Etiology of acute childhood encephalitis at The Hospital for Sick Children, Toronto, 1994-1995

Bibliometric analysis of publication trends and topics of influenza-related encephalopathy from 2000 to 2022

BACKGROUND

Influenza-related encephalopathy is a rapidly progressive encephalopathy that usually presents during the early phase of influenza infection and primarily manifests as central nervous system dysfunction. This study aimed to analyze the current research status and hotspots of influenza-related encephalopathy since 2000 through bibliometrics analysis.

METHODS

The Web of Science Core Collection (WOSCC) was used to extract global papers on influenza-related encephalopathy from 2000 to 2022. Meanwhile, the VOSviewer and CiteSpace software were used for data processing and result visualization.

RESULTS

A total of 561 published articles were included in the study. Japan was the country that published the most articles, with 205 articles, followed by the United States and China. Okayama University and Tokyo Medical University published the most articles, followed by Nagoya University, Tokyo University, and Juntendo University. Based on the analysis of keywords, four clusters with different research directions were identified: "Prevalence of H1N1 virus and the occurrence of neurological complications in different age groups," "mechanism of brain and central nervous system response after influenza virus infection," "various acute encephalopathy" and "diagnostic indicators of influenza-related encephalopathy."

CONCLUSIONS

The research progress, hotspots, and frontiers on influenza-related encephalopathy after 2000 were described through the visualization of bibliometrics. The findings will lay the groundwork for future studies and provide a reference for influenza-related encephalopathy. Research on influenza-related encephalopathy is basically at a stable stage, and the number of research results is related to outbreaks of the influenza virus.

Human herpes virus type-6 is associated with central nervous system infections in children in Sudan

Background

Human herpes virus type-6 (HHV-6) is increasingly recognised as a febrile agent in children. However, less is known in sub-Saharan African countries, including Sudan.

Objective

We investigated the involvement of HHV-6 in paediatric central nervous system (CNS) infections in Khartoum, Sudan.

Methods

Febrile patients aged up to 15 years with suspected CNS infections at Omdurman Hospital for Children from 01 December 2009 to 01 August 2010 were included. Viral DNA was extracted from leftover cerebrospinal fluid (CSF) specimens and quantitatively amplified by real-time polymerase chain reaction (PCR) at Umeå University in Sweden.

Results

Of 503 CSF specimens, 13 (2.6%) were positive for HHV-6 (33.0% [13/40 of cases with proven infectious meningitis]). The median thermal cycle threshold for all HHV-6-positive specimens was 38 (range: 31.9–40.8). The median number of virus copies was 281.3/PCR run (1 × 10⁵ copies/mL CSF; range: 30–44 × 10³ copies/PCR run [12 × 10³ – 18 × 10⁶ copies/mL CSF]). All positive patients presented with fever and vomiting; 86.0% had seizures. The male-to-female ratio was 1:1; 50.0% were toddlers, 42.0% infants and 8.0% teenagers. Most (83.0%) were admitted in the dry season and 17.0% in the rainy season. Cerebrospinal fluid leukocytosis was seen in 33.0%, CSF glucose levels were normal in 86.0% and low in 14.0%, and CSF protein levels were low in 14.0% and high in 43.0%.

Conclusion

Among children in Sudan with CNS infections, HHV-6 is common. Studies on the existence and spread of HHV-6 chromosomal integration in this population are needed.

Study protocol: The clinical features, epidemiology, and causes of paediatric encephalitis in southern Vietnam

Encephalitis is a major cause of morbidity and mortality worldwide. The clinical syndrome of encephalitis consists of altered mental status, seizures, neurologic signs, and is often accompanied by fever, headache, nausea, and vomiting. The encephalitis in children has been known that more common than in adult, with the incidence rate of infants was 3.9 times higher than that of people 20-44 years of age. The reported incidence of hospitalization attributed to paediatric encephalitis ranged from 3 to 13 admissions per 100,000 children per year with the overall mortality ranging from 0 to 7%. There are however more than 100 pathogens that can cause encephalitis and accurate diagnosis is challenging. Over 50% of patients with encephalitis are left undiagnosed despite extensive laboratory investigations. Furthermore, recent studies in high-income settings have suggested autoimmune encephalitis has now surpassed infectious aetiologies, mainly due to increased awareness and diagnostic capacity, which further challenges routine diagnosis and clinical management, especially in developing countries. There are limited contemporary data on the causes of encephalitis in children in Vietnam. Improving our knowledge of the causative agents of encephalitis in this resource-constrained setting remains critical to informing case management, resource distribution and vaccination strategy. Therefore, we conduct a prospective observational study to characterise the clinical, microbiological, and epidemiological features of encephalitis in a major children's hospital in southern Vietnam. Admission clinical samples will be collected alongside meta clinical data and from each study participants. A combination of classical assays (serology and PCR) and metagenomic next-generation sequencing will used to identify the causative agents. Undiagnosed patients with clinical presentations compatible with autoimmune encephalitis will then be tested for common forms of the disease. Finally, using direct- and indirect costs, we will estimate the economic burden of hospitalization and seven days post hospital discharge of paediatric encephalitis in our setting.

Study protocol: The clinical features, epidemiology, and causes of paediatric encephalitis in southern Vietnam

Encephalitis is a major cause of morbidity and mortality worldwide. The clinical syndrome of encephalitis consists of altered mental status, seizures, neurologic signs, and is often accompanied by fever, headache, nausea, and vomiting. The encephalitis in children has been known that more common than in adult, with the incidence rate of infants was 3.9 times higher than that of people 20-44 years of age. The reported incidence of hospitalization attributed to paediatric encephalitis ranged from 3 to 13 admissions per 100,000 children per year with the overall mortality ranging from 0 to 7%. There are however more than 100 pathogens that can cause encephalitis and accurate diagnosis is challenging. Over 50% of patients with encephalitis are left undiagnosed despite extensive laboratory investigations. Furthermore, recent studies in high-income settings have suggested autoimmune encephalitis has now surpassed infectious aetiologies, mainly due to increased awareness and diagnostic capacity, which further challenges routine diagnosis and clinical management, especially in developing countries. There are limited contemporary data on the causes of encephalitis in children in Vietnam. Improving our knowledge of the causative agents of encephalitis in this resource-constrained setting remains critical to informing case management, resource distribution and vaccination strategy. Therefore, we conduct a prospective observational study to characterise the clinical, microbiological, and epidemiological features of encephalitis in a major children's hospital in southern Vietnam. Admission clinical samples will be collected alongside meta clinical data and from each study participants. A combination of classical assays (serology and PCR) and metagenomic next-generation sequencing will used to identify the causative agents. Undiagnosed patients with clinical presentations compatible with autoimmune encephalitis will then be tested for common forms of the disease. Finally, using direct- and indirect costs, we will estimate the economic burden of hospitalization and seven days post hospital discharge of paediatric encephalitis in our setting.

Study protocol: The clinical features, epidemiology, and causes of paediatric encephalitis in southern Vietnam

Encephalitis is a major cause of morbidity and mortality worldwide. The clinical syndrome of encephalitis consists of altered mental status, seizures, neurologic signs, and is often accompanied by fever, headache, nausea, and vomiting. The encephalitis in children has been known that more common than in adult, with the incidence rate of infants was 3.9 times higher than that of people 20-44 years of age. The reported incidence of hospitalization attributed to paediatric encephalitis ranged from 3 to 13 admissions per 100,000 children per year with the overall mortality ranging from 0 to 7%. There are however more than 100 pathogens that can cause encephalitis and accurate diagnosis is challenging. Over 50% of patients with encephalitis are left undiagnosed despite extensive laboratory investigations. Furthermore, recent studies in high-income settings have suggested autoimmune encephalitis has now surpassed infectious aetiologies, mainly due to increased awareness and diagnostic capacity, which further challenges routine diagnosis and clinical management, especially in developing countries. There are limited contemporary data on the causes of encephalitis in children in Vietnam. Improving our knowledge of the causative agents of encephalitis in this resource-constrained setting remains critical to informing case management, resource distribution and vaccination strategy. Therefore, we conduct a prospective observational study to characterise the clinical, microbiological, and epidemiological features of encephalitis in a major children's hospital in southern Vietnam. Admission clinical samples will be collected alongside meta clinical data and from each study participants. A combination of classical assays (serology and PCR) and metagenomic next-generation sequencing will used to identify the causative agents. Undiagnosed patients with clinical presentations compatible with autoimmune encephalitis will then be tested for common forms of the disease. Finally, using direct- and indirect costs, we will estimate the economic burden of hospitalization and seven days post hospital discharge of paediatric encephalitis in our setting.

