Mimics of Pediatric Small Vessel Primary Angiitis of the Central Nervous System.

OBJECTIVE: Small vessel primary angiitis of the central nervous system is a rare and often severe disease characterized by central nervous system-restricted inflammatory vasculitis on histopathology. Diagnosis requires brain biopsy for confirmation and is suggested prior to starting immunotherapy when feasible. However, emerging evidence suggests that other neuroinflammatory conditions may have a clinical and radiographic phenotype that mimics small vessel primary angiitis, at times with overlapping pathologic features as well. Such diagnoses, including myelin oligodendrocyte glycoprotein antibody-associated disease and central nervous system-restricted hemophagocytic lymphohistiocytosis, can be non-invasively diagnosed with serum antibody or genetic testing that would prompt different monitoring and treatment paradigms. To determine the ultimate diagnosis of patients who were suspected prior to biopsy to have small vessel primary angiitis, we reviewed the clinical, radiographic, and pathological features of a cohort of patients at a single center undergoing brain biopsy for non-oncologic indications. METHODS: Clinical data were retrospectively extracted from the medical record. Pathology and neuroimaging review was conducted. RESULTS: We identified 21 patients over a 19-year time-period, of whom 14 (66.7%) were ultimately diagnosed with entities other than small vessel primary angiitis that would have obviated the need for brain biopsy. Diagnoses included anti-myelin oligodendrocyte glycoprotein antibody associated disease (n = 9), central nervous system-restricted hemophagocytic lymphohistiocytosis (n = 3), anti-GABAA receptor encephalitis (n = 1), and Aicardi-Goutières syndrome (n = 1). INTERPRETATION: This study highlights the importance of pursuing now readily available non-invasive testing for mimicking diagnoses before performing a brain biopsy for suspected small vessel primary angiitis of the central nervous system. ANN NEUROL 2023;93:109-119.

Clinical presentation of new onset refractory status epilepticus in children (the pSERG cohort).

OBJECTIVE: We aimed to characterize the clinical profile and outcomes of new onset refractory status epilepticus (NORSE) in children, and investigated the relationship between fever onset and status epilepticus (SE). METHODS: Patients with refractory SE (RSE) between June 1, 2011 and October 1, 2016 were prospectively enrolled in the pSERG (Pediatric Status Epilepticus Research Group) cohort. Cases meeting the definition of NORSE were classified as "NORSE of known etiology" or "NORSE of unknown etiology." Subgroup analysis of NORSE of unknown etiology was completed based on the presence and time of fever occurrence relative to RSE onset: fever at onset (≤24 h), previous fever (2 weeks-24 h), and without fever. RESULTS: Of 279 patients with RSE, 46 patients met the criteria for NORSE. The median age was 2.4 years, and 25 (54%) were female. Forty (87%) patients had NORSE of unknown etiology. Nineteen (48%) presented with fever at SE onset, 16 (40%) had a previous fever, and five (12%) had no fever. The patients with preceding fever had more prolonged SE and worse outcomes, and 25% recovered baseline neurological function. The patients with fever at onset were younger and had shorter SE episodes, and 89% recovered baseline function. SIGNIFICANCE: Among pediatric patients with RSE, 16% met diagnostic criteria for NORSE, including the subcategory of febrile infection-related epilepsy syndrome (FIRES). Pediatric NORSE cases may also overlap with refractory febrile SE (FSE). FIRES occurs more frequently in older children, the course is usually prolonged, and outcomes are worse, as compared to refractory FSE. Fever occurring more than 24 h before the onset of seizures differentiates a subgroup of NORSE patients with distinctive clinical characteristics and worse outcomes.

Current practices in the diagnosis and treatment of Rasmussen syndrome: Results of an international survey.

