Acute necrotizing encephalopathy: an underrecognized clinicoradiologic disorder

Acute necrotizing encephalopathy in an adult presenting with typical imaging findings and distinctive cerebrospinal fluid characteristics: a case report

BACKGROUND

Acute necrotizing encephalopathy is a rare, clinically distinct subgroup of acute encephalopathy, which may be a complication of coronavirus disease 2019.

CASE PRESENTATION

A 22-year-old male of Han Chinese with a yellow complexion presented with fever, psychological and behavioral abnormalities, seizures, and coma. Cerebrospinal fluid tests indicated leukocytosis, high protein concentrations, and significantly elevated levels of neuron-specific enolase, interleukin-2, interleukin-6, and interleukin-8. Magnetic resonance imaging revealed restricted diffusion in the bilateral thalami and splenium of the corpus callosum, and no hemorrhagic signals were detected on susceptibility-weighted imaging. Hyperintense and hypointense lesions in the bilateral thalami, brainstem, cerebellum, and splenium of the corpus callosum were observed in T1- and T2-weighted sequences without gadolinium enhancement. At the 6-month follow-up, the T1 and T2 sequences showed significant atrophy in the cerebellar hemispheres and brachium pontis and an enlarged fourth ventricle. After symptomatic and immunotherapy treatment, the prognosis was good.

CONCLUSION

We report a rare case of a 22-year-old male diagnosed acute necrotizing encephalopathy showing typical imaging findings and distinctive cerebrospinal fluid presentation. In adults, heightened awareness of acute necrotizing encephalopathy is crucial because early recognition and treatment have the potential to enhance prognosis.

Clinical characteristics and associated factors of pediatric acute necrotizing encephalopathy: a retrospective study

BACKGROUND

In the clinic, pediatric acute necrotizing encephalopathy (ANE) primarily affects children under 5 years of age and is characterized by severe brain damage and high mortality. However, some challenges remain regarding the diagnosis and treatment of ANE. In the present study, we analyzed the clinical characteristics and related factors of ANE with the aim of providing improved diagnostic and treatment strategies.

PURPOSE

The main purpose of this study is to gain a deeper understanding of the clinical characteristics and pathophysiology of ANE through a retrospective study, and to provide clinical practitioners with more effective. diagnostic and treatment strategies to improve patient survival rates and quality of life.

METHODS

Thirty-four pediatric ANE patients admitted to Zhejiang University School of Medicine Hospital between February 2019 and December 2023 were included in this study. To identify the factors associated with mortality, clinical, laboratory and imaging data were analyzed with independent-sample t tests, Mann-Whitney U tests, Fisher exact probability tests and receiver operating characteristic curve analyses.

RESULTS

In this cohort of 34 patients, the most common symptoms were fever, seizures, altered consciousness, vomiting, diarrhea and shock. The mortality rate was 55.9%. Laboratory tests revealed that patients who died had higher creatinine, lactate, activated partial thromboplastin time, thrombin time, interleukin (IL)-6, IL-10, creatine kinase, and D-dimer than survivors. Imaging examinations predominantly revealed symmetrical lesions in the thalamus. The fatal group displayed lower Glasgow Coma Scale (GCS) scores and severe complications. Other factors related to mortality included the arterial pH, GCS score and hospitalization duration.

CONCLUSION

The most common symptoms of ANE are fever, seizures, altered consciousness, vomiting, diarrhea and shock, and ANE has a high mortality rate. The GCS score and arterial pH are critical biomarkers for assessing the severity of ANE.

Predictive value of the serum procalcitonin level for fulminant virus-associated encephalopathy

BACKGROUND

Fulminant virus-associated encephalopathy (VAE) is a rare complication of viral infection that presents as acute brain dysfunction and requires respiratory support and/or vasoactive agents. However, the mechanism of VAE is undetermined. The mortality rate is high since there is no specific treatment for fulminant VAE. The aim of this study was to identify risk factors for children with fulminant VAE on the basis of clinical data since timely recognition and treatment might be needed to improve the poor prognosis.

METHODS

This retrospective study included children with fulminant VAE who were diagnosed between June 2018 and October 2023 in the PICU of Guangdong Women and Children Hospital. Clinical data were analyzed, and receiver operating characteristic (ROC) curve analysis was performed to determine the prognostic value of the selected variables.

RESULTS

Twenty-three children with fulminant VAE were included and divided into a survival group (n = 16) and a nonsurvival group (n = 7). The mortality rate of patients with fulminant VAE was 30.8%. Compared with the survival group, the nonsurvival group had higher incidences of shock 48 h after onset, a higher acute necrotizing encephalopathy severity score (ANE-SS), higher procalcitonin (PCT) levels, and lower platelet counts (p < 0.05). The serum PCT level was significantly higher in the children with shock than in those without shock (p = 0.015). The serum PCT concentration was positively correlated with the ANE-SS (correlation coefficient 0.544, p < 0.039). Combined immunotherapies might help to decrease PCT levels in some children. Low PCT levels might be related to a good outcome. The area under the curve (AUC) for PCT used to predict death in patients with fulminant VAEs was 0.821 (95% CI 0.626-1.00). The sensitivity and specificity of PCT > 101.58 ng/ml for predicting death in patients with fulminant VAE were 57.1% and 100.0%, respectively.

CONCLUSIONS

Patients with fulminant VAE deteriorate rapidly and are at high risk of death if they develop shock within 48 h after onset, exhibit extremely elevated serum PCT levels, or have decreased platelet counts. The serum PCT level might predict the death outcome of patients with fulminant VAE.

Child Neurology: Acute Necrotizing Encephalopathy of Childhood Associated With Dengue: Good Neurologic Outcome Despite a Fulminant Presentation

Acute necrotizing encephalopathy of childhood (ANEC) is characterized by a rapidly progressive encephalopathy after a viral febrile illness, with multiple, symmetrical lesions in the brain including the thalami. Acute dengue fever is a known, but rare, trigger for ANEC. The clinical course of ANEC is usually fulminant and is associated with high morbidity and mortality. We describe here a prospective cohort of 5 children who presented with ANEC associated with dengue infection characterized by encephalopathy within the first week of fever, followed by a rapidly deteriorating sensorium requiring intensive care unit admission. Dengue fever was diagnosed based on a positive nonstructural protein 1 antigen test. ANEC was diagnosed based on characteristic MRI brain findings including the "trilaminar sign" in bilateral thalami combined with clinical features of severe encephalopathy, thrombocytopenia, and transaminitis. All the children required prolonged hospital stay (mean duration 30 days), with 4 of 5 children requiring mechanical ventilation (mean duration 21 days). All the children received immunomodulation with IV methylprednisolone either alone or followed by IV immunoglobulin. Although these children were bedridden at discharge (modified Rankin Scale, mRS score 4 or 5), they showed a consistent recovery in follow-up. At 6 months of follow-up, all the children were fully independent in activities of daily living (mRS scores 1-2). These cases highlight good neurologic outcomes in children with ANEC associated with dengue despite a catastrophic presentation and a protracted hospital course. The most common residual neurologic deficits noted were hand tremors and extrapyramidal dysarthria.