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

BACKGROUND

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a common type of acute encephalopathy in Japan; the condition is clinically characterized by prolonged seizures as the initial neurological symptom, followed by late seizures 4-6 days later. It is difficult to differentiate AESD from prolonged febrile seizures (PFSs). Here, we explored the use of electroencephalography to differentiate AESD from PFSs.

METHODS

We studied the electroencephalograms (EEGs) of children <6 years of age diagnosed with AESD or PFSs; all EEGs were recorded within 48 h of seizure onset (i.e., before the late seizures of AESD). Two pediatric neurologists evaluated all EEGs, focusing on the basic rhythm, slowing during wakefulness/arousal by stimuli, spindles, fast waves, and slowing during sleep.

RESULTS

The EEGs of 14 children with AESD and 31 children with PFSs were evaluated. Spindles were more commonly reduced or absent in children with AESD than in those with PFSs (71% vs. 31%, p = 0.021). Fast waves were also more commonly reduced or absent in children with AESD (21% vs. 0%, p = 0.030). The rates of all types of slowing did not differ between children with AESD and those with PFSs, but continuous or frequent slowing during sleep was more common in the former (50% vs. 17%, p = 0.035).

CONCLUSIONS

EEG findings may usefully differentiate AESD from PFSs. Reduced or absent spindles/fast waves and continuous or frequent slowing during sleep are suggestive of AESD in children with prolonged seizures associated with fever.

The Clinical Profile of Cat-Scratch Disease’s Neuro-Ophthalmological Effects

Cat-scratch disease is an illness caused by Bartonella henselae that occurs as a result of contact with an infected kitten or dog, such as a bite or scratch. It is more prevalent in children and young adults, as well as immunocompromised individuals. There are limited publications examining the features of CSD in patients. As such, the purpose of this research was to assess the clinical neuro-ophthalmological consequences of CSD reported in the literature. Among the ophthalmologic disorders caused by cat-scratch disease in humans, Parinaud oculoglandular syndrome, uveitis, vitritis, retinitis, retinochoroiditis and optic neuritis are the most prevalent. The neurological disorders caused by cat-scratch disease in humans include encephalopathy, transverse myelitis, radiculitis, and cerebellar ataxia. The current review addresses the neuro-ophthalmological clinical manifestations of cat-scratch disease, as described in papers published over the last four decades (1980–2022). All the data gathered were obtained from PubMed, Medline and Google Scholar. The current descriptive review summarizes the most-often-encountered clinical symptomatology in instances of cat-scratch disease with neurological and ocular invasion. Thus, the purpose of this review is to increase knowledge of cat-scratch disease’s neuro-ophthalmological manifestations.

Dual arterial thrombosis: A diagnostic enigma

Cold agglutinin disease is a rare cause of arterial thrombosis leading to stroke, commonly encountered against a background of mycoplasma pneumonia infections. A 22-year-old patient presented with acute-onset left hemiplegia preceded by a short history of fever and cough. Magnetic resonance imaging (MRI) showed a right middle cerebral artery infarct. Serially repeated hemoglobin levels showed a progressive drop and peripheral smear showed evidence of hemolysis. Blood drawn for investigations would rapidly clot, suggesting a possibility of cold agglutinin-induced hemolysis. The patient was then worked up for all the possible causes of hemolytic anemia including secondary causes which were all negative except for significant immunoglobulin M mycoplasma levels with elevated cold antibody titers. The patient was then initiated on pulse steroids with azithromycin and doxycycline and hemoglobin levels stabilized. The patient also developed pulmonary thromboembolism which was managed with anticoagulation. The patient made a steady improvement, was discharged, and is on follow-up. Here, we present a unique case of mycoplasma associated cold agglutinin disease causing arterial thrombosis.

Diagnosis and Therapy of Infectious Encephalitis in Children: A Ten-Years Retrospective Study

BACKGROUND

Infectious encephalitis represents a rare but potentially severe clinical condition. However, limited international data are available in pediatric age.

METHODS

We conducted a retrospective study to review (a) the clinical presentation; (b) laboratory, radiology, and neurophysiology findings; (c) the correlations between these exams and outcome; and (d) the therapy performed.

RESULTS

Fifty-six patients were enrolled [22 female (39.6%), mean age 4.7 years, IQR 0.7-8.7 years], 19.6% presented neurologic sequelae. HSV was the single most frequently isolated pathogen (19.6%), although in most cases, the etiology remained undefined. 41.1% children presented prodromal before the development of neurologic signs. Fever was the most frequent constitutional symptom (83.9% of cases). Cerebrospinal fluid was normal in 48.5% of cases and electroencephalograpy in 24.5% cases. Brain computed tomography scans was normal in 33 (91.7%) cases, while cerebral magnetic resonance imaging (MRI) showed pathologic findings in 62.5% of cases. MRI was the only parameter associated with neurologic sequalae [P = 0.01; OR, 8.1 (95% CI: 1.52-42.84)].

CONCLUSIONS

Pediatric encephalitis is a heterogeneous entity with nonspecific clinical and laboratory findings, with undefined etiologies in most times. MRI can play a primary role, both on a diagnostic and prognostic point-of-view, and its role should be implemented and made more accessible. Further studies are needed to define the exact role and timing of steroids.

Epidemiology, Etiology and Clinical Aspects of Childhood Acute Encephalitis in a Tertiary Pediatric Hospital in Costa Rica

BACKGROUND

Limited data are available on childhood encephalitis in Latin America. Our study aimed to increase insight on clinical presentation, etiology and outcome of children with acute encephalitis in Costa Rica.

METHODS

We conducted a prospective, observational study during an 8-month period at the Hospital Nacional de Niños "Dr. Carlos Sáenz Herrera" in Costa Rica. Case definition was according to "International Encephalitis Consortium" in children <13 years. We analyzed demographic characteristics, clinical symptoms, neurologic imaging, etiology, treatment and mortality.

RESULTS

Forty patients were identified. Mean age was 5 years and 57.5% were male. Most frequently neurologic symptoms were altered mental status (100.0%), headache (57.5%) and seizures (52.5%). Etiology was determined in 52.5% of cases. Probable or confirmed viral etiology was identified in 6 cases (15.0%) and bacterial etiology in also 6 cases (15.0%). A possible etiology was identified in 7 cases (17.5%). Autoimmune encephalitis was diagnosed in 2 patients (5.0%). Enterovirus and Streptococcus pneumoniae were the most common confirmed agents. No cases of herpes simplex virus were found. Etiology of 19 cases (47.5%) remained unknown. Sequelae were reported in 45.0% of patients. Mortality rate was 15.0% (6 cases), 3 caused by virus (adenovirus, human herpesvirus 6, enterovirus), 2 by bacteria (S. pneumoniae, Haemophilus influenzae type b) and 1 of unknown etiology. Diffuse cerebral edema was the most important mortality predictor (P < 0.001).

CONCLUSIONS

Acute encephalitis in our study was associated with significant morbidity and mortality. Early and aggressive antiviral, antibiotic and anticerebral edema treatment is necessary when acute encephalitis is suspected.

Encephalitis in Previously Healthy Children

Encephalitis is defined as altered mental status for more than 24 hours accompanied by 2 or more findings concerning for inflammation of the brain parenchyma: fever, seizures or other focal neurologic disorders, cerebrospinal fluid pleocytosis, and abnormal neuroimaging and electroencephalographic findings. Herpes simplex virus causes the most severe form of virus-induced encephalitis; the early administration of acyclovir can improve the prognosis of this disease. The rising interest in autoimmune causes of encephalitis, most notably anti-N-methyl-d-aspartate receptor, should prompt the clinician to consider immunomodulatory treatments, which may improve outcomes. A broad testing panel may be necessary to detect the etiologic agent; a few published pediatric cases suggest that infectious and autoimmune causes may occur concurrently in the same patient with encephalitis. More than 40% of children diagnosed as having encephalitis will not return to their previous level of neurologic function after resolution of their disease, although outcomes are highly variable depending on the etiologic agent.

