Clinical Features of Acute Flaccid Myelitis Temporally Associated With an Enterovirus D68 Outbreak: Results of a Nationwide Survey of Acute Flaccid Paralysis in Japan, August-December 2015.

Background: Acute flaccid myelitis (AFM) is an acute flaccid paralysis syndrome with spinal motor neuron involvement of unknown etiology. We investigated the characteristics and prognostic factors of AFM clusters coincident with an enterovirus D68 (EV-D68) outbreak in Japan during autumn 2015. Methods: An AFM case series study was conducted following a nationwide survey from August to December 2015. Radiographic and neurophysiologic data were subjected to centralized review, and virology studies were conducted for available specimens. Results: Fifty-nine AFM cases (58 definite, 1 probable) were identified, including 55 children and 4 adults (median age, 4.4 years). The AFM epidemic curve showed strong temporal correlation with EV-D68 detection from pathogen surveillance, but not with other pathogens. EV-D68 was detected in 9 patients: 5 in nasopharyngeal, 2 in stool, 1 in cerebrospinal fluid (adult case), and 1 in tracheal aspiration, nasopharyngeal, and serum samples (a pediatric case with preceding steroid usage). Cases exhibited heterogeneous paralysis patterns from 1- to 4-limb involvement, but all definite cases had longitudinal spinal gray matter lesions on magnetic resonance imaging (median, 20 spinal segments). Cerebrospinal fluid pleocytosis was observed in 50 of 59 cases (85%), and 8 of 29 (28%) were positive for antiganglioside antibodies, as frequently observed in Guillain-Barré syndrome. Fifty-two patients showed variable residual weakness at follow-up. Good prognostic factors included a pretreatment manual muscle strength test unit score >3, normal F-wave persistence, and EV-D68-negative status. Conclusions: EV-D68 may be one of the causative agents for AFM, while host susceptibility factors such as immune response could contribute to AFM development.

Scalp EEG-recorded high-frequency oscillations can predict seizure activity in Panayiotopoulos syndrome.

OBJECTIVE: We studied the relationship between the clinical course of Panayiotopoulos syndrome (PS) and high-frequency oscillations (HFOs) captured during interictal scalp electroencephalography (EEG) to determine the feasibility of using HFOs to detect seizure activity in PS. METHODS: We analyzed the interictal scalp EEGs of 18 children with PS. Age parameters, seizure frequencies, and antiepileptic drugs were compared between the HFO-positive (HFOPG) and HFO-negative (HFONG) groups. RESULTS: Thirteen patients (72.2%) had HFOs while five patients (27.8%) had no HFOs in 194 interictal EEG records. We found no statistically significant differences in the mean age of epilepsy onset and last seizure, seizure frequency, or frequency of status epilepticus. However, the seizure activity period of the HFOPG was significantly longer than that of the HFONG. Patients with an HFO duration longer than 2 years were intractable to treatment. In most cases, seizures did not occur in the absence of HFOs, even when the spikes remained. CONCLUSIONS: HFOs are related to the seizure activity period in patients with PS. SIGNIFICANCE: We propose that HFOs are a biomarker of epileptogenicity and an indicator for drug reduction because seizures did not occur if HFOs disappeared even if the spikes remained.

Reduced PLP1 expression in induced pluripotent stem cells derived from a Pelizaeus-Merzbacher disease patient with a partial PLP1 duplication.

Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive disorder characterized by dysmyelination of the central nervous system (CNS). We identified a rare partial duplication of the proteolipid protein 1 gene (PLP1) in a patient with PMD. To assess the underlying effect of this duplication, we examined PLP1 expression in induced pluripotent stem (iPS) cells generated from the patient's fibroblasts. Disease-specific iPS cells were generated from skin fibroblasts obtained from the indicated PMD patient and two other PMD patients having a 637-kb chromosomal duplication including entire PLP1 and a novel missense mutation (W212C) of PLP1, by transfections of OCT3/4, C-MYC, KLF4 and SOX2 using retro-virus vectors. PLP1 expressions in the generated iPS cells were examined by northern blot analysis. Although PLP1 expression was confirmed in iPS cells generated from two patients with the entire PLP1 duplication and the missense mutation of PLP1, iPS cells generated from the patient with the partial PLP1 duplication manifesting a milder form of PMD showed null expression. This indicated that the underlying effect of the partial PLP1 duplication identified in this study was different from other PLP1 alterations including a typical duplication and a missense mutation.

