A 12-year prospective study of childhood herpes simplex encephalitis: is there a broader spectrum of disease?

Predictors of Neurological Disability at Hospital Discharge for Acyclovir-treated Pediatric Herpes Simplex Virus Encephalitis

BACKGROUND

Herpes simplex virus encephalitis (HSE) is a rare but serious neurological infection that causes neurological dysfunction. Research is lacking on the clinical predictors of neurological outcomes and the optimal duration of therapy for pediatric HSE patients. In this study of pediatric HSE patients, we identified factors predicting neurological disability at hospital discharge and examined associations of acyclovir therapy duration with neurological outcomes.

METHODS

This was a retrospective cohort study on 37 children diagnosed with HSE confirmed by polymerase chain reaction at age 1 month to 16 years from 2015 to 2021 in Ho Chi Minh City's Children's Hospital No. 2, Vietnam. For the acyclovir duration analysis, we examined 22 children with negative polymerase chain reaction on day 14 of treatment. Poisson regression was used to obtain the risk ratio and 95% confidence interval.

RESULTS

The study population consisted of 73% males, with a median age of 14 months (interquartile range: 9-35). Coma at acyclovir treatment, hypotension and the need for mechanical ventilation ≥48 hours significantly predicted neurological disability in the bivariate analysis. There were no significant associations between acyclovir duration (14 vs. 21 days) and neurological outcomes, adjusting for age at diagnosis and pediatric Glasgow Coma Scale score at acyclovir initiation.

CONCLUSION

We identified significant predictors of neurological disability unaffected by postacyclovir treatment factors. Among patients with negative HSE polymerase chain reaction on day 14, 14 days of acyclovir treatment may be as effective as 21 days. Additional studies on the effects of acyclovir duration are needed.

Neuroinfectious Diseases in Children: Pathophysiology, Outcomes, and Global Challenges

Pathogens with affinity for the central nervous system (CNS) in children are diverse in their mechanisms of infecting and attacking the brain. Infections can reach the CNS via hematogenous routes, transneurally thereby avoiding the blood-brain barrier, and across mucosal or skin surfaces. Once transmission occurs, pathogens can wreak havoc both by direct action on host cells and via an intricate interplay between the protective and pathologic actions of the host's immune system. Pathogen prevalence varies depending on region, and susceptibility differs based on epidemiologic factors such as age, immune status, and genetics. In addition, some infectious diseases are monophasic, whereas others may lie dormant for years, thereby causing a dynamic effect on outcomes. Outcomes in survivors are highly variable for each particular pathogen and depend on the vaccination and immune status of the patient as well as the speed by which the patient receives evidence-based treatments. Given pathogens cause communicable diseases that can cause morbidity and mortality on a population level when spread, the burden is often the greatest and the outcomes the worst in low-resource settings. Here we will focus on the most common infections with a propensity to affect a child's brain, the pathologic mechanisms by which they do so, and what is known about the developmental outcomes in children who are affected by these infections.

State of the Art: Acute Encephalitis

Encephalitis is a devastating neurologic disease often complicated by prolonged neurologic deficits. Best practices for the management of adult patients include universal testing for a core group of etiologies, including herpes simplex virus (HSV)-1, varicella zoster virus (VZV), enteroviruses, West Nile virus, and anti-N-methyl-D-aspartate receptor (anti-NMDAR) antibody encephalitis. Empiric acyclovir therapy should be started at presentation and in selected cases continued until a second HSV-1 polymerase chain reaction test is negative. Acyclovir dose can be increased for VZV encephalitis. Supportive care is necessary for other viral etiologies. Patients in whom no cause for encephalitis is identified represent a particular challenge. Management includes repeat brain magnetic resonance imaging, imaging for occult malignancy, and empiric immunomodulatory treatment for autoimmune conditions. Next-generation sequencing (NGS) or brain biopsy should be considered. The rapid pace of discovery regarding autoimmune encephalitis and the development of advanced molecular tests such as NGS have improved diagnosis and outcomes. Research priorities include development of novel therapeutics.

Characteristics of neonatal herpes simplex central nervous system disease in Australia (1997-2020)

BACKGROUND

Neonatal herpes simplex virus (HSV) central nervous system (CNS) disease can occur in isolation or as part of disseminated infection. We sought to describe neonatal HSV CNS disease in Australia over 24 years.

METHODS

Neonates (≤28 days) with confirmed HSV infection, reported prospectively to the Australian Paediatric Surveillance Unit (1997-2020), were evaluated for HSV CNS disease (laboratory confirmation with clinical evidence of encephalitis, e.g., lethargy, seizures, focal signs; and/or abnormalities on neuroimaging or electroencephalogram), and compared with neonates without CNS disease. CNS-restricted disease was compared with CNS-disseminated disease.

FINDINGS

Of 195 neonates with HSV disease; 87 (45%) had CNS disease (1.29 cases/100,000 live births per year, 95% CI: 1·04-1·59). Neonates with CNS disease were significantly more likely to be male than neonates without CNS disease (60% versus 39%, OR=2·32, 95% CI 1·29-4·18). Of the neonates with CNS disease, those with CNS-restricted disease (52/87, 60%) presented later than neonates with CNS-disseminated disease (35/87, 40%), (mean 12 versus 6 days). Twenty (23%) neonates with CNS disease died, the majority with CNS-disseminated disease (n = 19). Most neonates received aciclovir therapy (94·3%), however five neonates with unrecognised CNS disseminated disease (diagnosed at autopsy) had not been treated. Survivors of CNS disease were significantly more likely to have adverse neurological sequelae, compared with those without CNS disease (30% versus 4%, OR: 9·60, 95% CI: 2·6-35·0).

INTERPRETATION

Male neonates have a higher burden of HSV CNS disease. Despite the use of antiviral agents, morbidity following neonatal HSV CNS disease remains high. Evaluation of adjunctive therapies to improve outcomes is needed.

