Underlying Disorders in Children With Infection-Related Acute Encephalopathy.

BACKGROUND: Various factors contribute to the development of infection-related acute encephalopathy (AE) in children, such as infectious agents and chronic underlying disorders. We studied underlying disorders in children with AE to identify predisposing factors of AE. METHODS: We investigated underlying disorders or past histories in patients with two types of AE from the database in the Tokai area of Japan between 2009 and 2022: 204 patients with AE with reduced subcortical diffusion (AED) and 137 with clinically mild encephalopathy with a reversible splenial lesion (MERS). We compared them with 89 patients with acute disseminated encephalomyelitis (ADEM) to clarify the specific disorders in the two AE types. RESULTS: The prevalence of underlying disorders in AED (34%, 70 patients) was significantly higher than that in ADEM (12%, 11 patients) (P < 0.01). The prevalence of underlying disorders in MERS was 23% (32 patients). The underlying disorders included seizure disorders, premature birth, genetic/congenital disorders, and endocrine/renal diseases. In patients with seizure disorders in AED, five patients (18%) had Dravet syndrome and four (15%) had West syndrome, whereas none with MERS had these syndromes. Twenty-five (12%) of 204 patients with AED, three (2%) with MERS, and one (1%) with ADEM were preterm or low birth weight. CONCLUSIONS: The high prevalence of seizure disorders suggests that seizure susceptibility is an important predisposing factor in AED. Premature birth also has an impact on the development of AED. Caution is required regarding the development of AE in patients with chronic seizure disorders or premature birth.

Efficacy and safety of ketamine for pediatric and adolescent super-refractory status epilepticus and the effect of cerebral inflammatory conditions.

OBJECTIVE: To investigate the short-term benefits and adverse effects of ketamine in the treatment of pediatric and adolescent super-refractory status epilepticus (SRSE), with a focus on the inflammatory etiology. METHODS: This retrospective observational cohort study included a consecutive series of 18 pediatric to adolescent patients with SRSE admitted between 2008 and 2023 and treated with ketamine. Seizure frequency per hour before and after ketamine administration and response rate were calculated. Neurological decline, catecholamine administration, and adverse effects were also assessed. The patients were divided into inflammatory and non-inflammatory etiology groups. RESULTS: The median age at SRSE onset was 1 year 5 months (range: 11 days-24 years), and 78% of the patients were male individuals. The median duration of treatment was 7.5 days (interquartile range: 2.8-15.5 days). Fifteen (83%) patients achieved >50% seizure reduction. The median seizure frequency before and after ketamine treatment was 5.9 and 0.9, respectively, showing a significant reduction in seizure frequency (p < 0.0001). Ten patients had inflammatory etiologies including bacterial meningitis (n = 2), viral encephalitis (n = 3), and febrile infection related epilepsy syndrome (n = 5). The inflammatory etiology group required a longer treatment duration (p = 0.0453) and showed lower seizure reduction (p = 0.0264), lower response rate (p = 0.0044), and higher neurological decline (p = 0.0003) than the non-inflammatory etiology group. Three (17%) patients experienced transient adverse events requiring intervention within 24 h of initiating ketamine administration. CONCLUSIONS: Ketamine administration was associated with fewer serious adverse events and a reduced seizure frequency. Additionally, inflammatory conditions may weaken the efficacy of ketamine in patients with SRSE.

Single-channel qEEG characteristics distinguish delirium from no delirium, but not postoperative from non-postoperative delirium.

OBJECTIVE: This exploratory study examined quantitative electroencephalography (qEEG) changes in delirium and the use of qEEG features to distinguish postoperative from non-postoperative delirium. METHODS: This project was part of the DeltaStudy, a cross-sectional,multicenterstudy in Intensive Care Units (ICUs) and non-ICU wards. Single-channel (Fp2-Pz) four-minutes resting-state EEG was analyzed in 456 patients. After calculating 98 qEEG features per epoch, random forest (RF) classification was used to analyze qEEG changes in delirium and to test whether postoperative and non-postoperative delirium could be distinguished. RESULTS: An area under the receiver operatingcharacteristic curve (AUC) of 0.76 (95% Confidence Interval (CI) 0.71-0.80) was found when classifying delirium with a sensitivity of 0.77 and a specificity of 0.63 at the optimal operating point. The classification of postoperative versus non-postoperative delirium resulted in an AUC of 0.50 (95%CI 0.38-0.61). CONCLUSIONS: RF classification was able to discriminate delirium from no delirium with reasonable accuracy, while also identifying new delirium qEEG markers like autocorrelation and theta peak frequency. RF classification could not distinguish postoperative from non-postoperative delirium. SIGNIFICANCE: Single-channel EEG differentiates between delirium and no delirium with reasonable accuracy. We found no distinct EEG profile for postoperative delirium, which may suggest that delirium is one entity, whether it develops postoperatively or not.