Magnetic resonance imaging volumetry and clinical analysis of epilepsy patients with unilateral hippocampal abnormality.

BACKGROUND: In order to clarify the correlation between morphological characteristics and clinical features in epilepsy patients with unilateral hippocampal abnormality, morphological and morphometric magnetic resonance imaging studies were performed. METHODS: We selected a series of childhood-onset epilepsy patients with unilateral hippocampal abnormality. The volume of hippocampal formation and anterior temporal lobe were measured, and the hippocampal morphology was compared with their clinical features. The morphological characteristics of the hippocampal formation were classified into three groups: group I, diffuse and severe volume reduction of the hippocampal formation and anterior temporal lobe with abnormal signal; group II, focal atrophy or focal abnormal signal in the hippocampal formation; and group III, no significant volume reduction but an enlargement of the temporal horn. RESULTS: All of the patients in group I had a history of status epilepticus in infancy. Temporal lobe epilepsy (TLE) was found in three of four patients. Group II contained TLE in three and frontal lobe epilepsy in one. One patient with intractable TLE had a history of status epilepticus in infancy. Group III contained miscellaneous epilepsies, including benign partial epilepsy with centro-temporal spikes in three of seven patients. Five patients in group III showed some characteristic features of hippocampal malrotation, which refers to incomplete hippocampal infolding. CONCLUSIONS: Diffuse and severe volume reduction of the hippocampal formation and anterior temporal lobe with unilateral hippocampal sclerosis was strongly associated with status epilepticus in infancy. Both hippocampal sclerosis and hippocampal malrotation suggest significant roles in the pathogenesis of epilepsy.

Three-Year Longitudinal Motor Function and Disability Level of Acute Flaccid Myelitis.

BACKGROUND: We summarize the long-term motor outcome and disability level in a cluster of pediatric patients with acute flaccid myelitis (AFM) associated with the enterovirus D68 outbreak in 2015. METHODS: This is a nationwide follow-up questionnaire analysis study. Clinical data including the motor function (manual muscle strength test) and other neurological symptoms were collected at the acute (nadir), recovery (six months), and chronic (three years) stages. We use the Barthel index, which measures 10 variables describing activity of daily living and mobility to assess the disability level. RESULTS: Clinical data of 33 patients with AFM (13 females, 20 males; median age = 4.1 years) were available. Among patients with tetraplegia or triplegia, paraplegia, and monoplegia at the acute stage, two of seven, four of thirteen, and two of thirteen exhibited complete recovery without paralysis; of those five of seven, eight of thirteen, and two of thirteen showed improvement with lesser limb involvement at the chronic stage, respectively. Nine patients (27%) demonstrated improvement at the recovery-to-chronic period. All six patients with positive isolation of enterovirus D68 from biological samples at the acute stage showed persistent motor deficits. Other neurological findings had better prognosis than motor weakness. Better Barthel index score at the chronic stage was observed (P < 0.001; median difference [95% confidence interval], 53 [40 to 63]), implying an improved disability level even in patients with persistent motor deficits. CONCLUSIONS: AFM has a high rate of persistent motor deficits showing one- to two-limb paralysis. Disability level of patients with AFM, however, generally improved at the three-year time point.

Clinical and electrophysiological features of acute flaccid myelitis: A national cohort study.

