Clustered subclinical seizures in a patient with acute encephalopathy with biphasic seizures and late reduced diffusion

Using single-channel amplitude-integrated electroencephalography (aEEG), we monitored clustered seizures in a 12-month-old boy suffering from acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). He was admitted to our hospital after losing consciousness and experiencing repeated seizures in association with fever. Although the patient’s state of consciousness improved the next day, it declined on the fifth day of illness, and clinical seizures were observed. Diffusion-weighted images revealed abnormal high intensities in the frontal area bilaterally. On the same day, aEEG monitoring revealed an unexpected cluster of subclinical seizures. Attending pediatricians, nurses, and other caregivers did not recognize the presence of these frequent subclinical seizures. The efficacy of antiepileptic drugs could also be objectively assessed from aEEG findings. aEEG is useful for continuous monitoring in children with acute encephalopathy, may disclose subclinical seizures, and can contribute to an objective evaluation of the efficacy of antiepileptic drugs.     

Efficacy of hypothermia therapy in patients with acute encephalopathy with biphasic seizures and late reduced diffusion

BackgroundAcute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is characterized by biphasic seizures and impaired consciousness. The efficacy of hypothermia/normothermia therapy in patients with AESD has rarely been reported on.MethodsWe enrolled 15 patients with AESD admitted to Yamaguchi University Hospital and Yamaguchi-ken Saiseikai Shimonoseki General Hospital between 2005 and 2019 and retrospectively evaluated the long-term efficacy of hypothermia therapy compared to that of non-hypothermia therapy. We compared the long-term sequelae of patients with AESD treated with or without hypothermia therapy. We used the Pediatric Cerebral Performance Category (PCPC) scale and intelligence tests including the Wechsler Intelligence Scale for Children, Tanaka-Binet Intelligence Scale, and Enjoji Infantile Developmental Scale to evaluate neurological sequelae and mental disability. The preventive effect of hypothermia therapy was assessed based on the development of post-encephalopathic epilepsy (PEE).ResultsThere was no significant between-group difference in the PCPC score (p = 0.53). The subjects with severe mental disability in the hypothermia therapy group were 0 (0%), while those in the non-hypothermia group were 2 (29%); however, the difference was not significant. Notably, there were no patients with onset of PEE in the hypothermia therapy group, while there were 4 (57.1%) in the non-hypothermia group (p = 0.03).ConclusionsOur study suggests that hypothermia therapy may be effective in the long-term sequelae of AESD in terms of preventing the development of PEE. We propose that hypothermia therapy could contribute to improve the quality of life in these patients by preventing the subsequent onset of PEE.     

Early non-convulsive seizures are associated with the development of acute encephalopathy with biphasic seizures and late reduced diffusion

IntroductionChildren with either febrile seizure or acute encephalopathy exhibit seizures and/or impaired consciousness accompanied by fever of unknown etiology (SICF). Among children with SICF, we previously reported those who have refractory status epilepticus or prolonged neurological abnormalities with normal AST levels are at a high risk for the development of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), considered to be caused by excitotoxicity. Non-convulsive seizures (NCS) are common in critically ill children and cause excitotoxic neuronal injury. The aim of this study was to elucidate the prevalence of NCS in the acute phase of children at a high risk for developing AESD and the relationship between NCS in the acute phase and neurological outcomes.MethodsWe studied 137 children with SICF at a high risk for developing AESD and who underwent continuous electroencephalogram monitoring (cEEG) upon admission to a tertiary pediatric care center at Hyogo Prefectural Kobe Children’s Hospital between October 2007 and August 2018. Patient characteristics and outcomes were compared between patients with NCS and without NCS.ResultsOf the 137 children, NCS occurred in 30 children; the first NCS were detected in cEEG at the beginning in 63.3%, during the first hour in 90%, and within 12 h in 96.7%. Neurological sequelae were more common in NCS patients (20.0%) than in non-NCS patients (1.9%; p = 0.001). Five in 30 NCS patients (16.7%) and 3 in 107 non-NCS patients (2.8%) developed AESD (p = 0.013).ConclusionThe occurrence of NCS is associated with subsequent neurological sequelae, especially the development of AESD.     