Guidelines for the diagnosis and treatment of acute encephalopathy in childhood

The cardinal symptom of acute encephalopathy is impairment of consciousness of acute onset during the course of an infectious disease, with duration and severity meeting defined criteria. Acute encephalopathy consists of multiple syndromes such as acute necrotizing encephalopathy, acute encephalopathy with biphasic seizures and late reduced diffusion and clinically mild encephalitis/encephalopathy with reversible splenial lesion. Among these syndromes, there are both similarities and differences. In 2016, the Japanese Society of Child Neurology published 'Guidelines for the Diagnosis and Treatment of Acute Encephalopathy in Childhood', which made recommendations and comments on the general aspects of acute encephalopathy in the first half, and on individual syndromes in the latter half. Since the guidelines were written in Japanese, this review article describes extracts from the recommendations and comments in English, in order to introduce the essence of the guidelines to international clinicians and researchers.

Prospective Evaluation of Childhood Encephalitis: Predisposing Factors, Prevention and Outcome

BACKGROUND

Acute encephalitis in childhood is a serious condition. The severity varies between studies, partly reflecting differences in study design where only severe cases from referral centers often are reported. The aim of this study was to prospectively study the clinical picture and etiology of acute encephalitis in childhood at a primary and tertiary pediatric hospital in Sweden.

METHODS

All children with acute encephalitis were prospectively included from 2011 to 2016. Laboratory tests, investigations and follow-up were performed according to standardized study protocols.

RESULTS

Eighty-nine children were included (46 female and 43 male) with a median age of 53 months. An etiology was established in 61/89. Tick-borne encephalitis virus, enterovirus and rotavirus dominated and 34% were caused by a virus preventable by vaccination. Immune-mediated encephalitis was seen in 7 children. An abnormal electroencephalography picture was seen in 77/86, pathologic findings on neuroimaging in 13/49, and 38/89 children had seizures. Sequelae were reported by 49%. A high prevalence of previous contact with child and adolescent psychiatry was seen and, although not statistically significant, the need for extra support at school before encephalitis and the presence of central nervous system disease in the family seemed to predispose for a longer hospital stay.

CONCLUSION

Encephalitis is a condition with long-term consequences. Most children need admission to hospital, and many need surveillance in the intensive care unit. The etiology can be determined in a majority of cases, and 1/3 could have been prevented by vaccination. This study corroborates electroencephalography as a cornerstone in diagnosis.

Neurological Manifestations of Influenza A (H1N1): Clinical Features, Intensive Care Needs, and Outcome

OBJECTIVES

To describe neurological manifestations in children with Influenza A (H1N1).

METHODS

This retrospective study was conducted in the Pediatric intensive care unit (PICU) and Pediatric Neurology unit of a tertiary care teaching hospital in North India involving children with PCR confirmed Influenza A (H1N1) with neurological manifestations during 2019 outbreak.

RESULTS

Six children (5 females, 1 male) were enrolled. All presented with neurological symptoms (seizures and altered sensorium) accompanied with fever and respiratory symptoms with duration of illness of 2-7 d. The admission Glasgow Coma Scale ranged from 4 to 12. Only 2 cases showed cerebrospinal fluid pleocytosis. Neuroimaging was suggestive of diffuse cerebral edema, acute necrotizing encephalopathy of childhood, and acute disseminated encephalomyelitis. All were treated with Oseltamivir. Four cases had clinical features of raised intracranial pressure (ICP) and were managed in PICU, 3 of them needed mechanical ventilation, 3 needed vasoactive drugs, 3 received 3% saline infusion, 1 underwent invasive ICP monitoring, and 3 (cases 4, 5 and 6) received intravenous methylprednisolone (30 mg/kg) for 5 d. Total duration of hospital stay was 10-30 d. Case 2 expired due to refractory raised ICP. Among survivors, 3 children had residual neurological deficits and the remaining 2 had achieved premorbid condition.

CONCLUSIONS

Influenza A (H1N1) can present with isolated or predominant neurological manifestations which can contribute to poor outcome. The authors suggest to rule out H1N1 in any child who presents with unexplained neurological manifestations during seasonal outbreaks of H1N1.

Acute Childhood Viral Encephalitis in Southern Brazil

BACKGROUND

Viral meningoencephalitis is highly heterogeneous, varying by geographic location. The aim of this study was to characterize the etiology and reporting the clinical findings and outcome of viral encephalitis in children in southern Brazil.

METHODS

A cross-Sectional study was conducted at Hospital Pequeno Príncipe, Curitiba, Brazil, between January 2013 and December 2017. It included patients younger than 18 years, who fulfilled the criteria: altered mental status as a major criteria and 2 or more minor criteria (1) fever, (2) seizures, (3) focal neurologic findings, (4) central system fluid white cell count of ≥5 cells/mm, (5) abnormal brain imaging, and/or (6) electroencephalogram abnormalities.

RESULTS

Viral meningoencephalitis was diagnosed in 270 children, with median age of 2 years (interquartile range: 0-4), The etiology of viral meningoencephalitis was confirmed in 47% of patients. Enterovirus (18%) was the major cause of encephalitis in Southern Brazilian children, and a high prevalence of Epstein-Barr virus (6%) was demonstrated. Most patients presented with fever (81%), followed by vomiting (50%), focal neurologic findings (46%), seizures (31%) and headache (30%). Few abnormalities were detected on electroencephalograms and brain magnetic resonance images. On discharge from hospital, symptoms resolved completely in 87% of children. Sequelae were mainly observed in patients with focal neurologic symptoms (P<0.001), presence of seizures (P<0.001) and electroencephalogram abnormalities (P=0.024).

CONCLUSIONS

Enterovirus was the major cause of encephalitis. Etiologic agent of encephalitis seems to be influenced by the local virologic pattern. A poor outcome was identified in patients with seizures, focal neurologic findings and electroencephalogram abnormalities.

Factors associated with outcome of acute encephalitis in children: a retrospective study of three referral hospitals

BACKGROUND Encephalitis is more frequent in children and has a poor outcome. There was no data on encephalitis in children in Indonesia, so this study was aimed to evaluate clinical presentation and diagnostic examination of children with acute encephalitis, and factors related to outcome. METHODS This was a retrospective study of medical records between 2014 and 2018 in three referral hospitals in Jakarta and Tangerang. Clinical presentation at admission, cerebrospinal fluid analysis, neuroimaging, and electroencephalography (EEG) were documented. Outcome was determined at hospital discharge and classified as poor for severe neurological abnormalities at discharge or died. Logistic regression was used to evaluate associated factors with the outcome. RESULTS A total of 190 children were included and most were age >1 year (71%). Most subjects presented with fever (90%) and seizures (87%). Of those who had seizures, 80% experienced generalized seizures. Focal neurological deficit was seen in 90 patients (47%). EEG was positive in 90% subjects (n = 27/30). Probable cases were found in 51% of all subjects. The mortality was 23%. Focal seizures (odds ratio [OR] = 3.305, 95% confidence interval [CI] = 1.122–9.742) and age >1 year (OR = 3.076, 95% CI = 1.388–6.803) were risk factors for a poor outcome. CONCLUSIONS Acute encephalitis occurred most often in children aged >1 year. Fever and seizures were the most common symptoms. EEG was better than other examinations for confirming diagnosis of encephalitis. Focal seizures and age >1 year were associated with a three-fold increased risk for a poor outcome.

Emerging Tick-Borne Diseases

Increases in tick-borne disease prevalence and transmission are important public health issues. Efforts to control these emerging diseases are frustrated by the struggle to control tick populations and to detect and treat infections caused by the pathogens that they transmit. This review covers tick-borne infectious diseases of nonrickettsial bacterial, parasitic, and viral origins. While tick surveillance and tracking inform our understanding of the importance of the spread and ecology of ticks and help identify areas of risk for disease transmission, the vectors are not the focus of this document. Here, we emphasize the most significant pathogens that infect humans as well as the epidemiology, clinical features, diagnosis, and treatment of diseases that they cause. Although detection via molecular or immunological methods has improved, tick-borne diseases continue to remain underdiagnosed, making the scope of the problem difficult to assess. Our current understanding of the incidence of tick-borne diseases is discussed in this review. An awareness of the diseases that can be transmitted by ticks in specific locations is key to detection and selection of appropriate treatment. As tick-transmitted pathogens are discovered and emerge in new geographic regions, our ability to detect, describe, and understand the growing public health threat must also grow to meet the challenge.