Global expression and functional analysis of human piRNAs during HSV-1 infection

Piwi-interacting RNAs (piRNAs) are a class of non-coding RNAs that play a key role in spermatogenesis. However, little is known about their expression characterization and role in somatic cells infected with herpes simplex virus type 1 (HSV-1). In this study, we systematically investigated the cellular piRNA expression profiles of HSV-1-infected human lung fibroblasts. Compared with the control group, 69 differentially expressed piRNAs were identified in the infection group, among which 52 were up-regulated and 17 were down-regulated. The changes in the expression of 8 piRNAs were further verified by RT-qPCR with a similar expression trend. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the target genes of piRNAs were mainly involved in antiviral immunity and various human disease-related signaling pathways. Furthermore, we tested the effects of four up-regulated piRNAs on viral replication by transfecting piRNA mimics. The results showed that the virus titers of the group transfected with piRNA-hsa-28,382 (alias piR-36,233) mimic decreased significantly, and that of the group transfected piRNA-hsa-28,190 (alias piR-36,041) mimic significantly increased. Overall, our results revealed the expression characteristics of piRNAs in HSV-1-infected cells. We also screened two piRNAs that potentially regulate HSV-1 replication. These results may promote a better understanding of the regulatory mechanism of pathophysiological changes induced by HSV-1 infection.

Neurological sequelae after encephalitis associated with herpes simplex virus in children: systematic review and meta-analysis

BACKGROUND

Encephalitis is an inflammation of the cerebral parenchyma manifested by acute symptoms such as fever, headaches, and other neurological disorders. Its etiology is mostly viral, with herpes simplex virus being a frequent etiological agent in children. The development of neurological sequelae is a serious outcome associated with this infection.

OBJECTIVE

To assess the general prevalence and types of neurological sequelae in children after a case of acute viral encephalitis caused by HSV.

METHODS

This systematic review and meta-analysis was developed following the PRISMA guidelines. The literature search was carried out in the MEDLINE, Embase, SciELO, LILACS, Cochrane, CINAHL, PsycINFO, and Web of Science databases. Studies were included of children with confirmed HSV infection and that presented a description of neurological sequelae associated with that infection. For the meta-analysis of general prevalence and of the types of neurological sequelae a random effects model was used.

RESULTS

Of the 2827 articles chosen in the initial search, nine studies were included in the systematic review and meta-analysis. The general prevalence of neurological sequelae was 50.7% (95% CI 39.2-62.2). The most frequent sequelae were related to mental disability, with a 42.1% prevalence (95% CI 30-55.2); on the other hand, the least frequent sequelae were those related with visual impairment, with a 5.9% prevalence (95% CI 2.2-14.6). The included studies presented regular quality and substantial heterogeneity.

CONCLUSION

Even with antiviral therapy, half of patients will develop some type of disability.

Herpes simplex virus type 2 encephalitis in a child with chronic progressive white matter lesions: A case report

RATIONALE

This case is a rare manifestation of central nervous system infection of Herpes simplex virus (HSV)-2. Due to few studies in China, it provides a pathological basis for further diagnosis and treatment of HSV-2.

PATIENT CONCERNS

We describe a patient with HSV-2 virus infection who was diagnosed with HSV-2 encephalitis in a Chinese patient.

DIAGNOSIS

Based on brain biopsy and pathological findings, the patient was diagnosed with HSV-2 encephalitis.

INTERVENTIONS

Hormone and antiviral therapy were given.

OUTCOME

The patient eventually died.

LESSONS

The diagnosis and differential diagnosis of the disease is very difficult. Its differential diagnosis include cerebrovascular disease, bacteria or fungi and other viral infection of the brain.

Epilepsy diagnosis based on one unprovoked seizure and ≥60% risk. A systematic review of the etiologies

BACKGROUND

According to the International League Against Epilepsy (ILAE) criteria, epilepsy can be diagnosed after one unprovoked (or reflex) seizure when there is a ≥60% of seizure recurrence in the next decade. The application of this diagnostic criterion, however, is challenging because the risk of recurrence based on different etiologies is not easily retrievable from the literature.

OBJECTIVE

To assess etiologies that permit a diagnosis of epilepsy after a single unprovoked seizure.

METHODS

We conducted a systematic review of the literature search using PubMed, Scopus, and Cochrane library from January 1950 to December 2020 with the keywords: recurrence, risk of recurrence, absolute risk, risk ratio, risk, seizures, epilepsy, structural, infectious, metabolic, immune, and genetic. We included articles that reported estimates of risks of a subsequent unprovoked seizure. Etiologies were categorized according to the ILAE epilepsy classification. The quality of the evidence was evaluated with PRISMA. Descriptive statistics were used.

RESULTS

A total of 25,044 articles resulted from searching three databases. After authors removed duplicates, 18,911 articles remained. We screened by title and abstract, 40 articles were reviewed and finally, two articles were included. The mean follow-up was 8 years and the mean for a risk to present a subsequent unprovoked seizure was 66.6% and included structural etiologies as stroke, traumatic brain injury, cavernous malformation, arteriovenous malformation, and neuroinfections (unspecified agents). Study quality characteristics are classified with low strength of evidence and moderate-quality cohort.

CONCLUSIONS

We found that stroke, traumatic brain injury, cavernous or arteriovenous malformations, and unspecified CNS infections can meet the epilepsy diagnosis after one unprovoked seizure based on low strength of evidence and moderate quality of cohorts.

Atypical Presentation of Herpes Simplex Virus 1 Encephalitis in Pediatric Age

BACKGROUND: The annual incidence of herpes simplex encephalitis (HSE) is 1:250–500 thousand in developed countries, which makes it the most common viral cause of encephalitis. Encephalitis caused by HSV-1 probably accounts for most of the cases in the Herpesviridae family and typically affects older children. CASE REPORT: An atypical presentation of pediatric herpetic encephalitis is reported. The child presented with recurrent seizures that were initially unresponsive to several anticonvulsant drugs. EEG and MRI of the brain were not effective for diagnosis. PCR analysis of the cerebrospinal fluid indicated positivity for HSV DNA and was crucial for the diagnosis as a highly sensitive and specific test. CONCLUSION: Based on the clinical presentation of the child, viral encephalitis was deemed to be the most likely aetiological condition.

Atypical imaging presentation of herpes simplex virus encephalitis in paediatric immunocompromised oncology patients

INTRODUCTION

We aim to assess the imaging manifestations of brain involvement in paediatric immunocompromised patients with haematological malignancies on chemotherapy presenting with encephalitis and positive HSV CSF PCR. We also aim to determine whether our findings are similar or different to those described in literature for paediatric patients in general.

METHODS

A retrospective study was performed in paediatric ALL/lymphoma patients on chemotherapy, and cases with positive CSF HSV-PCR with at least one head MRI scan were included. On imaging, location(typical/atypical), post-contrast enhancement and haemorrhage/diffusivity/gliosis were evaluated.

