Normocellular CSF in herpes simplex encephalitis

Elsberg Syndrome With Albuminocytologic Dissociation - A Guillain-Barré Syndrome Mimic or Guillain-Barré Syndrome Variant?

Introduction

Elsberg Syndrome is a presumed infectious lumbosacral radiculitis, with or without accompanying lumbar myelitis, that is often attributed to herpes simplex virus type 2 (HSV-2).

Case

A 58-year-old man presented with lower extremity anesthesia, ataxic gait, radiological evidence of radiculitis, and CSF albuminocytologic dissociation. Polymerase chain reaction testing of CSF confirmed HSV-2 infection.

Conclusion

A variety of presentations are reported within the scope of Elsberg Syndrome, potentially with distinct disease mechanisms. Delayed onset of neurological symptoms after resolution of rash and absence of pleocytosis raises the possibility that some patients meeting criteria for Elsberg Syndrome have a post-infectious immune-mediated neuropathy. We advise a lower threshold for PCR testing of herpes viruses in patients with acute neuropathy and albuminocytologic dissociation, particularly in cases with early sacral involvement.

Clinical characteristics and factors affecting disease severity in hospitalized tick-borne encephalitis patients in Norway from 2018 to 2022

PURPOSE

To describe the clinical characteristics and factors associated with disease severity in a Norwegian cohort of hospitalized patients with tick-borne encephalitis (TBE).

METHODS

This observational multicenter study included hospitalized patients with TBE in the endemic area in the southeastern region of Norway from 2018 to 2022. Clinical signs and findings from laboratory tests, EEG, CT and MRI scans were recorded. Patient characteristics were compared among those with mild, moderate, and severe TBE, and factors associated with disease severity were identified.

RESULTS

Nearly all eligible patients were included in the final cohort (153/189 participants, 81%). The median age was 56 years, 63% were men, and 7% were vaccinated against TBE; no participants were fully vaccinated. TBE presented as mild (meningeal) disease in 31% of patients and as moderate or severe (encephalitic) disease in 54% and 14% of patients, respectively. We found that 46% of the patients had a monophasic course, 64% had hyponatremia, and 7% presented with central nervous system (CNS) symptoms without pleocytosis in cerebrospinal fluid (CSF). Dysesthesia, a symptom previously not described, was reported in 10% of the patients. Most objective findings were related to the CNS. Preexisting comorbidities, CRP and CSF protein levels were predictors of more severe disease.

CONCLUSION

This novel presentation of a large Norwegian cohort supports TBE as a serious disease in the southeastern region of Norway. The majority of hospitalized patients presented with encephalitis, and fewer presented with meningitis. Comorbidities, CRP and CSF protein levels were associated with more severe disease.

TRIAL REGISTRATION

Prosjekt #2,296,959 - The Norwegian Tick-borne Encephalitis Study - NOTES. Acute phase characteristics and long-term outcomes. - Cristin.

Herpes simplex viral encephalitis with acute memory impairment and low cellular cerebrospinal fluid: A case report with systematic review literature

Herpes simplex encephalitis (HSVE) is a potentially fatal infectious central nervous system (CNS) disorder. Thus, early detection is critical in determining the case's fate. Clinical history and examination, brain computed tomography, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and lumbar puncture have been used to establish a diagnosis. This report describes a case of HSVE with hypocellular cerebrospinal fluid (CSF) and an uncommon form of memory impairment. However, MRI results were consistent with HSVE, and CSF PCR tested positive for HSV-1 DNA that responded to treatment. We routinely advise patients to begin antiviral therapy as soon as possible to avoid complications.

