Presentation and Outcome of Acute Necrotizing Encephalopathy of Childhood: A 10-Year Single-Center Retrospective Study From Hong Kong

A case report and literature review on tocilizumab-cured acute necrotizing encephalopathy caused by influenza A virus

Introduction

Acute Necrotizing Encephalopathy (ANE), is a kind of severe Central Nervous System Disease. The commonest pathogen is the influenza virus. The pathogenesis of ANE is bound up to genetic susceptibility and cytokine storm. Interleukin-6 (IL-6) is deemed as the core function in cytokine storm of ANE and that plays a significant role in evaluating the severity of Influenza-Related ANE. Tocilizumab, an IL-6 antagonist, is known to be safe and effective in the treatment of ANE when used early and has an essential role in improving prognosis and preventing disability.

Case report

This case reports a 2 year 10 month old boy who developed ANE after being infected with influenza A virus (H1N1-2019). After treatment with Tocilizumab, the child's consciousness was clear, no convulsions occurred, the movement of limbs was improved, and the lesions of encephalopathy were significantly reduced.

Conclusion

The early use of Tocilizumab is safe and effective for the treatment of ANE caused by influenza virus.

Acute Necrotizing Encephalopathy in Adult Patients With COVID-19: A Systematic Review of Case Reports and Case Series

BACKGROUND AND PURPOSE

Acute necrotizing encephalopathy (ANE) is a rare neurological disorder that is often associated with viral infections. Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a few COVID-19-associated ANE cases have been reported. Since very little is known about ANE, the present study aimed to determine the clinical, biochemical, and radiological characteristics of affected patients.

METHODS

A search was conducted on PubMed, Scopus, Embase, and Web of Science databases for articles published up to August 30, 2022 using relevant keywords. Case reports and series in the English language that reported ANE in adult patients with COVID-19 confirmed by reverse transcription polymerase chain reaction were included in this study. Data on the demographic, clinical, laboratory, and radiological characteristics of patients were extracted and analyzed using the SPSS software (version 26).

RESULTS

The study included 30 patients (18 males) with COVID-19 and ANE who were aged 49.87±18.68 years (mean±standard deviation). Fever was the most-prevalent symptom at presentation (66.7%). Elevated C-reactive protein was observed in the laboratory assessments of 13 patients. Computed tomography and magnetic resonance imaging were the most-common radiological modalities used for brain assessments. The most commonly prescribed medications were methylprednisolone (30%) and remdesivir (26.7%). Sixteen patients died prior to discharge.

CONCLUSIONS

The diagnosis of COVID-19-associated ANE requires a thorough knowledge of the disease. Since the clinical presentations of ANE are neither sensitive nor specific, further laboratory and brain radiological evaluations will be needed to confirm the diagnosis. The suspicion of ANE should be raised among patients with COVID-19 who present with progressive neurological symptoms.

Expert Panel Curation of 113 Primary Mitochondrial Disease Genes for the Leigh Syndrome Spectrum

OBJECTIVE

Primary mitochondrial diseases (PMDs) are heterogeneous disorders caused by inherited mitochondrial dysfunction. Classically defined neuropathologically as subacute necrotizing encephalomyelopathy, Leigh syndrome spectrum (LSS) is the most frequent manifestation of PMD in children, but may also present in adults. A major challenge for accurate diagnosis of LSS in the genomic medicine era is establishing gene-disease relationships (GDRs) for this syndrome with >100 monogenic causes across both nuclear and mitochondrial genomes.

METHODS

The Clinical Genome Resource (ClinGen) Mitochondrial Disease Gene Curation Expert Panel (GCEP), comprising 40 international PMD experts, met monthly for 4 years to review GDRs for LSS. The GCEP standardized gene curation for LSS by refining the phenotypic definition, modifying the ClinGen Gene-Disease Clinical Validity Curation Framework to improve interpretation for LSS, and establishing a scoring rubric for LSS.

RESULTS

The GDR with LSS across the nuclear and mitochondrial genomes was classified as definitive for 31 of 114 GDRs curated (27%), moderate for 38 (33%), limited for 43 (38%), and disputed for 2 (2%). Ninety genes were associated with autosomal recessive inheritance, 16 were maternally inherited, 5 were autosomal dominant, and 3 were X-linked.

INTERPRETATION

GDRs for LSS were established for genes across both nuclear and mitochondrial genomes. Establishing these GDRs will allow accurate variant interpretation, expedite genetic diagnosis of LSS, and facilitate precision medicine, multisystem organ surveillance, recurrence risk counseling, reproductive choice, natural history studies, and determination of eligibility for interventional clinical trials. ANN NEUROL 2023;94:696-712.