OBJECTIVE: To summarize the neurophysiological properties of acute flaccid myelitis (AFM) and evaluate limb-based motor outcomes. METHODS: Nerve conduction studies (NCS) in 49 patients (21 females, 28 males; median age = 52 m) with AFM (median = 7 d after onset; range 1-122 d) were reviewed. Neurophysiological findings, together with treatment and prognosis, and neurophysiology-neuroimaging correlations were analyzed. RESULTS: The findings indicated that 64% of paralytic limbs during the acute stage (≤14 d after onset) showed diminished or absent compound muscle action potentials (CMAPs), 79% showed normal motor nerve conduction velocities, 55% showed decreased persistence or absent F-waves, and 95% showed normal sensory nerve conduction velocities. The rate of CMAP abnormalities increased from 41% on days 1-2 to 83% on days 13-14. The reduction in CMAP amplitude was correlated with weaker muscle strength at both the peak neurological deficit and the last follow-up. The baseline limb-based muscle strength at nadir and anterior horn-localized magnetic resonance imaging lesions at recovery stage (>14 d) were strong predictors of outcome at the last follow-up. CONCLUSIONS: AFM typically shows neurophysiological features of neuronopathy. SIGNIFICANCE: NCS is probably useful in the diagnosis and evaluation of AFM.

Mutational analysis of GABRG2 in a Japanese cohort with childhood epilepsies.

A few mutations in the gene encoding the gamma 2 subunit of the gamma-aminobutyric acid receptor type A (GABRG2) have been reported in various types of epilepsy. The aim of this study is to investigate the role of GABRG2 in the pathogenesis of childhood epilepsy in a large Japanese cohort. Genetic analysis of GABRG2 was performed on 140 Japanese patients with various childhood epilepsies largely including Dravet syndrome and genetic epilepsy with febrile seizures plus. The mutational analysis identified one novel missense mutation of GABRG2 (c.236A>G: p.N40S) in a patient with generalized tonic-clonic seizures (GTCS). The mutation was heterozygous and replacing a highly conserved Asn residue with a Ser. The affected amino acid was located at residue 40 of the mature GABRG2 protein, which was near the first one of two high-affinity benzodiazepine-binding domains of the gamma2 subunit (Lys-41-Trp-82). This mutation in such an important position may hamper the function of the channel and contribute to the case's pathogenesis of GTCS.

Survival and late effects on development of patients with infantile brain tumor.

BACKGROUND: Most infants with brain tumor may have a poor prognosis. The aim of the present study was to retrospectively analyze the survival and outcome with regard to mental and physical development in 11 subjects with brain tumor; these tumors were diagnosed when the patients were under 1 year of age. METHODS: The histological diagnoses of these tumors were astrocytoma, n = 3; pineocytoma, n = 2; teratoma, n = 1; ependymoma, n = 1; atypical teratoid/rhabdoid tumor, n = 1; glioblastoma, n = 1; medulloblastoma, n = 1; and choroid plexus papilloma, n = 1. Surgical resection was performed in eight patients, and adjuvant chemotherapy was administered to all except one patient with choroid plexus papilloma. Radiotherapy was additionally performed for four of the 10 chemotherapy patients. RESULTS: Six patients survived. Among the surviving patients, five were under no treatment for 50-167 months after the diagnosis (median duration, 89 months), while one received chemotherapy for 20 months. Five patients exhibited mental retardation, and one patient experienced normal development after surgical removal of his choroid plexus papilloma. Diencephalic syndrome developed in one patient with pilomyxoid astrocytoma that necessitated hormone replacement therapy, and bodyweight over +2 SD was observed in two patients. The remaining five patients died 11-111 months after diagnosis (median duration, 24 months). CONCLUSION: The prognosis of infantile brain tumor with regard to mortality and developmental outcome remains poor. Furthermore, survivors require comprehensive medical and social support for an extended period.

[Criteria for differential diagnosis of epilepsy and long QT syndrome presenting with seizures and EEG abnormalities].