Loss of myelinated axons and astrocytosis in an autopsy case of acute encephalopathy with biphasic seizures and late reduced diffusion

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most common pediatric encephalopathy in Japan, however, the exact neuropathology remains uncertain. The postmortem neuropathology in a patient with AESD revealed reduction of myelinated axons with early stage of astrocytosis in the absence of neuronal loss, which suggests the primary pathological damage in AESD involves myelinated axons and astrocytes rather than cortical neurons. An increased number of gemistocytic astrocytes at the corticomedullary junction may cause reduced diffusion, leading to the so-called bright tree appearance on magnetic resonance imaging, characteristic to AESD.     

Acute encephalopathy with biphasic seizures and late reduced diffusion in a Spanish girl

We report a case of a 22-month-old Spanish girl who presented acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). Serum procalcitonin (PCT) reached a maximum of 50.5 ng/mL on the first day whereas C-reactive protein (CRP) peaked at 1.21 mg/dL on the second. At the time of discharge, right spastic hemiparesis persisted. MR spectroscopy on day 23 revealed a decrease in N-acetylaspartate and an increase in choline. To our knowledge, we report the first case of AESD in Europe. These findings support the role of PCT and PCT/CRP ratio in the early diagnosis of AESD and correlation of MR spectroscopy findings with neurological outcome.     

Acute encephalopathy with biphasic seizures and late reduced diffusion associated with hemophagocytic syndrome

We reported a girl with HHV-6 infection associated with both acute encephalopathy with biphasic seizures and late reduced diffusion, and hemophagocytic syndrome. She had a prolonged convulsion after a one-day history of febrile illness. Cerebrospinal fluid or brain CT showed no abnormalities on admission and her consciousness was recovered on the next day. However, a prolonged seizure and deterioration of consciousness appeared on the sixth day of illness. Diffusion-weighted images revealed marked reduction of water diffusion in the bilateral frontal areas. HHV-6 infection was virologically proven by polymerase chain reaction. She was treated with γ-globulin, steroid pulse therapy, and brain hypothermia. In addition, decrease in white blood cells and platelet counts, and elevation of liver enzymes and ferritin were noted on the fourth day of illness. Hemophagocytic macrophages were revealed by bone marrow aspiration on the sixth day. Her hematological and blood chemistry abnormalities recovered gradually after steroid pulse therapy. An elevation of interleukin-6, -8, and -10, and tumor necrosis factor in the serum and that of interleukin-4, -6, and-8 in the cerebrospinal fluid were observed at the onset of a late seizure. These facts suggested that hypercytokinemia will be related to the pathogenesis of acute encephalopathy of our patient.     

Acute encephalopathy with biphasic seizures and late reduced diffusion: Predictive EEG findings

BackgroundAcute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a common type of acute encephalopathy in Japan; the condition is clinically characterized by prolonged seizures as the initial neurological symptom, followed by late seizures 4–6 days later. It is difficult to differentiate AESD from prolonged febrile seizures (PFSs). Here, we explored the use of electroencephalography to differentiate AESD from PFSs.MethodsWe studied the electroencephalograms (EEGs) of children <6 years of age diagnosed with AESD or PFSs; all EEGs were recorded within 48 h of seizure onset (i.e., before the late seizures of AESD). Two pediatric neurologists evaluated all EEGs, focusing on the basic rhythm, slowing during wakefulness/arousal by stimuli, spindles, fast waves, and slowing during sleep.ResultsThe EEGs of 14 children with AESD and 31 children with PFSs were evaluated. Spindles were more commonly reduced or absent in children with AESD than in those with PFSs (71% vs. 31%, p = 0.021). Fast waves were also more commonly reduced or absent in children with AESD (21% vs. 0%, p = 0.030). The rates of all types of slowing did not differ between children with AESD and those with PFSs, but continuous or frequent slowing during sleep was more common in the former (50% vs. 17%, p = 0.035).ConclusionsEEG findings may usefully differentiate AESD from PFSs. Reduced or absent spindles/fast waves and continuous or frequent slowing during sleep are suggestive of AESD in children with prolonged seizures associated with fever.     