The immunobiology of herpes simplex virus encephalitis and post-viral autoimmunity

Herpes simplex virus encephalitis (HSE) is the leading cause of non-epidemic encephalitis in the developed world and, despite antiviral therapy, mortality and morbidity is high. The emergence of post-HSE autoimmune encephalitis reveals a new immunological paradigm in autoantibody-mediated disease. A reductionist evaluation of the immunobiological mechanisms in HSE is crucial to dissect the origins of post-viral autoimmunity and supply rational approaches to the selection of immunotherapeutics. Herein, we review the latest evidence behind the phenotypic progression and underlying immunobiology of HSE including the cytokine/chemokine environment, the role of pathogen-recognition receptors, T- and B-cell immunity and relevant inborn errors of immunity. Second, we provide a contemporary review of published patients with post-HSE autoimmune encephalitis from a combined cohort of 110 patients. Third, we integrate novel mechanisms of autoimmunization in deep cervical lymph nodes to explore hypotheses around post-HSE autoimmune encephalitis and challenge these against mechanisms of molecular mimicry and others. Finally, we explore translational concepts where neuroglial surface autoantibodies have been observed with other neuroinfectious diseases and those that generate brain damage including traumatic brain injury, ischaemic stroke and neurodegenerative disease. Overall, the clinical and immunological landscape of HSE is an important and evolving field, from which precision immunotherapeutics could soon emerge.

Herpes simplex encephalitis initially presenting without fever or cerebrospinal fluid pleocytosis and with typical neuroimaging findings: a case report

Herpes simplex encephalitis (HSE) is a common viral encephalitis that can be fatal if not adequately treated. Fever, cerebrospinal fluid (CSF) pleocytosis, and typical neuroimaging findings are commonly observed in HSE cases. We encountered a patient with HSE who did not exhibit these classic clinical features. A 63-year-old male presented with his first-ever seizure. Fever did not develop until the fourth day of admission, and neither neuroimaging nor CSF analysis revealed abnormalities. Under suspicion of autoimmune encephalitis, methylprednisolone was administered. Subsequently, when the patient developed fever, a follow-up neuroimaging study was performed and revealed abnormalities consistent with HSE. The patient was promptly treated with acyclovir, which led to a full recovery. Diagnosing HSE in patients who present without fever or CSF pleocytosis and with typical neuroimaging findings poses a challenge. Therefore, prior to initiating immunosuppressive treatment, it is crucial to closely observe patients and to conduct follow-up tests, including neuroimaging and CSF analysis.

Diagnostic accuracy of clinical and laboratory characteristics in suspected non-surgical nosocomial central nervous system infections

BACKGROUND

The diagnosis of meningitis in non-surgical hospitalized patients is often difficult and diagnostic accuracy of clinical, laboratory, and radiological characteristics is unknown.

AIM

To assess diagnostic accuracy for individual clinical characteristics of patients suspected of non-surgical nosocomial central nervous system (CNS) infections.

METHODS

In a prospective multi-centre cohort study in the Netherlands with adults suspected of CNS infections, consecutive patients who underwent a lumbar puncture for the suspicion of a non-surgical nosocomial CNS infection were included. All episodes were categorized into five final clinical diagnosis categories, as reference standard: CNS infection, CNS inflammatory disease, systemic infection, other neurological disease, or non-systemic, non-neurological disease.

FINDINGS

Between 2012 and 2022, 114 out of 1275 (9%) patients included in the cohort had suspected non-surgical nosocomial CNS infection: 16 (14%) had a confirmed diagnosis, including four (25%) with bacterial meningitis, nine (56%) with viral CNS infections, two (13%) fungal meningitis, and one (6%) parasitic meningitis. Diagnostic accuracy of individual clinical characteristics was generally low. Elevated CSF leucocyte count had the highest sensitivity (81%; 95% confidence interval (CI): 54-96) and negative predictive value (NPV) (96%; 95% CI: 90-99). When combining the presence of abnormalities in neurological or CSF examination, sensitivity for diagnosing a CNS infection was 100% (95% CI: 79-100) and NPV 100% (95% CI: 78-100). CSF examination changed clinical management in 47% of patients.

CONCLUSION

Diagnostic accuracy for individual clinical characteristics was low, with elevated CSF leucocyte count having the highest sensitivity and NPV.