RESULT

A total of 28 scans were included in study from 16 patients fulfilling inclusion criteria, 12 (75%) HSV-1 and 4 (25%) HSV-2. Of the 16 initial scans (CT n = 10, MRI n = 6), 11 were normal (CT = 7, MRI = 4). Fourteen patients had follow-up MRI, of which two had normal scans. On the abnormal initial scan (5/16), only 20% had typical medial temporal/inferomedial frontal/cingulate involvement. Most had frontal (80%), parietal (60%) and non-medial temporal (40%) lesions. Abnormal diffusivity/haemorrhage was absent in all, and postcontrast enhancement was seen in 20%. On follow-up, more patients (33%) had typical medial temporal/inferomedial frontal/cingulate involvement. Widespread atypical site involvement of frontoparietal (75%), thalamus (58%), non-medial temporal (50%), occipital/basal ganglia (33%) and cerebellum (8%) was noted. Most lesions were cortical (91%)/subcortical (75%) with few periventricular lesions (58%). Few showed abnormal diffusivity (16%), post-contrast parenchymal enhancement/haemorrhage (8%), post-contrast meningeal enhancement (25%) and gliosis (16%).

CONCLUSION

Immunocompromised paediatric patients with haematological malignancies have widespread atypical brain involvement in herpes simplex encephalitis with lack of diffusion restriction and post-contrast enhancement, likely due to haematogenous spread of HSV across the blood-brain barrier, lack of cellular immunity and limited inflammatory cytokine response.

Viral and Prion Infections Associated with Central Nervous System Syndromes in Brazil

Virus-induced infections of the central nervous system (CNS) are among the most serious problems in public health and can be associated with high rates of morbidity and mortality, mainly in low- and middle-income countries, where these manifestations have been neglected. Typically, herpes simplex virus 1 and 2, varicella-zoster, and enterovirus are responsible for a high number of cases in immunocompetent hosts, whereas other herpesviruses (for example, cytomegalovirus) are the most common in immunocompromised individuals. Arboviruses have also been associated with outbreaks with a high burden of neurological disorders, such as the Zika virus epidemic in Brazil. There is a current lack of understanding in Brazil about the most common viruses involved in CNS infections. In this review, we briefly summarize the most recent studies and findings associated with the CNS, in addition to epidemiological data that provide extensive information on the circulation and diversity of the most common neuro-invasive viruses in Brazil. We also highlight important aspects of the prion-associated diseases. This review provides readers with better knowledge of virus-associated CNS infections. A deeper understanding of these infections will support the improvement of the current surveillance strategies to allow the timely monitoring of the emergence/re-emergence of neurotropic viruses.

Infectious Agents and Stroke: A Systematic Review

Introduction:

A major cause of injury and the second cause of death worldwide is stroke. Among several infectious agents considered as the risk factor of stroke, some pathogens demonstrated stronger robust associations with stroke. Proposing an accurate correlation between infectious microorganisms and stroke provides valuable information for early intervention and control of the infections.

Methods:

In this study, we searched the literature using the Web of Science, PMC/Medline via PubMed, and Scopus databases up to July 2018 without time and language restrictions. After quality assessment, 16 articles were included in the study. The whole data extraction process was independently conducted by two reviewers.

Results:

Based on the results of the studies, viruses, such as Hepatitis C virus (HCV), Hepatitis B virus (HBV), Human Immunodeficiency Virus (HIV), Herpes Simplex Virus Type-1, 2 (HSV-1, 2), Varicella-Zoster Virus (VZV or Chickenpox), and West Nile virus (WNV) seem to be common causes of ischemic stroke. Moreover, the association of other microbial categories, such as Streptococcus mutans (in bacteria), Toxocara spp. and Toxoplasma gondii (in parasites), and Rhizopus sp. (in fungi) with stroke was reported.

Conclusion:

Considering the adverse role of the above-mentioned microorganisms, it is necessary to implement some preventive measures for stroke treatment.

Seizures in the neonate: A review of etiologies and outcomes

Neonatal seizures occur in their majority in close temporal relation to an acute brain injury or systemic insult, and are accordingly defined as acute symptomatic or provoked seizures. However less frequently, unprovoked seizures may also present in the neonatal period as secondary to structural brain abnormalities, thus corresponding to structural epilepsies, or to genetic conditions, thus corresponding to genetic epilepsies. Unprovoked neonatal seizures should be thus considered as the clinical manifestation of early onset structural or genetic epilepsies that often have the characteristics of early onset epileptic encephalopathies. In this review, we address the conundrum of neonatal seizures including acute symptomatic, remote symptomatic, provoked, and unprovoked seizures, evolving to post-neonatal epilepsies, and neonatal onset epilepsies. The different clinical scenarios involving neonatal seizures, each with their distinct post-neonatal evolution are presented. The structural and functional impact of neonatal seizures on brain development and the concept of secondary epileptogenesis, with or without a following latent period after the acute seizures, are addressed. Finally, we underline the need for an early differential diagnosis between an acute symptomatic seizure and an unprovoked seizure, since it is associated with fundamental differences in clinical evolution. These are crucial aspects for neonatal management, counselling and prognostication. In view of the above aspects, we provide an outlook on future strategies and potential lines of research in this field.

Management and results of epilepsy surgery associated with acyclovir prophylaxis in four pediatric patients with drug-resistant epilepsy due to herpetic encephalitis and review of the literature

PURPOSE

Herpes simplex virus encephalitis (HSE) is the most common cause of sporadic viral encephalitis in children and is responsible for epilepsy in approximately half of patients. In addition to medical treatment, epilepsy surgery may be offered to drug-resistant patients but carries a high risk of relapse of herpetic encephalitis. We are reporting our series of patients operated on between 2000 and 2019 with the systematic administration of acyclovir (ACV).

RESULTS

Four pediatric patients aged 4.5-12.8 years with drug-resistant epilepsy post-HSE underwent a tailored focal resection following invasive recordings (three patients) and a complete callosotomy (one patient). The total number of the surgical procedures for the four patients was eight, and a systematic administration of ACV as a prophylactic treatment of herpetic encephalitis relapse was done at each step. No patients had a relapse and the ACV was well-tolerated in all the cases. Following surgery two patients are seizure free, the patient who underwent callosotomy is Engel 3 and the fourth patient, in whom a large epileptic zone has contraindicated a second surgery, is Engel 4.

CONCLUSIONS

Our series demonstrated the dramatic efficacy of systematic ACV prophylaxis during all cranial surgeries. Moreover, our results on epilepsy, together with those of the literature, encourage more consideration regarding epilepsy surgery in this specific etiology. All types of surgical procedures (curative or palliative) can be offered to the patients, but in the case of focal surgery, due to the poor anatomical limits, invasive recordings are highly recommended.

