Severe pediatric acute encephalopathy syndromes related to SARS-CoV-2.

Background and objectives: To clarify whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection cause acute encephalopathy in children and which are the most common syndromes that cause them and what are the outcomes. Methods: A nationwide web-based survey among all members of the Japanese Society of Child Neurology to identify pediatric patients aged < 18 years who developed acute encephalopathy in Japan between 1 January 2020 and 31 May 2022 associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection confirmed by polymerase chain reaction or antigen tests using pharyngeal swabs. Acute encephalopathy was defined as acute onset of impaired consciousness lasting > 24 h or an altered mental state; neurological symptoms arising within 2 weeks of onset of COVID-19 or multisystem inflammatory syndrome in children (MIS-C)/pediatric inflammatory multisystem syndrome (PIMS); evidence of SARS-CoV-2 infection; and reasonable exclusion of other diseases. Patients were divided into the known clinico-radiological acute encephalopathy syndrome group and unexplained or unclassifiable acute encephalopathy group. Outcomes were assessed by pediatric cerebral performance category (PCPC) score at hospital discharge. Results: Of the 3,802 society members, 217 representing institutions responded, and 39 patients with suspected acute encephalopathy were reported, of which 31 met inclusion criteria. Of these patients, 14 were diagnosed with known clinico-radiological acute encephalopathy syndromes, with acute encephalopathy with biphasic seizures and late reduced diffusion (five patients) being the most common. Five developed acute encephalopathy associated with MIS-C/PIMS. Among 31 patients, 9 (29.0%) had severe sequelae or died (PCPC ≥ 4). Two of three patients with encephalopathy with acute fulminant cerebral edema and two with hemorrhagic shock and encephalopathy syndrome died. The PCPC scores were higher in the known clinico-radiological acute encephalopathy syndrome group than in the unexplained or unclassifiable acute encephalopathy group (P < 0.01). Discussion: Acute encephalopathy related to SARS-CoV-2 infection was demonstrated to be more severe than that caused by other viruses in Japan. Acute encephalopathy syndromes characterized by specific neuroradiological findings was associated with poor clinical outcomes.

Interstitial microdeletions of 3q26.2q26.31 in two patients with neurodevelopmental delay and distinctive features.

Interstitial microdeletions in the long arm of chromosome 3 are rare. In this study, we identified two patients with approximately 5-Mb overlapping deletions in the 3q26.2q26.31 region. Both patients showed neurodevelopmental delays, congenital heart defects, and distinctive facial features. One of them showed growth deficiency and brain abnormalities, as shown on a magnetic resonance imaging scan. Haploinsufficiency of NLGN1 and FNDC3B present in the common deletion region was considered to be responsible for neurodevelopmental delay and the distinctive features, respectively. The possibility of unmasked variants in PLD1 was considered and analyzed, but no possible pathogenic variant was found, and the mechanism of the congenital heart defects observed in the patients is unknown. Because 3q26.2q26.31 deletions are rare, more information is required to establish genotype-phenotype correlations associated with microdeletions in this region.

Interstitial deletions in the proximal regions of 6q: 12 original cases and a literature review.

Interstitial microdeletions in the proximal region of the long arm of chromosome 6 are rare. Herein we have reported 12 patients with developmental delays associated with interstitial microdeletions in 6q ranging from q12 to q22. The microdeletions were detected by chromosomal microarray testing. To confirm the clinical significance of these deletions, genotype-phenotype correlation analysis was performed using genetic and predicted loss-of-function data. SIM1 was recognized as the gene responsible for developmental delay, particularly in Prader-Willi syndrome-like phenotypes. Other genes possibly related to developmental delay were ZNF292, PHIP, KCNQ5, and NUS1. To further establish the correlation between the genotype and phenotype, more patient information is required.

Acute encephalopathy with biphasic seizures and late reduced diffusion; posterior frontal hyperperfusion before late seizures revealed by arterial spin labeling: A case report.