PURPOSE: Rasmussen syndrome (RS) is marked by progressive unihemispheric atrophy, resulting in hemiparesis, refractory epilepsy, and cognitive/language decline. Detailed diagnostic and treatment algorithms are currently lacking. We aimed to survey medical providers on their current practices in the diagnosis and treatment of RS. METHODS: A steering committee was formed to create the survey, which was disseminated to the international medical community. One hundred twelve surveys were completed. Descriptive statistics, as well as comparisons by level of experience, patient age group cared for, and geographic region using Fisher's exact test, were conducted. RESULTS: Analysis of cerebrospinal fluid (82 %) and serum (78 %) for autoimmune encephalitis (AE) are completed by most, while approximately one-third obtain genetic and metabolic studies in all patients (36 % and 38 %, respectively). Providers in US and Europe more readily pursue serum AE antibody panels (85 % and 85 %, respectively, versus 67 %, p = 0.019) and genetic testing (56 % and 47 %, respectively, versus 14 %, p < 0.001) than the rest of the world. Thirty-six percent proceed to biopsy in patients otherwise meeting diagnostic criteria, and US providers are more likely to suggest this than others (73 % versus 14-41 %, p < 0.001). Opinions differed on the prioritization of hemispherectomy/hemispherotomy versus immunotherapy in 14 clinical scenarios with various neurologic deficit severity provided. Preferred immunotherapy regimens also varied, with US providers more often choosing IVIG as first-line (67 %) compared to others (28 %-32 %, p = 0.030). Surgical standard of care was identified as functional hemispherectomy or hemispherotomy by 90 %. CONCLUSION: The survey highlights trends but also significant variations in clinical practice that can serve as targets for future research and expert consensus guidelines.

Autoimmune-associated seizure disorders.

With the discovery of an expanding number of neural autoantibodies, autoimmune etiologies of seizures have been increasingly recognized. Clinical phenotypes have been identified in association with specific underlying antibodies, allowing an earlier diagnosis. These phenotypes include faciobrachial dystonic seizures with LGI1 encephalitis, neuropsychiatric presentations associated with movement disorders and seizures in NMDA-receptor encephalitis, and chronic temporal lobe epilepsy in GAD65 neurologic autoimmunity. Prompt recognition of these disorders is important, as some of them are highly responsive to immunotherapy. The response to immunotherapy is highest in patients with encephalitis secondary to antibodies targeting cell surface synaptic antigens. However, the response is less effective in conditions involving antibodies binding intracellular antigens or in Rasmussen syndrome, which are predominantly mediated by cytotoxic T-cell processes that are associated with irreversible cellular destruction. Autoimmune encephalitides also may have a paraneoplastic etiology, further emphasizing the importance of recognizing these disorders. Finally, autoimmune processes and responses to novel immunotherapies have been reported in new-onset refractory status epilepticus (NORSE) and febrile infection-related epilepsy syndrome (FIRES), warranting their inclusion in any current review of autoimmune-associated seizure disorders.

Isolated Psychiatric Symptoms in Children With Anti-N-Methyl-d Aspartate Receptor Encephalitis.

BACKGROUND: Isolated psychiatric symptoms can be the initial symptom of pediatric anti-N-methyl-d-aspartate (NMDA) receptor autoimmune encephalitis (pNMDARE). Here we report on the prevalence of isolated psychiatric symptoms in pNMDARE. We also assess whether initial neurodiagnostic tests (brain magnetic resonance imaging [MRI], electroencephalography [EEG], and/or cerebrospinal fluid [CSF] white blood cell count) are abnormal in children with isolated psychiatric symptoms and pNMDARE. METHODS: This multicenter retrospective cohort study from CONNECT (Conquering Neuroinflammation and Epilepsies Consortium) from 14 institutions included children under age 18 years who were diagnosed with pNMDARE. Descriptive statistics using means, medians, and comparisons for continuous versus discrete data was performed. RESULTS: Of 249 children included, 12 (5%) had only psychiatric symptoms without other typical clinical features of autoimmune encephalitis at presentation. All but one (11 of 12 = 92%) had at least one abnormal finding on initial ancillary testing: eight of 12 (67%) had an abnormal EEG, six of 12 (50%) had an abnormal MRI, and five of 12 (42%) demonstrated CSF pleocytosis. The single patient with a normal MRI, EEG, and CSF profile had low positive CSF NMDA antibody (titer of 1:1), and symptoms improved without immunotherapy. CONCLUSIONS: Isolated first-episode psychiatric symptoms in pNMDARE are uncommon, and the majority of children will exhibit additional neurodiagnostic abnormalities. Delaying immunotherapy in a child with isolated psychiatric symptoms and normal neurodiagnostic testing may be warranted while awaiting confirmatory antibody testing.