Serial analysis of cytokine and chemokine profiles and viral load in severe fever with thrombocytopenia syndrome: Case report and review of literature

RATIONALE

Severe fever with thrombocytopenia syndrome (SFTS) is a recently recognized fatal infectious disease caused by the SFTS virus, and severe cases are complicated by the presence of hemophagocytic lymphohistiocytosis (HLH) associated with a cytokine storm. Herein, we report on serial changes of serum cytokine levels and viral load in a severe case of SFTS.

PATIENT CONCERNS

A 63-year-old Japanese woman presented with high-grade fever, abdominal pain, diarrhea, impaired consciousness, leukocytopenia, and thrombocytopenia.

DIAGNOSIS

SFTS was diagnosed based on a positive serum test for SFTS virus RNA and electroencephalogram (EEG) findings of encephalopathy.

INTERVENTIONS

The patient was treated with supportive therapy, including steroid pulse therapy (intravenous methylprednisolone 1 g/d for 3 days) for HLH and intravenous recombinant thrombomodulin 19200 U/d for 7 days for disseminated intravascular coagulation.

OUTCOMES

Treatment for 7 days improved both symptoms and abnormal EEG findings, and SFTS virus RNA disappeared from the serum at day 10 from the onset of symptoms. The serum cytokines and chemokines analysis during the clinical course revealed 2 distinct phases: the acute phase and the recovery phase. The cytokines and chemokines elevated in the acute phase included interleukin (IL)-6, IL-10, interferon (IFN)-α2, IFN-γ, tumor necrosis factor-α, interferon-γ-induced protein-10, and fractalkine, while the IL-1β, IL-12p40, IL-17, and vascular endothelial growth factor levels were higher in the recovery phase.

CONCLUSION

These observations suggest that the cytokines and chemokines elevated in the acute phase may reflect the disease severity resulted in a cytokine storm, while those in the recovery phase may be attributed to T-cell activation and differentiation.

Differential In Vitro Infection of Neural Cells by Astroviruses

Encephalitis remains a diagnostic conundrum in humans as over 50% of cases are managed without the identification of an etiology. Astroviruses have been detected from the central nervous system of mammals in association with disease, suggesting that this family of RNA viruses could be responsible for cases of some neurological diseases that are currently without an ascribed etiology. However, there are significant barriers to understanding astrovirus infection as the capacity of these viruses to replicate in nervous system cells in vitro has not been determined. We describe primary and immortalized cultured cells of the nervous system that support infection by astroviruses. These results further corroborate the role of astroviruses in causing neurological diseases and will serve as an essential model to interrogate the neuropathogenesis of astrovirus infection.

Recent advances in unbiased pathogen discovery have implicated astroviruses as pathogens of the central nervous system (CNS) of mammals, including humans. However, the capacity of astroviruses to be cultured in CNS-derived cells in vitro has not been reported to date. Both astrovirus VA1/HMO-C (VA1; mamastrovirus 9) and classic human astrovirus 4 (HAstV4; mamastrovirus 1) have been previously detected from cases of human encephalitis. We tested the ability of primary human neurons, primary human astrocytes, and other immortalized human nervous system cell lines (SK-N-SH, U87 MG, and SW-1088) to support infection and replication of these two astrovirus genotypes. Primary astrocytes and SK-N-SH cells supported the full viral life cycle of VA1 with a >100-fold increase in viral RNA levels during a multistep growth curve, detection of viral capsid, and a >100-fold increase in viral titer. Primary astrocytes were permissive with respect to HAstV4 infection and replication but did not yield infectious virus, suggesting abortive infection. Similarly, abortive infection of VA1 was observed in SW-1088 and U87 MG cells. Elevated expression of the chemokine CXCL10 was detected in VA1-infected primary astrocytes and SK-N-SH cells, suggesting that VA1 infection can induce a proinflammatory host response. These findings establish an in vitro cell culture model that is essential for investigation of the basic biology of astroviruses and their neuropathogenic potential.

Infection and Propagation of Astrovirus VA1 in Cell Culture

Astrovirus VA1/HMO-C (VA1) is the representative genotype of mamastrovirus 9, a species of the single-stranded, positive-sense RNA viral family, Astroviridae. Astroviruses have been traditionally considered pathogens of the gastrointestinal tract but they have been recently associated with neurological diseases in humans, cattle, mink, sheep, and pigs. VA1 is the astrovirus genotype most commonly identified from human cases of meningoencephalitis and has been recently propagated in cell culture. VA1 can now be used as a model system to study pathogenesis of the neurological diseases associated with astrovirus infection. In this article, we describe two fundamental assays to quantify replication and propagation of VA1, a quantitative reverse transcription-PCR (qRT-PCR) to measure viral RNA and a 50% tissue culture infectious dose (TCID50 ) assay to measure infectious viral particles. © 2018 by John Wiley & Sons, Inc.

Adenovirus-Associated Central Nervous System Disease in Children

OBJECTIVE

To characterize the spectrum and salient clinical features of adenovirus-associated neurologic disease in immunocompetent children.

STUDY DESIGN

Previously healthy children (aged 1 month-18 years) with central nervous system (CNS) disease associated with adenovirus infection were identified via the Encephalitis Registry (1996-2016) and Microbiology Database (2000-2016) at The Hospital for Sick Children, Toronto, and by systematic review of the literature. The data were pooled and analyzed to identify the spectrum of illness, clinical outcome, and risk factors for death or neurologic impairment.

RESULTS

Neurologic complications associated with adenovirus infection in our institution included febrile seizures, encephalitis, acute disseminated encephalomyelitis, and aseptic meningitis. A total of 48 immunocompetent children with adenovirus-associated CNS disease were included in the pooled analysis-38 from the literature and 10 from our institution. In 85% of cases, the virus was detected in the respiratory or gastrointestinal tract, but not the cerebrospinal fluid. Eighteen of the 48 (38%) patients either died or suffered permanent neurologic sequelae. Predictors of adverse outcome included younger age, coagulopathy, the absence of meningismus, serotype 2 virus, and the presence of seizures. After multivariable adjustment, only seizures remained a significant risk factor.

CONCLUSION

Adenovirus is a rare cause of CNS disease in immunocompetent children. Disease spectrum is variable, ranging from mild aspetic meningitis and fully reversible encephalopathy to severe, potentially fatal, acute necrotizing encephalopathy.

A Rare Case of Bartonella Encephalitis With Hemiplegia

The authors describe a 12-year-old girl with an atypical presentation of Bartonella encephalitis. She presented with fever and altered mental status and developed flaccid paralysis of her left upper extremity a day later. An electroencephalogram showed slowing over her right hemisphere. She had mild leukocytosis and bandemia, but her imaging and cerebrospinal studies were unrevealing. After five days, her symptoms resolved and she was discharged home on doxycycline due to suspicion for Bartonella encephalitis. The patient admitted to playing with a kitten two months prior, but she lacked the classic regional lymphadenopathy. Bartonella titers were sent during her hospitalization and returned positive after her discharge. Cat scratch disease neurologic manifestations are uncommon, with hemiplegia being exceedingly rare. This case illustrates that focal neurologic signs may develop during cat scratch disease infection and suggests that cat scratch disease encephalitis should be considered during evaluation of a pediatric patient with acute flaccid paralysis.

Tick-Borne Flaviviruses, with a Focus on Powassan Virus

The tick-borne pathogen Powassan virus is a rare cause of encephalitis in North America and the Russian Far East. The number of documented cases described since the discovery of Powassan virus in 1958 may be <150, although detection of cases has increased over the past decade. In the United States, the incidence of Powassan virus infections expanded from the estimated 1 case per year prior to 2005 to 10 cases per year during the subsequent decade. The increased detection rate may be associated with several factors, including enhanced surveillance, the availability of improved laboratory diagnostic methods, the expansion of the vector population, and, perhaps, altered human activities that lead to more exposure. Nonetheless, it remains unclear whether Powassan virus is indeed an emerging threat or if enzootic cycles in nature remain more-or-less stable with periodic fluctuations of host and vector population sizes. Despite the low disease incidence, the approximately 10% to 15% case fatality rate of neuroinvasive Powassan virus infection and the temporary or prolonged sequelae in >50% of survivors make Powassan virus a medical concern requiring the attention of public health authorities and clinicians. The medical importance of Powassan virus justifies more research on developing specific and effective treatments and prevention and control measures.