Isopropyl Alcohol Intoxication Treated With Hemodialysis: A Case Report and Short Review.

Isopropyl alcohol (IPA) is a common constituent of rubbing alcohol, household cleaning agents, and antiseptic agents. Ingestion of IPA usually leads to self-resolving mild symptoms in most cases but can result in severe symptoms, including central nervous system depression or hemodynamic instability. Treatment is mainly supportive, and hemodialysis is generally reserved for severe intoxication. Limited data are available on the use of hemodialysis to treat IPA intoxication. We are presenting a case of accidental ingestion of IPA in an elderly female with dementia leading to severe intoxication requiring hemodialysis at relatively non-toxic serum levels of IPA. The patient had a prompt recovery without any post-procedural or hospital-acquired complications.

Acute encephalopathy with biphasic seizures and late reduced diffusion with concurrent transverse myelitis.

We describe a patient with acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) with unique features, including concurrent transverse myelitis. A 2-year-old previously healthy girl had clinical findings consistent with AESD, occurring in association with influenza A infection. The posterior brain regions were most severely affected, resulting in cortical blindness. She also developed bilateral limb weakness, and spine MRI revealed transverse myelitis in the cervical region. She was treated acutely with intravenous methylprednisolone. Serum anti-myelin oligodendrocyte glycoprotein and anti-aquaporin-4 antibodies were negative, as was an anti-extractable nuclear antigen panel. Although her clinical presentation was severe, she improved dramatically over the following months, and 6 months following initial presentation, her parents felt she had returned to baseline. This is the first report of AESD occurring in combination with transverse myelitis. The co-occurrence of the two conditions is unlikely to be coincidental, suggesting that there may be a shared or overlapping immunological pathway involved. The patient's recovery was impressive, which could partially relate to the acute treatment with corticosteroids.

High-dose glucocorticoids in COVID-19 patients with acute encephalopathy: clinical and imaging findings in a retrospective cohort study.

OBJECTIVES: Acute encephalopathy (AE) has been described as a severe complication of COVID-19. Inflammation has been suggested as a pathogenic mechanism, with high-dose glucocorticoids (GC) showing a beneficial effect. Here, we retrospectively analyzed the clinical and radiological features in a group of COVID-19 AE patients who received GC treatment (GT) and in a non-treated (NT) group. METHOD: Thirty-six patients with COVID-19 AE (mean age 72.6 ± 11 years; 86.11% men) were evaluated for GC treatment. Twelve patients (mean age 73.6 ± 4.5 years; 66.67% men) received GC, whereas 24 patients who showed signs of spontaneous remission were not treated with GC (mean age 70.1 ± 8.6 years; 95.83% men). Differences in clinical characteristics and correlations with imaging features were explored. RESULTS: The GT group showed signs of vulnerability, with a longer hospitalization (p = 0.009) and AE duration (p = 0.012) and a higher hypertensive arteriopathy (HTNA) score (p = 0.022), when compared to NT group. At hospital discharge, the two groups were comparable in terms of clinical outcome (modified Rankin scale; p = 0.666) or mortality (p = 0.607). In our whole group analyses, AE severity was positively correlated with periventricular white matter hyperintensities (p = 0.011), deep enlarged perivascular spaces (p = 0.039) and HTNA score (p = 0.014). CONCLUSION: This study suggests that, despite signs of radiological vulnerability and AE severity, patients treated by high-dose GC showed similar outcome at discharge, with respect to NT patients. Imaging features of cerebral small vessel disease correlated with AE severity, supporting the hypothesis that brain structural vulnerability can impact AE in COVID-19.

[A case of Hashimoto's encephalopathy with acute onset of psychiatric symptoms and diffuse deep white matter lesions on brain MRI].