Dural Arteriovenous Fistula Mimicking Acute Encephalitis

We herein report a case of acute neurological symptoms and a fever initially suspected of being encephalitis but later revealed to be dural arteriovenous fistula (dAVF). An 84-year-old woman had a fever and cerebral edema and was initially treated for encephalitis. A review of her magnetic resonance imaging findings revealed abnormal blood flow signals. After cerebral angiography, the patient was finally diagnosed with left transverse-sigmoid sinus dAVF. The present case showed that dAVF can also present with an acute onset and a fever, mimicking acute encephalitis. Because the treatments for encephalitis and dAVF differ greatly, the possibility of dAVF should also be considered when diagnosing encephalitis.

Infectious leukoencephalopathies

Leukoencephalopathy from infectious agents may have a rapid course, such as human simplex virus encephalitis; however, in many diseases, it may take months or years before diagnosis, such as in subacute sclerosing panencephalitis or Whipple disease. There are wide geographic distributions and susceptible populations, including both immunocompetent and immunodeficient patients. Many infections have high mortality rates, such as John Cunningham virus and subacute sclerosing panencephalitis, although others have effective treatments if suspected and treated early, such as herpes simplex encephalitis. This chapter will describe viral, bacterial, and protozoal infections, which predominantly cause leukoencephalopathy. We focus on the clinical presentation of these infectious agents briefly covering epidemiology and subtypes of infections. Next, we detail current pathophysiologic mechanisms causing white matter injury. Diagnostic and confirmatory tests are discussed. We cover predominantly MRI imaging features of leukoencephalopathies, and in addition, summarize the common imaging features. Additionally, we detail how imaging features may be used to narrow the differential of a leukoencephalopathy clinical presentation. Lastly, we present an outline of common treatment approaches where available.

Evaluation of the Performance Characteristics of a New POC Multiplex PCR Assay for the Diagnosis of Viral and Bacterial Neuromeningeal Infections

Point-of-care syndromic PCR (POC SPCR) assays are useful tools for the rapid detection of the most common causative agents of community-acquired infections responsible for meningitis and encephalitis infections. We evaluated the performance characteristics of the new QIAstat-Dx® Meningitis/Encephalitis panel (QS) compared to the laboratory reference methods and the POC SPCR Biofire® FilmArray® Meningitis Encephalitis Panel (FA). Viral (Enterovirus, Parechovirus, HSV-1, HSV-2, HHV-6, VZV) and bacterial (E. coli K1, H. influenzae, L. monocytogenes, encapsulated N. meningitidis, M. pneumoniae, S. agalactiae, S. pneumoniae, S. pyogenes) pathogens were suspended at low concentrations and tested with the POC SPCR systems. The reproducibility, analytical specificity, carryover contamination, interferences and clinical samples were evaluated. All samples tested positive with both QS and FA except for those containing the lowest concentrations of Enterovirus-D68-B3, Echovirus-30 and S. agalactiae which were only detected by FA. In terms of analytical specificity, we observed 3 false positive results out of 48 QS tests versus 1 out of 37 FA tests. For the other studied criteria, both QS and FA performed as expected. Our results suggest that the performance characteristics of QS are close to those of FA. A prospective multicenter study would be useful to complete the performances evaluation of QS.

Case report: Tongdu Xingshen acupuncture for a patient with persistent vegetative state after herpes simplex virus encephalitis

Introduction

A persistent vegetative state (PVS) can be caused by traumatic or non-traumatic brain injury. PVS is a complex clinical condition with numerous complications. Nursing care, medical treatment, and comprehensive rehabilitation are necessary to improve the outcomes of PVS. However, the prognosis remains unsatisfactory. Acupuncture therapy has been used as a rehabilitation strategy to treat patients with PVS in China, showing better results in the recovery of consciousness, intellectual capability, and motor function.

