Acute necrotizing encephalopathy with widespread edematous lesions of symmetrical distribution

International consensus definitions for infection-triggered encephalopathy syndromes

AIM

To develop standardized diagnostic criteria for 'infection-triggered encephalopathy syndrome (ITES)' and five specific clinical syndromes of ITES.

METHOD

The draft definitions were based on existing criteria, standardized, and discussed by a panel of international experts using nominal group technique over 18 months to achieve consensus. All criteria use the same format: (1) presence of infection/fever; (2) clinical features including encephalopathy; (3) neuroradiological features on magnetic resonance imaging; (4) exclusion of other causes.

RESULTS

We first highlighted differences between ITES and infectious and autoimmune encephalitis, which is the most important differential diagnosis. Consensus was achieved to define five specific ITESs: acute encephalopathy with biphasic seizures and late reduced diffusion; acute necrotizing encephalopathy; mild encephalopathy with a reversible splenial lesion; acute fulminant cerebral oedema; and acute shock with encephalopathy and multiorgan failure. Two further conditions that are currently classified as epilepsy syndromes but have similar features to ITES, namely febrile infection-related epilepsy syndrome and hemiconvulsion-hemiplegia-epilepsy syndrome, are also discussed.

INTERPRETATION

The consensus definition is expected to improve awareness of this disease concept, provide diagnostic framework, and facilitate future international research and clinical trials.

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 and cytokine profile of adult acute necrotizing encephalopathy

Background

Acute necrotizing encephalopathy (ANE), a fulminant encephalopathy, is often found in childhood. It is still uncertain whether adult patients with ANE display clinical features different from patients with typical pediatric onset. Furthermore, alterations in neuroinflammatory factors in patients with ANE have not been well-characterized. Here, we present an adult patient with ANE, and review all reported adult ANE cases in the literature.

Methods

Serum levels of five cytokines were checked in an adult patient with ANE and compared with gender/age-matched controls. Literature search was performed with PubMed, using the term as “acute necrotizing encephalopathy” with the filter of adult 19 + years.

Results

A total of 13 adult patients were reviewed. Compared with pediatric patients, adult ANE patients had similar clinical symptoms, biochemical data, and neuroimage findings, whereas adult ANE were more female-biased (female:male, 9:4) with a worse prognosis. Elevated cytokine levels in the serum and/or CSF is found in both adult-onset and pediatric-onset ANE. We found significantly elevated serum levels of IL-6 (17.17 pg/mL; healthy control: 1.43 ± 1.22 pg/mL) and VCAM-1 (3033.92 ng/mL; healthy control: 589.71 ± 133.13 ng/mL), and decreased serum TGF-β1 level (14.78 ng/mL, healthy controls: 25.81 ± 6.97 ng/mL) in our patient.

Conclusions

Our findings clearly delineate the clinical features and further indicate the potential change in cytokine levels in adult patients with ANE, advancing our understanding of this rare disease.

Elderly-onset acute necrotizing encephalopathy mimicking severe heat stroke: a case report and review of the literature

Background

Acute necrotizing encephalopathy (ANE), known as influenza-associated encephalitis, typically affects children.

Case presentation

A 70-year-old woman was admitted to the hospital with altered consciousness, a high temperature, and severe hypotension. Computed tomography (CT) of the head showed no abnormalities; thus, a diagnosis of suspected severe heat stroke was made. On day 2, repeated head CT revealed bilateral symmetrical lesions to the thalamus, and a rapid influenza antigen test was positive. Based on the CT findings and the medical history of influenza, a differential diagnosis of ANE was made. Subsequently, brain edema spread across the whole brain, and the patient died on day 21.

Conclusion

In elderly patients, differentiating ANE from severe heat stroke in a high-temperature environment is difficult because of the similarities in clinical symptoms due to multiple organ failure.

Serial outcomes in acute necrotising encephalopathy of childhood: A medium and long term study

OBJECTIVE

Acute necrotising encephalopathy (ANEC) is a severe, debilitating childhood disorder. We used the ANEC scoring system (ANE-ss) and standardised neurodevelopmental scores to objectively characterise medium and long term outcomes.

METHODS

Retrospective review of children with ANEC at KK Women's and Children's Hospital, Singapore, from 2005 to 2012. ANE-ss was determined from clinical features and neuroimaging, and neurodevelopmental scores (Pediatric Glasgow Outcome Scale Extended, Pediatric Cerebral Performance Category scale and Pediatric Overall Performance Category scale) were applied at 1, 6, 12 and 24months post diagnosis.