Management of Critically Ill Children with Acute Necrotizing Encephalitis during an H1N1 Outbreak in a Tertiary Pediatric Hospital: A Series of Three Cases and Literature Review

Acute necrotizing encephalopathy (ANE) is a severe neurological condition that is diagnosed clinically and upon specific radiological imaging. Medical treatment of this condition is uncertain, and timing is likely very important to minimize brain damage and systemic inflammation. The present case series describes three patients suffering from ANE secondary to influenza A/H1N1 infection during a recent outbreak, treated with increasingly aggressive anti-inflammatory approach, and with significantly different outcomes.

Clinical prognostication in acute necrotizing encephalopathy of childhood: the role of magnetic resonance imaging severity assessment

BACKGROUND

Acute necrotizing encephalopathy of childhood is a unique entity with bilateral gray and white matter involvement.

OBJECTIVE

The aim of this study is to explore whether the severity of findings on imaging scans is indicative of the prognosis and clinical outcomes for pediatric patients with acute necrotizing encephalopathy.

MATERIALS AND METHODS

A retrospective cross-sectional study was conducted on 42 patients diagnosed with acute necrotizing encephalopathy. A severity score based on MR imaging was computed for each patient, utilizing a point system determined by the existence of factors such as hemorrhage, cavitation, enhancement, diffusion restriction, and lesion location. The scoring was categorized into mild, moderate, and severe. Clinical outcomes were determined at the time of discharge and at follow-ups as mild disability, moderate disability, severe disability, and death according to the modified Rankin Scale. Associations were determined by Fisher's exact test, chi-square test, and one-way ANOVA.

RESULTS

The study included 21 boys and 21 girls with a mean age of 71.5 months. A statistically significant connection (P=0.027) was found between the severity score from MR imaging and the clinical outcome. A statistically significant relationship was also observed between diffusion restriction (P=0.008), cerebellar involvement (P=0.048), and an unfavorable clinical outcome. Additionally, individuals who experienced shock exhibited a correlation with adverse outcomes (P=0.01).

CONCLUSION

In predicting the outcome of acute necrotizing encephalopathy, cerebellar involvement and presence of diffusion restriction were associated with worse clinical outcomes in our study. Developing a comprehensive MR-based severity score is crucial for improving diagnostic accuracy and patient outcomes. Our findings underscore the importance of including diffusion restriction and cerebellar involvement in the scoring system.

Acute necrotizing encephalopathy caused by bacterial infection

PURPOSE

Acute necrotizing encephalopathy (ANE), a rare and severe brain disorder, is typically linked to prior infections. ANE predominantly affects children, with most reported cases attributed to viral infections. However, instances of bacterial-induced ANE are infrequent. Here, we present a case of adult-onset ANE associated with bacterial infection.

CASE DESCRIPTIONS

The patient exhibited a hyperinflammatory state following a urinary tract bacterial infection, with neurological function rapidly declining into a coma as the illness progressed. Gram culture of blood suggested Escherichia coli infection. A magnetic resonance imaging (MRI) scan of the brain showed symmetrical hyperintense lesions involving bilateral thalami and pons in T2-weighted and fluid-attenuated inversion recovery images. These lesions also presented with diffuse cerebral edema and diffusion restriction and subacute hemorrhage. Based on clinical symptoms and typical brain MRI, ANE was diagnosed, and the patient underwent immunotherapy.

CONCLUSIONS

This case underscores the occurrence of ANE triggered by bacterial infection, expanding our understanding of the pathogens associated with this condition. It suggests that ANE may be an immune-mediated disorder rather than solely an infectious disease.

Acute necrotizing encephalopathy in adult patients with influenza: a case report and review of the literature

The neurological complications of influenza affect mainly the pediatric Asian population. In the category of influenza-associated encephalopathy, acute necrotizing encephalopathy (ANE) is a rapidly progressive and fulminant brain disorder associated with significant neurological sequelae and mortality. To date, only a few adult cases of influenza-associated ANE have been reported. We describe a 44-year-old woman who presented with rapid progression of consciousness impairment and recurrent generalized convulsions. Influenza was diagnosed three days prior to presentation, and infection with influenza A (H3N2) pdm09 was subsequently confirmed. A diagnosis of ANE was made based on the presence of characteristic brain MRI findings, the exclusion of central nervous system infection, and an elevated serum interleukin-6 level. Pulse steroid therapy followed by tocilizumab was initiated, which led to clinical stabilization and improvement. Genetic testing revealed that the patient carried heterozygous human leukocyte antigen DQB1 03:03 and DRB1 09:01 genotypes. An analysis of the adult cases of influenza-associated ANE in the literature and the present case revealed a wide range of ages (22-71 years), a short interval (median 3 days) between the clinical onset of influenza and ANE, and a high overall mortality rate (32%). The thalamus was the most frequent (91%) location of the lesions. Our report highlights the importance of identifying this devastating but treatable neurological complication of influenza in adults, especially those of Asian descent. As a cytokine storm is the most accepted pathogenic mechanism for ANE, cytokine-directed therapies may be promising treatments for which further investigation is warranted.

Acute necrotizing encephalopathy infected with the SARS-CoV-2 in children: Case series and literature review of clinical outcomes with the use of Tocilizumab

BACKGROUND AND OBJECTIVE

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes acute necrotizing encephalopathy (ANE), which has a high mortality rate and severe sequelae. This study aimed to identify ANE early and evaluate the usefulness of tocilizumab in ANE treatment.

METHODS

We retrospectively included eight paeefediatric ANE cases infected with SARS-CoV-2 at Xi'an Children's Hospital, China, from December 1, 2022 to May 1, 2023. A literature search was performed using the PUBMED, SPRING, SCOPUS, and EMBASE databases. This study included eleven patients. Clinical characteristics, laboratory test results, imaging features, and treatment options were analysed.

