片側痙攣・片麻痺・てんかん症候群

BACKGROUND: Infection-triggered encephalopathy syndromes (ITES) are acute, para-infectious disorders that can cause disability or death. Recognition is increasingly important in viral pandemics, but clinical features and outcomes remain poorly understood. METHODS: PubMed search (inception to 6 March 2024) identified studies with published individual patient data (raw data were not collected from authors). The search was updated on 14 May 2026 using the same terms to identify reports and cases published after the data extraction cutoff. Data were extracted by paediatric neurologists using a standardised proforma. Major syndromes included acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), acute necrotising encephalopathy (ANE), acute shock with encephalopathy and multiorgan failure (ASEM), hemiconvulsion-hemiplegia-epilepsy syndrome (HHE), febrile infection-related epilepsy syndrome (FIRES) and mild encephalopathy with reversible splenial lesion (MERS). We performed a pooled analysis of individual-level published data investigating patient characteristics, infections, and clinical outcomes measured by six-month modified Rankin Scale (mRS). Infection-syndrome associations were analysed with chi-square normalised residuals. FINDINGS: 1946 patients from 656 studies (by ascending age of onset) included 164 ASEM (median age 0.78 years), 217 AESD (1.3 years), 95 HHE (2 years), 414 ANE (3.4 years), 562 FIRES (9 years), and 422 MERS (9.25 years). An updated search identified 658 cases from 171 studies that could be eligible for inclusion. AESD was linked to human herpesvirus 6 (z = 12.87); ANE with influenza A (z = 11.1), SARS-CoV-2 (z = 9.1) and influenza B (z = 4.3); MERS with rotavirus infection (z = 7.48); and FIRES with absence of microbiological identification (z = 18.2) (all p < 0.001).Neuroimaging was often delayed. Magnetic resonance imaging (MRI) brain restricted diffusion was the commonest finding, typically bilateral (except HHE). Characteristic patterns included thalamic involvement with or without haemorrhagic changes in ANE, corpus callosum involvement in MERS, and subcortical white matter involvement in AESD and HHE. Cerebrospinal fluid pleocytosis occurred mostly in FIRES and MERS, and elevated protein in ANE.Immunotherapy (commonly steroids, immunoglobulin) including biologics (anakinra, tocilizumab) was used most in ANE and FIRES. Acute mortality was 12% (227/1946), highest in ASEM (50%) and ANE (35%). There was good six-month outcome (mRS 0-2) in 52% (95% CI 50-55; 615/1174): MERS 99% (95% CI 97-100; 323/326), AESD 54% (95% CI 44-64; 50/93), FIRES 38% (95% CI 33-44; 120/314), ANE 33% (95% CI 27-38; 88/269), HHE 16% (95% CI 7-32; 5/32), and ASEM 15% (95% CI 9-24; 14/91). INTERPRETATION: ITES showed distinct demographic, clinico-radiological features and outcomes. This largest ITES cohort to date highlights the importance of timely imaging, intervention, and future global collaboration to advance diagnosis, treatment, and pandemic preparedness. FUNDING: No funding was received for this work.

AIMS: To summarize the clinical and genetic characteristics of DNM1L-related disorders and explore genotype-phenotype correlations and prognosis. METHODS: We retrospectively analyzed clinical data from 18 children with DNM1L variants diagnosed between 2015 and October 2025. Combined with systematic literature review (2007-October 2025) to analyze reported DNM1L variant types and clinical phenotypes. RESULTS: The cohort included 18 children (10 male, 8 female) with a median onset age of 3.5 years. Epilepsy occurred in 88.9% of patients, with 72.2% developing super-refractory status epilepticus; 66.7% had dystonia. Most patients exhibited brain MRI and EEG abnormalities. Eight novel pathogenic variants were identified (four missense, three frameshift, one compound heterozygous). Notably, eight patients with middle domain variants (primarily p.Arg403Cys) presented a novel "hemiconvulsion-hemiplegia-epilepsy syndrome" phenotype. At last follow-up, 83.3% had a modified Rankin Scale score ≥4, indicating severe disability and poor prognosis. Literatures review confirmed DNM1L variants are predominantly missense, with the middle domain as a hotspot. The p.Arg403Cys variant is recurrent and highly prevalent in the Chinese. Middle domain variants are more common in Asians, while GTPase domain variants are more frequent in Europeans. Missense variants in the middle domain correlated with higher rates of neurological dysfunction and mortality. CONCLUSIONS: This study represents an extension of our earlier work by incorporating an additional 18 cases, which expands the genetic and phenotypic spectrum of DNM1L-related disorders. It identifies "hemiconvulsion-hemiplegia-epilepsy syndrome" as a distinct feature and potential prognostic indicator for middle domain variants. The established genotype-phenotype patterns, based on protein domains and ethnic differences, provide critical insights for precise diagnosis and management.

INTRODUCTION AND OBSERVATIONS: Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a rare complication of prolonged focal status epilepticus in childhood. The typical course follows a complex febrile convulsion and status epilepticus, typically in a child under 4 years of age, accompanied by cytotoxic edema of one hemisphere, evolving secondarily to atrophy and refractory seizures. We present a case series from Mayotte Island, providing a clinical and radiological chronological picture of this neurological disorder, with Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scans taken at different stages of the disease. CONCLUSION: HHE syndrome is a rare clinic-radiological syndrome that complicates prolonged febrile illness. Understanding the spontaneous evolution of this pathology makes it possible to limit explorations and even to project on the long-term prognosis, in the absence of known therapies.

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a rare pediatric epilepsy syndrome characterized by prolonged focal febrile seizures, postictal hemiparesis, and progressive unilateral brain injury, often followed by chronic epilepsy. We report a previously healthy 10-month-old girl who presented with a prolonged left-sided focal fever-associated seizure. She tested positive for SARS-CoV-2 but did not meet criteria for multisystem inflammatory syndrome in children. On admission, she had left-sided flaccid hemiparesis. Brain MRI showed mild diffusion restriction and marked hyperperfusion of the right hemispheric gray matter, most prominently in the frontal, temporo-occipital, and hippocampal regions. EEG showed high-amplitude slowing over the right hemisphere without epileptiform discharges. No further seizures occurred, and long-term antiseizure treatment was not required. At 9-month follow-up, the patient was seizure-free and developmentally age-appropriate, but the hemiparesis persisted. Serial MRI showed progressive right hemispheric cortical and subcortical atrophy and hippocampal sclerosis. Extensive diagnostic workup found no other structural, infectious, or metabolic cause. This case illustrates the classical biphasic course of HHE syndrome and highlights the diagnostic value of early MRI, EEG, and genetic testing. The patient carried a paternally inherited heterozygous IRF3 variant, a gene essential for innate antiviral immunity. Although causality cannot be established, the temporal association with SARS-CoV-2 infection and an IRF3 variant suggests a possible genetic predisposition to infection-triggered injury. Continued clinical vigilance and long-term follow-up are essential, as epilepsy develops in most children with HHE. Greater awareness of this syndrome may support earlier recognition and timely rehabilitation to optimize functional outcomes.