Seizures and epilepsy secondary to viral infection in the central nervous system

Viral infection in the central nervous system (CNS) is a common cause of seizures and epilepsy. Acute symptomatic seizures can occur in the context of almost all types of acute CNS viral infection. However, late unprovoked seizures and epilepsy may not be frequent after viral infection of the CNS. The incidence of seizures and epilepsy after CNS viral infection is mainly dependent on the brain region of infection. It remains to be determined whether treatment of CNS viral infection using antiepileptic drugs (AEDs) can prevent seizures and subsequent epilepsy in patients, particularly with regard to the timing, drug choice and dosage, and duration of AEDs. The postoperative outcome of seizures in patients with intractable epilepsy caused by viral encephalitis primarily depends on the epileptogenic zone. In addition, neuroinflammation is known to be widely involved in the generation of seizures during CNS viral infection, and the effects of anti-inflammatory therapies in preventing seizures and epilepsy secondary to CNS viral infection require further studies. In this review, we discuss the incidence, mechanisms, clinical management and prognosis of seizures and epilepsy secondary to CNS viral infection, and summarize common CNS viral infections that cause seizures and epilepsy.

Patterns of Herpes Simplex Virus 1 Infection in Neural Progenitor Cells

This study employed human induced pluripotent stem cells (hiPSCs) to model the interaction of HSV-1 with NPCs, which reside in the neurogenic niches of the CNS and play a fundamental role in adult neurogenesis. Herein, we provide evidence that in NPCs infected at an MOI as low as 0.001, HSV-1 can establish a latent state, suggesting that (i) a variant of classical HSV-1 latency can be established during earlier stages of neuronal differentiation and (ii) neurogenic niches in the brain may constitute additional sites of viral reactivation. Lytic HSV-1 infections impaired NPC migration, which represents a critical step in neurogenesis. A difference in susceptibility to HSV-1 infection between two-dimensional (2D) and three-dimensional (3D) NPC cultures was observed, highlighting the potential value of 3D cultures for modeling host-pathogen interactions. Together, our results are relevant in light of observations relating HSV-1 infection to postencephalitic cognitive dysfunction.

Herpes simplex virus 1 (HSV-1) can induce damage in brain regions that include the hippocampus and associated limbic structures. These neurogenic niches are important because they are associated with memory formation and are highly enriched with neural progenitor cells (NPCs). The susceptibility and fate of HSV-1-infected NPCs are largely unexplored. We differentiated human induced pluripotent stem cells (hiPSCs) into NPCs to generate two-dimensional (2D) and three-dimensional (3D) culture models to examine the interaction of HSV-1 with NPCs. Here, we show that (i) NPCs can be efficiently infected by HSV-1, but infection does not result in cell death of most NPCs, even at high multiplicities of infection (MOIs); (ii) limited HSV-1 replication and gene expression can be detected in the infected NPCs; (iii) a viral silencing mechanism is established in NPCs exposed to the antivirals (E)-5-(2-bromovinyl)-2′-deoxyuridine (5BVdU) and alpha interferon (IFN-α) and when the antivirals are removed, spontaneous reactivation can occur at low frequency; (iv) HSV-1 impairs the ability of NPCs to migrate in a dose-dependent fashion in the presence of 5BVdU plus IFN-α; and (v) 3D cultures of NPCs are less susceptible to HSV-1 infection than 2D cultures. These results suggest that NPC pools could be sites of HSV-1 reactivation in the central nervous system (CNS). Finally, our results highlight the potential value of hiPSC-derived 3D cultures to model HSV-1–NPC interaction.

IMPORTANCE This study employed human induced pluripotent stem cells (hiPSCs) to model the interaction of HSV-1 with NPCs, which reside in the neurogenic niches of the CNS and play a fundamental role in adult neurogenesis. Herein, we provide evidence that in NPCs infected at an MOI as low as 0.001, HSV-1 can establish a latent state, suggesting that (i) a variant of classical HSV-1 latency can be established during earlier stages of neuronal differentiation and (ii) neurogenic niches in the brain may constitute additional sites of viral reactivation. Lytic HSV-1 infections impaired NPC migration, which represents a critical step in neurogenesis. A difference in susceptibility to HSV-1 infection between two-dimensional (2D) and three-dimensional (3D) NPC cultures was observed, highlighting the potential value of 3D cultures for modeling host-pathogen interactions. Together, our results are relevant in light of observations relating HSV-1 infection to postencephalitic cognitive dysfunction.

Epidemiology and Etiology of Severe Childhood Encephalitis in The Netherlands

BACKGROUND

Limited data are available on childhood encephalitis. Our study aimed to increase insight on clinical presentation, etiology, and clinical outcome of children with severe encephalitis in the Netherlands.

METHODS

We identified patients through the Dutch Pediatric Intensive Care Evaluation database and included children diagnosed with encephalitis <18 years of age admitted to 1 of the 8 pediatric intensive care units (PICU) in the Netherlands between January 2003 and December 2013. We analyzed demographic characteristics, clinical symptoms, neurologic imaging, etiology, treatment and mortality.

RESULTS

We included 121 children with a median age of 4.6 years (IQR 1.3-9.8). The most frequently described clinical features were headache (82.1%), decreased consciousness (79.8%) and seizures (69.8%). In 44.6% of the children, no causative agent was identified. Viral- and immune-mediated encephalitis were diagnosed in 33.1% and 10.7% of the patients. A herpes simplex virus infection (13.2%) was mainly seen in children <5 years of age, median age, 1.73 years (IQR 0.77-5.01), while immune-mediated encephalitis mostly affected older children, median age of 10.4 years (IQR, 3.72-14.18). An age of ≥ 5 years at initial presentation was associated with a lower mortality (OR 0.2 [CI 0.08-0.78]). The detection of a bacterial (OR 9.4 [CI 2.18-40.46]) or viral (OR 3.7 [CI 1.16-11.73]) pathogen was associated with a higher mortality.

CONCLUSIONS

In almost half of the Dutch children presenting with severe encephalitis, a causative pathogen could not be identified, underlining the need for enhancement of microbiologic diagnostics. The detection of a bacterial or viral pathogen was associated with a higher mortality.