RESULTS

Eight of the 19 cases (42 %) died, one (5 %) recovered, and nine (47 %) improved with residual neurological dysfunction. Eighteen patients presented with fever, with 56 % having ≥40 °C. Twelve patients (63 %) presented with dysfunction consciousness. Eight (42 %) patients experienced frequent convulsions. All eight patients in our hospital had elevated procalcitonin levels (mean: 21.32 ng/mL, range: 0.10-89.40 ng/mL). Alanine aminotransferase levels were elevated (mean: 632.81 U/L, range: 13.00-2251.00 U/L) in six patients. Seven patients showed elevated uric acid levels(mean: 396.50 μmol/L, range: 157.00-660.00 μmol/L). Brain imaging indicated that all the patients had symmetrical injuries to the bilateral thalami, accompanied by symmetrical injuries in the cerebrum, cerebellum, basal ganglia, and brain stem. Compared with the classical treatment (n = 9), the combination with tocilizumab (n = 6) showed a statistically difference in mortality (p = 0.028 < 0.05).

CONCLUSION

The typical clinical manifestations of ANE in children with SARS-CoV-2 infection are acute onset with high fever, frequent convulsions and rapidly worsening disturbance of consciousness. Tocilizumab treatment could reduces mortality in ANE.

COVID-19 Neuroimaging Update: Pathophysiology, Acute Findings, and Post-Acute Developments

COVID-19 has prominent effects on the nervous system with important manifestations on neuroimaging. In this review, we discuss the neuroimaging appearance of acute COVID-19 that became evident during the early stages of the pandemic. We highlight the underlying pathophysiology mediating nervous system effects and neuroimaging appearances including systemic inflammatory response such as cytokine storm, coagulopathy, and para/post-infections immune mediated phenomena. We also discuss the nervous system manifestations of COVID-19 and the role of imaging as the pandemic has evolved over time, including related to the development of vaccines and the emergence of post-acute sequalae such as long COVID.

Clinical characteristics and genetic analysis of children with Omicron BF.7.14 type novel coronavirus-related acute necrotizing encephalopathy

Background

To explore the clinical characteristics, etiological factors, and clinical-related genetic variant of children with acute necrotizing encephalopathy (ANE) related to the Omicron BF.7.14 novel coronavirus.

Methods

Genomic variations were detected through whole exome sequencing. Additionally, we summarized the clinical data to explore the inheritance patterns associated with novel coronavirus-related ANE.

Results

This study included four patients (2 males and 2 females) with an average age of 2.78 ± 1.93 years. All the patients had prodromal symptoms of Omicron BF.7.14 virus infection, and exhibited symptoms such as altered consciousness, seizures and cognitive/language disturbances. Cranial MRI scans revealed damage to the thalamus, basal ganglia and brainstem. The cerebrospinal fluid (CSF) cell counts were nearly normal, but protein level in CSF increased significantly. Genetic analysis revealed a novel truncated variant of CRMP2 gene in one patient who suffered more severe coma score and prognosis and dead in the later stages. All children exhibited a decrease in the absolute count of T lymphocytes, helper T cells, suppressor T cells, and NK cells to varying degrees. Furthermore, levels of cytokines, including IL-1 β, IL-5, IL-6 and IL-8 were significantly elevated in the CSF, especially in patient with truncated variant of CRMP2 gene.

Conclusion

The Omicron BF.7.14 type novel coronavirus can lead to ANE, characterized by T cell immunosuppression and a significant increase in cytokine levels in the CSF. The truncated variation of CRMP2 gene may affect the prognosis of ANE by affecting the migration of cerebral T cells.

MRI Findings of COVID-19 Associated Acute Necrotizing Encephalopathy in Two Pediatric Patients: Case Report and Literature Review

Acute necrotizing encephalopathy (ANE) is a rare immune-mediated complication of a viral infection commonly involving the bilateral thalamus and has been reported mainly in children. Here, we describe the MRI findings of coronavirus disease 2019 (COVID-19)-associated ANE in two pediatric patients, including a 7-year-old girl with fever and mental change, and a 6-year-old girl with fever and generalized seizures. Brain MRI revealed symmetrical T2 fluid attenuated inversion recovery high-signal intensity lesions in the bilateral thalamus with central hemorrhage. In one patient, the thalamic lesions showed a trilaminar pattern on the apparent diffusion coefficient map. This report emphasizes the importance of creating awareness regarding these findings in patients with COVID-19, particularly in children with severe neurological symptoms. Furthermore, it provides a literature review of several documented cases of COVID-19 presenting with bilateral thalamic hemorrhagic necrosis, suggesting a diagnosis of ANE.

A Young Girl with Acute Encephalopathy Who Presented with Status Epilepticus Following a Flu-Like Illness

BACKGROUND Acute necrotizing encephalopathy of childhood (ANEC) is a rare form of acute encephalopathy in children that is characterized by rapid and progressive deterioration in the patient's clinical condition. Our aim in reporting the case is to highlight the importance of early diagnoses and aggressive early management of ANEC to achieve a better outcome. We report the case of a 5-year-old girl who presented with acute progressive encephalopathy with bilateral symmetrical thalamic involvement and brainstem lesion proceeded by a flu-like illness. CASE REPORT We report a 5-year-old girl who was previously healthy. She presented with rapid progressive encephalopathy and status epilepticus following a flu-like illness. Her magnetic resonance imaging (MRI) showed significance symmetrical bilateral thalamic enhancement with brainstem lesions, which is consistent with the diagnosis of ANEC of childhood, and her initial electroencephalogram (EEG) showed severe encephalopathy. Despite extensive management of ANEC, the patient showed a poor prognosis. CONCLUSIONS ANEC is a rare, specific, devastating condition in the pediatric population. Early diagnosis and aggressive management should be initiated immediately to avoid the high mortality associated with the condition. Furthermore, to highlight the importance of the clear history of the patient who presented with rapid and progressive deterioration in the level of consciousness and status epilepticus proceeded by viral illness, a rapid neuroradiological images such as brain MRI should be obtained to confirm the diagnosis of this rare condition. We also seek to increase awareness of this disorder among healthcare workers and general practitioners.

A Rare Case of Acute Necrotizing Encephalopathy of Childhood: A Case Report

Acute necrotizing encephalopathy of childhood (ANEC) is a severe neurological disorder characterized by rapid-onset encephalopathy, often associated with viral infections. Acute necrotizing encephalopathy of childhood is associated with a very high mortality rate, and survivors may face long-term neurological sequelae. Acute necrotizing encephalopathy of childhood needs to be differentiated from its closest differential diagnosis, acute disseminated encephalomyelitis (ADEM). Most of the patients with ADEM recover, with a few of them having residual neurological deficits. We present a case of an eight-year-old boy with an acute history of fever, febrile seizures, and drowsiness. Magnetic resonance imaging revealed a symmetric tricolor appearance of bilateral thalamic lesions, characteristic of ANEC.

Ferritin as an Effective Predictor of Neurological Outcomes in Children With Acute Necrotizing Encephalopathy

BACKGROUND

Acute necrotizing encephalopathy (ANE) is a fulminant disease with poor prognosis. Cytokine storm is the important phenomenon of ANE that affects the brain and multiple organs. The study aimed to identify whether hyperferritinemia was associated with poor prognosis in patients with ANE.