Mechanisms and Emerging Therapies for Treatment of Seizures in Pediatric Autoimmune Encephalitis and Autoinflammatory/Autoimmune-Associated Epilepsy.

There has been increasing understanding of the role of inflammation in seizures and epilepsy, as well as targeted immunomodulatory treatments. In children, immune-mediated seizures often present acutely in the setting of autoimmune encephalitis and are very responsive to immunotherapy with low rates of subsequent epilepsy. Conversely, seizures in autoimmune-associated epilepsies, such as Rasmussen syndrome, can remain refractory to multimodal therapy, including immunomodulation. In this review, the authors discuss the presentations of immune-mediated seizures in children, underlying mechanisms, and emerging therapies.

Long-term neuropsychological outcomes in children with febrile infection-related epilepsy syndrome (FIRES) treated with anakinra.

Background: Febrile-infection related epilepsy syndrome (FIRES) is a rare epilepsy syndrome in which a previously healthy individual develops refractory status epilepticus in the setting of a preceding febrile illness. There are limited data regarding detailed long-term outcomes. This study aims to describe the long-term neuropsychological outcomes in a series of pediatric patients with FIRES. Methods: This is a retrospective multi-center case series of pediatric patients with a diagnosis of FIRES treated acutely with anakinra who had neuropsychological testing at least 12 months after status epilepticus onset. Each patient underwent comprehensive neuropsychological evaluation as part of routine clinical care. Additional data collection included the acute seizure presentation, medication exposures, and outcomes. Results: There were six patients identified with a median age of 11.08 years (IQR: 8.19-11.23) at status epilepticus onset. Anakinra initiation was a median of 11 days (IQR: 9.25-13.50) after hospital admission. All patients had ongoing seizures and none of the patients returned to baseline cognitive function with a median follow-up of 40 months (IQR 35-51). Of the five patients with serial full-scale IQ testing, three demonstrated a decline in scores over time. Testing results revealed a diffuse pattern of deficits across domains and all patients required special education and/or accommodations for academic learning. Conclusions: Despite treatment with anakinra, neuropsychological outcomes in this series of pediatric patients with FIRES demonstrated ongoing diffuse neurocognitive impairment. Future research will need to explore the predictors of long-term neurocognitive outcomes in patients with FIRES and to evaluate if acute treatment interventions improve these outcomes.

Creation of a Novel Child Simulator and Curriculum to Optimize Administration of Seizure Rescue Medication.

INTRODUCTION: Although most cases of pediatric convulsive status epilepticus start in the prehospital setting, many patients do not receive treatment. The use of prehospital seizure rescue medications by caregivers is crucial, but studies suggest a lack of proper training on medication use. METHODS: We created a novel proof of principle mannequin and simulation for training proper administration of rectal diazepam, with a scoring paradigm to standardize and assess the educational process. RESULTS: Twenty-three health care providers (nurses and nurse practitioners, residents/fellows, and attending physicians) and 5 patient guardians/parents were included in the study. The rectal diazepam simulator displayed a high degree of physical and emotional realism (mean ≥ 4/5 on Likert scale survey) that effectively decreased time to treatment (-12.3 seconds; SD, 16.3) and improved the accuracy of medication delivery in a simulation setting (-4.2 points; SD, 3.1). The scoring technique had appropriate interrater reliability (≥86% on all but 2 prompts) and was a feasible instrument to assess the effectiveness of the educational intervention. CONCLUSIONS: A unique procedure-focused child simulator and rescue medication score offer an innovative and effective means to train caregivers on the use of lifesaving seizure rescue medications.

MRI Features and Their Association With Outcomes in Children With Anti-NMDA Receptor Encephalitis.