RESULTS

Seven patients with ANEC were studied. All had a viral prodrome with fever, and encephalopathy at presentation, and received immunotherapy (steroids or immunoglobulin). ANE-ss scores were medium risk in 4 patients and high risk in 3 patients. One died (high risk ANE-ss) and outcome was determined in the 6 survivors. At 1month post diagnosis, 3 patients (50%) were mildly affected and 3 (50%) were severely affected. Morbidity rates improved by 12months, with 67% and 33.3% scoring in the mildly affected and severely affected ranges, respectively. Medium risk patients did well with majority having little or no neurological deficits and good outcome scores.

CONCLUSION

Mortality and severe morbidity correlated well with high risk ANE-ss. However, our patients with medium risk ANE-ss had good neurodevelopmental sequelae. Serial disability scoring is useful in evaluating the progress of ANEC patients on follow up. Assessment at 1month post diagnosis can aid prognostication of long term outcome.

Lipids and Oxidative Stress Associated with Ethanol-Induced Neurological Damage

The excessive intake of alcohol is a serious public health problem, especially given the severe damage provoked by chronic or prenatal exposure to alcohol that affects many physiological processes, such as memory, motor function, and cognitive abilities. This damage is related to the ethanol oxidation in the brain. The metabolism of ethanol to acetaldehyde and then to acetate is associated with the production of reactive oxygen species that accentuate the oxidative state of cells. This metabolism of ethanol can induce the oxidation of the fatty acids in phospholipids, and the bioactive aldehydes produced are known to be associated with neurotoxicity and neurodegeneration. As such, here we will review the role of lipids in the neuronal damage induced by ethanol-related oxidative stress and the role that lipids play in the related compensatory or defense mechanisms.

A severity score for acute necrotizing encephalopathy

OBJECTIVE

To develop a score that predicts the prognosis of children with acute necrotizing encephalopathy (ANE).

METHOD

We retrospectively evaluated clinical variables and neurological outcome in two cohorts of children with ANE. Firstly, we developed the ANE severity score (ANE-SS) according to the clinical variables that correlated with neurological outcome in 41 children who were included in our previous reports in 2009. We then applied the scoring system to a second cohort of 32 patients who were newly collected in 2011. We investigated the correlation between the ANE-SS and neurological outcome in all 73 patients.

RESULTS

In the first cohort, brain stem lesions on MRI and state of shock at onset were significantly correlated with outcome. Age over 48 months, elevated CSF protein, and low platelet counts tended to be correlated with outcome. No types of treatment were correlated with outcome. The developed ANE-SS ranged from 0 to 9 points, with 3 points for existence of shock, 2 points for brain stem lesions, 2 points for age over 48 months, 1 point for platelet count below 100,000/μL, and 1 point for CSF protein above 60 mg/dl. Patients were classed as low risk (ANE-SS 0-1 points), medium risk (ANE-SS 2-4 points), or high risk (ANE-SS 5-9 points). ANE-SS was significantly correlated with outcome in the group of 73 patients.

CONCLUSION

ANE-SS can be used to predict outcome in patients with ANE. More effective treatments need to be developed for high-risk patients.

Delirious behavior in children with acute necrotizing encephalopathy

OBJECTIVE

To clarify the features of delirious behavior in patients with acute necrotizing encephalopathy.

METHODS

We retrospectively evaluated the clinical course of 38 children with acute necrotizing encephalopathy diagnosed on the basis of neuroradiological findings. The patients were divided into two groups according to the presence or absence of delirious behavior. We compared clinical features, laboratory data, neuroimaging findings, and outcome between those with and without delirious behavior. In patients with delirious behavior, chronological sequence of neurological symptoms and the characteristics of delirious behavior were investigated.

RESULTS

Delirious behavior was observed in 8 patients. Patient characteristics or most laboratory data on admission were not significantly different between those with and without delirious behavior. Brainstem lesions were more frequent in patients with delirious behavior than in those without. In contrast, lesions in lentiform nuclei, cerebral hemisphere, or cerebellum were relatively more frequent in patients without delirious behavior. It was the initial neurological symptom in 7 of 8 patients. Stupor and seizures were observed after delirious behavior in most patients.

CONCLUSIONS

Delirious behavior was not uncommon in children with acute necrotizing encephalopathy. Brainstem lesions may be related to the development of delirious behavior of children with acute necrotizing encephalopathy.

Outcome of acute necrotizing encephalopathy in relation to treatment with corticosteroids and gammaglobulin

OBJECTIVE

To examine the relation between outcome and treatment with steroids and gammaglobulin in children with acute necrotizing encephalopathy.

METHODS

We retrospectively evaluated the clinical course and outcome of 34 children with acute necrotizing encephalopathy. They were divided into two groups; 17 patients with brainstem lesion and 17 patients without brainstem lesion. Early steroid use was defined as when steroids were administered within 24h after the onset. The outcome was judged as good when a patient had no or mild cognitive impairment and poor when a patient had more severe sequelae, or died.