Case description

We present the case of a 4-month-long PVS after herpes simplex virus encephalitis (HSVE) in a 3.5-year-old boy who underwent Tongdu Xingshen acupuncture integrated with Western medicine and rehabilitation. The patient regained consciousness post-treatment. His intelligence and motor function gradually recovered after seven treatment sessions.

Conclusion

Tongdu Xingshen acupuncture is a potential complementary therapy to optimize clinical outcomes in PVS.

Herpes Simplex Virus Type 2 Encephalitis in an Immunocompetent Adult: A Case Report on an Unusual but Relevant Cause of Significant Neurological Morbidity

Encephalitis refers to inflammation of the brain that is most frequently caused by viral infection (particularly herpes simplex virus type 1 [HSV-1]). In some instances, it may be associated with substantial neurological mortality and long-term morbidity. Although HSV-1 is the most common agent involved in producing neurological infections and disorders, herpes simplex virus type 2 (HSV-2) can occasionally affect the central nervous system, particularly in immunocompromised patients. We discuss the case of an immunocompetent male patient with a history of well-controlled diabetes who presented with symptoms of encephalitis. Our patient did not have a history of herpes infection, indicating the presence of subclinical infections. His initial magnetic resonance imaging was inconclusive, but the diagnosis was established following a lumbar puncture and subsequent cerebrospinal fluid analyses.

Contribution of diffusion-weighted imaging to distinguish herpetic encephalitis from auto-immune encephalitis at an early stage

OBJECTIVES

To determine whether diffusion-weighted imaging (DWI) can help to distinguish early stage autoimmune (AI) and herpes simplex virus (HSV) encephalitides.

METHODS

This case-control study included patients from a multi-center cohort of AI encephalitides whose initial MRI including DWI was performed within ten days after symptoms onset. They were compared with patients with HSV encephalitis enrolled prospectively in a single-center from June, 2020 to December, 2020. The final diagnosis of AI encephalitis required a positive autoantibody assay, and that of HSV encephalitis required a positive HSV polymerase chain reaction based on cerebrospinal fluid. Brain MRI were evaluated for restricted diffusion, fluid-inversion recovery (FLAIR) abnormalities, lesion topography, hemorrhagic changes, and contrast enhancement.

RESULTS

Forty-nine patients were included of which, 19 (38.8%) had AI encephalitis. Twenty-seven patients (55.1%) were males and the median age was 46.0 years (interquartile range (IQR):[22.0; 65.0]). Brain MRI were performed after a median of 4 days (IQR:[2.0; 7.0]) of symptom onset and time between symptom onset and MRI was not significantly different (p=0.60). Twenty-six patients had restricted diffusion lesions in the medial temporal lobe, including 25/30 in the HSV encephalitis group (p<0.001). FLAIR abnormalities were observed in 36 patients, including 29/30 in the HSV encephalitis group (p<0.001). Lesion topography, hemorrhagic changes, and contrast enhancement did not differ significantly between the two groups.

CONCLUSION

Our results suggest that restricted diffusion lesions in the medial temporal lobe are a hallmark of HSV encephalitis and may help distinguish it from early-stage AI encephalitis.

Polymerase Chain Reaction (PCR)-Negative Herpes Simplex Virus (HSV) Encephalitis in a 62-Year-Old Woman With p-ANCA Vasculitis

We present the case of a 62-year-old woman with a past medical history significant for p-ANCA vasculitis (on immunosuppression) who was found to have polymerase chain reaction (PCR)-negative herpes simplex virus (HSV) encephalitis. We also present a review of all identifiable reports of PCR-negative HSV encephalitis in the past 20 years. To our knowledge, this is the first case of PCR-negative HSV encephalitis in a patient with p-ANCA vasculitis and the thirteenth overall in this timeframe. The patient presented with new-onset fever, encephalopathy, and a first-in-lifetime focal motor seizure progressing to status epilepticus. Cerebrospinal fluid (CSF) PCR was negative for HSV on three separate instances between the first and thirteenth days since symptom onset, and the CSF profile was not typical for HSV encephalitis. The patient underwent a brain biopsy, which confirmed the presence of HSV. She continued to worsen despite aggressive seizure control and six days of empiric acyclovir. Unfortunately, she expired despite the reinitiation of acyclovir. When faced with the classical features of encephalitis in the immunocompromised, the suspicion of HSV should remain high despite negative PCR results. The completion of a full course of acyclovir in the absence of clinical improvement should be considered.