A 51-year-old man developed acute disturbances in consciousness and psychiatric symptoms one month prior to admission. He was referred and admitted to the Department of Psychiatry of our hospital and transferred to the neurology department because diffuse white matter lesions were found on his brain during MRI. 123I-IMP-SPECT showed extensive cerebral hypoperfusion mainly in the frontal lobes. Anti-Tg, anti-TPO, and anti-NAE antibodies were positive. These findings led to a diagnosis of Hashimoto's encephalopathy. The patient responded to steroid pulse therapy, high-dose steroid therapy, and intravenous immunoglobulin therapy, showing improvement in symptoms and imaging findings. Hashimoto's encephalopathy often presents with MRI findings similar to those of limbic encephalitis, when the patient presents with acute consciousness disturbance and psychiatric symptoms. However, this case showed diffuse white matter lesions, which may be clinically important for the differential diagnosis.

Clinical characteristics of SARS-CoV-2-associated encephalopathy in children: Nationwide epidemiological study.

OBJECTIVE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sometimes triggers acute encephalopathy as a serious neurological complication in children. We previously reported the clinico-radiological findings of SARS-CoV-2-associated encephalopathy. The advent of the SARS-CoV-2 omicron variant led to a marked increase in pediatric patients with coronavirus disease 2019 (COVID-19); however, epidemiological changes with acute encephalopathy according to the emergence of SARS-CoV-2 have not yet been documented. Therefore, the present study investigated epidemiological differences in SARS-CoV-2-associated encephalopathy during the BA.1/BA.2 and BA.5 predominant periods and also between SARS-CoV-2-associated and non-SARS-CoV-2-associated encephalopathy. METHODS: We conducted a nationwide survey of SARS-CoV-2-associated encephalopathy in Japanese children between June and November 2022. We compared the present results during the BA.5 predominant period and previous findings during the BA.1/BA.2 predominant period. We also compared the clinico-radiological syndromes of encephalopathy between SARS-CoV-2-associated and non-SARS-CoV-2-associated encephalopathy. RESULTS: Although many patients with SARS-CoV-2-associated encephalopathy in the BA.5 predominant period had seizures as their initial symptoms, no significant differences were observed in the clinical features. Patients with SARS-CoV-2-associated encephalopathy had worse outcomes than those with non-SARS-CoV-2-associated encephalopathy (p-value = 0.003). Among 103 patients with SARS-CoV-2-associated encephalopathy, 14 (13.6%) had severe types of acute encephalopathy, namely, encephalopathy with acute fulminant cerebral edema (AFCE) and hemorrhagic shock and encephalopathy syndrome (HSES). Also, 28 (27.2%) patients with SARS-CoV-2-associated encephalopathy had poor outcome: severe neurological sequelae or death. Ninety-five patients (92.2%) were not vaccinated against SARS-CoV-2. CONCLUSIONS: In SARS-CoV-2-associated encephalopathy, high percentages of AFCE and HSES can result in poor outcomes.

Factors influencing the development of infantile traumatic brain injury with a biphasic clinical course and late reduced diffusion.

BACKGROUND: Infantile traumatic brain injury (TBI) with a biphasic clinical course and late reduced diffusion (TBIRD) has been reported as a type of TBI. However, it remains uncertain which pediatric patients with TBI develop TBIRD. METHODS: Patients with TBI who were admitted to our hospital and underwent magnetic resonance imaging (MRI) between December 2006 and October 2022 were included in this study. A diagnosis of TBIRD was made in patients with or suspected TBI, with initial symptoms being convulsions or disturbance of consciousness and late-onset subcortical reduced diffusion, the so-called bright tree appearance. Clinical features, neuroimaging (computed tomography (CT) and MRI) findings, laboratory data, and Tada score were retrospectively compared between TBIRD and non-TBIRD patients. Neurological prognosis was assessed using the Pediatric Cerebral Performance Category scale. RESULTS: Of 21 patients who met the inclusion criteria, a diagnosis of TBIRD was made in 7 patients (median age: 8 months). The factors contributing to TBIRD development were seizures lasting over 30 min as the initial symptom (5/7 in TBIRD vs. 0/14 in non-TBIRD), tracheal intubation during initial treatment (5/7 vs. 0/14), and brain parenchymal lesions on CT (3/7 vs. 0/14), suggesting that severe TBI may progress to TBIRD. The Tada score was more positive in patients with TBIRD (6/7) than in those without (0/14). CONCLUSIONS: It is important to monitor infant patients with severe TBI for the development of TBIRD. The Tada score can be a useful tool for TBIRD prediction.