Treatment of severe acute necrotizing encephalopathy of childhood with interleukin-6 receptor blockade in the first 24 h as add-on immunotherapy shows favorable long-term outcome at 2 years

BACKGROUND

Acute necrotizing encephalopathy (ANE) of childhood is a rare and devastating infection-associated acute encephalopathy. While there are no consensus treatments for ANE, recent case reports suggest a beneficial role for the use of tocilizumab, a recombinant humanized monoclonal antibody against the interleukin-6 (IL-6) receptor. The correlation of the timing of add-on tocilizumab in relation to long-term outcome has not been reported.

METHODS

We report on the timing of administration of tocilizumab in two patients classified as high-risk using the ANE severity score (ANE-SS) with respect to the long-term outcome at 2 years.

RESULTS

Case 1 was a 19-month-old previously well boy who presented to a tertiary children's hospital with seizures, evolving status dystonicus and shock. Case 2 was a three-year-old boy who presented to a peripheral hospital with fever, sepsis and encephalopathy. The patients were transferred to the tertiary intensive care unit and MRI confirmed ANE with extensive brainstem involvement. Case 1 received intravenous immunoglobulin (IVIg), methylprednisolone and tocilizumab at 21, 39 and 53 h respectively. His modified Rankin scale (mRS) at discharge and two years was unchanged at 5. The functional independence measure - for children (WeeFIM) at two years was very low (19/126). Case 2 received dexamethasone at 1 h, methylprednisolone at 21 h and IVIg and tocilizumab at 22 h. The mRS at discharge and two years was 4 and 3 respectively. The WeeFIM score at two years showed substantial improvement (96/126).

CONCLUSION

The very early use of interleukin-6 blockade as 'add-on' immunotherapy in the first 24 h demonstrates potential for improving the long-term outcome in patients classified as high-risk using the ANE-SS.

Acute Necrotizing Encephalitis Due to Influenza B in a Child: A Case Report

Acute necrotizing encephalitis (ANE) is a rare and life-threatening form of encephalitis associated with influenza virus and other pathogens. It is characterized by a rapid onset of neurological symptoms and has been linked to a cytokine storm within the brain. We present a unique case of an eight-year-old female with influenza B-associated ANE, involving multiple brain areas including the cerebellum and brainstem and cauda equina involvement. The patient had a rapid neurological deterioration, and MRI findings revealed extensive multifocal areas of abnormal brain parenchyma and inflammation with Guillain-Barre appearance in the cauda equina. To the best of our knowledge, this is the first reported case of ANE with cauda equina involvement leading to neurological deficits. Despite treatment with oseltamivir, steroids, and intravenous immunoglobulins, the patient had poor neurological outcomes, similar to those reported in the literature.

Pediatric recurrent acute necrotizing encephalomyelitis, RANBP2 genotype and Sars-CoV-2 infection: Diagnosis, pathogenesis and targeted treatments from a case study

Acute necrotizing encephalopathy (ANE) is a rare disease not yet described in children with Covid-19. RANBP2 gene variations are implicated in recurrences in the genetic form of ANE, the so called ANE1. We report the first case of pediatric ANE1 following Sars-CoV-2 infection. She had a first episode at 2 years of age following influenza type A with full recovery, many other respiratory and non-respiratory febrile viral infections without recurrences and a severe recurrence following Sars-CoV-2 infection, suggesting a potentiation effect on cytokine cascade. Her MRI showed the typical pattern of injury resembling that of mitochondrial disorders, and supported the role of RANBP2 in mitochondrial homeostasis. This case rises attention on diagnostic challenges and offers several interesting tips for discussion about new perspectives in pathogenesis and targeted treatments.

Roles of Nucleoporin RanBP2/Nup358 in Acute Necrotizing Encephalopathy Type 1 (ANE1) and Viral Infection

Ran Binding Protein 2 (RanBP2 or Nucleoporin358) is one of the main components of the cytoplasmic filaments of the nuclear pore complex. Mutations in the RANBP2 gene are associated with acute necrotizing encephalopathy type 1 (ANE1), a rare condition where patients experience a sharp rise in cytokine production in response to viral infection and undergo hyperinflammation, seizures, coma, and a high rate of mortality. Despite this, it remains unclear howRanBP2 and its ANE1-associated mutations contribute to pathology. Mounting evidence has shown that RanBP2 interacts with distinct viruses to regulate viral infection. In addition, RanBP2 may regulate innate immune response pathways. This review summarizes recent advances in our understanding of how mutations in RANBP2 contribute to ANE1 and discusses how RanBP2 interacts with distinct viruses and affects viral infection. Recent findings indicate that RanBP2 might be an important therapeutic target, not only in the suppression of ANE1-driven cytokine storms, but also to combat hyperinflammation in response to viral infections.