Stroke Associated With Recent Mycoplasma Pneumoniae Infection: A Systematic Review of Clinical Features and Presumed Pathophysiological Mechanisms

Introduction: An association between Mycoplasma pneumoniae (MP) infection and stroke has been described, especially in children. However, current knowledge on this rare potential cause of stroke is scant. The purpose of this systematic review of all published cases was to help better understand the relationships between recent MP infection and ischemic stroke on a clinical, radiological and pathophysiological perspective.

Material and Methods: A PubMed and Embase search was performed in September 2018 to identify all published cases of stroke occurring within 4 weeks after MP infection.

Results: Twenty-eight patients with ischemic stroke associated with MP infection were identified. Median age was 8 years (range: neonate to 57). The middle cerebral artery territory was involved in 25 (89%) patients. Fifteen (54%) patients had at least one arterial occlusion. Elevated D-dimer and/or fibrinogen was reported in 8 (29%) patients. Four patients had transient anticardiolipin IgM antibodies. Cerebrospinal fluid analysis showed pleocytosis in 7/20 (35%) patients (median: 19 leucocytes/μL, range: 10 to 63) and MP PCR was positive in 3/8 (38%) patients. The etiological work-up was considered inconclusive in 25 (89%) patients. Three (11%) patients died during follow-up, all of early respiratory deterioration. Neurological functional outcome was good in 22/27 (81%) patients.

Conclusion: The association between MP infection and ischemic stroke in children and young adults is rare. Underlying pathogenesis might include hypercoagulability and vasculitis. Most patients achieve a favorable recovery. Whether MP infection could be a long-term risk factor for stroke by promoting atherosclerosis is uncertain and deserves further investigation.

Powassan virus, a scoping review of the global evidence

BACKGROUND

Powassan virus (POWV), a flavivirus discovered in 1958, causes sporadic but severe cases of encephalitis in humans. Since 2007, the number of human Powassan cases diagnosed each year in the USA has steadily increased. This is in agreement with predictions that Powassan cases may increase in North America as a result of increased exposure to infected ticks. However, the increase may also reflect improved diagnostics and reporting among other factors.

METHODS

A scoping review was prioritized to identify and characterize the global literature on POWV. Following an a priori developed protocol, a comprehensive search strategy was implemented. Two reviewers screened titles and abstracts for relevant research and the identified full papers were used to characterize the POWV literature using a predetermined data characterization tool.

RESULTS

One hundred and seventy-eight articles were included. The majority of the studies were conducted in North America (88.2%) between 1958 and 2017. Both genotypes of POWV (Powassan lineage 1 and Deer Tick virus) were isolated or studied in vitro, in vectors, nonhuman hosts and human populations. To date, POWV has been reported in 147 humans in North America. The virus has also been isolated from five tick species, and several animals have tested positive for exposure to the virus. The relevant articles identified in this review cover the following eight topics: epidemiology (123 studies), pathogenesis (66), surveillance (33), virus characterization (22), POWV transmission (8), diagnostic test accuracy (8), treatment (4) and mitigation strategies (3).

CONCLUSION

The literature on POWV is relatively small compared with other vector-borne diseases, likely because POWV has not been prioritized due to the small number of severe sporadic human cases. With the projected impact of climate change on tick populations, increases in the number of human cases are expected. It is recommended that future research efforts focus on closing some of the important knowledge gaps identified in this scoping review.

Systematic review of rehabilitation intervention outcomes of adult and paediatric patients with infectious encephalitis

OBJECTIVE

Although a range of rehabilitation interventions have been applied to restore function after infectious encephalitis, there is a lack of literature summarising the benefits of these interventions. This systematic review aims to synthesise current scientific knowledge on outcome measures following rehabilitative interventions among children and adults with infectious encephalitis, with a specific focus on the influence of the age, sex, baseline status and intervention type.

SEARCH STRATEGY

Five scholarly databases (MEDLINE, Embase, PsycINFO, CINAHL and Cochrane Central Register of Controlled Trials), three sources of grey literature (Google, Google Scholar and Grey Matters) and reference lists of included publications were systematically searched. Literature published before 15 December 2017 and focused on patients with infectious encephalitis in any rehabilitation setting were included. Quality assessment was completed using the Downs and Black rating scale.

RESULTS

Of the 12 737 reference titles screened, 20 studies were included in this review. All of the studies had sample sizes of less than 25 patients and received a score of less than 15 out of 31 points on the Downs and Black rating scale. Findings showed a variety of interventions has been applied to alleviate sequelae from infectious encephalitis, including using cognitive therapy (nine studies), behavioural therapy (five studies), physical therapy (two studies) or two or more therapies (four studies). There was inconclusive evidence on the effect of sex, age and baseline functional abilities on outcomes. Due to clinical and methodological heterogeneity between studies, meta-analyses were not performed.

CONCLUSION

Evidence suggests the potential for a beneficial effect of rehabilitation interventions in patients with infectious encephalitis. Future research is required to identify all effect modifiers and to determine the effect of time in the natural course of recovery. An enhanced set of known effect modifiers will support the process of future evaluation of a client-centred rehabilitation intervention.

TRIAL REGISTRATION NUMBER

CRD42015029217.

Long-Term Outcomes and Risk Factors Associated With Acute Encephalitis in Children

BACKGROUND

Factors associated with poor outcomes of children with encephalitis are not well known. We sought to determine whether electroencephalography (EEG) findings, magnetic resonance imaging (MRI) abnormalities, or the presence of seizures at presentation were associated with poor outcomes.

METHODS

A retrospective review of patients aged 0 to 21 years who met criteria for a diagnosis of encephalitis admitted between 2000 and 2010 was conducted. Parents of eligible children were contacted and completed 2 questionnaires that assessed current physical and emotional quality of life and neurological deficits at least 1 year after discharge.

RESULTS

During the study period, we identified 142 patients with an International Classification of Diseases 9th Revision diagnosis of meningitis, meningoencephalitis, or encephalitis. Of these patients, 114 met criteria for a diagnosis of encephalitis, and 76 of these patients (representing 77 hospitalizations) had complete data available. Forty-nine (64%) patients were available for follow-up. Patients admitted to the intensive care unit were more likely to have abnormal EEG results (P = .001). The presence of seizures on admission was associated with ongoing seizure disorder at follow-up. One or more years after hospitalization, 78% of the patients had persistent symptoms, including 35% with seizures. Four (5%) of the patients died. Abnormal MRI findings and the number of abnormal findings on initial presentation were associated with lower quality-of-life scores.

CONCLUSIONS

Encephalitis leads to significant morbidity and death, and incomplete recovery is achieved in the majority of hospitalized patients. Abnormal EEG results were found more frequently in critically ill children, patients with abnormal MRI results had lower quality-of-life scores on follow-up, and the presence of seizures on admission was associated with ongoing seizure disorder and lower physical quality-of-life scores.

A Rare Cause of Childhood Cerebellitis-Influenza Infection: A Case Report and Systematic Review of Literature

Acute cerebellitis is a benign neurologic condition generally caused by viral or bacterial infections. Influenza associated cerebellitis is extremely rare; a 6-year-old boy with acute cerebellitis, who presented with fever, vomiting, weakness, febrile seizure, and acute cerebellar features, is discussed in this article.

Analysis of Risk Factors for Severe Acute Respiratory Infection and Pneumonia and among Adult Patients with Acute Respiratory Illness during 2011-2014 Influenza Seasons in Korea

Background

The World Health Organization recommends the surveillance of influenza-like illness (ILI) and severe acute respiratory infection (SARI) to respond effectively to both seasonal influenza epidemics and pandemics. In Korea, the “Hospital-based Influenza Morbidity and Mortality (HIMM)” surveillance system has been operated to monitor ILI and SARI occurrences.