OBJECTIVES: How brain MRI lesions associate with outcomes in pediatric anti-NMDA receptor encephalitis (pNMDARE) is unknown. In this study, we correlate T2-hyperintense MRI brain lesions with clinical outcomes in pNMDARE. METHODS: This was a multicenter retrospective cohort study from 11 institutions. Children younger than 18 years with pNMDARE were included. One-year outcomes were assessed by the modified Rankin Score (mRS) with good (mRS ≤2) and poor (mRS ≥3) outcomes. RESULTS: A total of 175 pNMDARE subjects were included, with 1-year mRS available in 142/175 (81%) and 60/175 (34%) had abnormal brain MRIs. The most common T2-hyperintense lesion locations were frontal, temporal, and parietal. MRI features that predicted poor 1-year outcomes included abnormal MRI, particularly T2 lesions in the frontal and occipital lobes. After adjusting for treatment within 4 weeks of onset, improvement within 4 weeks, and intensive care unit admission, MRI features were no longer associated with poor outcomes, but after multiple imputation for missing data, T2 frontal and occipital lesions associated with poor outcomes. DISCUSSION: Abnormal frontal and occipital lesions on MRI may associate with 1-year mRS in pNMDARE. MRI of the brain may be a helpful prognostication tool that should be examined in future studies.

Identifying Barriers to Care in the Pediatric Acute Seizure Care Pathway.

Objective: We aimed to describe the acute seizure care pathway for pediatric patients and identify barriers encountered by those involved in seizure care management. We also proposed interventions to bridge these care gaps within this pathway. Methods: We constructed a process map that illustrates the acute seizure care pathway for pediatric patients at Boston Children's Hospital (BCH). The map was designed from knowledge gathered from unstructured interviews with experts at BCH, direct observation of patient care management at BCH through a quality improvement implemented seizure diary and from findings through three studies conducted at BCH, including a prospective observational study by the pediatric Status Epilepticus Research Group, a multi-site international consortium. We also reviewed the literature highlighting gaps and strategies in seizure care management. Results: Within the process map, we identified twenty-nine care gaps encountered by caregivers, care teams, residential and educational institutions, and proposed interventions to address these challenges. The process map outlines clinical care of a patient through the following settings: 1) pre-hospitalization setting, defined as residential and educational settings before hospital admission, 2) BCH emergency department and inpatient settings, 3) post-hospitalization setting, defined as residential and educational settings following hospital discharge or clinic visit and 4) follow-up BCH outpatient settings, including neurology, epilepsy, and primary care provider clinics. The acute seizure care pathway for a pediatric patient who presents with seizures exhibits at least twenty-nine challenges in acute seizure care management. Significance: Identification of care barriers in the acute seizure care pathway provides a necessary first step for implementing interventions and strategies in acute seizure care management that could potentially impact patient outcomes.

Infantile Hemiconvulsion-Hemiplegia and Epilepsy (IHHE) in a boy with tuberous sclerosis complex.

Tuberous sclerosis complex (TSC) is a rare autosomal dominant disease due to pathogenic variants in TSC1 or TSC2 genes. In the brain, TSC is associated with multiple cortical and subcortical malformations including tubers and abnormalities of radial neuronal migration. Approximately 80% of patients develop epilepsy in the first two years of life, most often focal seizures and infantile spasms. As with all seizure disorders, systemic illness and fever can trigger a seizure, and result in status epilepticus or even refractory status epilepticus. Infantile Hemiconvulsion-Hemiplegia and Epilepsy (IHHE) is considered a subcategory of new-onset refractory status epilepticus (NORSE) and presents with hemiclonic seizures in the setting of fever, unihemispheric brain imaging abnormality and hemiparesis. Here, we present an 18-month-old boy with TSC who developed IHHE. His extensive brain malformations and neuronal hyperexcitability in peri-tuberal tissue could have predisposed him to IHHE. In addition to these factors, we postulate that another prerequisite for IHHE is likely a genetic predisposition for an excessive inflammatory response that is yet to be elucidated.

Proposal to optimize evaluation and treatment of Febrile infection-related epilepsy syndrome (FIRES): A Report from FIRES workshop.

Febrile infection-related epilepsy syndrome (FIRES) is a rare catastrophic epileptic encephalopathy that presents suddenly in otherwise normal children and young adults causing significant neurological disability, chronic epilepsy, and high rates of mortality. To suggest a therapy protocol to improve outcome of FIRES, workshops were held in conjunction with American Epilepsy Society annual meeting between 2017 and 2019. An international group of pediatric epileptologists, pediatric neurointensivists, rheumatologists and basic scientists with interest and expertise in FIRES convened to propose an algorithm for a standardized approach to the diagnosis and treatment of FIRES. The broad differential for refractory status epilepticus (RSE) should include FIRES, to allow empiric therapies to be started early in the clinical course. FIRES should be considered in all previously healthy patients older than two years of age who present with explosive onset of seizures rapidly progressing to RSE, following a febrile illness in the preceding two weeks. Once FIRES is suspected, early administrations of ketogenic diet and anakinra (the IL-1 receptor antagonist that blocks biologic activity of IL-1ß) are recommended.