We report a 13-year-old girl with congenital long QT syndrome (LQTS) who developed a cluster of generalized tonic clonic seizures with post-ictal EEG abnormality. The provisional diagnosis was epilepsy. However, ECG monitoring showed torsade de pointes, and thus the final diagnosis was LQTS. Although LQTS can be potentially misdiagnosed as epilepsy when it presents with seizures, it is important to differentiate LQTS from epilepsy because patients with LQTS are at risk of sudden death. We reviewed 11 previously reported cases with LQTS and EEG abnormalities who were initially diagnosed as epilepsy. We emphasized the importance of the following five criteria in the differentiation of LQTS from epilepsy: 1) awareness that LQT2 and LQT3 can cause life-threatening arrhythmia at rest or during sleep, 2) examination of arterial pulse during seizures, 3) monitoring ECG during EEG recording, 4) careful establishment of the correct diagnosis taking into consideration the interictal EEG findings, and 5) reconsidering the possibility of cardiac origin when the attacks cannot be controlled even by therapeutic levels of antiepileptic drugs in the blood.

Serial MRI findings of acute flaccid myelitis during an outbreak of enterovirus D68 infection in Japan.

OBJECIVE: To clarify the neuroimaging findings of children with acute flaccid myelitis during an outbreak of EV-D68 infection. METHODS: We performed a detailed review of the spinal and cranial MRI results of 54 children with acute flaccid myelitis. We focused on the range of longitudinal lesions, the localization and appearance of lesions within a horizontal section, Gadolinium-enhancement, and changes over time. RESULTS: All children had longitudinal spinal lesions involving central gray matter. Twenty-six children had lesions spanning the entire spine. Six of them had weakness in all limbs, whereas seven had weakness of only one limb. Thirty-eight children had lesions in both gray and white matter and limb weakness tended to be more severe in these children. During the acute period, spinal lesions showed bilateral ill-defined widespread T2 hyperintensity. During the subacute period, lesions were well defined and confined to the anterior horn. The distribution of limb weakness was correlated with the appearance of lesions during the subacute period. Gadolinium enhancement was performed in 37 children, and enhancement was seen in the cauda equina in 29 children. Enhancement was infrequent within 2 days after onset but was seen in almost all children thereafter. Twenty-two children had brainstem lesions continuous with spinal lesions. CONCLUSION: Extensive longitudinal spinal lesions were characteristic in children with acute flaccid myelitis. Lesions were usually bilateral and widespread during the acute period, whereas localization to the anterior horn could become obvious. Although enhancement of the cauda equina was often observed, its appearance was sometimes delayed.

Microchromosomal deletions involving SCN1A and adjacent genes in severe myoclonic epilepsy in infancy.

PURPOSE: Genetic abnormalities of the gene encoding alpha1 subunit of the sodium channel (SCN1A), which can be detected by direct sequencing, are present in more than 60% of patients with severe myoclonic epilepsy in infancy (SMEI) or its borderline phenotype (SMEB). Microchromosomal deletions have been recently reported as additional causes of SMEI. This study examines whether such microdeletions are associated with SMEI as well as with SMEB. METHODS: We recruited patients with SMEI (n = 35) and SMEB (n = 34), who were confirmed previously to have no mutations of SCN1A by direct sequencing. Microdeletions were sought by multiplex ligation-dependent probe amplification (MLPA), and then confirmed and characterized by fluorescence in situ hybridization (FISH) and array-based comparative genomic hybridization (aCGH), respectively. RESULTS: Heterozygous multiple exonic deletions were identified in 7/35 SMEI patients (20%) and 0/34 SMEB patients (0%), with a net frequency of 10.1% (7/69 patients). Deletions were confirmed by FISH and aCGH analysis. The concomitant deletions of adjacent genes were revealed by aCGH. None of the parents who agreed to undergo the analysis had such deletions suggesting that the deletions were de novo. The phenotypes of patients with the deletions were indistinguishable from those of SMEI resulting from point mutations. DISCUSSION: Our findings indicate that microchromosomal deletion, often involving not only SCN1A but also several adjacent genes, is associated with core SMEI. As microchromosomal deletion cannot be anticipated by the phenotypes or detected by conventional methods, genetic abnormalities in SMEI should be carefully sought by techniques that can detect microdeletions.

Recurrent autonomic and sensory neuropathy in a patient with anti-ganglionic acetylcholine receptor antibodies.