Materials and Methods

A multi-center prospective observational study was conducted. Adult patients with acute respiratory infection (ARI) were enrolled during the 2011-12, 2012-2013, and 2013-2014 influenza seasons at the 10 university hospitals using the HIMM surveillance system. With respect to SARI and pneumonia development, risk profiles were analyzed in patients with ARI in Korea.

Results

A total of 5,459 cases were eligible for this analysis. Among 5,459 cases with ARI, 2,887 cases (52.9%) were identified that they had influenza infection. Among enrolled cases, 750 cases belonged to the SARI group, while 4,709 cases belonged to the non-SARI group. With respect to pneumonia development, 317 cases were accompanied by pneumonia, and 5,142 cases were not. Multivariate analyses revealed that the following factors were associated with an increased risk of SARI: Old age (≥65 years) (odds ratio [OR] 2.69, 95% confidence interval [CI] 2.2-3.32), chronic heart disease (CHD) (OR 2.24, 95% CI 1.68-2.98), cerebrovascular disease (CVD) (OR 1.49, 95% CI 1.05-2.10), chronic obstructive pulmonary disease (COPD) (OR 2.34, 95% CI 1.48-3.69), asthma (OR 2.33, 95% CI 1.62-3.36), chronic kidney disease (CKD) (OR 2.62, 95% CI 1.73-3.99), chronic liver disease (OR 1.71, 95% CI 1.04-2.81), and autoimmune diseases (OR 2.53, 1.57-4.08). Multivariate analyses revealed that the following factors were independent risk factors for pneumonia development: Old age (≥65 years) (OR 5.71, 95% CI 4.10-7.94), CHD (OR 1.54, 95% CI 1.07-2.22), COPD (OR 2.34, 95% CI 1.48-3.69), asthma (OR 2.33, 95% CI 1.62-3.36), CKD (OR 2.62, 95% CI 1.73-3.99), immunocompromised conditions (OR 3.12, 95% CI 1.47-6.62), and autoimmune diseases (OR 3.35, 95% CI 1.79-6.27). The risk of SARI and pneumonia was increased by the number of concurrent chronic medical conditions.

Conclusion

The risk of SARI and pneumonia development among adult patient with ARI was significantly increased by the presence or number of concurrent chronic medical conditions in Korea.

Mycoplasma pneumoniae-associated mild encephalitis/encephalopathy with a reversible splenial lesion: report of two pediatric cases and a comprehensive literature review

BACKGROUND

No literature review exists on Mycoplasma pneumoniae-associated mild encephalitis/encepharopathy with a reversible splenial lesion (MERS).

METHODS

M.pneumoniae-associated MERS cases were searched till August 2016 using PubMed/Google for English/other-language publications and Ichushi ( http://www.jamas.or.jp/ ) for Japanese-language publications. Inclusion criteria were children fulfilling definition for encephalitis, M.pneumoniae infection, and neuroimaging showing hyperintensity in the splenium of the corpus callosum (SCC) alone (type I) or SCC/other brain areas (type II).

RESULTS

We described two children with type I and II M.pneumoniae-associated MERS. Thirteen cases found by the search and our 2 cases were reviewed. Mean age, male/female ratio, duration of prodromal illness was 8.3 years, 1.5 and 3.5 days. The most common neurological symptom was drowsiness, followed by abnormal speech/behavior, ataxia, seizure, delirium, confusion, tremor, hallucination, irritability, muscle weakness, and facial nerve paralysis. Fever was the most common non-neurological symptom, followed by cough, headache, gastrointestinal symptoms, headache, lethargy and dizziness. Seizure and respiratory symptoms were less common. All were diagnosed for M.pneumoniae by serology. Cerebrospinal fluid (CSF) M.pneumoniae was undetectable by PCR in the 3 patients. Three patients were clarithromycin-resistant. Leukocytosis, positive C-reactive protein, hyponatremia, CSF pleocytosis and slow wave on electroencephalography frequently occurred. All except 2 were type I MERS. Neuroimaging abnormalities disappeared within 18 days in the majority of patients. All type I patients completely recovered within 19 days. Two type II patients developed neurological sequelae, which recovered 2 and 6 months after onset.

CONCLUSIONS

Prognosis of M.pneumoniae-associated MERS is excellent. Type II MERS may increase a risk of neurological sequelae.

Cytokine and Chemokine Expression in CSF May Differentiate Viral and Autoimmune NMDAR Encephalitis in Children

Childhood encephalitis is a potentially devastating condition with significant morbidity and mortality. Researchers currently lack biomarkers for differentiating infectious encephalitis from those with autoimmune causes which may delay adequate treatment. The authors studied the possibility of using cerebrospinal fluid cytokine and chemokine levels for this purpose. Children admitted to hospital care fulfilling criteria for encephalitis were prospectively included. Children who underwent lumbar puncture but were not classified as central nervous system infections served as controls. Cytokine and chemokine levels in the cerebrospinal fluid obtained upon initial presentation were analyzed using Luminex technology. In children with infectious encephalitis (n = 13), the cerebrospinal fluid displayed markedly elevated mean levels of IL6, IL7, and IL13 as compared to N-methyl-D-aspartate receptor (NMDAR) encephalitis (n = 4) and controls (n = 13). The expression of IL6 appeared to precede that of IL13. Analysis of selected cerebrospinal fluid cytokines may thus allow differential diagnosis of infectious and NMDAR encephalitis already at the initial lumbar puncture and enable immediate therapy.

Review of a Large Clinical Series: Outcome of Pediatric Status Epilepticus Admitted to Intensive Care

The authors determine the relationship between seizure duration, etiology, and outcome in a modern intensive care setting and assess the usefulness of computed tomography (CT) and the empiric use of antimicrobial therapy. The design was a retrospective chart review. The setting was a tertiary pediatric critical care unit. Patients included 161 consecutive admissions to the critical care unit at the Hospital for Sick Children, Toronto, with status epilepticus over a 3-year period. There were no interventions. The overall mortality was 5.6%. A further 11% experienced an adverse neurological outcome as determined on hospital discharge. Mean seizure duration was 1.5 ± 2.8 hours in those children with a normal outcome, 1.7 ± 1.2 hours in those survivors with an abnormal neurological outcome ( P > 0.05), and 6.8 ± 12 hours in those who died ( P < 0.05). The CT scan was abnormal in 41% of cases. New findings that directly affected immediate management decisions were found in 20% of CT scans. Both the duration and etiology of status epilepticus affect the outcome. CT scanning should be done without delay, once the patient is stable. Antiviral therapy should be started empirically now that encephalitis is far more common than bacterial meningitis in this group of patients. Studies are lacking that compare the efficacy of drugs available to treat status epilepticus. These studies need to be done, as the findings could affect the duration of status.

Rehabilitation interventions in children and adults with infectious encephalitis: a systematic review protocol

INTRODUCTION

Many encephalitis survivors can benefit from rehabilitation. However, there is currently no comprehensive review describing rehabilitation intervention outcomes among children and adults with infectious encephalitis. This is a protocol for a systematic review that will summarise the current literature on outcomes following rehabilitative interventions among children and adults with infectious encephalitis. With a sufficient sample size, a sex-stratified analysis of the findings will also be presented, as variability between male and female patients with neurological disorders, including encephalitis, regarding outcomes after rehabilitative interventions has been noted in the literature.

METHODS AND ANALYSIS

This review will systematically search MEDLINE, MEDLINE In-Process, EMBASE, Cochrane Central Register of Controlled Trials, and PsycINFO using the concepts 'encephalitis' and 'rehabilitation'. Grey literature will be searched using Grey Matters: A practical search tool for evidence-based medicine and the Google search engine. In addition, reference lists of eligible articles will be screened for any relevant studies. 2 reviewers will independently evaluate the retrieved studies based on predetermined eligibility criteria and perform a quality assessment on eligible studies.

ETHICS AND DISSEMINATION

The results from this review hold the potential to advance our knowledge on the value of rehabilitative interventions targeting children and adults with infectious encephalitis and any sex differences among patients with regard to rehabilitative intervention outcomes. The authors will publish findings from this review in a peer-reviewed scientific journal (electronic and in-print) and present the results at national and international conferences.

TRIAL REGISTRATION NUMBER

CRD42015029217.