Clinical Manifestations and Pathogenesis of Acute Necrotizing Encephalopathy: The Interface Between Systemic Infection and Neurologic Injury

Acute necrotizing encephalopathy (ANE) is a devastating neurologic condition that can arise following a variety of systemic infections, including influenza and SARS-CoV-2. Affected individuals typically present with rapid changes in consciousness, focal neurological deficits, and seizures. Neuroimaging reveals symmetric, bilateral deep gray matter lesions, often involving the thalami, with evidence of necrosis and/or hemorrhage. The clinical and radiologic picture must be distinguished from direct infection of the central nervous system by some viruses, and from metabolic and mitochondrial disorders. Outcomes following ANE are poor overall and worse in those with brainstem involvement. Specific management is often directed toward modulating immune responses given the potential role of systemic inflammation and cytokine storm in potentiating neurologic injury in ANE, though benefits of such approaches remain unclear. The finding that many patients have mutations in the nucleoporin gene RANBP2, which encodes a multifunctional protein that plays a key role in nucleocytoplasmic transport, may allow for the development of disease models that provide insights into pathogenic mechanisms and novel therapeutic approaches.

Clinical evaluation of acute necrotizing encephalopathy in children

OBJECTIVE

Acute necrotizing encephalopathy (ANE) is a rare but severe encephalopathy and is associated with a high morbidity and mortality. We aimed to analyze and compare the clinical features and predictive indicators of pediatric ANE.

MATERIALS AND METHODS

This retrospective study included children with ANE diagnosed at Guangzhou Women and Children's Medical Center between November 2018 and January 2020. Pediatric patients' information, including clinical characteristics, laboratory tests, neuroelectrophysiology and brain magnetic resonance imaging (MRI) findings, MRI score, brainstem auditory evoked potential (BAEP) grades, ANE severity scores (ANE-SS), and modified Rankin scale (mRS), were collected.

RESULTS

Twelve ANE patients were included. Among them, one patient (8.3%) died from brainstem dysfunction, one (8.3%) recovered and 10 (83.3%) experienced neurological sequelae. All patients had an initial viral infection and neurological symptoms such as acute disturbance of consciousness (ADOC) or seizure, and the interval from onset of the disease to neurological manifestations was 3 (1.25-3) days. MRI score-I ranged from 1 to 3 (1.8 ± 0.7), MRI score-II ranged from 1 to 4 (2.5 ± 1.1). ANE-SS varied from 1 to 6 (3.9 ± 1.3). The scores of mRS were from 0 to 6 (2.9 ± 1.7). Higher MRI score were associated with worse outcomes, while the BAEP grade and ANE-SS score were not significantly associated with mRS.

CONCLUSION

ANE is a severe encephalopathy syndrome with rapid progression, resulting in serious neurological sequelae. Compared with BAEP grade and ANE-SS, brain MRI shows more comprehensive advantages in predicting the prognosis of ANE patients. More in-depth research and better indicators are still needed to support the evaluation and treatment of ANE.

Acute Necrotizing Encephalopathy: 2 Case Reports on RANBP2 Mutation

Infection-induced acute encephalopathy 3 (IIAE3) is an autosomal dominant disease resulting from a pathogenic variant in the RANBP2 gene. IIAE3 results in the susceptibility to the recurrence of acute necrotizing encephalopathy (ANE1) which presents as bilateral symmetric thalamic, midbrain and/or hindbrain lesions that typically develops within 1-4 days post-acute viral infection, commonly occurring before age 6.^1-6 These case reports highlight a retrospective analysis of clinical data and radiographic studies on 2 ANE1 cases from our institution. The novel p.Leu450Phe variant of the RANBP2 gene was analyzed using in silico algorithms (PolyPhen-2, SIFT, Mutationtaster) which suggests the p.Leu450Phe variant is probably deleterious.⁷ An expansion of documented ANE1 case presentations and clinically significant RANBP2 gene mutations has the potential to improve long term outcomes if more informed therapeutic decision making can be achieved.

Plasma exchange therapy for acute necrotizing encephalopathy of childhood

IMPORTANCE

Acute necrotizing encephalopathy (ANE) is a rare disease with high mortality. Plasma exchange (PLEX) has recently been reported to treat ANE of childhood (ANEC), but its efficacy is uncertain.