We report a case of recurrent neuropathy with predominant autonomic and sensory involvement whose serum was positive for anti-ganglionic acetylcholine receptor (anti-gAChR) antibodies, a diagnostic marker of autoimmune autonomic ganglionopathy. An 11-year-old girl complained of numbness and limb pain after gastroenteritis. Although hyperalgesia and autonomic dysfunctions, such as orthostatic intolerance and gastrointestinal dysmotility subsequently developed, these symptoms faded after a few days. Similar sensory and autonomic impairments recurred three times within 12 months after the first episode. The sensory and autonomic symptoms were rapidly ameliorated by the administration of intravenous immunoglobulin (IVIg) at the second and third relapse; however, the symptoms persisted even after the administration of IVIg at the fourth relapse. The residual symptoms disappeared after methylprednisolone pulse therapy. The patient's serum was found to be positive for anti-gAChR antibodies at the second relapse, and was negative after methylprednisolone pulse therapy. Further studies are needed to clarify the efficacy of treatment and the nosological position in the spectrum of neuropathies that are associated with autonomic and sensory impairments.

Long-term efficacy and safety of lamotrigine monotherapy in Japanese and South Korean pediatric patients with newly diagnosed typical absence seizures: An open-label extension study.

PURPOSE: To investigate the efficacy and safety of long-term lamotrigine (LTG) monotherapy in Japanese and South Korean pediatric patients with newly diagnosed typical absence seizures. METHODS: Six Japanese patients and one South Korean patient were enrolled in the extension phase of the study after completing the 12-week maintenance phase of an open-label clinical study of LTG monotherapy. During the extension phase, patients underwent efficacy and safety evaluation every 12 weeks. RESULTS: Of the seven patients, six patients completed the extension phase. The seizure-free rate confirmed by hyperventilation (HV)-electroencephalography ranged from 71.4% to 100.0% at each visit up to Week 168 of the extension phase. Similar effects were confirmed by HV-clinical signs and seizure diaries. Although no unexpected adverse events were observed, one Japanese patient was withdrawn from the extension phase due to mild drug-related rash developed 842 days after the start of LTG. CONCLUSION: Although the number of patients is limited, long-term LTG monotherapy appeared to be effective and generally well tolerated in Japanese and South Korean pediatric patients with typical absence seizures.

[Wernicke encephalopathy in a chronic peritoneal dialysis patient--correlation between diffusion MR and pathological findings].

Wernicke encephalopathy (WE) is a neurologic disorder caused by a nutritional deficiency of thiamine. Since the lesion in WE consists of brain edema, diffusion weighted imaging (DWI) is quite useful for detecting the pathologic changes in WE, and can differentiate between reversible extracellular (vasogenic) and irreversible cellular (cytotoxic) edema. We report here a 16-year-old man with WE who had been treated with continuous ambulatory peritoneal dialysis for chronic renal failure. He underwent repeated DWI and postmortem examination. DWI, which was performed 8 days after the onset of neurological symptoms, showed high intensity areas in the bilateral thalami, mammillary bodies, tegmentum mesencephali and pons. Apparent diffusion coefficient (ADC) map also showed slightly high intensity in the periaqueductal gray matter and pons, which indicated extracellular edema. On the other hand, ADC map showed low intensity areas in the most medial part of the thalami and marginal area of the tegmentum mesencephali, which indicated cellular edema. In the postmortem examination, the areas that showed low intensity on ADC map exhibited mild neuronal loss. Based on the correlation between the DWI and pathologic findings, the cytotoxic edema of the bilateral medial thalami and marginal tegmentum mesencephali in this patient was considered to be glial cell edema which may protect against neuronal cell damage.

Benign convulsion with mild gastroenteritis and benign familial infantile seizure.

The authors present Japanese siblings of a 6-year-old girl and a 4-year-old boy, who concurrently experienced convulsions with mild gastroenteritis. These siblings, their father and paternal grandfather had afebrile seizures that intermittently occurred without symptoms of gastroenteritis and terminated within a few days at their infancy. An underlying genetic factor might not only cause benign familial infantile seizures but it might also confer the susceptibility to the convulsions with mild gastroenteritis in these siblings.