Acute Childhood Encephalitis at 2 Tertiary Care Children's Hospitals in Israel: Etiology and Clinical Characteristics

OBJECTIVES

The clinical characteristics, pathogens, and outcome were analyzed to investigate the etiology of acute pediatric encephalitis in 2 tertiary pediatric medical centers in Israel.

METHODS

A retrospective study among children aged 1 month to 18 years hospitalized with the diagnosis of acute encephalitis between January 1999 and December 2009. Data on presenting symptoms, clinical findings, microbiological, virologic, electroencephalographic and neuroimaging studies, laboratory results, and hospital course were retrieved from the medical records and the computerized microbiology database.

RESULTS

Forty-four children were included. An etiologic agent was identified in 11 (25%): Mycoplasma pneumoniae (n = 2), enterovirus (n = 3), herpes simplex virus (HSV) (n = 1), Epstein-Barr virus (n = 2), human herpes virus 6 (n = 1), influenza virus type A (n = 1), and varicella zoster virus (n = 1). Presenting features included fever (90% of patients), seizures (39%), focal neurological signs (18%), and decreased consciousness (67%). Diagnostic findings included pleocytosis in the cerebrospinal fluid (76% of patients), electroencephalographic abnormalities (78%), and neuroimaging abnormalities (34%). All patients were treated with acyclovir until negative result for HSV polymerase chain reaction was received from cerebrospinal fluid, the child with HSV encephalitis was treated with intravenous acyclovir for 3 weeks. The outcomes at the time of discharge were: normal (66%), motor difficulties (14%), global neurological deficits (7%), visual defects (2%), and hearing impairment (2%) and no deaths.

CONCLUSIONS

The etiology of acute encephalitis remains unknown in the majority of cases. There was no correlation between adverse outcome and a specific etiologic agent. The high morbidity rate may suggest that current therapeutic modalities may not be sufficient.

A Population-Based Acute Meningitis and Encephalitis Syndromes Surveillance in Guangxi, China, May 2007-June 2012

Objectives

Acute meningitis and encephalitis (AME) are common diseases with the main pathogens being viruses and bacteria. As specific treatments are different, it is important to develop clinical prediction rules to distinguish aseptic from bacterial or fungal infection. In this study we evaluated the incidence rates, seasonal variety and the main etiologic agents of AME, and identified factors that could be used to predict the etiologic agents.

Methods

A population-based AME syndrome surveillance system was set up in Guigang City, Guangxi, involving 12 hospitals serving the study communities. All patients meeting the case definition were investigated. Blood and/or cerebrospinal fluid were tested for bacterial pathogens using culture or RT-PCR and serological tests for viruses using enzyme-linked immunosorbent assays. Laboratory testing variables were grouped using factor analysis. Multinomial logistic regression was used to predict the etiology of AME.

Results

From May 2007 to June 2012, the annual incidence rate of AME syndrome, and disease specifically caused by Japanese encephalitis (JE), other viruses, bacteria and fungi were 12.55, 0.58, 4.57, 0.45 and 0.14 per 100,000 population, respectively. The top three identified viral etiologic agents were enterovirus, mumps virus, and JE virus, and for bacteria/fungi were Streptococcus sp., Cryptococcus neoformans and Staphylococcus sp. The incidence of JE and other viruses affected younger populations and peaked from April to August. Alteration of consciousness and leukocytosis were more likely to be caused by JE, bacteria and fungi whereas CSF inflammation was associated with bacterial/fungal infection.

Conclusions

With limited predictive validity of symptoms and signs and routine laboratory tests, specific tests for JE virus, mumps virus and enteroviruses are required to evaluate the immunization impact and plan for further intervention. CSF bacterial culture cannot be omitted in guiding clinical decisions regarding patient treatment.

Autoimmune encephalitis and its relation to infection

Encephalitis, an inflammatory condition of the brain that results in substantial morbidity and mortality, has numerous causes. Over the past decade, it has become increasingly recognized that autoimmune conditions contribute significantly to the spectrum of encephalitis causes. Clinical suspicion and early diagnosis of autoimmune etiologies are of particular importance due to the need for early institution of immune suppressive therapies to improve outcome. Emerging clinical observations suggest that the most commonly recognized cause of antibody-mediated autoimmune encephalitis, anti-N-methyl-D-aspartate (NMDA) receptor encephalitis, may in some cases be triggered by herpes virus infection. Other conditions such as Rasmussen's encephalitis (RE) and febrile infection-related epilepsy syndrome (FIRES) have also been posited to be autoimmune conditions triggered by infectious agents. This review focuses on emerging concepts in central nervous system autoimmunity and addresses clinical and mechanistic findings linking autoimmune encephalitis and infections. Particular consideration will be given to anti-NMDA receptor encephalitis and its relation to herpes simplex encephalitis.

Acute pediatric encephalitis neuroimaging: single-institution series as part of the California encephalitis project

PURPOSE

Diagnosing pediatric encephalitis is challenging because of varied clinical presentation, nonspecific neuroimaging features, and rare confirmation of causality. We reviewed acute neuroimaging of children with clinically suspected encephalitis to identify findings that may correlate with etiology and length of stay.

METHODS

Imaging of 141 children with clinically suspected encephalitis as part of The California Encephalitis Project from 2005 to 2012 at a single institution was reviewed to compare the extent of neuroimaging abnormalities to patient age, gender, length of stay, and unknown, possible, or confirmed pathogen. Scan review was blinded and categorized by extent and distribution of abnormal findings.

RESULTS

Abnormal findings were evident on 23% (22/94) of computed tomography and 50% (67/134) of magnetic resonance imaging studies in the acute setting. Twenty children with normal admission computed tomography had abnormal findings on magnetic resonance imaging performed within 2 days. Length of stay was significantly longer among children with abnormal acute magnetic resonance imaging (P < 0.001) and correlated with increased complexity (Spearman rho = 0.4, P < 0.001) categorized as: no imaging abnormality, meningeal enhancement and/or focal nonenhancing lesion, multifocal lesions, confluent lesions, and lesions plus diffusion restriction, hemorrhage, or hydrocephalus. There was no correlation between neuroimaging findings and an identifiable pathogen (P = 0.8).

CONCLUSION

Abnormal magnetic resonance imaging findings are more common than abnormal computed tomography findings in pediatric encephalitis. Increasing complexity of magnetic resonance imaging findings correlated with disease severity as evidenced by longer length of stay, but were not specific for an identifiable pathogen using a standardized diagnostic encephalitis panel.

Infectious and autoantibody-associated encephalitis: clinical features and long-term outcome

BACKGROUND AND OBJECTIVES

Pediatric encephalitis has a wide range of etiologies, clinical presentations, and outcomes. This study seeks to classify and characterize infectious, immune-mediated/autoantibody-associated and unknown forms of encephalitis, including relative frequencies, clinical and radiologic phenotypes, and long-term outcome.

METHODS

By using consensus definitions and a retrospective single-center cohort of 164 Australian children, we performed clinical and radiologic phenotyping blinded to etiology and outcomes, and we tested archived acute sera for autoantibodies to N-methyl-D-aspartate receptor, voltage-gated potassium channel complex, and other neuronal antigens. Through telephone interviews, we defined outcomes by using the Liverpool Outcome Score (for encephalitis).

RESULTS

An infectious encephalitis occurred in 30%, infection-associated encephalopathy in 8%, immune-mediated/autoantibody-associated encephalitis in 34%, and unknown encephalitis in 28%. In descending order of frequency, the larger subgroups were acute disseminated encephalomyelitis (21%), enterovirus (12%), Mycoplasma pneumoniae (7%), N-methyl-D-aspartate receptor antibody (6%), herpes simplex virus (5%), and voltage-gated potassium channel complex antibody (4%). Movement disorders, psychiatric symptoms, agitation, speech dysfunction, cerebrospinal fluid oligoclonal bands, MRI limbic encephalitis, and clinical relapse were more common in patients with autoantibodies. An abnormal outcome occurred in 49% of patients after a median follow-up of 5.8 years. Herpes simplex virus and unknown forms had the worst outcomes. According to our multivariate analysis, an abnormal outcome was more common in patients with status epilepticus, magnetic resonance diffusion restriction, and ICU admission.

