Recurrent acute necrotizing encephalopathy in a Korean child: the first non-Caucasian case

Acute necrotizing encephalopathy associated with RANBP2 mutation: value of MRI findings for diagnosis and intervention

INTRODUCTION

Acute necrotizing encephalopathy (ANEC) is a rare entity characterized by encephalopathy following a febrile illness. Most patients are sporadic; however, recurrent and familial cases have been associated with RAN-binding protein 2 (RANBP2) mutation. Well-defined MRI findings can even be life-saving with early diagnosis and treatment.

METHODS

In this article, nine pediatric cases diagnosed with ANEC1 both clinically and radiologically, and with least one variation in the RANBP2 gene, are presented.

RESULTS

All patients were previously healthy and presented with encephalopathy after an acute febrile infection. The patients of 44% had a similar attack history in their family. Influenza A/B was detected in 7 patients (78%). One patient was admitted at age 32 years old. The first clinical findings of patients were encephalopathy (100%), seizure (44%), vision problems (33%), ataxia (11%), and monoplegia (11%). Recurrent attacks were seen in two (22%) patients. Brain MRI findings including bilateral thalamus, external capsules, and brainstem involvements were highly suggestive for RANBP2 mutation. Based on MRI findings, genetic analyses were quickly performed and confirmed. All of the patients were treated with empirical encephalitis treatment, oseltamivir, intravenous immunoglobulin (IVIG), high-dose steroid and, if necessary, plasmapheresis, but three (33%) patients died despite treatment.

CONCLUSION

ANEC associated with RANBP2 mutation may occur early or late-onset and can be recurrent and fatal. Therefore, early diagnosis and treatment have the potential to modify the severity of this encephalopathy. Well-defined MRI findings are highly instructive for early diagnosis.

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.

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.

Multi-parametric magnetic resonance imaging in acute necrotizing encephalopathy of children: validity and prognostic value

Background

Acute necrotizing encephalopathy of children (ANEC) is a rare fulminant type of acute encephalopathy that mainly occurs in children with a characteristic clinico-radiological pattern. It is commonly preceded by viral infections. The condition carries a poor prognosis with high morbidity and mortality rates. We highlight the relationship between diagnostic multi-parametric magnetic resonance imaging (MRI) findings and correlate them with the clinical outcome of children with ANEC by enrollment of MRI scoring.

Results

The thalami were involved in all 30 patients, brain stem in 80%, basal ganglia (13.3%), cerebral white matter (WM) in 73%, and cerebellar WM in 33%. Hemorrhage was present in 86.7% patients, edema 80%, and necrosis in 13.3%. We found that the patients having the highest MRI scores were in the poor outcome category; whereas the patients with lower MR score (1 or 2) had better outcomes. Statistically positive correlation (r= 0.1198) was found between the multi-parametric MR score and the outcome category.

Conclusion

An extended multi-parametric MRI should be performed in ANEC, allowing early detection and scoring of the disease for better prognosis. There is a positive correlation between the clinical outcome and the MR scoring.

Familial acute necrotizing encephalopathy without RANBP2 mutation: Poor outcome

Most childhood cases of acute necrotizing encephalopathy (ANE) involve neither family history nor recurrence. ANE occasionally occurs, however, as a familial disorder or recurs in Caucasian patients. A mutation of RAN-binding protein 2 (RANBP2) has been discovered in more than one half of familial or recurrent ANE patients. In contrast, there has been no report of this mutation in East Asia. Here, we report the first sibling cases of typical ANE in Japan, with poor outcome. DNA analysis of genes associated with ANE or other encephalopathies, including RANBP2 and carnitine palmitoyl transferase II (CPT2), indicated neither mutations nor disease-related polymorphisms. On literature review, recurrent or familial ANE without the RANBP2 mutation has a more severe outcome and greater predilection for male sex than that with the RANBP2 mutation. This suggests that there are unknown gene mutations linked to ANE.

Acute necrotizing encephalopathy: an underrecognized clinicoradiologic disorder

Acute necrotizing encephalopathy (ANE) is a rare but distinctive type of acute encephalopathy with global distribution. Occurrence of ANE is usually preceded by a virus-associated febrile illness and ensued by rapid deterioration. However, the causal relationship between viral infections and ANE and the exact pathogenesis of ANE remain unclear; both environmental and host factors might be involved. Most cases of ANE are sporadic and nonrecurrent, namely, isolated or sporadic ANE; however, few cases are recurrent and with familial episodes. The recurrent and familial forms of ANE were found to be incompletely autosomal-dominant. Further the missense mutations in the gene encoding the nuclear pore protein Ran Binding Protein 2 (RANBP2) were identified. Although the clinical course and the prognosis of ANE are diverse, the hallmark of neuroradiologic manifestation of ANE is multifocal symmetric brain lesions which are demonstrated by computed tomography (CT) or magnetic resonance imaging (MRI). The treatment of ANE is still under investigation. We summarize the up-to-date knowledge on ANE, with emphasis on prompt diagnosis and better treatment of this rare but fatal disease.

H1N1 triggered recurrent acute necrotizing encephalopathy in a family with a T653I mutation in the RANBP2 gene

A 28-month-old infant presented with fever, vomiting and encephalopathy. Magnetic resonance imaging findings and family history confirmed a diagnosis of recurrent familial acute necrotizing encephalopathy (ANE1). We believe that this is the first description implicating the H1N1 viral strain as a trigger and the second report of a T653I mutation in the RANBP2 gene described in relation to ANE1.

Clinical outcome of acute necrotizing encephalopathy in related to involving the brain stem of single institution in Korea

Purpose

Acute necrotizing encephalopathy (ANE) is a fulminant disease of the brain characterized by bilateral thalamic lesions, and is prevalent among children in East Asia. The prognosis of ANE is usually poor with a high mortality rate and neurological sequelae. This study aimed to delineate the clinical characteristics and prognostic factors of ANE.

Methods

We retrospectively analyzed clinical data of 399 pediatric patients with encephalitis who were admitted to Samsung Medical Center from December 1998 to March 2011. We enrolled ten patients (11 cases) with ANE and analyzed their demographic, clinical, and neuroimaging data. The location and extent of the brain regions were checked based on fluid-attenuated inversion recovery, T1-, and T2-weighted imaging findings; the presence of contrast enhancement, restricted diffusion, and hemorrhage.

Results

Ten patients were identified, including one patient with two episodes. The median age of onset was 1.5 years (0.4-8.4 years). The mortality rate was 40%, and only 30% of patients survived without neurological sequelae. The definite involvement of the brainstem on brain magnetic resonance imaging was significantly correlated with mortality (P=0.04).

Conclusion

Broad and extensive brainstem involvement suggested the fulminant course of ANE. Early diagnosis of ANE before brainstem involvement, through careful identification of symptoms of brain dysfunction, may be the best way to achieve better neurological outcomes.