Antiviral susceptibility of recombinant Herpes simplex virus 1 strains with specific polymerase amino acid changes

Acyclovir (ACV) and penciclovir and their prodrugs are recommended for therapy or prophylaxis of Herpes simplex virus 1 (HSV-1) infections. Their administration, however, can lead to the emergence of resistant strains with altered viral thymidine kinase (TK) function, especially in immunocompromised patients. Furthermore, amino acid (aa) changes of the viral deoxyribonucleic acid polymerase (POL) may contribute to resistance to the aforementioned nucleoside analogues. Given this, treatment with foscarnet (FOS) or cidofovir (CDV) may represent an important alternative. Both drugs directly affect POL activity. Several aa changes of POL, such as L49I, E70K, L359I, E421V, P829S, T1121M, and M1226I, have been observed in ACV-resistant clinical strains which also carried relevant aa changes in their TK. Their contribution to ACV, FOS, and CDV resistance is not fully understood. In this study, these seven aa changes with unknown significance for ACV, FOS and CDV resistance were introduced separately into the POL of a recombinant HSV-1 strain rHSV-1(17+)Lox, equipped with or without information for expression of green fluorescent protein (GFP). The GFP-expressing variants were tested for susceptibility to ACV, FOS and CDV. An rHSV-1(17+)Lox GFP strain with the S724N change conferring resistance to ACV and FOS was generated and included as a control. Only the S724N change was confirmed to induce ACV and FOS resistance, whereas the other changes did not contribute to resistance. The underlying nucleotide substitutions of the POL gene should be therefore considered as natural polymorphism. These data will improve sequence-based prediction of antiviral susceptibility.

Microbiological Outcomes Associated With Low Leukocyte Counts in Cerebrospinal Fluid

The significance of low leukocyte counts in cerebrospinal fluid (CSF) remains unclear. We performed a 2-year retrospective study to examine microbiological outcomes associated with CSF leukocytes at 6–10/mm³. Of the 178 samples examined, we detected positive results for 11 samples, including 5 cases of tick-borne encephalitis virus infection.

Cerebrospinal fluid confirmed COVID-19-associated encephalitis treated successfully

The COVID-19 pandemic that attracted global attention in December 2019 is well known for its clinical picture that is consistent with respiratory symptoms. Currently, the available medical literature describing the neurological complications of COVID-19 is gradually emerging. We hereby describe a case of a 31-year-old COVID-19-positive patient who was admitted on emergency basis. His clinical presentation was primarily neurological, rather than the COVID-19’s classical respiratory manifestations. He presented with acute behavioural changes, severe confusion and drowsiness. The cerebrospinal fluid analysis was consistent with COVID-19 encephalitis, as well as the brain imaging. This experience confirms that neurological manifestations might be expected in COVID-19 infections, despite the absence of significant respiratory symptoms. Whenever certain red flags are raised, physicians who are involved in the management of COVID-19 should promptly consider the possibility of encephalitis. Early recognition of COVID-19 encephalitis and timely management may lead to a better outcome.