METHODS

All patients with ANE had multiple symmetric lesions located in the bilateral thalami and other regions such as brainstem tegmentum, cerebral white matter, and cerebellum. Neurological outcome at discharge was evaluated by pediatric neurologists using the Pediatric Cerebral Performance Category Scale. All risk factors associated with poor prognosis were further analyzed using receiver operating characteristic curve analysis.

RESULTS

Twenty-nine patients with ANE were enrolled in the current study. Nine (31%) patients achieved a favorable neurological outcome, and 20 (69%) patients had poor neurological outcomes. results The group of poor neurological outcome had significantly higher proportion of shock on admission and brainstem involvement. Based on multivariate logistic regression analysis, ferritin, aspartate aminotransferase (AST), and ANE severity score (ANE-SS) were the predictors associated with outcomes. The appropriate cutoff value for predicting neurological outcomes in patients with ANE was 1823 ng/mL for ferritin, 78 U/L for AST, and 4.5 for ANE-SS. Besides, comparison analyses showed that higher level of ferritin and ANE-SS were significantly correlated with brainstem involvement (P < 0.05).

CONCLUSIONS

Ferritin may potentially be a prognostic factor in patients with ANE. Hyperferritinemia is associated with poor neurological outcomes in patients with ANE and ferritin levels more than 1823 ng/mL have about eightfold increased risk of poor neurological outcome.

Clinical characteristics and prognostic analysis of acute necrotizing encephalopathy of childhood: a retrospective study at a single center in China over 3 years

Objective

Acute Necrotizing Encephalopathy of Childhood (ANEC) is a rare, fulminant neurological disease in children with unknown mechanisms and etiology. This study summarized the clinical characteristics, treatment, and prognosis of ANEC through a retrospective analysis, providing insights into the ANEC early diagnosis and prognosis assessment.

Methods

Clinical data of children diagnosed with ANEC at the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University from July 1, 2020, to June 30, 2023, were retrospectively analyzed.

Results

There were 25 cases, 14 males and 11 females, with a median age of 3 years. Hospital admissions were mainly in the winter (14/25, 56%) and spring (9/25, 36%). All patients presented with varying degrees of fever and altered consciousness, with 92% (23/25) experiencing high body temperatures (>39.1°C) and 88% (22/25) having a Glasgow coma scale (GCS) score of ≤8. Seizures were observed in 88% (22/25) of patients. Laboratory findings indicated 100% B lymphocyte activation (14/14), and 78% (14/18) of patients showed cytokine storm (interleukin (IL)-6, IL-8, IL-10, interferon (IFN)-α). Neuroimaging showed symmetrical thalamus involvement, commonly involving basal ganglia and brainstem regions. Viral infection (23/24, 96%) was the predominant etiological finding, with 42% (10/24) of cases due to SARS-CoV-2 infection and 42% (10/24) to influenza A virus infection. Multi-organ dysfunction occurred in 68% (17/25) of patients, and 52% (13/25) died. Correlation analysis revealed the death group exhibited higher proportion of male, lower GCS scores, higher IL-6 level and a greater likelihood of associated brainstem impairment (p < 0.05).

Conclusion

ANEC is more prevalent in the winter and spring, and its etiology may be associated with B lymphocyte activation and cytokine storm following viral infections. Clinical manifestations lack specific features, with fever, consciousness disturbances, and seizures being the main presentations, particularly in cases of high fever and hyperpyrexia. ANEC progresses rapidly and has a high mortality rate. The child's gender, GCS score, IL-6 levels, and the presence of brainstem involvement can serve as important risk factors for assessing the risk of mortality.

The youngest infant with COVID-19-associated necrotizing encephalitis in Asia: A case report

Acute necrotic encephalopathy in children is a very rare complication of severe acute respiratory syndrome coronavirus 2 infection and has rarely been reported worldwide. A 45-day-old girl was admitted to our hospital with fever and listlessness. A nose swab tested positive for the novel coronavirus nucleic acid, and her cerebrospinal fluid was positive for severe acute respiratory syndrome coronavirus 2. An early head magnetic resonance imaging scan indicated multiple abnormal signals in her bilateral cerebral hemispheres, and encephalitis was diagnosed. Twenty-three days after hospitalization, bilateral cerebral atrophy-like changes were observed on magnetic resonance imaging, with multiple softening lesions in the bilateral cerebral hemispheres, accompanied by convulsions. She was admitted to the hospital for mechanically assisted ventilation, and her condition improved after treatment of her symptoms with antiepileptic medication, anti-infection drugs, glucocorticoids, and immunoglobulins. Acute necrotic encephalopathy associated with severe acute respiratory syndrome coronavirus 2 infection in children should be detected and treated as early as possible. Satisfactory short-term efficacy can be obtained, but long-term neurological sequelae often linger.

Anti-NMDAR encephalitis secondary to acute necrotizing encephalopathy caused by herpes simplex virus infection in infants: Case series

BACKGROUND

To describe the clinical characteristics of anti-NMDAR encephalitis secondary to acute necrotizing encephalopathy caused by herpes simplex virus encephalitis in infants, and aid in its early recognition, diagnosis and treatment.

CASE PRESENTATION

A total of 4 infants were included; all presented with fever, seizures, and progressive disturbances of consciousness and were diagnosed with herpes simplex virus (HSV-1) encephalitis. Cerebrospinal fluid (CSF) protein levels progressively increased, and the head MRI showed necrotizing encephalopathy. There was no significant improvement or recurrence after treatment with acyclovir, dexamethasone, or immunoglobulins. CSF reexamination at 3 weeks to 3 months showed positive anti-NMDAR IgG antibodies and gradual improvement after high-dose methylprednisolone therapy.

CONCLUSION

Infants with ANE associated with HSV can develop secondary anti-NMDAR encephalitis, recognition of which is critical to ensure the appropriate institution of immunotherapy after active CNS infection has been ruled out.