RESULTS

Among patients without brainstem lesions, the outcome was good in 7 of 12 with early steroid, whereas it was poor in all 5 patients without early steroid. There was no significant difference in sex, age, and laboratory data between patients with and without early steroid. The outcome was not correlated with gammaglobulin treatment. As to patients without brainstem lesions, the outcome was not correlated with early steroid or gammaglobulin treatment.

CONCLUSIONS

Steroid within 24 h after the onset was related to better outcome of children with acute necrotizing encephalopathy without brainstem lesions. Early steroid treatment will be an important option of the treatment for acute necrotizing encephalopathy.

Acute necrotizing encephalopathy: a comparison between influenza and non-influenza cases

The aim of this study was to clarify the difference between influenza and non-influenza cases in clinical symptoms, laboratory and neuroimaging findings, and outcome in children with ANE. We retrospectively studied 22 children with ANE. Eleven of them had virological proof of influenza infection and the other 11 were judged as non-influenza infection. There was no significant difference between influenza and non-influenza cases in sex, antipyretics use and neurological symptoms. Although laboratory data were not different between the two groups, brainstem lesions were relatively more frequent in influenza cases than in non-influenza cases. Outcome was not different between the two groups. The results of our study suggest that the pathogenesis of acute necrotizing encephalopathy will not be dependent on infectious agents.

Acute necrotizing encephalopathy associated with human herpesvirus-6 infection

An extremely rare case of acute necrotizing encephalopathy caused by human herpesvirus-6 variant type B infection is reported. The patient, a 14-month-old previously healthy female, presented with high fever and generalized tonic convulsion followed by rapid deterioration of consciousness. On the second day of the illness, the protein level of the cerebrospinal fluid increased without pleocytosis. On the third day, magnetic resonance images demonstrated symmetric, abnormal signal intensity lesions in the bilateral thalamus, cerebellum, and brainstem. On the fourth day, characteristic maculopapular rash of exanthema subitum appeared on the trunk. Human herpesvirus-6 deoxyribonucleic acid was detected by the polymerase chain reaction in the serum, and immunoglobulin G and immunoglobulin M of serum human herpesvirus-6 were positive. On the twelfth day of illness, the patient died as a result of severe brain damage. Acute necrotizing encephalopathy should be included in the differential diagnosis when examining infants and young children with fulminating consciousness disturbance and intractable convulsion. In addition, as a causative virus, human herpesvirus-6 has to be considered at the pre-eruptive stage of exanthema subitum. Magnetic resonance images are useful because they reveal the characteristic distribution of lesions specific to acute necrotizing encephalopathy.

Acute necrotizing encephalopathy of childhood: a novel form of acute encephalopathy prevalent in Japan and Taiwan

The clinical, radiological and pathological features of acute necrotizing encephalopathy of childhood, a disease entity established recently, are described. This disease predominantly affects infants and young children living in Japan and Taiwan, and manifests itself as acute encephalopathy following viral infections. The hallmark of this encephalopathy is multifocal, symmetric brain lesions affecting the bilateral thalamus, brainstem tegmentum, cerebral periventricular white matter and cerebellar medulla, which can be visualized by computed tomography and magnetic resonance imaging. Both the gray and white matter are involved, with neuropathological evidence of local breakdown of the blood-brain barrier (dysoria). The prognosis was poor in the 1980s, but has improved recently. A characteristic combination of focal neurologic signs is often recognized as the sequelae. Its distinction from clinically similar conditions, such as the Reye syndrome, and from pathologically related conditions, such as the Leigh and Wernicke encephalopathies, is also discussed.

Acute necrotising encephalopathy of childhood: a new syndrome presenting with multifocal, symmetric brain lesions

The clinicopathological features of a previously unrecognised type of acute encephalopathy prevalent among Japanese children is described by reviewing the records of 13 consecutive patients treated and 28 previously reported cases. The hallmark of this encephalopathy, proposed to be a novel entity termed acute necrotising encephalopathy of childhood, is multiple, necrotic brain lesions showing a symmetric distribution. The encephalopathy was noted in previously healthy children after respiratory tract infections, with presenting symptoms of coma, convulsions, vomiting, hyperpyrexia, and hepatomegaly. Laboratory examinations disclosed liver dysfunction, uraemia, and hypoproteinaemia. The histological appearance of the liver was variable and non-specific. Cerebrospinal fluid contained an increased amount of protein. Computed tomography and MRI showed the presence of symmetrically distributed brain lesions of the thalamus, cerebral white matter, brainstem, and cerebellum. Necropsy examination confirmed extensive fresh necrosis of these regions with evidence of local breakdown of the blood-brain barrier. Based on the characteristic combination of clinical and pathological findings, acute necrotising encephalopathy of childhood can be distinguished from previously known encephalopathies, including Reye's syndrome.