Molecular Biology and Epidemiology of Neurotropic Viruses

Neurotropic viruses are those viruses that can cause central nervous system (CNS) diseases with both neuroinvasive and neurovirulence properties. It comprises a wide range of viruses, including herpes simplex virus, poliovirus, enteroviruses, parechovirus, West Nile virus, Japanese encephalitis virus, measles, and mumps viruses among others. Some of these viruses are highly neuroinvasive and neurovirulent, while others are weakly neuroinvasive and neurovirulent. Moreover, some of them, like herpes simplex viruses, are highly neuroinvasive but weakly neurovirulent for the peripheral nervous system and highly neurovirulent but weakly neuroinvasive for the central nervous system. All these disparities are a result of differences in their genomic constitution, associated vectors, geographical region, and environmental factors. Therefore, a successful intervention will be almost impossible without a clear understanding of the molecular biology and epidemiology of these viruses. Thus, we conducted a review of the published studies on the molecular biology and epidemiology of the common neurotropic viruses to make the viral genetic makeup more understandable for targeted intervention and provide the morbidity and mortality data of the different neurotropic viruses for more serious action.

Third time's a charm: diagnosis of herpes simplex encephalitis after two negative polymerase chain reaction results

Introduction

Polymerase chain reaction (PCR) testing of cerebrospinal fluid (CSF) is a sensitive and specific method in diagnosing herpes simplex virus (HSV) encephalitis. However there are increasing reports of false negative HSV PCR.

Case description

We present a patient in the 9^th decade of life with abnormal behavior and focal seizures with MRI showing a right temporal T2 hyperintense non-enhancing lesion with electrographic evidence of right lateralized periodic discharges. CSF analysis and PCR for HSV-1 and 2 yielded negative results twice, and therefore acyclovir was discontinued. Patient initially improved following correction of hyponatremia. Patient however deteriorated and imaging revealed a new right parietal lesion. Third CSF sample showed lymphocytic pleocytosis with positive HSV-1 PCR. Patient improved following antiviral treatment.

Discussion

Acyclovir treatment should continue in high clinical suspicion scenarios despite negative HSV PCR. We further discuss causes of PCR false negatives and challenges it poses for patient care.

HSV-1 Encephalitis in an Elderly Man Receiving Ibrutinib for Waldenstrom's Macroglobulinemia

Ibrutinib is a major new addition to the therapeutic armamentarium for chronic lymphocytic leukemia, mantle cell lymphoma, Waldenstrom's macroglobulinemia, and chronic graft versus host disease. Though ibrutinib has proven to be a revolutionary new small molecule agent, and has relatively minimal toxicity as compared to traditional chemotherapy, infections have emerged as a major complication of therapy. While fungal infections have been the most problematic (including CNS aspergillosis), zoster, hepatitis B reactivation, and chronic hepatitis E have been reported in association with ibrutinib therapy. This report describes a case of herpes encephalitis in an 86-year-old Waldenstrom's patient receiving ibrutinib and speculates as to whether this late life encephalitis may have been related to ibrutinib.

Meningoencefalitis por herpes simple: una visión de la infección viral que causa el mayor compromiso cerebral

La inflamación del sistema nervioso central secundaria a la infección por la familia herpesviridae puede generar un compromiso difuso del parénquima encefálico, la cual puede ser fatal en ausencia de un rápido diagnóstico y tratamiento. Objetivo: revisar las diferentes características biológicas, fisiopatológicas, clínicas, terapéuticas y pronóstico de la meningoencefalitis causada por VHS-1 y 2. Materiales y métodos: revisión de la literatura científica (revisión crítica), llevada a cabo mediante las bases de datos Medline y buscadores específicos IMBIOMED, PUBMEDE, SCIENCEDIRECT, SCIELO, con un total de 150 artículos, se priorizaron 67 los cuales fueron leídos a profundidad. Resultados y discusión: debido el neurotropismo del herpes virus simple puede causar neuroinvasividad, neurotoxicidad y latencia en el SNC. Por sus características semiológicas inespecíficas se requiere un estudio exhaustivo para lograr el diagnóstico acertado. Los métodos actuales tales como neuroimágenes y PCR han aportado al esclarecimiento del diagnóstico etiológico de esta patología. La detección temprana de la entidad y la instauración precoz del tratamiento, se asocian con un aumento en la tasa de supervivencia y a una disminución de las secuelas neurológicas. Conclusión: conocer la biología del virus, su comportamiento, las características clínicas y el tratamiento de la entidad es una estrategia eficaz para disminuir secuelas y desenlaces fatales.