Case report: Acute necrotizing encephalopathy: a report of a favorable outcome and systematic meta-analysis of outcomes with different immunosuppressive therapies

Acute Necrotizing Encephalopathy (ANE) is a condition characterized by symmetric, bilateral lesions affecting the thalamus and potentially other areas of the brain following an acute febrile illness. It manifests clinically as abrupt development of encephalopathy, or alteration in mental status that often includes development of seizures and progression to coma. Treatment strategies combine immunosuppressive therapies and supportive care with varying levels of recovery, however there are no universally accepted, data-driven, treatment algorithms for ANE. We first report a case of a previously healthy 10-year-old female with acute onset diplopia, visual hallucinations, lethargy, and seizures in the setting of subacute non-specific viral symptoms and found to have bilateral thalamic and brainstem lesions on MRI consistent with ANE. She was treated with a combination of immunomodulatory therapies and ultimately had a good outcome. Next, we present a meta-analysis of 10 articles with a total of 158 patients meeting clinical and radiographic criteria for ANE. Each article reported immunosuppressive treatments received, and associated morbidity or mortality outcome for each individual patient. Through our analysis, we confirm the effectiveness of high-dose, intravenous, methylprednisolone (HD-IV-MP) therapy implemented early in the disease course (initiation within 24 h of neurologic symptom onset). There was no significant difference between patients treated with and without intravenous immunoglobulin (IVIG). There was no benefit of combining IVIG with early HD-IV-MP. There is weak evidence suggesting a benefit of IL-6 inhibitor tocilizumab, especially when used in combination with early HD-IV-MP, though this analysis was limited by sample size. Finally, plasma exchange (PLEX) improved survival. We hope this meta-analysis will be useful for clinicians making treatment decisions for patients with this potentially devastating condition.

Biallelic variants in ribonuclease inhibitor (RNH1), an inflammasome modulator, are associated with a distinctive subtype of acute, necrotizing encephalopathy

PURPOSE

Mendelian etiologies for acute encephalopathies in previously healthy children are poorly understood, with the exception of RAN binding protein 2 (RANBP2)-associated acute necrotizing encephalopathy subtype 1 (ANE1). We provide clinical, genetic, and neuroradiological evidence that biallelic variants in ribonuclease inhibitor (RNH1) confer susceptibility to a distinctive ANE subtype.

METHODS

This study aimed to evaluate clinical data, neuroradiological studies, genomic sequencing, and protein immunoblotting results in 8 children from 4 families who experienced acute febrile encephalopathy.

RESULTS

All 8 healthy children became acutely encephalopathic during a viral/febrile illness and received a variety of immune modulation treatments. Long-term outcomes varied from death to severe neurologic deficits to normal outcomes. The neuroradiological findings overlapped with ANE but had distinguishing features. All affected children had biallelic predicted damaging variants in RNH1: a subset that was studied had undetectable RNH1 protein. Incomplete penetrance of the RNH1 variants was evident in 1 family.

CONCLUSION

Biallelic variants in RNH1 confer susceptibility to a subtype of ANE (ANE2) in previously healthy children. Intensive immunological treatments may alter outcomes. Genomic sequencing in children with unexplained acute febrile encephalopathy can detect underlying genetic etiologies, such as RNH1, and improve outcomes in the probands and at-risk siblings.

Volume mismatch indicates tumors in paramedial bithalamic diseases: a retrospective study

OBJECTIVE

This study aimed to investigate the diagnostic performance of volume mismatch sign on discriminating paramedial bithalamic tumors from non-tumors.

METHODS

In this study, we recruited patients with tumors or non-tumors of the paramedial bithalamus. We confirmed the diagnosis by pathology, laboratory tests documented in medical records, medical imaging at the baseline, or through at least 1 year of follow-up. Cases with paramedial thalamic lesions on only one side or purely midbrain illnesses were excluded. Additionally, any case without involvement of the medial thalami (i.e., those with one or both-sided anterior, lateral, or posterior thalamic lesions) was excluded. Two neuroradiologists were trained independently to evaluate volume mismatch sign on magnetic resonance T2-weighted images or T2 fluid-attenuated inversion recovery images. A positive volume mismatch sign means that the ratio of the larger-sided lesion volume to the smaller-sided lesion volume is >150%. The volume of each lesion was calculated by multiplying the anteroposterior diameter by the left-right diameter and by the height of the lesion and then dividing by 2. The kappa value was calculated to show the consistency between the two observers. The chi-square test was used to evaluate differences in volume mismatch sign between the bilthalamic midline tumor and non-tumor groups. The positive (PPV) and negative (NPV) predictive values, sensitivity, and specificity were calculated to evaluate the ability of volume mismatch sign to differentiate paramedial bilateral thalamus tumors from non-tumors. A two-tailed P ≤ 0.05 was considered to be statistically significant. The analyses were performed using the statistical software SPSS version 26.

RESULTS

A total of 96 patients were enrolled in this study between March 2012 and October 2022. A high agreement between the two observers on the volume mismatch sign of bilateral paramedian thalamic diseases was found, and the Kappa value was 0.828. A statistically significant difference was observed for the volume mismatch sign between the paramedial bithalamic tumor and the non-tumorous groups (χ2 = 35.465, P < 0.001). The presence of volume mismatch sign in paramedial bithalamic illnesses predicted the presence of tumors with a sensitivity and specificity of 69.2% and 90.9%, respectively, and PPV and NPV were 90.0% and 71.4%.

CONCLUSION

Volume mismatch sign may indicate tumors in paramedian bithalamic diseases.

Pathogenesis and Management of Acute Necrotizing Encephalopathy

INTRODUCTION

During the COVID-19 pandemic, many cases of acute necrotizing encephalopathy (ANE) secondary to COVID-19 have been reported. ANE is characterized by a rapid onset, a fulminant course, and low morbidity and fatality rates. Therefore, clinicians need to be vigilant for such disorders, especially during the influenza virus and COVID-19 epidemics.

AREAS COVERED

The authors summarize the most recent studies on the clinical spectrum and treatment essentials of ANE to provide references for prompt diagnosis and improved treatment of this rare but fatal disease.

EXPERT OPINION

ANE is a type of necrotizing lesion of the brain parenchyma. There are two major types of reported cases. One is isolated and sporadic ANE, which is primarily caused by viral infections, particularly influenza and HHV-6 virus. The other type is familial recurrent ANE, which is caused by RANBP2 gene mutations. ANE patients have rapid progression and a very poor prognosis, with acute brain dysfunction occurring within days of viral infection and requiring admission to the intensive care unit. Clinicians still need to investigate and find solutions for the problems of early detection and treatment of ANE.

Case report: Distinct neurologic manifestation and cytokine profile of a child with COVID-19-associated acute fulminant encephalitis

The neurologic manifestations of coronavirus disease 2019 (COVID-19) may range from mild symptoms such as headache or confusion to profound encephalopathy with variable outcomes and sequelae. Here, we reported a case of fatal COVID-19-associated encephalitis with acute fulminant cerebral edema, presenting first with visual hallucination and then a rapid progression into comatose status in a few hours. Serial brain computed tomography depicted cerebral edematous changes from bilateral ventral temporal lobe to the whole brain leading to brain herniation. Multiple cytokines in serum and cerebrospinal fluid (CSF) were increased, with a more prominent rise in the CSF. Therefore, we postulated a hypothesis regarding the mechanism of this fulminant encephalitis that the SARS-CoV-2 virus attacked ventral temporal lobes initially, triggered a severe cytokine storm, and then led to subsequent disruption of the blood-brain barrier, diffuse brain edema, and brain herniation. The trend of cytokine profiles over time may aid in diagnosing and evaluating the severity and prognosis of COVID-19-associated encephalitis.