Advancing specificity in delirium: The delirium subtyping initiative.

BACKGROUND: Delirium, a common syndrome with heterogeneous etiologies and clinical presentations, is associated with poor long-term outcomes. Recording and analyzing all delirium equally could be hindering the field's understanding of pathophysiology and identification of targeted treatments. Current delirium subtyping methods reflect clinically evident features but likely do not account for underlying biology. METHODS: The Delirium Subtyping Initiative (DSI) held three sessions with an international panel of 25 experts. RESULTS: Meeting participants suggest further characterization of delirium features to complement the existing Diagnostic and Statistical Manual of Mental Disorders Fifth Edition Text Revision diagnostic criteria. These should span the range of delirium-spectrum syndromes and be measured consistently across studies. Clinical features should be recorded in conjunction with biospecimen collection, where feasible, in a standardized way, to determine temporal associations of biology coincident with clinical fluctuations. DISCUSSION: The DSI made recommendations spanning the breadth of delirium research including clinical features, study planning, data collection, and data analysis for characterization of candidate delirium subtypes. HIGHLIGHTS: Delirium features must be clearly defined, standardized, and operationalized. Large datasets incorporating both clinical and biomarker variables should be analyzed together. Delirium screening should incorporate communication and reasoning.

A nationwide survey of adenovirus-associated encephalitis/encephalopathy in Japan.

BACKGROUND: Adenovirus is a major pathogen causing febrile illness among children. It may also cause acute encephalitis/encephalopathy. This study aimed to elucidate the clinical features of adenovirus-associated encephalitis/encephalopathy (AdVE) among children in Japan. METHODS: A nationwide survey of children with AdVE was conducted. An initial survey was distributed among pediatricians to obtain information about children with AdVE treated between January 2014 and March 2019. A second survey was used to obtain the clinical information of children with AdVE from hospitals that responded to the initial survey and those identified from a literature search of the reported cases. We collected demographic data and information about symptoms of infection, neurological symptoms, laboratory parameters, treatment, and outcomes. Outcomes were determined using the Pediatric Cerebral Performance Category Score. RESULTS: Clinical information was available for 23 children with a median age of 39 months. Two had preexisting neurological disorders and six had a history of febrile seizures. The outcome was good in 15 patients and poor in eight patients. Serum lactate dehydrogenase, glucose, and ammonia levels were higher among children with a poor outcome compared to those with a good outcome. Clinically mild encephalitis/encephalopathy with a reversible splenial lesion was the most common type (n = 8), followed by acute encephalopathy with biphasic seizures and late reduced diffusion (n = 7). CONCLUSION: A prior history of febrile seizures was frequent in children with AdVE. Several different subtypes of acute encephalopathy were seen in children with AdVE, and the outcome was poor in those with acute encephalopathy with biphasic seizures and late reduced diffusion and hemorrhagic shock and encephalopathy syndrome. Elevated lactate dehydrogenase, glucose, and ammonia levels on admission were found to correlate with a poor outcome.

Risk factors for post-encephalopathic epilepsy in patients with acute encephalopathy with biphasic seizures and late reduced diffusion.

BACKGROUND: Post-encephalopathic epilepsy (PEE) is a serious complication of acute encephalopathy syndromes, and is more frequent in patients with acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) than in children with acute encephalopathy. However, a risk factor analysis using laboratory findings in the acute phase of AESD has not yet been performed. Therefore, the present study examined risk factors of AESD-related PEE using laboratory parameters in the acute phase of AESD. METHODS: We retrospectively screened 27 pediatric patients with AESD for inclusion, and enrolled 20 ("the PEE group", n = 6; "the non-PEE group", n = 14) according to inclusion criteria. RESULTS: The incidence of AESD-related PEE was 30 %, and the median duration from the onset of AESD to the development of PEE was 2.5 months (range, 1-32). The most common types of seizures were focal seizures, epileptic spasms, and startle seizures: 4 out of 6 patients (66.7 %) had intractable epilepsy. The median values of alanine aminotransferase (ALT) in the 1st and 2nd seizure phases of AESD and aspartate aminotransferase (AST) in the 2nd seizure phase were significantly higher in the PEE group than in the non-PEE group (p < 0.01). CONCLUSIONS: This is the first study to report higher serum levels of ALT and AST at the onset of AESD as risk factors for AESD-related PEE. We also provided a detailed description on the clinical characteristics on AESD-related PEE, which are consistent with previous findings.