The prevalence, characteristics and outcome of seizure in tuberculous meningitis

Seizures are a common finding in patients with tuberculous meningitis (TBM), and associate with four times increased risk of death and neurological disability, especially in children. It has been reported that brain inflammation, diffuse neuronal injury, and reactive gliosis may all contribute to the pathogenesis of seizures in TBM. Early seizure onset may be associated with meningeal irritation and cerebral oedema; while, the late seizures are usually due to infarction, hydrocephalus, tuberculoma and paradoxical response. Moreover, recurrent uncontrolled seizures can evolve to status epileptics resulting in an increased risk of chronic epilepsy and poor prognosis. Therefore, this review aimed to assess the frequency of seizures in patients with TBM, and discuss the etiologies, mechanisms, and characteristics of seizures in TBM. Besides, we have searched the literature to identify the prognostic factors for chronic epilepsy after TBM.

Clinical features and surgical treatment of epilepsy after viral encephalitis

Encephalitis is an acute inflammatory process of the brain parenchyma, which is often caused by viral infection. It is an vital cause of acute symptomatic seizures and subsequent epilepsy. The incidence of unprovoked and recurrent seizures after previous infections of the central nervous system is high and accounts for 1%~5% of the cases of epilepsy. Viral encephalitis (VE) is directly caused by viral infection. The occurrence of seizures after VE is associated with poor prognosis. In survivors of VE, among other neurological sequelae, the risk of developing epilepsy is increased 10-fold. The risk of severe neurological sequelae after VE is particularly high in very young children. Studies on seizure occurrence, possible underlying mechanisms, clinical characteristics, and clinical treatment (especially surgical treatment) of VE have yielded only limited detailed data. We reviewed the most recent literature on the clinical features and surgical treatment of post-VE epilepsy.

Understanding parental perspectives on outcomes following paediatric encephalitis: A qualitative study

Background

Encephalitis, characterised as inflammation of the brain tissue, is an important cause of acquired brain injury in children. Objective clinical outcomes vary significantly between affected patients, however they do not always correlate with quality of life as reported by parents. The aim of this study was to explore how parents experience and interpret outcomes in relation to their child who has been affected by encephalitis.

Methods

Data were derived from in-depth, semi-structured interviews, with 15 parents of 12 children and young people affected by encephalitis. Paediatric cases were identified from the retrospective arm of the research programme ‘ENCEPH-UK-Understanding and Improving the Outcome of Encephalitis’, and from the prospective UK childhood meningitis and encephalitis cohort study (UK-ChiMES, 2012 to 2016). Data were analysed thematically.

Results

Parents’ perspectives on important outcomes for their child and family changed during the different stages of the encephalitis illness trajectory: from acute illness, recovery and rehabilitation, then reintegration into everyday life. Parents’ understanding of their children’s overall outcome was informed by their own experiences, involving comparisons with other children and reflections on their child’s problems before, during and after the acute illness.

Conclusion

Outcomes in paediatric encephalitis need to be understood in terms of the context of the patient and family experience as well as the timeframe of recovery. The research highlights the need to include more patient, parent and/or carer reported outcome measures during patient assessment, and that assessment should be repeated during recovery as family concerns change. In the longer term, these parameters could be included in clinical and rehabilitation practice to further support child recovery.

A 20-Month-Old Girl With Fever, Seizures, Hemiparesis, and Brain Lesions Requiring a Diagnostic Brain Biopsy

We report a case of a 20-month-old girl with atypical presentation of a fairly common condition. She presented with acute onset of fever, seizures, and hemiparesis. Her cerebrospinal fluid showed total nucleated cells 10/mm³ with lymphocyte dominance. Polymerase chain reaction was negative for herpes simplex virus. Computed tomography of head showed a cerebral hemorrhage of the left frontal lobe and small subarachnoid hemorrhage in the right frontal region. Brain magnetic resonance imaging revealed multiple foci of hyperintensity in bilateral parietal lobes and right basal ganglia. She remained clinically stable without a specific therapy. Her diagnosis was made after a brain biopsy.

Neurological Disorders Associated with Human Alphaherpesviruses

Herpes simplex virus (HSV) encephalitis is the most common cause of sporadic fatal encephalitis worldwide, and central nervous system (CNS) involvement is observed in approximately one-third of neonatal HSV infections . In recent years, single-gene inborn errors of innate immunity have been shown to be associated with susceptibility to HSV encephalitis . Temporal lobe abnormalities revealed by magnetic resonance imaging-the most sensitive imaging method for HSV encephalitis-are considered strong evidence for the disease. Detection of HSV DNA in the cerebrospinal fluid by polymerase chain reaction (PCR) is the gold standard for the diagnosis of HSV encephalitis and neonatal meningoencephalitis. Intravenous acyclovir for 14-21 days is the standard treatment in HSV encephalitis. Neurological outcomes in neonates are improved by intravenous high-dose acyclovir for 21 days followed by oral acyclovir suppressive therapy for 6 months. Varicella-zoster virus (VZV) causes a wide range of CNS manifestations. VZV encephalitis typically occurs after primary infection, and reactivation of VZV may cause encephalitis. On the other hand, VZV infection of cerebral arteries produces vasculopathy, which can manifest as ischemic stroke. Vasculopathy can occur after primary infection or reactivation of VZV. PCR detection of VZV DNA in the cerebrospinal fluid can be used for the diagnosis of encephalitis or vasculopathy. Although there are no controlled treatment trials to assess VZV treatments of encephalitis or vasculopathy, intravenous acyclovir is a common treatment.

Care beyond the hospital ward: understanding the socio-medical trajectory of herpes simplex virus encephalitis

BACKGROUND

Herpes simplex virus (HSV) encephalitis is a life-threatening infection of the brain, which has significant physical, cognitive and social consequences for survivors. Despite increasing recognition of the long-term effects of encephalitis, research and policy remains largely focused on its acute management, meaning there is little understanding of the difficulties people face after discharge from acute care. This paper aims to chart the problems and challenges which people encounter when they return home after treatment for HSV encephalitis.

METHODS

The paper reports on data from 30 narrative interviews with 45 people affected by HSV encephalitis and their significant others. The study was conducted as part of the ENCEPH-UK programme grant on Understanding and Improving the Outcome of Encephalitis.

RESULTS

The findings show the diverse challenges which are experienced by people after treatment for HSV encephalitis. We first chart how peoples' everyday lives are fragmented following their discharge from hospital. Second, we document the social consequences which result from the longer-term effects of encephalitis. Finally, we show how the above struggles are exacerbated by the lack of support systems for the post-acute effects of encephalitis, and describe how people are consequently forced to devise their own care routines and strategies for managing their problems.