Acute necrotizing encephalopathy of childhood from Eastern Africa

Key Clinical Message

Acute necrotizing encephalopathy leads to devastating neurological sequelae and even death. Clinician should try not to miss this diagnosis especially in the pediatrics whenever there are neurological symptoms due to viral infection.

Abstract

Acute necrotizing encephalopathy (ANE) is a rare disease affecting the central nervous system. It leads to devastating neurological sequelae with a mortality rate of approximately 30%. Clinicians should have high suspicion whenever there is neurologic deficit and history of viral infections especially involving upper respiratory tract in the pediatric age group.

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.

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.

Neurological complications associated with influenza in hospitalized children

BACKGROUND

Influenza is a known respiratory and potential neurotropic virus. This study aimed to determine the prevalence and outcomes of influenza-related neurological complications among hospitalized children.

METHODS

All medical records of hospitalized children aged <18 years old diagnosed with influenza at a tertiary care hospital in Bangkok were retrospectively reviewed. Influenza infection was confirmed by rapid antigen or reverse transcription polymerase chain reaction tests. Neurological characteristics and clinical outcomes were analyzed using the Pediatric Cerebral Performance Category Scale.

RESULTS

From 2013 to 2018, 397 hospitalized children with a median age of 3.7 years (interquartile range [IQR]: 1.6-6.9) were included. The prevalence of neurological complications, including seizure or acute encephalopathy, was 16.9% (95% confidence interval [CI]: 13.3-20.9). Influenza A and B were identified in 73.1% and 26.9% of the patients, respectively. Among 39 (58.2%) acute symptomatic seizure cases, 25 (37.3%) children had simple febrile seizures, 7 (10.4%) had repetitive seizures, and 7 (10.4%) had provoked seizures with pre-existing epilepsy. For 28 (41.8%) encephalopathy cases, the clinical courses were benign in 20 (29.9%) cases and severe in 8 (11.9%) cases. Ten (14.9%) children needed intensive care monitoring, and 62 (93.5%) fully recovered to their baselines at hospital discharge. Predisposing factors to the neurological complications included a history of febrile seizure (adjusted odds ratio [aOR]: 20.3; 95% CI: 6.6-63.0), pre-existing epilepsy (aOR: 3.6; 95% CI: 1.3-10.2), and a history of other neurological disorders (aOR: 3.5; 95% CI: 1.2-10.2).

CONCLUSIONS

One fifth of hospitalized children with influenza had neurological complications with a favorable outcome. Children with pre-existing neurological conditions were at higher risk for developing neurological complications.

Recurrent acute hemorrhagic necrotizing encephalopathy associated with RAN-binding protein-2 gene mutation in a pediatric patient

A young male child presented with recurrent episodes of seizures and altered mental status following febrile episodes on three separate occasions between his first and third birthdays. Laboratory evaluations identified SARS-CoV-2 infection during the first episode and no infective agents or antibodies in the cerebrospinal fluid during all the episodes. Brain imaging with CT and MRI revealed bilaterally symmetric patchy hemorrhagic necrotic foci in the deep brain nuclei and medial temporal lobes, prompting suspicion for an underlying predisposition to recurrent acute hemorrhagic necrotizing encephalopathy. Gene analysis confirmed a mutation in the RAN-binding protein-2 (RANBP2) gene. The patient made good recovery following treatment with IVIG, steroids and plasmapheresis, and follow-up brain imaging showed no progression of brain lesions. Early suspicion from characteristic imaging features in appropriate clinical settings will inform timely appropriate treatment and better outcome. We therefore provided short review of imaging features of acute hemorrhagic necrotizing encephalopathy.

Positive Impact of Inpatient Respiratory Rehabilitation in a Rare Case of Acute Necrotizing Encephalopathy

Acute necrotizing encephalopathy, also known as acute necrotizing encephalopathy of childhood (ANEC) is a rare disorder characterized by respiratory or gastrointestinal infections, high fever, and rapid changes in consciousness and seizures. ANEC is a rare form of encephalopathy characterized by multiple bilateral brain lesions, primarily involving the thalami and putamina internal and external capsules, cerebellar white matter, and the brainstem segmentum. Here we present, a rare case of acute necrotizing encephalopathy in a pediatric patient, a 13-year-old boy, who was admitted with acute onset of fever. The fever was intermittent and high grade along with chills, rigor, and respiratory distress five days back. The chest x-ray showed heterogeneous opacities in bilateral lung fields. Thalami, brainstem, cerebellum, and white matter have all been shown to have a symmetric lesion in this disease on magnetic resonance imaging (MRI). Ventilation, immunoglobulin, and other supporting measures, as well as respiratory rehabilitation, were used to treat him. In pediatric intensive care units (PICU), physiotherapy is considered an important aspect of patient care. Respiratory rehabilitation included patients and their family member's counseling, airway clearance techniques, energy conservation methods, and adaptation to complex positions with the maintenance of oxygen saturation (SpO₂). We conclude Respiratory rehabilitation with efficient family counseling is effective in the overall improvement of the patient’s condition with acute respiratory failure in acute necrotizing encephalopathy.

Evaluation of multiple consensus criteria for autoimmune encephalitis and temporal analysis of symptoms in a pediatric encephalitis cohort

Objective

To evaluate the sensitivity and specificity of current criteria for the diagnosis of autoimmune encephalitis (AE) and the temporal onset of neuropsychiatric symptoms (NP) in a pediatric encephalitis cohort.

Background

Multiple criteria for AE have been developed, including the Graus and pediatric-focused Cellucci consensus criteria, and the Determining Etiology in Encephalitis (DEE) score for patients with encephalitis. Early identification and treatment of AE is crucial to improve outcomes, but this can be difficult given the frequent overlap of clinical presentation between AE and infectious encephalitis (IE).

Design/methods

A retrospective review was conducted of patients seen at our institution from 2000 to 2021 with a final diagnosis of AE or IE. These were narrowed through multiple exclusions to etiology-confirmed IE or antibody-positive/negative AE. Time of onset or results of all symptoms and diagnostics were recorded. Sensitivity and specificity of each criterion under various clinical scenarios were calculated over the first month after initial NP symptom onset.