Lamotrigine monotherapy for newly diagnosed typical absence seizures in children: A multi-center, uncontrolled, open-label study.

PURPOSE: To evaluate the efficacy and safety of lamotrigine (LTG) monotherapy for treating Japanese and South Korean pediatric patients with newly diagnosed typical absence seizures. METHODS: Twenty patients with newly diagnosed typical absence seizures aged 4-12 years were enrolled in the study and were administered LTG at an initial dose of 0.3 mg/kg/day for 2 weeks, followed by 0.6 mg/kg/day for an additional 2 weeks. Thereafter, the dose was increased by 0.6 mg/kg/day up to a maximum of 10.2 mg/kg/day or 400 mg/day (whichever was the lower dose) until patients were confirmed to be seizure free induced by hyperventilation (HV). After confirmation, the dose was increased by one level (0.6 mg/kg/day). If the patient was found to be seizure free by HV-electroencephalography (EEG) on the following two consecutive visits, the patient entered the 12-week maintenance phase. After the maintenance phase, patients could enter the extension phase if clinically indicated. RESULTS: The seizure-free rate confirmed by HV-EEG at the end of the maintenance phase was 35.0% (7/20 patients). Most of patients who were confirmed to be seizure free during the escalation phase had maintained seizure control during the 12-week maintenance phase and the 12-week extension phase. The most frequently noted adverse events were bronchitis, headache, and rash (20% each). No serious adverse events were reported. CONCLUSION: Lamotrigine monotherapy in Japanese and South Korean children with typical absence seizures was well tolerated and 35.0% of patients were seizure free at the end of maintenance phase.

[A case of parietal lobe epilepsy with ictal laughter].

We report here about an 8-year-old boy with parietal lobe epilepsy (PLE) and ictal laughter. At the age of 6, he began to experience drop seizures, followed by sensory fits. Interictal EEG showed frequent spikes at C3, C4, P3 and Cz. Despite treatment with antiepileptic drugs, he often fell down in seizures after feeling abnormal sensations in the right shoulder. On ictal video EEG at the age of 7 years, (1) he became motionless and complained of fear and pain in the right hand, (2) he had clonic seizures of the right upper limb and fell down to his left, (3) he laughed though he did not feel funny. Ictal EEG showed spikes which originated in Pz and then were generalized. In many of the previously reported cases, ictal laughter is associated with hypothalamic hamartomas, infantile spasms,. complex partial seizures of frontal, temporal, or parietal origin. We diagnosed the present case as having PLE. However, other localization could not be roled out because the spikes were generalized quickly. To date, there are two reported cases of ictal laughter with PLE, but ictal EEG is lacking in these patients. Ictal laughter is rare in non-lesional cryptogenic PLE, but it may imply PLE's pathogenesis.

Favorable seizure outcome in Kabuki make-up syndrome associated with epilepsy.

Kabuki make-up syndrome is a mental retardation-malformation syndrome affecting multiple organ systems, with a broad spectrum of neuromuscular dysfunction and mental ability. The incidence of seizures associated with this syndrome ranges from 10 to 40%. However, details of the seizures in this syndrome have not been adequately reported or thoroughly evaluated. In this study, we analyzed seizure characteristics and clinical outcomes in nine patients with Kabuki make-up syndrome. Four patients had generalized seizures and two patients had complex partial seizures, extended to secondary generalized seizures. West's syndrome, complex partial seizure, and atonic seizure were seen in one case each, respectively. Electroencephalograms showed focal spikes in seven cases, diffuse spike and wave burst in one case, and hypsarrhythmia in one case. Seizures were well controlled in eight cases and incompletely controlled in only one case. Together with mental retardation, epilepsy can be a primary feature of Kabuki make-up syndrome. Epilepsy associated with Kabuki make-up syndrome is mainly localization-related epilepsy with a favorable seizure outcome.