CONCLUSIONS

We have defined clinical and radiologic phenotypes of infectious and immune-mediated/autoantibody-associated encephalitis. In this resource-rich cohort, immune-mediated/autoantibody-associated etiologies are common, and the recognition and treatment of these entities should be a clinical priority.

Acute encephalitis in children: Progress and priorities from an Australasian perspective

Encephalitis is a complex neurological syndrome caused by inflammation of the brain that occurs with highest incidence in children. It is challenging to diagnose and manage due to the variety of aetiologies and non-specific clinical presentations. We discuss the recent progress in clinical case definitions; review recent, large, prospective epidemiological studies; and describe aetiologies. We emphasise infectious causes relevant to children in Australasia but also consider emerging immune-mediated syndromes responsive to immune therapies. We identify priorities for future research in children, given the potential for climate change and international travel to influence the emergence of infectious agents in our region.

Neurologic manifestations and complications of pandemic influenza A H1N1 in Malaysian children: what have we learnt from the ordeal?

INTRODUCTION

In 2009, pandemic influenza A H1N1 emerged in Mexico and subsequently spread worldwide. In Malaysia, there were more than a thousand of confirmed cases among children. The general clinical characteristics of these children have been well-published. However, the description of neurologic complications is scarce.

OBJECTIVE

This study aims to describe the characteristics of neurologic manifestations and complications in a national paediatric cohort with pandemic influenza A H1N1.

METHODS

During the pandemic, children (12 years or less) admitted for novel influenza A H1N1 in 68 Malaysian public hospitals, were prospectively enrolled into national database. The clinical, laboratory and neuro-imaging data for children with neurologic manifestations, hospitalized from 15th June 2009 till 30th November 2009, was reviewed.

RESULTS

Of 1244 children with influenza A H1N1 during the study period, 103 (8.3%) presented with influenza-related neurological manifestations. The mean age of our study cohort was 4.2 years (SD: 3.3 years). Sixty percent of them were males. Sixty-nine (66.9%) were diagnosed as febrile seizures, 16 (15.5%) as breakthrough seizures with underlying epilepsy, 14 (13.6%) as influenza-associated encephalopathy or encephalitis (IAE) and 4 (3.9%) as acute necrotizing encephalopathy of childhood (ANEC). All 4 available CSF specimens were negative for influenza viral PCR. Among 14 children with brain-imaging done, 9 were abnormal (2: cerebral oedema, 4: ANEC and 3: other findings). There were four deaths and three cases with permanent neurological sequelae.

CONCLUSION

About one-tenth of children with pandemic influenza A H1N1 presented with neurologic complications. The most common diagnosis was febrile seizures. One-fifth of those children with neurologic presentation had IAE or ANEC, which carried higher mortality and morbidity. This large national study provides us useful data to better manage children with neurologic complications in the future pandemic influenza outbreaks.

Outcome of children with acute encephalitis and refractory status epilepticus

Acute encephalitis in children is a life-threatening neurological emergency. However, little is reported about the outcome of this devastating illness in the United States. The authors retrospectively reviewed the charts of patients admitted to a regional pediatric intensive care unit with the diagnosis of acute encephalitis between 2006 and 2011. In 41 cases that met the inclusion criteria, the most common presenting symptoms were fever (65.9%), altered mental status (61%), and seizures (58.5%). Eight patients (19.5%) who presented with refractory status epilepticus had a longer median length of stay in the pediatric intensive care unit (46 vs. 4 days; P < .0001) and a significant worsening of Pediatric Cerebral Performance Category score on discharge by 2 or more points (odds ratio 20.38; 95% confidence interval, 2.89-143.52). All children survived to hospital discharge. In conclusion, children with acute encephalitis who present with refractory status epilepticus have a worse neurological outcome and a longer stay in the pediatric intensive care unit.

Central nervous system complications of varicella-zoster virus

OBJECTIVE

To describe the spectrum of central nervous system complications of varicella-zoster virus (VZV) in children admitted to The Hospital for Sick Children between January 1999 and December 2012.

STUDY DESIGN

Children aged 1 month to 18 years (n = 84) admitted with neurologic manifestations associated with a characteristic VZV rash or a confirmatory laboratory test (positive lesion scraping or cerebrospinal fluid polymerase chain reaction) were included in the study. Acute neurologic complications were included if they occurred within 4 weeks of VZV infection. Stroke was considered related to VZV if it occurred within 6 months of VZV infection, the neuroimaging was characteristic, and other causes were excluded.

RESULTS

Clinical syndromes included acute cerebellar ataxia (n = 26), encephalitis (n = 17), isolated seizures (n = 16), stroke (n = 10), meningitis (n = 10), Guillain-Barré syndrome (n = 2), acute disseminated encephalomyelitis (n = 2), and Ramsay Hunt syndrome (n = 1). In those with acute complications (nonstroke), neurologic symptoms occurred a median of 5 days after rash onset (range -6 to +16). The time between rash onset and stroke ranged from 2 weeks to 26 weeks (median 16.0 weeks). Three children with encephalitis died. Residual neurologic sequelae at one year occurred in 9 of 39 (23%) of children with follow-up data. Only 4 children were reported to have received the varicella vaccine.

CONCLUSION

Neurologic complications of VZV infection continue to occur despite the availability of an effective vaccine. Neurologic symptom onset can predate the appearance of the VZV exanthem and in rare cases may occur in the absence of an exanthem.

Diagnosis and management of acute encephalitis: A practical approach

Encephalitis results in considerable morbidity and mortality in the United States and worldwide. Neurologists are often consulted or directly care for patients with encephalitis admitted to the hospital and must be able to discriminate between encephalitis and the many conditions that mimic it. Moreover, neurologists must be familiar with the myriad causes of encephalitis in order to develop a practical approach to diagnostic testing and treatment. An understanding of recent advances in management, particularly with respect to autoimmune etiologies and critical care approaches, is equally important. Here, we summarize a general approach to the care of adult patients with encephalitis.

Delayed primary HHV-7 infection and neurologic disease

BACKGROUND

Primary human herpesvirus 7 (HHV-7) infection occurs almost universally during the first 5 years of life and is rarely accompanied by central nervous system (CNS) symptoms such as febrile seizures. The present retrospective study investigated the role of primary HHV-7 infection in CNS disease in children, including adolescents.

METHODS

The study included all children who had neurologic disease aged younger than 18 years seen at the Hospital for Sick Children, Toronto, Canada, between April 1, 1998 and December 31, 2011, whose cerebrospinal fluid (CSF) was found by polymerase chain reaction to contain HHV-7 DNA. Where sera were available, HHV-7 IgG antibody titers and avidity were measured to differentiate primary from past infection.

RESULTS

HHV-7 DNA was detected in the CSF of 57 (1.9%) of the 2972 children tested. In 3 adolescents primary HHV-7 infection (low avidity IgG) was confirmed as the cause of neurologic disease, 2 who had encephalitis and 1 who had Guillain-Barré syndrome. Eighteen children had possible HHV-7 disease (no alternative cause identified and indeterminate antibody result or serum not available), 7 encephalitis, 8 meningitis, and 3 demyelinating disorders. HHV-7 disease was excluded in 36 children on the basis of past infection (high IgG avidity) and/or an alternative cause.

CONCLUSIONS

Primary HHV-7 infection delayed into adolescence can cause serious neurologic disease. HHV-7 DNA in CSF alone is insufficient to prove an etiologic association. Combining CSF polymerase chain reaction with serology is essential to prove primary infection when investigating HHV-7 CNS disease.

Acute disseminated encephalomyelitis following meningoencephalitis: case report and literature review

Meningoencephalitis and acute disseminated encephalomyelitis (ADEM) are both neurological disease processes, but there have been few cases of meningoencephalitis progressing to ADEM in the pediatric population. A case of a 4-year-old girl with an initial diagnosis of meningoencephalitis is presented here, whose initial presentation was manifested by prolonged fever, gray matter signal abnormality on brain magnetic resonance imaging, cerebrospinal fluid pleocytosis, and a markedly irritable mental status. As her neurological examination changed with focal abnormalities, a repeat magnetic resonance imaging demonstrated new areas of both gray and white matter signal abnormality, consistent with ADEM. Her symptoms and imaging findings completely resolved with a course of methylprednisolone. Based on the literature and this current case, it is our recommendation to consider ADEM as a diagnosis if meningoencephalitis is not improving.