Results

A total of 23 antibody-positive AE, 9 antibody-negative AE and 23 IE patients were included in final analysis. Under an idealized scenario with rapid initial diagnostic evaluations, the sensitivity for pediatric AE by day 28 after onset of NP symptoms approached 90% for both Cellucci and Graus criteria. Specificity within these 28 days was low without infectious testing results, increasing the greatest with rapid PCR testing and second with infectious antibody testing-reaching ~90% with both. A DEE score of 3 provided a specificity of 100% in identifying IE, but low sensitivity (29%). Symptoms were noted to cluster within several days of onset in IE, but in AE were spread out. Personality/behavioral change, speech change, affective disorder, and sleep disturbance were noted more often in AE, while fever, elevated C-reactive protein or CSF protein, and abnormal MRI-Brain occurred more often in IE.

Conclusion

In this study, we provide the first evaluation of the Cellucci criteria and the first validation of the DEE score in the differentiation of pediatric AE and IE. Further refinement of AE criteria is needed to improve early detection and treatment of pediatric AE.

Adult-onset Still's disease with concurrent acute necrotizing encephalopathy: a case report

Background

Acute necrotizing encephalopathy (ANE) is a rare encephalopathy characterized by multiple symmetrical brain lesions, mainly involving thalami. Adult-onset Still’s disease (AOSD) is a rare systemic inflammatory condition of unknown cause characterized by fever, sore throat, rash and joint pain. Both entities are considered to be triggered by infections and associated with hypercytokinemia.

Case presentation

A 46-year-old male was diagnosed with AOSD at local hospital because of 3-week-long high fever, sore throat, arthralgia, transient skin rash, lymphadenopathy, leukocytosis, hyperferritinemia, and absence of antinuclear antibodies (ANA) and rheumatoid factor (RF). Corticosteroids were not used because of delayed diagnosis. Three weeks after the onset, the patient suddenly fell unconscious and was transferred to our hospital. Brain CT and MRI revealed symmetrical lesions involving thalami, striatum and brain stem, consistent with ANE. One day after admission, his condition aggravated and brain CT revealed hemorrhage in the lesions. He died 3 days after admission.

Conclusion

We report a rare case of ANE preceded by AOSD. The underlying mechanism is still unclear. Early recognizing of the two conditions is difficult but prognostically important.

Covid-19 and Parkinson's disease: Acute clinical implications, long-COVID and post-COVID-19 parkinsonism

The Coronavirus Disease 2019 (Covid-19), caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), has led to unprecedented challenges for the delivery of healthcare and has had a clear impact on people with chronic neurological conditions such as Parkinson's disease (PD). Acute worsening of motor and non-motor symptoms and long-term sequalae have been described during and after SARS-CoV-2 infections in people with Parkinson's (PwP), which are likely to be multifactorial in their origin. On the one hand, it is likely that worsening of symptoms has been related to the viral infection itself, whereas social restrictions imposed over the course of the Covid-19 pandemic might also have had such an effect. Twenty cases of post-Covid-19 para-infectious or post-infectious parkinsonism have been described so far where a variety of pathophysiological mechanisms seem to be involved; however, a Covid-19-induced wave of post-viral parkinsonism seems rather unlikely at the moment. Here, we describe the interaction between SARS-CoV-2 and PD in the short- and long-term and summarize the clinical features of post-Covid-19 cases of parkinsonism observed so far.

Outcomes in influenza and RANBP2 mutation-associated acute necrotizing encephalopathy of childhood

AIM

To evaluate clinical and imaging features in patients with acute necrotizing encephalopathy of childhood (ANEC) to identify predictors of RANBP2 mutations, influenza association, and long-term outcomes.

METHOD

A retrospective chart review in patients with ANEC (2012-2020) seen at a tertiary pediatric center was performed. Children were included if they had acute inflammatory lesions in the basal ganglia and pons. Variables included presenting features, imaging characteristics, RANBP2 gene testing, nasopharyngeal swab findings, therapies, and long-term outcomes.

RESULTS

Twenty patients were included (average age at presentation 3y 6mo, interquartile range  3y 7mo, SD  2y 8mo; 14 females, six males). Three of the 20 experienced recurrences; one of the 20 died. Ten patients were influenza positive. Seven patients were RANBP2 mutation positive. A higher likelihood of hemorrhage was observed in patients who were influenza positive compared to influenza negative (p=0.048). Patients with influenza had a higher degree of thalamic hemorrhage (2, p=0.035) and greater extent of diffusion restriction (3, p=0.035) in semiquantitive analysis.

INTERPRETATION

Children with ANEC who are positive for influenza are more likely to have hemorrhage and greater thalamic swelling. RANBP2 status was predictive of relapse but not predictive of overall outcome.

Clinical features and imaging manifestations of acute necrotizing encephalopathy in children

PURPOSE

We summarized the clinical features of acute necrotizing encephalopathy (ANE) in children.

METHODS

Clinical data of 14 children with ANE at one center from January 2017 to January 2020 were retrospectively analyzed. ANE severity score (ANE-ss) was used to assess ANE severity, and the Glasgow Outcome Scale-Extended was used to assess functional outcomes.

RESULTS

Peak incidence was between 1 and 3 years of age (71%), and a large percentage of males were affected (79%). The main manifestations included fever (100%), seizure (86%), and impaired consciousness (100%). Seven patients (58%) developed status epilepticus. The etiology was identified in 10 patients (71%) and mainly included H1N1 (36%) and Epstein-Barr virus (29%).Complications included multiple organ failure (MOF), predominantly liver (36%), heart (21%) and kidney (7%) failure, gastrointestinal hemorrhage (21%), hypernatremia (7%), hematuria (7%), disseminated intravascular coagulation (7%), and shock (7%). Pleocytosis was observed in two patients, and increased cerebrospinal fluid protein was found in 11 patients. A missense mutation in RANBP2 (c.1754C>T: p.Thr585Met) was observed in one patient. Magnetic resonance imaging revealed increased T2 and T1 signal density in multifocal and symmetric brain lesions (bilateral thalami, 100%) in all patients during the acute phase. There were no deaths. Nine children retained neurological sequelae affecting movement, cognition, speech, vision, and/or seizure. Four children recovered almost completely. There was a significant correlation between risk classification and outcome by ANE-ss.

CONCLUSION

ANE is a group of clinical and imaging syndromes. Most patients have severe neurological sequelae, and ANE may have lower mortality. And ANE-ss can assess prognosis.

Case Report: Acute Necrotizing Encephalopathy Following COVID-19 Vaccine

Objectives

Acute necrotizing encephalopathy (ANE) is a rare neurological disorder arising from a para- or post-infectious "cytokine storm. "It has recently been reported in association with coronavirus disease 2019 (COVID-19) infection.