An improved phenylarsine oxide-affinity method identifies triose phosphate isomerase as a candidate redox receptor protein.

Reversible oxidation on proteins of vicinal thiols to form intraprotein disulfides is believed to be an important means by which redox sensitivity is conferred on cellular signaling and metabolism. Affinity chromatography using immobilized phenylarsine oxide (PAO), which binds preferentially to vicinal thiols over monothiols, has been used in very limited studies to isolate the fraction of cellular proteins that exhibit reversible oxidation of vicinal thiols to presumed disulfide bonds. A challenge to the use of PAO-affinity chromatography for isolation of readily oxidizable vicinal thiol proteins (VTPs) has been the lack of a disulfide reducing agent that reverses oxidation of the PAO-binding protein thiols and maintains these in the reduced state necessary to bind PAO but does not also compete with the VTPs for binding to the immobilized PAO. The present study demonstrates that the capture from a detergent-soluble rat brain extract of VTPs by PAO-affinity chromatography was improved greatly by use of the reducing agent tris(2-carboxyethyl)-phosphine which, unlike more traditional disulfide-reducing agents, does not contain a thiol group. Moreover, we show that, while a substantial fraction of total brain proteins contain PAO-binding thiols, only a fraction of these were readily and reversibly oxidized. The two most abundant of these redox-active proteins were identified as albumin and triose phosphate isomerase (TPI). We propose that TPI is a candidate intracellular redox receptor protein. The improved PAO-affinity method detailed here should enable the discovery of lower abundance novel redox-active regulatory proteins.

Pharmacotherapy for Pediatric Convulsive Status Epilepticus.

Convulsive status epilepticus (CSE) is one of the most common pediatric neurological emergencies. Ongoing seizure activity is a dynamic process and may be associated with progressive impairment of gamma-aminobutyric acid (GABA)-mediated inhibition due to rapid internalization of GABAA receptors. Further hyperexcitability may be caused by AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) and NMDA (N-methyl-D-aspartic acid) receptors moving from subsynaptic sites to the synaptic membrane. Receptor trafficking during prolonged seizures may contribute to difficulties treating seizures of longer duration and may provide some of the pathophysiological underpinnings of established and refractory SE (RSE). Simultaneously, a practice change toward more rapid initiation of first-line benzodiazepine (BZD) treatment and faster escalation to second-line non-BZD treatment for established SE is in progress. Early administration of the recommended BZD dose is suggested. For second-line treatment, non-BZD anti-seizure medications (ASMs) include valproate, fosphenytoin, or levetiracetam, among others, and at this point there is no clear evidence that any one of these options is better than the others. If seizures continue after second-line ASMs, RSE is manifested. RSE treatment consists of bolus doses and titration of continuous infusions under continuous electro-encephalography (EEG) guidance until electrographic seizure cessation or burst-suppression. Ultimately, etiological workup and related treatment of CSE, including broad spectrum immunotherapies as clinically indicated, is crucial. A potential therapeutic approach for future studies may entail consideration of interventions that may accelerate diagnosis and treatment of SE, as well as rational and early polytherapy based on synergism between ASMs by utilizing medications targeting different mechanisms of epileptogenesis and epileptogenicity.

Interleukin-6 Blockade With Tocilizumab in Anakinra-Refractory Febrile Infection-Related Epilepsy Syndrome (FIRES).

Febrile infection-related epilepsy syndrome (FIRES) is characterized by new onset refractory status epilepticus in a previously healthy child that is associated with poor cognitive outcomes and chronic epilepsy. Innate immune system dysfunction is hypothesized to be a key etiologic contributor, with a potential role for immunotherapy blocking pro-inflammatory cytokines, such as interleukin-1ß and interleukin-6. We present a case of FIRES refractory to anakinra, an interleukin-1 receptor antagonist, subsequently treated with the ketogenic diet and tocilizumab, an interleukin-6 receptor antagonist, temporally associated with seizure cessation and a favorable 1-year outcome.