Serum and cerebrospinal fluid levels of visinin-like protein-1 in acute encephalopathy with biphasic seizures and late reduced diffusion

Background: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) has recently been recognized as an encephalopathy subtype. Typical clinical symptoms of AESD are biphasic seizures, and MRI findings show reduced subcortical diffusion during clustering seizures with unconsciousness after the acute phase. Visinin-like protein-1 (VILIP-1) is a recently discovered protein that is abundant in the central nervous system, and some reports have shown that VILIP-1 may be a prognostic biomarker of conditions such as Alzheimer’s disease, stroke, and brain injury. Methods: However, there have been no reports regarding serum and cerebrospinal fluid (CSF) levels of VILIP-1 in patients with AESD. We measured the serum and CSF levels of VILIP-1 in patients with AESD, and compared the levels to those in patients with prolonged febrile seizures (FS). Results: Both serum and CSF levels of VILIP-1 were significantly higher in patients with AESD than in patients with prolonged FS. Serum and CSF VILIP-1 levels were normal on day 1 of AESD. Conclusions: Our results suggest that both serum and CSF levels of VILIP-1 may be one of predictive markers of AESD.     

Refractory status epilepticus with fever due to mumps vaccine-induced encephalitis caused secondary encephalopathy mimicking acute encephalopathy with biphasic seizures and late reduced diffusion

BackgroundEncephalitis due to vaccination for mumps is a rare complication that occurs in 0.00004% of recipients, and there has been no report of serious neurological sequelae. Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) has been reported as the most frequent type among acute encephalopathy syndromes in the pediatric population in Japan. There has been no report of AESD caused by vaccinations.Case presentationWe present the clinical course of a 1-year and 10-month-old boy who had no preexisting condition, and developed mumps vaccine-induced severe primary encephalitis. Refractory status epilepticus due to encephalitis persisted for 16 h and resulted in secondary encephalopathy as a form of AESD mimic. He had serious neurological sequelae, such as West syndrome, transient spastic tetraplegia, and intellectual disability, despite intensive treatments.DiscussionThe presented boy is the first patient to develop mumps vaccine-induced primary encephalitis with severe central nervous system (CNS) damage. Screening of the immunological background in the presented patient revealed no abnormalities; therefore, it is unclear why he developed such severe adverse events. In patients with acute encephalitis caused by the herpes simplex virus 1, inborn immune errors in CNS based on mutations in single genes are involved in its pathophysiology. Consequently, some immunogenetic alterations could be found by further analysis in the presented patient.     

A case of acute encephalopathy with biphasic seizures and late reduced diffusion: Utility of arterial spin labeling sequence

A 1-year-old boy was admitted because of febrile status epilepticus (FSE). A secondary cluster of seizures was seen on day 5 after onset, and the patient eventually displayed developmental delay. Conventional magnetic resonance imaging (MRI) showed no abnormal findings on day 1 after onset, but showed reduced diffusion in the subcortical regions of bilateral frontal lobes on day 5 after onset. Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) was diagnosed. Arterial spin labeling (ASL) revealed reduced cerebral blood flow (CBF) in bilateral frontal lobes on day 1 after onset and showed increased CBF in the corresponding region in the subacute phase. Outcomes after prolonged febrile seizures are usually good, but mental deficit and/or epilepsy often remain in AESD. Discriminating between these syndromes is difficult, because no useful biomarkers have been identified. Reduced CBF in bilateral frontal lobes was observed on ASL on day 1 of FSE in the present case, and this finding may be predictive of developing AESD.     

A case of acute encephalopathy with biphasic seizures and late reduced diffusion associated with Streptococcus pneumoniae meningoencephalitis

Acute encephalopathy with biphasic seizures and reduced diffusion (AESD) encompasses a group of encephalopathy characterized by biphasic seizures and disturbance of consciousness in the acute stage followed in the subacute stage by reduced diffusion in the subcortical white matter on magnetic resonance imaging. The etiology of AESD is viral infection and associated pathological changes. Here we report the first case of AESD caused by bacterial infection (Streptococcus pneumoniae meningitis) in a 1-year-old boy.     