Methods

A 56-year-old male with a diagnosis of ANE 48 h following the first dose of ChAdOx1 nCoV-19 vaccination was investigated. Cytokine analyses on serum and cerebrospinal fluid (CSF) were performed. The patient was treated with high-dose corticosteroids and followed clinically and radiologically.

Results

Favorable clinical and radiological outcomes were noted. There was an upregulation in serum levels of CXCL5, CXCL1, Il-8, IL-15, CCL2, TGF-B, and EGF, and up-regulation in CSF levels of CXCL5, IL-2, IL-3, and IL-8.

Discussion

As COVID-19 infection has been previously reported as a possible rare cause of ANE, we speculate on an aberrant immune response mechanism that was brought about by the vaccine. To increase our understanding of the pathogenesis of ANE in the context of COVID-19 vaccination and to better define its clinical features and outcomes, clinicians and scientists should continue reporting convincing cases of such entities.

Coronavirus Disease 2019 and related Parkinsonism: the clinical evidence thus far

Background

The Coronavirus disease 2019 (Covid‐19) pandemic has fueled both research and speculation, as to whether it could be a “perfect storm” for a post‐Covid emergence of parkinsonism in some susceptible individuals, analogous to the post‐encephalitic parkinsonism reported after the 1918 influenza epidemic. This theory is further augmented by reports of a pathogenic effect of the Severe Acute Respiratory Syndrome Coronavirus‐2 (SARS‐CoV‐2) on the central nervous system with specific impact on the dopaminergic pathway, as well as the possibility of the virus to selectively bind to Angiotensin‐Converting Enzyme‐2 (ACE‐2); these molecules are expressed abundantly in the midbrain dopamine neurons and, are likely involved in several cellular mechanisms cited in Parkinson's Disease (PD) pathophysiology.

Objectives—Methods

Therefore, we performed a review of the literature up to February 2022 to explore the current landscape considering published cases of new‐onset parkinsonism after a SARS‐CoV‐2 infection in otherwise healthy individuals. We summarized their clinical features, diagnostic and treatment approaches, discussing potential underlying mechanisms in light of PD pathogenesis theories.

Results

Twenty cases that developed parkinsonian features simultaneously or shortly after a reported SARS‐CoV‐2 infection were reviewed. In 11 of them, parkinsonism appeared in the context of encephalopathy, while four patients developed post‐infectious parkinsonism without encephalopathy, and four bore similarities to idiopathic PD. Nine patients exhibited a good response to dopaminergic therapy, while four responded to immunomodulatory treatment.

Conclusions

Available data does not yet justify a clear association between the Covid‐19 pandemic and a parkinsonism wave. However, vigilance is necessary, as long‐term effects might have not been revealed.

Post-Infectious Autoimmunity in the Central (CNS) and Peripheral (PNS) Nervous Systems: An African Perspective

The direct impact and sequelae of infections in children and adults result in significant morbidity and mortality especially when they involve the central (CNS) or peripheral nervous system (PNS). The historical understanding of the pathophysiology has been mostly focused on the direct impact of the various pathogens through neural tissue invasion. However, with the better understanding of neuroimmunology, there is a rapidly growing realization of the contribution of the innate and adaptive host immune responses in the pathogenesis of many CNS and PNS diseases. The balance between the protective and pathologic sequelae of immunity is fragile and can easily be tipped towards harm for the host. The matter of immune privilege and surveillance of the CNS/PNS compartments and the role of the blood-brain barrier (BBB) and blood nerve barrier (BNB) makes this even more complex. Our understanding of the pathogenesis of many post-infectious manifestations of various microbial agents remains elusive, especially in the diverse African setting. Our exploration and better understanding of the neuroimmunology of some of the infectious diseases that we encounter in the continent will go a long way into helping us to improve their management and therefore lessen the burden. Africa is diverse and uniquely poised because of the mix of the classic, well described, autoimmune disease entities and the specifically "tropical" conditions. This review explores the current understanding of some of the para- and post-infectious autoimmune manifestations of CNS and PNS diseases in the African context. We highlight the clinical presentations, diagnosis and treatment of these neurological disorders and underscore the knowledge gaps and perspectives for future research using disease models of conditions that we see in the continent, some of which are not uniquely African and, where relevant, include discussion of the proposed mechanisms underlying pathogen-induced autoimmunity. This review covers the following conditions as models and highlight those in which a relationship with COVID-19 infection has been reported: a) Acute Necrotizing Encephalopathy; b) Measles-associated encephalopathies; c) Human Immunodeficiency Virus (HIV) neuroimmune disorders, and particularly the difficulties associated with classical post-infectious autoimmune disorders such as the Guillain-Barré syndrome in the context of HIV and other infections. Finally, we describe NMDA-R encephalitis, which can be post-HSV encephalitis, summarise other antibody-mediated CNS diseases and describe myasthenia gravis as the classic antibody-mediated disease but with special features in Africa.

SARS-CoV-2 Morbidity in the CNS and the Aged Brain Specific Vulnerability

The infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be the cause of a fatal disease known as coronavirus disease 2019 (COVID-19) affecting the lungs and other organs. Particular attention has been given to the effects of the infection on the brain due to recurring neurological symptoms associated with COVID-19, such as ischemic or hemorrhagic stroke, encephalitis and myelitis, which are far more severe in the elderly compared to younger patients. The specific vulnerability of the aged brain could derive from the impaired immune defenses, from any of the altered homeostatic mechanisms that contribute to the aging phenotype, and from particular changes in the aged brain involving neurons and glia. While neuronal modifications could contribute indirectly to the damage induced by SARS-CoV-2, glia alterations could play a more direct role, as they are involved in the immune response to viral infections. In aged patients, changes regarding glia include the accumulation of dystrophic forms, reduction of waste removal, activation of microglia and astrocytes, and immunosenescence. It is plausible to hypothesize that SARS-CoV-2 infection in the elderly may determine severe brain damage because of the frail phenotype concerning glial cells.

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.

A case of successive development of possible acute necrotizing encephalopathy after COVID-19 pneumonia

COVID-19 infection often results in an excessive inflammatory response with a spectrum of neurological manifestations. Here, we describe an 81-year-old female with severe COVID-19 pneumonia and subsequent alteration of consciousness after high-dose intravenous dexamethasone and remdesivir. A non-contrast head computed tomography (CT) demonstrated bilateral hypodensities involving bilateral cerebellar hemispheres, thalami, cerebral peduncles and medial parieto-occipital areas. There was no improvement and repeat CT showed progression with findings suggestive of acute necrotizing encephalopathy. Interleukin-6 levels were initially normal; however, subsequent levels were found to be markedly elevated. Acute necrotizing encephalopathy associated with COVID-19 may occur in the setting of severe pneumonia and may represent an immune-mediated process involving inflammatory cytokines such as interleukin-6.

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.