Restricted Diffusion in the Bilateral Subcortical Motor Areas Associated with Status Epilepticus in an Infant with Kawasaki Disease.

Status epilepticus (SE) often causes neuronal death in the cerebrum and consequent long-term sequelae. Acute encephalopathy with biphasic seizures and late reduced diffusion is clinically characterized by SE associated with fever and seizure clusters that occur 3-9 days after symptom onset. MRI reveals reduced diffusion in the frontal or frontoparietal subcortical white matter, with sparing of the perirolandic region following seizure clusters. Kawasaki disease (KD) is an acute self-limited vasculitis secondary to activation of the immune system; KD is rarely complicated by acute encephalopathy. We report the case of a male infant who developed SE associated with KD and showed late reduced diffusion in the subcortical white matter beneath the bilateral motor cortices (primary motor, premotor and supplementary motor areas) and the right frontal cortex. The patient had characteristic neurological sequelae in the chronic phase, including clumsiness of fingers and forearms, impaired discrimination of tactile sensation and position sense on digits in his hands and feet, corresponding to the lesions with reduced diffusion at the acute phase.

Exploring the Spectrum of RHOBTB2 Variants Associated with Developmental Encephalopathy 64: A Case Series and Literature Review.

Background: Rho-related BTB domain-containing protein 2 (RHOBTB2) is a protein that interacts with cullin-3, a crucial E3 ubiquitin ligase for mitotic cell division. RHOBTB2 has been linked to early infantile epileptic encephalopathy, autosomal dominant type 64 (OMIM618004), in 34 reported patients. Methods: We present a case series of seven patients with RHOBTB2-related disorders (RHOBTB2-RD), including a description of a novel heterozygous variant. We also reviewed previously published cases of RHOBTB2-RD. Results: The seven patients had ages ranging from 2 years and 8 months to 26 years, and all had experienced seizures before the age of one (onset, 4-12 months, median, 4 months), including various types of seizures. All patients in this cohort also had a movement disorder (onset, 0.3-14 years, median, 1.5 years). Six of seven had a baseline movement disorder, and one of seven only had paroxysmal dystonia. Stereotypies were noted in four of six, choreodystonia in three of six, and ataxia in one case with multiple movement phenotypes at baseline. Paroxysmal movement disorders were observed in six of seven patients for whom carbamazepine or oxcarbazepine treatment was effective in controlling acute or paroxysmal movement disorders. Four patients had acute encephalopathic episodes at ages 4 (one patient) and 6 (three patients), which improved following treatment with methylprednisolone. Magnetic resonance imaging scans revealed transient fluid-attenuated inversion recovery abnormalities during these episodes, as well as myelination delay, thin corpus callosum, and brain atrophy. One patient had a novel RHOBTB2 variant (c.359G>A/p.Gly120Glu). Conclusion: RHOBTB2-RD is characterized by developmental delay or intellectual disability, early-onset seizures, baseline movement disorders, acute or paroxysmal motor phenomena, acquired microcephaly, and episodes of acute encephalopathy. Early onsets of focal dystonia, acute encephalopathic episodes, episodes of tongue protrusion, or peripheral vasomotor disturbances are important diagnostic clues. Treatment with carbamazepine or oxcarbazepine was found to be effective in controlling acute or paroxysmal movement disorders. Our study highlights the clinical features and treatment response of RHOBTB2-RD.

Case report: Influenza A virus and Human herpesvirus 1 infection-associated acute encephalopathy in children with the mutations in the SLC25A19 andTICAM1 gene, respectively.

Background: Infection-associated acute encephalopathy (AE) is a clinical condition caused by a variety of pathogens, particularly common viruses. In some cases, this condition could be characterized by a sudden onset and a rapid progression, leading to severe neurological sequelae, including acute encephalopathy with biphasic seizures and late reduced diffusion, hemorrhagic shock and encephalopathy syndrome, etc. Case presentation: In this study, it was reported that three previously healthy children developed acute encephalopathy/encephalitis symptoms with different neurological sequelae after either Influenza A Virus or Human Herpesvirus 1 infection, presenting with fever and convulsions. What's more, after performing the gene exon detection for these three children, it was found that there are abnormal genes corresponding to their neurological sequelae, including SLC25A19 and TICAM1. Conclusions: Therefore, comparing to children with common encephalitis, for children with encephalitis whose progression is rapid and clinical manifestations such as recurrent fever and frequent convulsions is difficult to improve, whole-exome sequencing can be a valuable tool for identifying encephalitis-associated genetic variants and providing strong evidence for prognostic prediction.