A serial analysis of serum aspartate aminotransferase levels in patients with acute encephalopathy with biphasic seizures and late reduced diffusion and prolonged febrile seizure

BackgroundThere are no established biomarkers for diagnosing acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) in the early acute phase, called “the 1st seizure phase”. Based on our clinical experience, we hypothesized that serial examinations of blood levels of aspartate aminotransferase (AST) in children with febrile convulsive status epilepticus (FCSE) revealed higher levels in patients with AESD in the 1st seizure phase than in those with prolonged febrile seizures (PFs).MethodsTo test our presented hypothesis, we retrospectively investigated changes in serum AST in patients with FCSE due to AESD (n = 11) or PFs (n = 27) who were serially examined within 48 h of the onset of convulsions.ResultsThe rate of increase in AST was significantly higher in patients with AESD than in those with PFs. The rate of increase in AST correlated with previously reported scoring systems, i.e., Yokochi and Tottori scores, for the prediction of AESD. A positive correlation between the rate of increase in AST and creatinine levels in the first examination were observed; however, creatinine levels did not significantly differ between the AESD and PFs groups in the first or second examination. Blood levels of pH, ammonia, and sugar in the first examination and C-reactive protein in the second examination were significantly higher in the AESD group than in the PFs group.ConclusionsThe present study revealed that the rate of increase in AST was significantly higher in patients with AESD than in those with PFs. A novel predictive scoring system needs to be established in combination with the rate of increase in AST and reported clinical parameters, which will improve the prognosis of patients with FCSE.     

Late-onset epilepsy in children with acute febrile encephalopathy with prolonged convulsions: A clinical and encephalographic study

The aim of this study is to analyze the characteristics of epilepsies as the sequelae of acute febrile encephalopathy with prolonged convulsions during childhood. Sixteen patients (M:F = 9:7) aged 2–13 years (mean 6.1 years) with history of febrile acute encephalopathy were retrospectively reviewed. These patients experienced febrile encephalopathy at the age of 11 months to 4 years, with 11 individuals presenting with findings of a biphasic clinical course (n = 5), frontal predominant (n = 8) lesions, and/or reduced diffusivity in the cerebral white matter on magnetic resonance imaging (MRI; n = 3). The remaining 5 patients had unilateral lesions that manifested the phenotype of hemiconvulsion–hemiplegia–epilepsy syndrome (HHES). Epilepsy emerged with a latent period of 2 months to 2 years after the acute phase of febrile encephalopathy. Head nodding or spasm with subsequent motion arrest and brief tonic seizures were the main seizure phenotypes. Ictal records of epileptic seizures were available in 9 patients. Epileptiform discharges with a focal or uneven distribution appeared at the seizure onset and lasted less than 1 s in all patients; these were followed by either generalized attenuation or fast activity in 8 patients with head nodding, spasm, or brief tonic seizures, and by localized fast activity in 1 patient with versive tonic seizures. Notably, the seizure onset area was often located outside the severe lesions on MRI, i.e., in the parietal areas in patients with frontal predominant lesions, and in the spared hemisphere of HHES. Although phenobarbital, zonisamide, carbamazepine, clobazam, clonazepam, and clorazepate were partially effective in some patients, daily seizures persisted in 11 patients. Callosotomy was performed in 2 patients, and beneficial effects were observed in both. These characteristics suggested a broad distribution of augmented excitability in these patients, resulting in the rapid propagation of epileptic activity in the initial phase of ictal phenomena. Thus, this study investigates the most severe subgroup of epilepsy following febrile acute encephalopathy and provides the basis for further exploration of the pathogenesis and treatment of characteristic seizures in this population.     

Carnitine palmitoyl transferase II polymorphism is associated with multiple syndromes of acute encephalopathy with various infectious diseases

The high incidence of acute encephalopathy in East Asia suggests the role of genetic factors in its pathogenesis. It has recently been reported that variations of the CPT II (carnitine palmitoyl transferase II) gene may be associated with fatal or severe cases of influenza-associated encephalopathy. In the present study, we examined the genotype of CPT II in cases of acute encephalopathy associated with various preceding infections. Twenty-nine Japanese patients with acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) or acute necrotizing encephalopathy (ANE) were studied. The frequency of F352C of CPT II exon 4 was significantly higher in patients than in controls. All patients who had allele C in F352C had allele I in V368I and allele M in M647V (CIM haplotype), which reportedly decreases CPT II activity to one third of that with FIM or FVM haplotype. The frequency of CIM haplotype was significantly different between patients and controls, but not between AESD and ANE. Our results revealed that having at least one CIM allele is a risk factor for the onset of acute encephalopathy, regardless of its antecedent infections.     