BACKGROUND: Arterial spin labeling, a magnetic resonance imaging modality that can evaluate cerebral perfusion without using a contrast material or ionizing radiation, is becoming increasingly accessible. However, only a few reports have used this method to assess the perfusion abnormalities observed in acute encephalopathy with biphasic seizures and late reduced diffusion. PATIENT DESCRIPTION: A 10-month-old Japanese girl presented with febrile status epilepticus (early seizures). Her convulsions ceased after the administration of intravenous phenobarbital, although her impaired consciousness was protracted. Five days later, diffusion-weighted imaging revealed slightly high signal intensity lesions in the bilateral posterior frontal areas. Arterial spin labeling revealed bilateral frontal-dominant hypoperfusion and posterior frontal hyperperfusion. On day 6, she had three convulsions (late seizures) and was diagnosed with acute encephalopathy with biphasic seizures and late reduced diffusion. She received treatment accordingly and recovered eventually. DISCUSSION: Based on previous reports, hypoperfusion within 1-2 days of early seizures and hyperperfusion accompanied by bright tree appearance on diffusion-weighted imaging within 1-2 days of late seizures are typical in acute encephalopathy with biphasic seizures and late reduced diffusion. In our patient, the first magnetic resonance imaging scan was performed one day prior to the onset of late seizures. We observed posterior frontal hyperperfusion accompanied by high signals on diffusion-weighted imaging, which leads us to speculate that this could be a predictive marker of late seizures.

Acute encephalopathy in children with tuberous sclerosis complex.

OBJECTIVE: We examined the clinical manifestations of acute encephalopathy (AE) and identify risk factors for AE in children with tuberous sclerosis complex (TSC). METHODS: The clinical data of 11 children with clinically diagnosed TSC associated with AE and 109 children with clinically diagnosed TSC alone aged 4 years or older were collected from 13 hospitals. RESULTS: Of the 11 children with AE, 5 had histories of febrile seizures (FS), and all had histories of febrile status epilepticus (FSE). AE developed within 24 h after fever onset in all children with seizures lasting 30 min or longer. All children developed coma after seizure cessation. Head magnetic resonance imaging (MRI) revealed widespread abnormalities in the cerebral cortex, subcortical white matter, corpus callosum, basal ganglia, and thalamus. One child died; seven had severe neurological sequelae; and the other three, mild sequelae. Logistic regression analysis revealed that a history of FSE was correlated with the development of AE. SIGNIFICANCE: AE in children with TSC was characterized by sudden onset after fever, followed by coma, widespread brain edema evident on MRI, and poor outcomes. A history of FSE was a risk factor for the development of AE.

Behavioral problems and family distress in tuberous sclerosis complex.

BACKGROUND: Tuberous sclerosis complex (TSC)-associated neuropsychiatric disorders (TAND) have a large impact on patients and their families. Improving intellectual ability outcomes using preventive vigabatrin (VGB) treatment has recently been reported. AIM: The aim of this study was to investigate the severity of behavioral problems and degree of distress among families of patients with TSC with and without a history of VGB treatment. METHOD: The study enrolled 21 children and adolescents who were patients with TSC from four hospitals: 14 in the VGB group and 7 in the no-VGB group. To evaluate patients' psychiatric and neurological symptoms, we used the TAND Checklist, Aberrant Behavior Checklist (ABC), Social Communication Questionnaire (SCQ), and Social Responsive Scale-2nd edition (SRS-2). RESULTS: All VGB-group patients were administered VGB after the onset of epileptic seizures. No obvious differences were observed between the VGB and no-VGB groups in behavioral problem scores on the TAND Checklist, or on the ABC, SCQ, and SRS-2 total scores. Behavioral problem scores were lower in patients with normal intelligence than in those with mild intellectual disability (ID; P = 0.042). Degrees of family distress assessed with the TAND Checklist were not correlated with the intelligence quotient/developmental quotient (IQ/DQ) or seizure frequency but were correlated with the total SRS-2 scores (P = 0.022). For several patients, there were large discrepancies between familial and physician ratings of the TAND impact score. CONCLUSION: Children and adolescents with TSC may present with significant behavioral difficulties and family distress, regardless of whether they were treated with VGB or not after the onset of seizures. Difficulties in social communication may have the strongest "TAND impact" on families.