Magnetic resonance imaging-guided laser-induced thermal therapy for functional hemispherotomy in a child with refractory epilepsy and multiple medical comorbidities.

Magnetic resonance imaging-guided laser-induced thermal therapy (MRgLITT) is a minimally invasive surgical approach increasingly employed for precise targeted ablation of epileptogenic brain foci. Recent reports have described corpus callosotomy using MRgLITT, though its application in more extensive functional disconnections has not been documented. Here, the authors detail its use in achieving a palliative hemispherotomy in a 5-year-old with medically refractory hemiclonic seizures following a hemispheric infarction, highlighting a novel use of this surgical technique. In this particular case, open craniotomy was deemed high risk given the multiple medical comorbidities including congenital cardiac disease and end-stage renal failure. MRgLITT was considered an alternative approach with a lower risk for periprocedural hemodynamic perturbations. The patient tolerated the procedure well, attaining an Engel class IB outcome at 16 months' follow-up. This suggests that MRgLITT may be an alternative approach to an open hemispherectomy, particularly in cases in which multiple comorbidities pose significant risks and preclude an open procedure.

Posterior-onset Rasmussen's encephalitis with ipsilateral cerebellar atrophy and uveitis resistant to rituximab.

Rasmussen encephalitis (RE) is a disorder characterized by drug-resistant seizures and progressive unihemispheric atrophy, hemiparesis, and varying degrees of cognitive decline. The pathophysiology of RE remains elusive, with hypotheses suggesting underlying autoimmune- and T cell-mediated processes. In this case report, we describe a single patient's clinical course from the first day of presentation until definitive treatment for atypical Rasmussen encephalitis at a tertiary care pediatric center. The patient exhibited several atypical features of Rasmussen encephalitis, including a posterior predominance of initial seizure onset with the development of severe choreoathetosis and ipsilateral cerebellar atrophy. He subsequently developed coexistent autoimmune disorders in the form of psoriasis and uveitis, and underwent multiple forms of immunotherapy with limited benefit. This patient shows an association of RE with other autoimmune conditions supporting an autoimmune mechanism of disease while exhibiting several atypical features of RE. Rarely, occipital lobe seizures have been documented as the presenting semiology of this syndrome. This case highlights the need to be mindful of atypical features that may delay hemispherectomy, which remains the definitive treatment. It also suggests that children may be predisposed to the development of autoimmune disorders in later stages of the disease.

Anakinra usage in febrile infection related epilepsy syndrome: an international cohort.

Febrile-infection related epilepsy syndrome (FIRES) is a devastating neurological condition characterized by a febrile illness preceding new onset refractory status epilepticus (NORSE). Increasing evidence suggests innate immune dysfunction as a potential pathological mechanism. We report an international retrospective cohort of 25 children treated with anakinra, a recombinant interleukin-1 receptor antagonist, as an immunomodulator for FIRES. Anakinra was potentially safe with only one child discontinuing therapy due to infection. Earlier anakinra initiation was associated with shorter duration of mechanical ventilation, ICU and hospital length of stay. Our retrospective data lay the groundwork for prospective consensus-driven cohort studies of anakinra in FIRES.

Baseline and outcome assessment in pediatric status epilepticus.

PURPOSE: To summarize different aspects of short and long-term outcomes associated with SE, including mortality, recurrence, subsequent epilepsy, neurocognitive dysfunction, imaging abnormalities, and health-related quality of life. METHODS: We searched MEDLINE for studies that assessed the short-term and long-term outcome of status epilepticus in pediatric population, including mortality, recurrence of seizure and status epilepticus, neurological, cognitive, or behavioral impairment, and health-related quality of life. We excluded studies that exclusively assessed the adult population. RESULTS: Mortality in pediatric SE is relatively low, while morbidity poses more challenges. The underlying cause of SE has been shown to be a major determinant in the outcome after SE. However, it is difficult to establish the net effect of SE on outcome due to the heterogeneity of the studies. Notably, this review highlights that health-related quality of life, an important aspect of long-term outcome in pediatric SE, is under-addressed and merits further investigation. CONCLUSION: There is a need to acquire high-quality long-term data evaluating QoL, neuroimaging, use of continuous infusions, and cognitive and behavioral outcome of children who experience SE.