Immune-mediated pediatric epilepsies

Diagnosing autoimmune encephalitis based on clinical features and autoantibody findings

INTRODUCTION

Autoimmune encephalitides have been accepted as a reproducible and treatable new group of diseases. At present, there is concern that such diagnoses might be made too liberally. Areas covered: This article suggests how to make valid diagnoses. They should consist of three elements: the clinical syndrome, the associated antibody and the presumed cause or predisposition. Recently, an international consortium published formal clinical criteria for autoimmune encephalitides to enable diagnoses even if antibody testing is not (immediately) available and to prevent overinterpretation of questionable antibody results. Antibody testing has greatly benefitted from the introduction of cell-based assays for the demonstration of antibodies against surface antigens. Paraneoplastic or post-infectious situations, side effects of tumor therapies or genetic predispositions help to explain why a patient develops autoimmune encephalitis. Expert opinion: With the application of this three-fold diagnostic system, clinicians can counsel patients regarding therapy and prognosis, while researchers can form meaningful patient cohorts. An operationalization of criteria would be advantageous.

Type 1 diabetes and GAD65 limbic encephalitis: a case report of a 10-year-old girl

Limbic encephalitis is a rare neurological disorder that may be difficult to recognize. Clinical features include memory impairment, temporal lobe seizures and affective disturbance. We report the case of a 10-year-old girl with type 1 diabetes mellitus that presented with seizures, depressed mood and memory changes. The diagnosis of glutamic acid decarboxylase 65 (GAD65) mediated limbic encephalitis relied on cerebral magnetic resonance imaging lesions and high serological and cerebrospinal fluid GAD65-antibodies titers. High-dose steroidal therapy was started with clinical improvement. Relapse led to a second high-dose steroid treatment followed by rituximab with remission. A correlation between serum GAD65-antibodies levels and symptoms was found, demonstrating GAD65-antibodies titers may be useful for clinical follow-up and immunotherapy guidance. This report raises awareness of this serious neurological condition that may be associated with type 1 diabetes, underlining the importance of an early diagnosis and prompt treatment for a better prognosis.

Current and Emerging Therapies of Severe Epileptic Encephalopathies

In this article, we review the treatment options for the pediatric epileptic encephalopathies and provide an update on the new and emerging therapies targeted at the underlying pathophysiology of many of these syndromes. We illustrate how the identification of the specific genetic and autoimmune causes has made possible the evaluation and development of novel, better targeted therapies, as and at times, avoidance of potentially offending agents.

Virus and Immune-Mediated Encephalitides: Epidemiology, Diagnosis, Treatment, and Prevention

Virus encephalitis remains a major cause of acute neurological dysfunction and permanent disability among children worldwide. Although some disorders, such as measles encephalomyelitis, subacute sclerosing panencephalitis, and varicella-zoster virus-associated neurological conditions, have largely disappeared in resource-rich regions because of widespread immunization programs, other disorders, such as herpes simplex virus encephalitis, West Nile virus-associated neuroinvasive disease, and nonpolio enterovirus-induced disorders of the nervous system, cannot be prevented. Moreover, emerging viral disorders pose new, potential threats to the child's nervous system. This review summarizes current information regarding the epidemiology of virus encephalitis, the diagnostic methods available to detect central nervous system infection and identify viral pathogens, and the available treatments. The review also describes immune-mediated disorders, including acute disseminated encephalomyelitis and N-methyl-D-aspartate receptor antibody encephalitis, conditions that mimic virus encephalitis and account for a substantial proportion of childhood encephalitis.

Efficacy of intravenous immunoglobulin in a cohort of children with drug-resistant epilepsy

OBJECTIVES

We describe the experience of a pediatric epilepsy center regarding the efficacy of intravenous immunoglobulin for drug-resistant seizures in children.

METHODS

A retrospective chart review of all children in a community-based, children's hospital neurology clinic from 2006 to 2012, inclusive, with intractable epilepsy who were treated with intravenous immunoglobulin for a minimum of six cycles was performed. Data collected included patient demographics, seizure and epilepsy syndrome type, presumed etiology for the seizures, and seizure frequency. Response to intravenous immunoglobulin was defined as "positive" if either seizure freedom or ≥50% reduction of seizures was achieved.

RESULTS

Twenty-seven children (3-17 years old) were identified and included in the analysis. Following treatment with intravenous immunoglobulin, the following outcomes were noted: four were seizure-free, eight had 90% reduction, five had 75% reduction, and five had 50% reduction. A total of 22 (81%) patients had a positive clinical response to treatment from baseline. Five patients (19%) were not responsive. No clear relationship of responsiveness to intravenous immunoglobulin with regard to age, gender, or epilepsy syndrome was apparent; however, the small numbers in each category precluded meaningful statistical analysis.

SIGNIFICANCE

Our findings and those of others suggest that intravenous immunoglobulin is a potentially high efficacy, low side effect profile therapy in the treatment of children with drug-resistant epilepsies. Intravenous immunoglobulin was able to reduce multiple seizure types in a variety of epilepsy etiologies, including those of unknown cause.

The Peptide Network between Tetanus Toxin and Human Proteins Associated with Epilepsy

Sequence matching analyses show that Clostridium tetani neurotoxin shares numerous pentapeptides (68, including multiple occurrences) with 42 human proteins that, when altered, have been associated with epilepsy. Such a peptide sharing is higher than expected, nonstochastic, and involves tetanus toxin-derived epitopes that have been validated as immunopositive in the human host. Of note, an unexpected high level of peptide matching is found in mitogen-activated protein kinase 10 (MK10), a protein selectively expressed in hippocampal areas. On the whole, the data indicate a potential for cross-reactivity between the neurotoxin and specific epilepsy-associated proteins and may help evaluate the potential risk for epilepsy following immune responses induced by tetanus infection. Moreover, this study may contribute to clarifying the etiopathogenesis of the different types of epilepsy.