Arterial spin labeling image findings in the acute phase in paediatric patients with acute encephalopathy with biphasic seizures and late reduced diffusion.

Introduction: Diagnosing acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) after the first seizure (early seizure/seizures, ES/ESs) is challenging because a reduced apparent diffusion coefficient (ADC) in the cortical or subcortical white matter, often described as having a "bright-tree appearance (BTA)," is usually not observed until secondary seizures (late seizures, LSs) occur. Previous studies have reported hypoperfusion on arterial spin labeling (ASL) within 24 h after ES/ESs in patients with AESD and hyperperfusion within 24 h after LS onset. This study aimed to investigate cerebral blood flow in the hyperacute phase (between ES/ESs and LSs) using ASL in patients with AESD. Methods: Eight ASL images were acquired in six patients with AESD admitted to our hospital from October 2021 to October 2022. ASL findings in the hyperacute phase were investigated and video-electroencephalogram findings obtained around ASL image acquisition in the hyperacute phase were evaluated. Results: Four ASL images were obtained for three patients before LS onset, with three images showing hyperperfusion areas and one image showing hypoperfusion areas. These hyperperfuion regions coincided with BTA on subsequent images of these patients.In one patient, the first ASL image was obtained in the late hyperacute phase and revealed hyperperfusion areas with a slightly abnormal change on diffusion-weighted image (DWI), which were not accompanied by ADC abnormalities. The second ASL image obtained 51 h after the first ASL, and before LS onset revealed more prominent hyperperfusion areas than the first ASL image, which were accompanied by BTA. In another patient, the ASL image obtained 82 h after ES revealed hyperperfusion areas without abnormal change on DWI or ADC. Conclusion: This study revealed that two patients exhibited hyperperfusion regions and another patient exhibited hypoperfusion regions among three patients who underwent ASL imaging during the period from 24 h after ES/ESs to LSs in patients with LSs or cooling initiation in patients without LSs due to early anaesthesia induction (late hyperacute phase). Further prospective studies on cerebral blood flow are required to explore the relationship among the timing of image acquisition, the presence of electrographic seizures, and ASL findings in patients with AESD.

Timing of therapeutic interventions against infection-triggered encephalopathy syndrome: a scoping review of the pediatric literature.

Our goal was to conduct a scoping review of the literature on the treatment of infection-triggered encephalopathy syndrome/acute encephalopathy in children, focusing on treatment targets and treatment initiation timing. We performed literature searches using PubMed for articles reporting treatments of infection-triggered encephalopathy syndrome/acute encephalopathy. We included articles describing specific treatments for acute encephalopathy with control groups. For the purpose of searching new therapies only experimentally tried in the case series, we also included case series studies without control groups in this review, if the studies contained at least two cases with clear treatment goals. Therapies were classified based on their mechanisms of action into brain protection therapy, immunotherapy, and other therapies. We operationally categorized the timing of treatment initiation as T1 (6-12 h), T2 (12-24 h), T3 (24-48 h), and T4 (>48 h) after the onset of seizures and/or impaired consciousness. Thirty articles were included in this review; no randomized control study was found. Eleven retrospective/historical cohort studies and five case-control studies included control groups with or without specific therapies or outcomes. The targeted conditions and treatment timing varied widely across studies. However, the following three points were suggested to be effective in multiple studies: (1) Careful seizure management and targeted temperature management within 12 h (T1) of onset of febrile seizure/prolonged impaired consciousness without multiple organ failure may reduce the development of acute encephalopathy with biphasic seizures and late reduced diffusion; (2) immunotherapy using corticosteroids, tocilizumab, or plasma exchange within 24 h (T1-T2) of onset of acute necrotizing encephalopathy may reduce sequelae; and (3) anakinra therapy and ketogenic diet demonstrate little evidence of neurologic sequelae reduction, but may reduce seizure frequency and allow for weaning from barbiturates, even when administered weeks (T4) after onset in children with febrile infection-related epilepsy syndrome. Although available studies have no solid evidence in the treatment of infection-triggered encephalopathy syndrome/acute encephalopathy, this scoping review lays the groundwork for future prospective clinical trials.