CONCLUSION

The paper argues that in order to improve long-term outcomes in encephalitis, it is vital that we develop pathways of support for the condition beyond the acute hospital setting. We conclude by making recommendations to enhance communication and care for the post-acute consequences of encephalitis, to ensure those affected are fully supported through the chronic effects of this devastating disease.

Cytokine expression profile in hospitalized children with herpes simplex virus-1 infection

Aim: We aim to demonstrate the cytokine expression profile of children with herpes simplex virus-1 (HSV-1) infection. Methods: One hundred eighty three children with acute encephalitis were enrolled in this study. Out of those with HSV-1, multiple cytokines were measured. Results: Cytokine analysis of 13 HSV-1-infected patients revealed that IL-8 and granulocyte macrophage colony stimulating factor accumulated at significantly higher levels than macrophage inflammatory protein-1β in the cerebrospinal fluid. Additionally, IFN-γ in serum and cerebrospinal fluid was positively correlated with course of illness, while IL-10 in cerebrospinal fluid was negatively correlated with course of illness. Conclusion: Granulocyte macrophage colony stimulating factor, IL-8, macrophage inflammatory protein-1β, IFN-γ and IL-10 are involved in the HSV-1 immune response and pathogenesis.

Rapid Molecular Panels: What Is in the Best Interest of the Patient? A Review of Patient Outcome Studies for Multiplex Panels Used in Bloodstream, Respiratory, and Neurological Infections

In the clinical microbiology laboratory, the focus when choosing new tests is often on performance, turnaround time, and labor needs. This review examines available rapid, multiplexed tests from a different perspective: that of the patient. It considers whether published evidence supports the notion that use of rapid, on-demand tests (as opposed to batched testing) leads to better patient outcomes and whether broad, syndrome-based, multiplexed panels translate into better patient care than narrower monoplex or duplex assays. Finally, we examine how synergy between the clinical microbiology and antimicrobial stewardship programs is necessary to ensure that rapid tests, if implemented, impact the patients they are designed to support.

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.

Hospitalized Children With Encephalitis in the United States: A Pediatric Health Information System Database Study

OBJECTIVES

Given the paucity of data on resource utilization among children with encephalitis, the objective of this study was to describe the epidemiology and evaluate resource utilization and discharge data of children with encephalitis admitted to US hospitals from 2004 to 2013.

METHODS

We conducted a retrospective cohort study utilizing the Pediatric Health Information System database of children aged 0 to 18 years with the International Classification of Diseases, Ninth Revision codes for encephalitis from 2004 to 2013. Only the initial admissions were included, and the age group analyzed was 0 to 18 years.

RESULTS

Among 7298 children with encephalitis, 2933 (40%) were admitted to a pediatric intensive care unit. The median age was nine years, the overall median length of stay was 16 days, and children requiring critical care had a median length of stay of 25 days. Children in the pediatric intensive care unit were more likely to have seizures (P <0.001) and head magnetic resonance imaging (P <0.001) than children on the floor. Similarly, children requiring critical care were more likely to have a broad diagnostic evaluation sent including cerebrospinal fluid cultures, blood bacterial and fungal cultures, western equine encephalitis antibody, St. Louis equine encephalitis antibody, varicella-zoster serology, human immunodeficiency virus 1 antibody, human immunodeficiency virus DNA polymerase chain reaction, acid-fast stain, and Lyme disease serology. Seventeen percent of children were treated with intravenous immunoglobulin, and 4% underwent plasmapheresis. There was a trend of increasing use of intravenous immunoglobulin and plasmapheresis in children with encephalitis over the study period. A total of 5944 (81%) children were discharged home, and the mortality in this cohort was 3% (230). The mean charges for hospitalization for a child with encephalitis was $64,604 and for those requiring critical care was $260,012.

CONCLUSIONS

Encephalitis is a significant cause of morbidity and mortality in children. Children with encephalitis admitted to the pediatric intensive care unit are more likely to have seizures and to undergo a more extensive evaluation to determine the cause of encephalitis. Use of plasmapheresis and intravenous immunoglobulin is on the rise in hospitalized children. Prospective studies are necessary to better understand treatment and intervention strategies for children with encephalitis and their impact on outcomes.

Herpes Simplex Virus-1 Encephalitis in Adults: Pathophysiology, Diagnosis, and Management

Herpetic infections have plagued humanity for thousands of years, but only recently have advances in antiviral medications and supportive treatments equipped physicians to combat the most severe manifestations of disease. Prompt recognition and treatment can be life-saving in the care of patients with herpes simplex-1 virus encephalitis, the most commonly identified cause of sporadic encephalitis worldwide. Clinicians should be able to recognize the clinical signs and symptoms of the infection and familiarize themselves with a rational diagnostic approach and therapeutic modalities, as early recognition and treatment are key to improving outcomes. Clinicians should also be vigilant for the development of acute complications, including cerebral edema and status epilepticus, as well as chronic complications, including the development of autoimmune encephalitis associated with antibodies to the N-methyl-D-aspartate receptor and other neuronal cell surface and synaptic epitopes. Herein, we review the pathophysiology, differential diagnosis, and clinical and radiological features of herpes simplex virus-1 encephalitis in adults, including a discussion of the most common complications and their treatment. While great progress has been made in the treatment of this life-threatening infection, a majority of patients will not return to their previous neurologic baseline, indicating the need for further research efforts aimed at improving the long-term sequelae.

Diagnostic Pathways as Social and Participatory Practices: The Case of Herpes Simplex Encephalitis

Herpes simplex virus (HSV) encephalitis is a potentially devastating disease, with significant rates of mortality and co-morbidities. Although the prognosis for people with HSV encephalitis can be improved by prompt treatment with aciclovir, there are often delays involved in the diagnosis and treatment of the disease. In response, National Clinical Guidelines have been produced for the UK which make recommendations for improving the management of suspected viral encephalitis. However, little is currently known about the everyday experiences and processes involved in the diagnosis and care of HSV encephalitis. The reported study aimed to provide an account of the diagnosis and treatment of HSV encephalitis from the perspective of people who had been affected by the condition. Thirty narrative interviews were conducted with people who had been diagnosed with HSV encephalitis and their significant others. The narrative accounts reveal problems with gaining access to a diagnosis of encephalitis and shortfalls in care for the condition once in hospital. In response, individuals and their families work hard to obtain medical recognition for the problem and shape the processes of acute care. As a consequence, we argue that the diagnosis and management of HSV encephalitis needs to be considered as a participatory process, which is co-produced by health professionals, patients, and their families. The paper concludes by making recommendations for developing the current management guidelines by formalising the critical role of patients and their significant others in the identification, and treatment of, HSV encephalitis.