Early prognostic factors for acute encephalopathy with reduced subcortical diffusion

Objective

The aim of this study was to determine the prognostic factors for acute encephalopathy with reduced diffusion (AED) during the acute phase through retrospective case evaluation.

Epidemiology of acute encephalopathy in Japan, with emphasis on the association of viruses and syndromes

A research committee supported by the Japanese government conducted a nationwide survey on the epidemiology of acute encephalopathy in Japan using a questionnaire. A total of 983 cases reportedly had acute encephalopathy during the past 3 years, 2007-2010. Among the pathogens of the preceding infection, influenza virus was the most common, followed by human herpesvirus-6 (HHV-6) and rotavirus. Among syndromes of acute encephalopathy, acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) was the most frequent, followed by clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS), acute necrotizing encephalopathy (ANE) and hemorrhagic shock and encephalopathy syndrome (HSES). Influenza virus was strongly associated with ANE and MERS, HHV-6 with AESD, and rotavirus with MERS. Mortality was high in ANE and HSES, but was low in AESD, MERS and HHV-6-associated encephalopathy. Neurologic sequelae were common in AESD and ANE, but were absent in MERS.     

Two cases of traumatic head injury mimicking acute encephalopathy with biphasic seizures and late reduced diffusion

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) presents a distinct clinical course of biphasic seizures and impaired consciousness. These symptoms are followed by reduced diffusion in the subcortical white matter on magnetic resonance imaging that is typically observed between 3 and 9 days after illness onset. Here, we report two cases of traumatic head injury with clinical and radiological features similar to those for AESD. The similarities between our cases and AESD may be useful in understanding the pathogenesis of AESD.     

Cortical gray matter lesions in acute encephalopathy with febrile convulsive status epilepticus

In acute encephalopathy with febrile convulsive status epilepticus (AEFCSE), subcortical white matter lesions on diffusion-weighted images are sometimes encountered on magnetic resonance imaging (MRI), such as in acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). We report here a severe case of AEFCSE following respiratory syncytial virus infection, with emphasis on the cranial MRI findings. MRI in this patient showed widespread T2-hyperintensity along the cerebral cortical gray matter from day 3 to day 22. Lesions with reduced diffusion were noted on day 3 in the deep zone of gray matter of the left occipito–temporo–parietal cortex, but on day 7 they shifted to the subcortical white matter of both the cerebral hemispheres. These MRI findings provide radiologic evidence for damage to the cortical gray matter in AEFCSE. The serial change of diffusion-weighted images suggests that the cortical gray matter may be injured prior to the involvement of the subcortical white matter.     

Growth and differentiation factor-15 as a potential prognostic biomarker for status-epilepticus-associated-with-fever: A pilot study

ObjectiveBiomarkers predicting poor outcomes of status-epilepticus-associated-with-fever (SEF) at an early stage may contribute to treatment guidance. However, none have been reported thus far. We investigated the dynamics of serum growth and differentiation factor (GDF)-15 after seizure onset in patients with SEF and determined whether GDF-15 can predict poor outcomes, particularly in the first 6 h after seizure onset.MethodsWe enrolled 37 pediatric patients with SEF and eight patients with simple febrile seizures (SFS) and collected their blood samples within 24 h of seizure onset and eight febrile control patients between March 1, 2017 and September 30, 2020. All patients were aged ≤15 years.ResultsIn the SEF group, the median post-seizure serum GDF-15 values were 1,065 (<6h), 2,720 (6–12 h), and 2,411 (12–24 h) pg/mL. The median serum GDF-15 in the first 6 h was measured in patients with SEF without a significant past medical history (n = 21) and was found to be statistically significantly higher (1,587 pg/mL) than in the febrile control (551 pg/mL) and SFS (411 pg/mL) groups. The median serum GDF-15 was statistically significantly higher in patients with SEF with sequelae (n = 5) and patients with acute encephalopathy with biphasic seizures/reduced diffusion/hemorrhagic shock and encephalopathy syndrome (n = 6) than in patients with SEF without sequelae (n = 16) (15,898 vs 756 pg/mL) and patients with prolonged FS (n = 15) (9,448 vs 796 pg/mL).ConclusionsThis study demonstrates the dynamics of serum GDF-15 in patients with SEF and indicates the potential of GDF-15 as an early predictor of poor outcomes.