50) years. Thirty-five patients (19 males) were identified as SRSE cases, with a median age of 4.5 (1.91–8.45) years. Univariate analysis did not show significant differences between the groups for: sex, age, etiology, prior SE, diagnosis of epilepsy, in-hospital seizure onset, generalized tonic-clonic seizures or continuous SE. SRSE patients had delayed first line treatment initiation (71(15–135.5) vs. 16(5–40.5) min; p = 0.017), longer ICU stay (17(9–42) vs. 3(1.86–8.66) days; p  Conclusion SRSE patients had delayed first-line treatment administration in comparison to non-SRSE patients. Once SRSE was established, children had significantly higher morbidity and mortality. Treatment approaches were heterogeneous, probably reflecting limited evidence to guide clinical decision-making in SRSE. (Funded by the Pediatric Epilepsy Research Foundation and Epilepsy Research Fund ).

LGI1 and CASPR2 neurological autoimmunity in children

The clinical phenotype of leucine‐rich glioma‐inactivated protein 1 (LGI1) and contactin‐associated proteinlike 2 (CASPR2) autoimmunity is well defined in adults. Data for children are limited (<10 cases). Among 13,319 pediatric patients serologically tested for autoimmune neurological disorders (2010–2017), 264 were seropositive for voltage‐gated potassium channel‐complex–IgG (radioimmunoprecipitation). Only 13 (4.9%) were positive by transfected cell‐binding assay for LGI1‐IgG (n = 7), CASPR2‐IgG (n = 3), or both (n = 3). This is significantly less than in adults. Encephalopathy, seizures, and peripheral nerve hyperexcitability were common, as was coexisting autoimmunity. No faciobrachial dystonic seizures or cancers were identified. Functional neurologic disorders were frequently the initial diagnosis, and immunotherapy appeared beneficial. Ann Neurol 2018;84:473–480