Infections, inflammation and epilepsy

Epilepsy is the tendency to have unprovoked epileptic seizures. Anything causing structural or functional derangement of brain physiology may lead to seizures, and different conditions may express themselves solely by recurrent seizures and thus be labelled "epilepsy." Worldwide, epilepsy is the most common serious neurological condition. The range of risk factors for the development of epilepsy varies with age and geographic location. Congenital, developmental and genetic conditions are mostly associated with the development of epilepsy in childhood, adolescence and early adulthood. Head trauma, infections of the central nervous system (CNS) and tumours may occur at any age and may lead to the development of epilepsy. Infections of the CNS are a major risk factor for epilepsy. The reported risk of unprovoked seizures in population-based cohorts of survivors of CNS infections from developed countries is between 6.8 and 8.3 %, and is much higher in resource-poor countries. In this review, the various viral, bacterial, fungal and parasitic infectious diseases of the CNS which result in seizures and epilepsy are discussed. The pathogenesis of epilepsy due to brain infections, as well as the role of experimental models to study mechanisms of epileptogenesis induced by infectious agents, is reviewed. The sterile (non-infectious) inflammatory response that occurs following brain insults is also discussed, as well as its overlap with inflammation due to infections, and the potential role in epileptogenesis. Furthermore, autoimmune encephalitis as a cause of seizures is reviewed. Potential strategies to prevent epilepsy resulting from brain infections and non-infectious inflammation are also considered.

Prognostic Value of Initial Standard EEG and MRI in Patients with Herpes Simplex Encephalitis

Background and Purpose

Herpes simplex encephalitis (HSE) is the most common type of sporadic encephalitis worldwide, and it remains fatal even when optimal antiviral therapy is applied. There is only a weak consensus on the clinical outcomes and prognostic factors in patients with HSE. This study examined whether the radiological and electrophysiological findings have a prognostic value in patients with HSE.

Methods

We retrospectively analyzed patients who were diagnosed with HSE by applying the polymerase chain reaction to cerebrospinal fluid and who received intravenous acyclovir at our hospital from 2000 to 2014. We evaluated the clinical outcomes at 6 months after onset and their correlations with initial and clinical findings, including the volume of lesions on MRI, the severity of EEG findings, and the presence of epileptic seizures at the initial presentation.

Results

Twenty-nine patients were enrolled (18 men and 11 women). Univariate analysis revealed that the presence of severe EEG abnormality and epileptic seizures at the initial presentation were significant correlated with a poor clinical outcome at 6 months (p=0.005 and p=0.009, respectively). In multivariate analysis, the presence of severe EEG abnormality was the only independent predictor of a poor outcome at 6 months (p=0.006).

Conclusions

In cases of HSE, the initial EEG severity and seizure presentation may be useful predictive factors for the outcome at 6 months after acyclovir treatment.

Acute opercular syndrome in 4-year-old boy

Acute opercular syndrome is a rare described syndrome caused by a sudden damage of the cerebral cortex and subcortical white matter, located around the insula. A rare cause of this syndrome can be an infectious agent, particularly herpes simplex virus. Quick diagnosis and immediate initiation of treatment significantly reduce the risk of neurological consequences and mortality. We present a case of encephalitis of unknown etiology and severe course, with the symptoms of acute opercular syndrome in 4-year-old boy.

Neurological Outcomes After Presumed Childhood Encephalitis

OBJECTIVE

To evaluate factors during acute presumed childhood encephalitis that are associated with development of long-term neurological sequelae.

METHODS

A total of 217 patients from Rady Children's Hospital San Diego with suspected encephalitis who met criteria for the California Encephalitis Project were identified. A cohort of 99 patients (40 females, 59 males, age 2 months-17 years) without preexisting neurological conditions, including prior seizures or abnormal brain magnetic resonance imaging scans was studied. Mean duration of follow-up was 29 months. Factors that had a relationship with the development of neurological sequelae (defined as developmental delay, learning difficulties, behavioral problems, or focal neurological findings) after acute encephalitis were identified.

RESULTS

Neurological sequelae at follow-up was associated with younger age (6.56 versus 9.22 years) at presentation (P = 0.04) as well as an initial presenting sign of seizure (P = 0.03). Duration of hospital stay (median of 7 versus 15.5 days; P = 0.02) was associated with neurological sequelae. Of the patients with neurological sequelae, a longer hospital stay was associated with patients of an older age (P = 0.04). Abnormalities on neuroimaging (P = 1.00) or spinal fluid analysis (P = 1.00) were not uniquely associated with neurological sequelae. Children who were readmitted after their acute illness (P = 0.04) were more likely to develop neurological sequelae. There was a strong relationship between the patients who later developed epilepsy and those who developed neurological sequelae (P = 0.02).

SIGNIFICANCE

Limited data are available on the long-term neurological outcomes of childhood encephalitis. Almost half of our patients were found to have neurological sequelae at follow-up, indicating the importance of earlier therapies to improve neurological outcome.

Epilepsy After Resolution of Presumed Childhood Encephalitis

OBJECTIVE

To evaluate factors associated with the development of epilepsy after resolution of presumed childhood encephalitis.

METHODS

A total of 217 patients with suspected encephalitis who met criteria for the California Encephalitis Project were identified. Evaluable outcome information was available for 99 patients (40 girls, 59 boys, ages 2 months to 17 years) without preexisting neurological conditions, including prior seizures or abnormal brain magnetic resonance imaging scans. We identified factors correlated with the development of epilepsy after resolution of the acute illness.

RESULTS

Development of epilepsy was correlated with the initial presenting sign of seizure (P < 0.001). With each additional antiepileptic drug used to control seizures, the odds ratio of developing epilepsy was increased twofold (P < 0.001). An abnormal electroencephalograph (P < 0.05) and longer hospital duration (median of 8 versus 21 days) also correlated with development of epilepsy (P < 0.01). The need for medically induced coma was associated with epilepsy (P < 0.001). Seizures in those patients were particularly refractory, often requiring longer than 24 hours to obtain seizure control. Individuals who required antiepileptic drugs at discharge (P < 0.001) or were readmitted after their acute illness (P < 0.001) were more likely to develop epilepsy. Of our patients who were able to wean antiepileptic drugs after being started during hospitalization, 42% were successfully tapered off within 6 months.

CONCLUSIONS

Limited data are available on the risk of developing epilepsy after childhood encephalitis. This is the first study that not only identifies risk factors for the development of epilepsy, but also provides data regarding the success rate of discontinuing antiepileptic medication after resolution of 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.