A case of pyridoxine-dependent epilepsy with novel ALDH7A1 mutations.

Pyridoxine-dependent epilepsy (PDE) is a rare autosomal-recessive disorder typically presenting with neonatal seizures and is sometimes difficult to diagnose, because the clinical features mimic those of birth asphyxia. A Japanese newborn boy presented with pulmonary haemorrhage and convulsions on the day of birth. Brain computed tomography showed diffuse, but mild, low-density cerebral white matter and a thin subdural hematoma in the posterior fossa. He did not have thrombocytopenia or coagulopathy. His respiratory status improved with conservative treatment, but his convulsions were persistent even after prescription of several antiepileptic drugs. His serum and cerebrospinal fluid showed decreased vitamin B6 vitamers and increased upstream metabolites of α-aminoadipic semialdehyde dehydrogenase, strongly suggesting a diagnosis of PDE; the epileptic spasms ceased after administration of intravenous pyridoxal phosphate hydrate. Gene analysis revealed novel compound heterozygous mutations in ALDH7A1 that included NM_001182.4:[c.1196G > T] and [c.1200 + 1G > A]. Atypical birth asphyxia with persistent neonatal seizure should prompt vitamin B6/metabolite screening.

Thermolabile polymorphism of carnitine palmitoyltransferase 2: A genetic risk factor of overall acute encephalopathy.

OBJECTIVES: Acute encephalopathy is an acute brain dysfunction after preceding infection, consisting of multiple syndromes. Some syndromes, such as acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), are severe with poor outcome, whereas others, such as clinically mild encephalitis/encephalopathy with reversible splenial lesion (MERS), are mild with favorable outcome. Previous study reported the association of the thermolabile polymorphism in Carnitine Palmitoyltransferase 2 (CPT2) gene and severe syndromes of acute encephalopathy. To further explore the pathogenetic role of CPT2 in acute encephalopathy, we conducted a case-control association study of a typical thermolabile CPT2 polymorphism, rs2229291, in 416 patients of acute encephalopathy, including both severe and mild syndromes. METHODS: The case cohort consisted of 416 patients, including AESD, MERS, and other syndromes. The control subjects were 100 healthy Japanese. rs2229291 was genotyped by Sanger sequencing. Genetic distribution was compared between the patients and controls using Cochran-Armitage trend test. RESULTS: Minor allele frequency of rs2229291 was significantly higher in AESD (p = 0.044), MERS (p = 0.015) and entire acute encephalopathy (p = 0.044) compared to the controls. The polymorphism showed no significant association with influenza virus, or with outcome. CONCLUSIONS: This study provided evidence that CPT2 is a susceptibility gene for overall acute encephalopathy, including both severe and mild syndromes, and suggested that impairment of mitochondrial metabolism is common to various syndromes of acute encephalopathy.

Sweet Potato Was Not So Sweet: Undetected Foreign-body Aspiration in a Healthy Child Leading to Acute Bronchial Asthma.

INTRODUCTION: Sweet potato may contain furanoterpenoids, including ipomeamarone, which cause lung edema. CASE PRESENTATION: A 10-year-old schoolgirl was hospitalized with asthma exacerbation and acute pneumonia. Chest radiographs showed a diffuse opacity of the left lung and hyperpermeability of the right lung. Computed tomography indicated foreign-body aspiration. Flexible bronchoscopy revealed an inhaled piece of sweet potato obstructing the left main bronchus. Although the patient's dyspnea worsened after removal of the sweet potato, she recovered with the treatment based on the 2014 Japanese Childhood Asthma Guidelines. CONCLUSION: Cases of sweet potato aspiration need careful treatment after removal of the foreign body.

Rhinovirus-associated acute encephalitis/encephalopathy and cerebellitis.