Herpes Simplex Virus 1-Induced Blood-Brain Barrier Damage Involves Apoptosis Associated With GM130-Mediated Golgi Stress

Herpes simplex encephalitis (HSE) caused by herpes simplex virus 1 (HSV-1) infection can lead to a high mortality rate and severe neurological sequelae. The destruction of the blood-brain barrier (BBB) is an important pathological mechanism for the development of HSE. However, the specific mechanism underlying the BBB destruction remains unclear. Our previous study found that the Golgi apparatus (GA) plays a crucial role in maintaining the integrity of the BBB. Therefore, this present study aimed to investigate the role of the GA in the destruction of the BBB and its underlying mechanisms. Mouse brain endothelial cells (Bend.3) were cultured to establish a BBB model in vitro, and then infected with HSV-1. The results showed that HSV-1 infection caused downregulation of the Golgi-associated protein GM130, accompanied by Golgi fragmentation, cell apoptosis, and downregulation of tight junction proteins occludin and claudin 5. Knockdown of GM130 with small interfering RNA in uninfected Bend.3 cells triggered Golgi fragmentation, apoptosis, and downregulation of occludin and claudin 5. However, overexpression of GM130 in HSV-1 infected Bend.3 cells by transient transfection partially attenuated the aforementioned damage caused by HSV-1 infection. When the pan-caspase inhibitor Z-VAD-fmk was used after HSV-1 infection to inhibit apoptosis, the protein levels of GM130, occludin and claudin 5 were partially restored. Taken together, these observations indicate that HSV-1 infection of Bend.3 cells triggers a GM130-mediated Golgi stress response that is involved in apoptosis, which in turn results in downregulation of occludin and claudin 5 protein levels. Meanwhile, GM130 downregulation is partially due to apoptosis triggered by HSV-1 infection. Our findings reveal an association between the GA and the BBB during HSV-1 infection and identify potentially novel targets for protecting the BBB and therapeutic approaches for patients with HSE.

Applicability of molecular assays for detection and typing of herpes simplex viruses in encephalitis cases

Herpes simplex viruses (HSVs) cause a latent infection in humans which is mainly associated with characteristic cold sores or fever blisters and genital blisters. Large segments of the world population are suffering from the HSV infection and early diagnosis as well as treatments are needed to avoid further complications. HSV surveillance is very sparse, especially from developing countries including India. The aim of the present study is to develop and evaluate molecular assays for rapid detection and typing of HSV. In the present study, viral DNA was extracted from cerebro-spinal fluid from HSV suspected encephalitis patients. The conventional multiplex PCR for HSV-1 and HSV-2 was optimized and their comparative analysis was done with Real-Time qPCR for detection and typing of HSV. Out of 137 clinical samples, eleven samples (8.03%) were diagnosed as HSV positive by Real-Time qPCR while ten (7.3%) by conventional multiplex PCR which were further typed as subtyping HSV-1 (nine) and HSV-2 (two). Real-Time qPCR is highly sensitive and able to detect 9.4 × 10¹ to 3.1 × 10⁶ copies/ml of HSV DNA. Conventional PCR was found to be having 99.21% specificity with 100% sensitivity. The positive predictive value was 90.91% whereas negative predictive value was 100%. Logistic regression indicates blisters with pain and skin rash as the most significant symptoms associated with HSV infection. The present study could be applied for rapid, specific, sensitive and cost-effective diagnosis of HSV-1 and HSV-2 thereby helpful in better patient management through early detection and treatment of HSV.

Herpesvirus Infections of the Nervous System

PURPOSE OF REVIEW

This article reviews the spectrum of neurologic disease associated with human herpesvirus infections.