OBJECTIVE

This study aimed to investigate the effectiveness of PLEX on ANEC.

METHODS

A retrospective study was conducted in four pediatric intensive care units from December 2014 to December 2020. All patients who were diagnosed with ANEC were included; however, these patients were excluded if their length of stay was less than 24 h. Participants were classified into PLEX and non-PLEX groups.

RESULTS

Twenty-nine patients with ANEC were identified, 10 in the PLEX group and 19 in the non-PLEX group. In the PLEX group, C-reactive protein, procalcitonin, alanine aminotransferase, and aspartate aminotransaminase levels were significantly lower after 3 days of treatment than before treatment (13.1 vs. 8.0, P = 0.043; 9.8 vs. 1.5, P = 0.028; 133.4 vs. 31.9, P = 0.028; 282.4 vs. 50.5, P = 0.046, respectively). Nine patients (31.0%, 9/29) died at discharge, and a significantly difference was found between the PLEX group and non-PLEX group [0 vs. 47.4% (9/19), P = 0.011]. The median follow-up period was 27 months, and three patients were lost to follow-up. Thirteen patients (50.0%, 13/26) died at the last follow-up, comprising three (33.3%, 3/9) in the PLEX group and ten (58.8%, 10/17) in the non-PLEX group, but there was no significant difference between the two groups (P = 0.411). Three patients (10.3%, 3/29) fully recovered.

INTERPRETATION

PLEX may reduce serum C-reactive protein and procalcitonin levels and improve liver function in the short term. PLEX may improve the prognosis of ANEC, and further studies are needed.

Treatment Timing, EEG, Neuroimaging, and Outcomes After Acute Necrotizing Encephalopathy in Children

BACKGROUND

Acute necrotizing encephalopathy (ANE) is a rare condition associated with rapid progression to coma and high incidence of morbidity and mortality.

METHODS

Clinical, electroencephalographic (EEG), and brain magnetic resonance imaging (MRI) characteristics and immunomodulatory therapy timing were retrospectively analyzed in children with ANE. ANE severity scores (ANE-SS) and MRI scores were also assessed. The associations of patient characteristics with 6-month modified Rankin scale (mRS) and length of hospitalization were determined using either univariate linear regression or one-way analysis of variance.

RESULTS

7 children were retrospectively evaluated. Normal EEG sleep spindles (P = .024) and early treatment (R² = .57, P = .030) were associated with improved outcomes (ie, decreased mRS). Higher ANE-SS (R² = .79, P = .011), higher age (R² = .62, P = .038), and presence of brainstem lesions (P = .015) were associated with longer length of hospitalization. Other patient characteristics were not significantly associated with mRS or length of hospitalization.

CONCLUSION

Early immunomodulatory therapy and normal sleep spindles are associated with better functional outcome in children with ANE.

Malaysian outcome of acute necrotising encephalopathy of childhood

OBJECTIVE

Describe the outcome of a Malaysian cohort of children with acute necrotising encephalopathy (ANE).

METHOD

Retrospective study of children with ANE seen at University of Malaya Medical Centre from 2014 to 2019. All clinical details including ANE-severity score (ANE-SS), immunomodulation treatment and neurodevelopmental long-term outcome were collected.

RESULTS

Thirteen patients had ANE and brainstem death occurred in 5. In 10 patients (77%) viruses were isolated contributing to ANE: 8 influenza virus, 1 acute dengue infection, and 1 acute varicella zoster infection. The ANE-SS ranged 2-7: 9 were high risk and 4 were medium risk. Among the 8 survivors; 1 was lost to follow-up. Follow-up duration was 1-6 years (median 2.2). At follow-up among the 4 high-risk ANE-SS: 2 who were in a vegetative state, 1 remained unchanged and 1 improved to severe disability; the other 2 with severe disability improved to moderate and mild disability respectively. At follow-up all 3 medium-risk ANE-SS improved: 2 with severe disability improved to moderate and mild disability respectively, while 1 in a vegetative state improved to severe disability. Early treatment with immunomodulation did not affect outcome.

CONCLUSION

Our ANE series reiterates that ANE is a serious cause of encephalopathy with mortality of 38.5%. All survivors were in a vegetative state or had severe disability at discharge. Most of the survivors made a degree of recovery but good recovery was seen in 2. Follow-up of at least 12 months is recommended for accurate prognostication. Dengue virus infection needs to be considered in dengue endemic areas.