BACKGROUND: Rhinovirus is a common respiratory pathogen for children throughout the year; nevertheless, its central nervous system involvement is extremely rare, and only two cases have been reported to date: meningitis and sepsis-like illness. PATIENT: A previously healthy 2-year-old Japanese boy developed fever, followed by seizures and lethargy. His cerebrospinal fluid cell count and protein level were slightly increased; brain magnetic resonance imaging showed abnormal intensities in the bilateral cerebellar dentate nuclei, which were prominent in diffusion-weighted images. After his consciousness disturbance improved, cerebellar dysfunction became apparent. He was treated symptomatically, without steroids or any other immunosuppressants. He almost recovered within a few months; however, cerebellar atrophy became evident on brain magnetic resonance imaging. Using acute specimens, human rhinovirus A was detected in his throat swab and cerebrospinal fluid. DISCUSSION: Acute cerebellitis, in which cerebellar inflammation is predominant, is occasionally accompanied by cerebral symptoms, such as consciousness disturbance and seizures. As a causative pathogen, rotavirus is the most common; however, rhinovirus-associated acute encephalitis/encephalopathy and concurrent cerebellitis have not been reported before. Further research, using recent molecular techniques to detect various central nervous system pathogens, including rhinovirus, is needed to delineate the underlying pathophysiology.

De novo variants in CAMK2A and CAMK2B cause neurodevelopmental disorders.

Objective: α (CAMK2A) and ß (CAMK2B) isoforms of Calcium/calmodulin-dependent protein kinase II (CaMKII) play a pivotal role in neuronal plasticity and in learning and memory processes in the brain. Here, we explore the possible involvement of α- and ß-CaMKII variants in neurodevelopmental disorders. Methods: Whole-exome sequencing was performed for 976 individuals with intellectual disability, developmental delay, and epilepsy. The effect of CAMK2A and CAMK2B variants on CaMKII structure and firing of neurons was evaluated by computational structural analysis, immunoblotting, and electrophysiological analysis. Results: We identified a total of five de novo CAMK2A and CAMK2B variants in three and two individuals, respectively. Seizures were common to three individuals with CAMK2A variants. Using a minigene splicing assay, we demonstrated that a splice site variant caused skipping of exon 11 leading to an in-frame deletion of the regulatory segment of CaMKII α. By structural analysis, four missense variants are predicted to impair the interaction between the kinase domain and the regulatory segment responsible for the autoinhibition of its kinase activity. The Thr286/Thr287 phosphorylation as a result of release from autoinhibition was increased in three mutants when the mutants were stably expressed in Neuro-2a neuroblastoma cells. Expression of a CaMKII α mutant in primary hippocampal neurons significantly increased A-type K+ currents, which facilitated spike repolarization of single action potentials. Interpretation: Our data highlight the importance of CaMKII α and CaMKII ß and their autoinhibitory regulation in human brain function, and suggest the enhancement of A-type K+ currents as a possible pathophysiological basis.

A case of mumps-related acute encephalopathy with biphasic seizures and late reduced diffusion.

BACKGROUND: Mumps is a common childhood viral disease characterized by fever and swelling of the parotid gland. The prognosis is generally good, although some complications, such as encephalitis (0.1%), exist. Acute encephalopathy with biphasic seizures and late reduced diffusion is the most common type of acute encephalopathy. However, this type of encephalopathy has not been reported in association with mumps infection. PATIENT: A previously healthy 3-year-old Japanese boy had a brief convulsion after fever for 3days, and then had conscious disturbance and parotitis. After several days, he had a second brief convulsion and was admitted. Increased serum amylase levels and presence of anti-mumps immunoglobulin M antibody confirmed mumps parotitis. The patient had another brief seizure later the day of admission. He did not have status or cluster seizures, although the biphasic nature of his seizures, conscious disturbance between the seizures, no pleocytosis in cerebrospinal fluid, and brain magnetic resonance images were consistent with acute encephalopathy with biphasic seizures and late reduced diffusion. DISCUSSION: In Japan, the mumps vaccine is not administered as a part of routine immunizations. It thus has low coverage (30-40%), and as a result, mumps infections are still common. However, this is the first case of mumps-related acute encephalopathy with biphasic seizures and late reduced diffusion. This case may be representative of only a minority of patients with mumps-associated central nervous system involvement. Nevertheless, this diagnostic possibility may be considered. In order to prevent mumps-related complications, routine mumps vaccination might be warranted.