Neuroimaging in acute infection-triggered encephalopathy syndromes.

Acute encephalopathy associated with infectious diseases occurs frequently in Japanese children (400-700 children/year) and is the most common in infants aged 0-3 years. Acute encephalopathy is classified into several clinicoradiological syndromes; acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most common subtype, followed by clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) and acute necrotizing encephalopathy (ANE). Neuroimaging, especially magnetic resonance imaging (MRI), is useful for the diagnosis, assessment of treatment efficacy, and evaluation of the pathophysiology of encephalopathy syndromes. MRI findings essential for diagnosis include delayed subcortical reduced diffusion (bright tree appearance) for AESD, reversible splenial lesions with homogeneously reduced diffusion for MERS, and symmetric hemorrhagic thalamic lesions for ANE. We reviewed several MRI techniques that have been applied in recent years, including diffusion-weighted imaging for the characterization of cerebral edema, arterial spin labeling for evaluating cerebral perfusion, and magnetic resonance spectroscopy for evaluating metabolic abnormality.

Infantile Hypoxic Encephalopathy Mimicking Acute Encephalopathy with Biphasic Seizures and Late Reduced Diffusion (AESD) Identified as an Episode of Brief Resolved Unexplained Event (BRUE).

Acute encephalopathy with biphasic seizures and reduced diffusion (AESD) is characterized by biphasic seizures following febrile viral infections and delayed reduced diffusion of the cerebral white matter on magnetic resonance imaging (MRI) diffusion-weighted imaging (DWI) (bright tree appearance, BTA). However, hypoxic encephalopathy with biphasic seizures and AESD-mimicking imaging findings has not been reported. We report a case of hypoxic encephalopathy due to suffocation with concomitant biphasic seizures and BTA, mimicking AESD. On day 1, a healthy 5-month-old girl was found face down with decreased breathing and a deteriorating consciousness level, suggesting a brief resolved unexplained event (BRUE). Electroencephalography (EEG) revealed periodic epileptic discharges, suggesting possible nonconvulsive status epilepticus. Despite improvements in consciousness level and EEG abnormalities on day 2, her consciousness level deteriorated again with generalized tonic-clonic seizures on day 3, and a head MRI-DWI revealed restricted diffusion predominantly in the subcortical areas, suggesting BTA. Treatment for acute encephalopathy resolved the clinical seizures and EEG abnormalities. Persistence of abnormal EEG, reflecting abnormal excitation and accumulation of neurotoxic substances caused by hypoxia, may have contributed to the development of AESD-like findings. As hypoxic encephalopathy causes AESD-like biphasic seizures, monitoring consciousness level, seizure occurrence, and EEG abnormalities even after acute symptoms have temporarily improved following hypoxia is essential.

Risk Factors of Prehospital Emergency Care for Acute Encephalopathy in Children With Febrile Status Epilepticus.

BACKGROUND: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) often develops in children with febrile status epilepticus (FSE) with neurological sequelae. No study has investigated the associations between prehospital emergency care and AESD onset. METHODS: We retrospectively collected the data of children with FSE (>30 min) treated in Tottori University Hospital. We evaluated the prehospital emergency care information, investigating its association with AESD development. RESULTS: We identified 11 patients with AESD and 44 with FSE. The time from onset to the arrival of the emergency medical services (EMS) (OR: 1.12, P = 0.015) and hospital arrival (OR: 1.07, P = 0.009) was positively associated with AESD development. In contrast, oxygen saturation levels in ambulances (OR: 0.901, P = 0.013) are negatively associated with AESD development. The time from onset to arrival at the hospital was associated with the time from onset to the administration of antiseizure medications (ASMs) (correlation coefficient: 0.857, P < 0.001), which was significantly associated with AESD development (OR: 1.04, P = 0.039). The cutoff values were 17 minutes from onset to the arrival of EMS (OR: 27.2, P = 0.003), 38 minutes to hospital arrival (OR: 5.71, P = 0.020), and 50 minutes of administration of ASMs (OR: 7.11, P = 0.009). CONCLUSIONS: Prolonged time from onset to hospital arrival and hypoxia in ambulances were associated with AESD development. Shortening transport time, improving respiratory management in ambulances, and the early administration of ASMs might play a role in preventing the development of AESD.