Autoimmune encephalitis as differential diagnosis of infectious encephalitis

PURPOSE OF REVIEW

This review describes the main types of autoimmune encephalitis with special emphasis on those associated with antibodies against neuronal cell surface or synaptic proteins, and the differential diagnosis with infectious encephalitis.

RECENT FINDINGS

There is a continuous expansion of the number of cell surface or synaptic proteins that are targets of autoimmunity. The most recently identified include the metabotropic glutamate receptor 5 (mGluR5), dipeptidyl-peptidase-like protein-6 (DPPX), and γ-aminobutyric acid-A receptor (GABAAR). In these and previously known types of autoimmune encephalitis [N-methyl-D-aspartate receptor (NMDAR), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), γ-aminobutyric acid-B receptor (GABABR), leucine-rich glioma inactivated protein 1 (LGI1), contactin-associated protein-like 2 (CASPR2)], the prodromal symptoms or types of presentations often suggest a viral encephalitis. We review here clues that help in the differential diagnosis with infectious encephalitis. Moreover, recent investigations indicate that viral encephalitis (e.g., herpes simplex) can trigger synaptic autoimmunity. In all these disorders, immunotherapy is usually effective.

SUMMARY

Autoimmune encephalitis comprises an expanding group of potentially treatable disorders that should be included in the differential diagnosis of any type of encephalitis.

VIDEO ABSTRACT

http://links.lww.com/CONR/A25,

Postencephalitic epilepsy: clinical characteristics and predictors

OBJECTIVE

To describe the etiologies, clinical presentations, outcomes, and predictors of postencephalitic epilepsy (PE) in a large series of adult patients with acute encephalitis.

METHODS

We conducted a retrospective review of patients diagnosed with acute encephalitis at Mayo Clinic, Rochester, between January 2000 and December 2012. The patients were categorized into two groups based on the presence or absence of PE at last follow-up. Multivariate logistic regression analysis was used to analyze factors associated with PE.

RESULTS

We identified 198 consecutive patients (100 [50.5%] male and 98 [49.5%] female) with a median age of 58 years (range 41.8-69). Etiologies included viral infection (n=95, 48%), autoimmune (n=44, 22%), and unknown/others (n=59, 30%). During hospitalization, seizures were seen in patients with autoimmune encephalitis (n=24, 54.5%), unknown/others (n=20, 33.9%), and viral encephalitis (n=23, 24.2%). Interictal epileptiform discharges on electroencephalography (EEG) were present in 34 (54%), whereas periodic lateralized epileptiform discharges (PLEDs) and generalized periodic discharges (GPDs) were seen in 14 (41.2%) and 2 (5.9%) patients. Forty-six patients with seizures (70.8%) had fluid-attenuated inversion recovery (FLAIR)/T2 abnormalities, 20 (31.3%) diffusion abnormalities, and 43 (66.2%) cortical involvement. Good outcome at discharge among patients with seizures was seen in 8/23 patients with viral etiology (34.8%), 10/24 patients with autoimmune encephalitis (45.5%), and 12/20 patients with unknown cause (60%). PE was present in 43 patients (29.9%). On multivariate regression analysis, the factors associated with PE were generalized seizures during hospitalization (p=0.03), focal seizures (p≤0.001), and the presence of FLAIR/T2 abnormalities on brain magnetic resonance imaging (MRI) (p=0.003).

SIGNIFICANCE

The presence of seizures during hospitalization and an abnormal brain MRI are the strongest predictors of the development of PE. The etiology of encephalitis, presence of focal neurologic deficits, and interictal EEG abnormalities did not influence the development of PE.

Herpes PCR testing and empiric acyclovir use beyond the neonatal period

BACKGROUND

Diagnostic strategies based on empirical testing and treatment to identify herpes simplex virus (HSV) infection in neonates may not be appropriate for older children in whom the most common presentation of severe infection is encephalitis, a rare and clinically recognizable condition.

METHODS

Use of acyclovir in infants and children in 6 common non-HSV infection-related diagnosis-related groups was characterized between 1999 and 2012 at 15 US pediatric hospitals by using the Pediatric Health Information System database. Characteristics of non-neonatal patients at 1 institution tested for HSV encephalitis over a 6.5-year period were then analyzed to identify factors associated with potentially unnecessary testing and treatment.

RESULTS

Acyclovir use increased from 7.6% to 15.6% (P < .001) from 1999 to 2012. Much of this increase came in infants 30 to 60 days of age (82.7% increase, P < .001) and in patients with milder disease severity (44.8% increase, P < .001). Length of stay was increased by 2 days for children treated with acyclovir (P < .001). At our institution, 1394 HSV cerebrospinal fluid polymerase chain reactions were performed in children >30 days old, with only 3 positive results (0.22%). Comparison of the 3 subjects with positive testing and 55 with negative testing revealed that all cases, but only 4% (95% confidence interval 1.2%-14.0%) of noncases had clinical characteristics typical of HSV encephalitis.

CONCLUSIONS

Strategies for diagnosis and empirical treatment of suspected HSV encephalitis beyond the neonatal period have trended toward the approach common for neonates without evidence of an increase in disease incidence. This may result in increased medical costs and risk to patients.

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.

Early-onset neonatal sepsis

Early-onset sepsis remains a common and serious problem for neonates, especially preterm infants. Group B streptococcus (GBS) is the most common etiologic agent, while Escherichia coli is the most common cause of mortality. Current efforts toward maternal intrapartum antimicrobial prophylaxis have significantly reduced the rates of GBS disease but have been associated with increased rates of Gram-negative infections, especially among very-low-birth-weight infants. The diagnosis of neonatal sepsis is based on a combination of clinical presentation; the use of nonspecific markers, including C-reactive protein and procalcitonin (where available); blood cultures; and the use of molecular methods, including PCR. Cytokines, including interleukin 6 (IL-6), interleukin 8 (IL-8), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), and cell surface antigens, including soluble intercellular adhesion molecule (sICAM) and CD64, are also being increasingly examined for use as nonspecific screening measures for neonatal sepsis. Viruses, in particular enteroviruses, parechoviruses, and herpes simplex virus (HSV), should be considered in the differential diagnosis. Empirical treatment should be based on local patterns of antimicrobial resistance but typically consists of the use of ampicillin and gentamicin, or ampicillin and cefotaxime if meningitis is suspected, until the etiologic agent has been identified. Current research is focused primarily on development of vaccines against GBS.