Asymptomatic congenital cytomegalovirus infection with neurological sequelae: A retrospective study using umbilical cord.

BACKGROUND: Congenital cytomegalovirus (CMV) infection causes various neurological sequelae. However, most infected infants are asymptomatic at birth, and retrospective diagnosis is difficult beyond the neonatal period. OBJECTIVE: This study aimed to investigate the aspects of neurological sequelae associated with asymptomatic congenital CMV infection. METHODS: We retrospectively analyzed 182 patients who were suspected of having asymptomatic congenital CMV infection with neurological symptoms in Japan. Congenital CMV infection was diagnosed by quantitative polymerase chain reaction amplification of CMV from dried umbilical cord DNA. RESULTS: Fifty-nine patients (32.4%) who tested positive for CMV were confirmed as having congenital CMV infection. Among 54 congenital CMV patients, major neurological symptoms included intellectual disability (n=51, 94.4%), hearing impairment (n=36, 66.7%) and cerebral palsy (n=21, 38.9%), while microcephaly (n=16, 29.6%) and epilepsy (n=14, 25.9%) were less common. In a brain magnetic resonance imaging (MRI) study, cortical dysplasia was observed in 27 CMV-positive patients (50.0%), and all patients (100%) had cerebral white matter (WM) abnormality. Intracranial calcification was detected by CT in 16 (48.5%) of 33 CMV-positive patients. Cerebral palsy, cortical dysplasia and a WM abnormality with a diffuse pattern were associated with marked intellectual disability. CONCLUSIONS: Brain MRI investigations are important for making a diagnosis and formulating an intellectual prognosis. Analysis of umbilical cord tissue represents a unique and useful way to retrospectively diagnose congenital CMV infection.

Mucolipidosis IV: A milder form with novel mutations and serial MRI findings.

BACKGROUND: Mucolipidosis IV (MLIV; OMIM #252650) is an autosomal recessive lysosomal storage disorder, frequently observed in the Ashkenazi Jewish population. MLIV typically results in intellectual disability, corneal opacities, and delayed motor milestones during infancy, with a relatively static course. To date, reports of MLIV in other ethnic groups have been sparse. PATIENT: The present study is a case report of a 9-year-old Japanese boy, diagnosed via whole-exome sequencing, with compound heterozygous mutations of MCOLN1 (OMIM(*)605248): c.410T>C (p.Leu137Pro) and c.802_803delAG (p.Ser268Trpfs*17). Although his clinical course was mild (due to a lack of corneal clouding), other relevant features were present. These included strabismus, white matter signal abnormalities, and a hypoplastic corpus callosum at 2years of age. After a molecular diagnosis, a markedly elevated serum gastrin level (which is also common in MLIV) was confirmed. DISCUSSION: The present results suggest that MLIV could be added as a differential diagnosis for white matter disorders, regardless of ethnicity. Beyond neurological or ophthalmologic findings, serum gastrin could be a useful diagnostic marker for MLIV.

A mild case of giant axonal neuropathy without central nervous system manifestation.

An 11-year-old boy presented with progressive walking disturbances. He exhibited severe equinovarus feet that together presented with hyperreflexia of the patellar tendon and extensor plantar, resembling spastic paraplegia or upper neuron disease. He showed mild distal muscle atrophy, as well. We did not observe signs of cognitive impairment, cerebellar signs, or brain magnetic resonance imaging abnormalities. Nerve biopsy showed giant axon swellings filled with neurofilaments. Gene analysis revealed novel compound heterozygous missense mutations in the gigaxonin gene, c.808G>A (p.G270S) and c.1727C>A (p.A576E). He was diagnosed with mild giant axonal neuropathy (GAN) without apparent central nervous system involvement. Patients with classical GAN manifest their symptoms during early childhood. Mild GAN, particularly in early stages, can be misdiagnosed because of lack of typical hair features and incomplete or indistinct peripheral and central nervous system symptoms. This case is important since it can aid to identify atypical and milder clinical courses of GAN. This report widens the mild GAN clinical spectrum, alerting physicians for correct diagnosis.

Predictive score for early diagnosis of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD).

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) at onset manifests an early seizure (ES) usually lasting more than 30 min. Following ES, some patients exhibit almost clear consciousness with no neurological symptoms, and no MRI abnormality for a few days, which may lead to an initial misdiagnosis of prolonged febrile seizures (PFS). To allow an early diagnosis of AESD, we retrospectively analyzed clinical manifestations, laboratory data, and radiologic and EEG findings in patients with AESD (n=62) having ES of over 30 min, and ones with PFS (n=54), using logistic regression analyses. Multivariate logistic regression analysis revealed that an age below 1.5 years and a Glasgow Coma Scale score of 14 or less than 14 (Japan Coma Scale score of 1 or higher) were high risk factors of developing AESD. We proposed an AESD prediction score system consisting of consciousness level, age, duration of convulsions, enforcement of mechanical intubation, and aspartate aminotransferase, blood glucose and creatinine levels (full score: 9), the mean scores in AESD and PFS being 5.9 and 1.8, which were significantly different (p<0.001). We herein propose a scoring system for differentiating patients with AESD and PFS around the time of ES (score of 4 or more than 4 suggesting AESD), which may contribute to early therapeutic intervention and an improved neurologic outcome.

De novo KCNT1 mutations in early-onset epileptic encephalopathy.

KCNT1 mutations have been found in epilepsy of infancy with migrating focal seizures (EIMFS; also known as migrating partial seizures in infancy), autosomal dominant nocturnal frontal lobe epilepsy, and other types of early onset epileptic encephalopathies (EOEEs). We performed KCNT1-targeted next-generation sequencing (207 samples) and/or whole-exome sequencing (229 samples) in a total of 362 patients with Ohtahara syndrome, West syndrome, EIMFS, or unclassified EOEEs. We identified nine heterozygous KCNT1 mutations in 11 patients: nine of 18 EIMFS cases (50%) in whom migrating foci were observed, one of 180 West syndrome cases (0.56%), and one of 66 unclassified EOEE cases (1.52%). KCNT1 mutations occurred de novo in 10 patients, and one was transmitted from the patient's mother who carried a somatic mosaic mutation. The mutations accumulated in transmembrane segment 5 (2/9, 22.2%) and regulators of K(+) conductance domains (7/9, 77.8%). Five of nine mutations were recurrent. Onset ages ranged from the neonatal period (<1 month) in five patients (5/11, 45.5%) to 1-4 months in six patients (6/11, 54.5%). A generalized attenuation of background activity on electroencephalography was seen in six patients (6/11, 54.5%). Our study demonstrates that the phenotypic spectrum of de novo KCNT1 mutations is largely restricted to EIMFS.

Protein-losing enteropathy as a rare complication of the ketogenic diet.

INTRODUCTION: The ketogenic diet is a valuable therapy for patients with intractable epilepsy, but it can result in a variety of complications that sometimes limits its usefulness. Hypoproteinemia is one of the common adverse effects of this diet, although the underling mechanism is largely unknown except for the diet's reduced protein intake. Only one case of protein-losing enteropathy during the ketogenic diet has been reported. PATIENT DESCRIPTION: A previously healthy 9-year-old girl experienced fever for 5 days then suddenly developed convulsive seizures that subsequently evolved to severe refractory status epilepticus. After multiple antiepileptic drugs failed to improve the patient's condition, we introduced the ketogenic diet. Although her seizures diminished, her course was complicated by hypoproteinemia. An abdominal dynamic scintigraphy and colonoscopy findings indicated protein-losing enteropathy with nonspecific mucosal inflammation. Her nutritional status deteriorated; thus, we discontinued the ketogenic diet. Her nutritional status gradually improved, whereas her seizures increased. DISCUSSION: Hypoproteinemia during the ketogenic diet is common, but the underlying etiologies are not well understood. Abdominal dynamic scintigraphy could be valuable for clarifying the etiology of hypoproteinemia during the ketogenic diet.