RECENT FINDINGS

As more patients are becoming therapeutically immunosuppressed, human herpesvirus infections are increasingly common. Historically, infections with human herpesviruses were described as temporal lobe encephalitis caused by herpes simplex virus type 1 or type 2. More recently, however, additional pathogens, such as varicella-zoster virus, Epstein-Barr virus, cytomegalovirus, and human herpesvirus 6 have been identified to cause serious neurologic infections. As literature emerges, clinical presentations of herpesvirus infections have taken on many new forms, becoming heterogeneous and involving nearly every location along the neuraxis. Advanced diagnostic methods are now available for each specific pathogen in the herpesvirus family. As data emerge on viral resistance to conventional therapies, newer antiviral medications must be considered.

SUMMARY

Infections from the herpesvirus family can have devastating neurologic outcomes without prompt and appropriate treatment. Clinical recognition of symptoms and appropriate advanced testing are necessary to correctly identify the infectious etiology. Knowledge of secondary neurologic complications of disease is equally important to prevent additional morbidity and mortality. This article discusses infections of the central and peripheral nervous systems caused by herpes simplex virus type 1 and type 2, varicella-zoster virus, Epstein-Barr virus, cytomegalovirus, and human herpesvirus 6. The pathophysiology, epidemiology, clinical presentations of disease, diagnostic investigations, imaging characteristics, and treatment for each infectious etiology are discussed in detail.

Proteomics analysis of HSV-1-induced alterations in mouse brain microvascular endothelial cells

Herpes simplex virus 1 (HSV-1) is a predominant cause of herpes simplex encephalitis (HSE), leading to a high mortality rate and severe neurological sequelae worldwide. HSE is typically accompanied by the blood-brain barrier (BBB) disruption, but the underlying mechanisms are unclear. To explore the disruption mechanisms of the BBB, quantitative analysis of the cellular proteome was carried out to investigate the proteomic changes that occur after infection. In this study, bEnd.3 cells were infected with HSV-1, followed by liquid chromatography-tandem mass spectrometry. A total of 6761 proteins were identified in three independent mass spectrometry analyses. Compared to the uninfected cells, 386 and 293 differentially expressed proteins were markedly upregulated or downregulated, respectively. Bioinformatic analysis showed that the activator protein-1 factor, including Fos, Jun, and ATF family proteins and cell adhesion molecules were significantly changed. Further validation of the changes observed for these proteins was carried out by western blotting and quantitative real-time PCR. Transendothelial electrical resistance (TEER) studies were performed to explore the effects of ATF3, Fra1, or JunB overexpression on the function of bEnd.3 cells. Characterization of the differential expression of these proteins in bEnd.3 cells will facilitate further exploration of BBB disruption upon HSV-1 infection.

Acute encephalitis in immunocompetent adults

Encephalitis is a condition of inflammation of the brain parenchyma, occurs as a result of infectious or autoimmune causes, and can lead to encephalopathy, seizures, focal neurological deficits, neurological disability, and death. Viral causes account for the largest proportion, but in the last decade there has been growing recognition of anti-neuronal antibody syndromes. This Seminar focuses on the diagnosis and management of acute encephalitis in adults. Although viral and autoimmune causes are highlighted because of their prominent roles in encephalitis, other infectious pathogens are also considered. The role of cerebrospinal fluid studies, MRI, and novel diagnostic modalities (eg, next-generation sequencing) are discussed. Management approaches, including treatment of acute neurological complications and the use of immune suppressive and modulatory drugs for cases of suspected or confirmed autoimmune cause, are covered. Additionally, we discuss the remaining challenges in the diagnosis, management, and prognosis of encephalitis.

Causes of albuminocytological dissociation and the impact of age-adjusted cerebrospinal fluid protein reference intervals: a retrospective chart review of 2627 samples collected at tertiary care centre

OBJECTIVE

We set out to test the discriminative power of an age-adjusted upper reference limit for cerebrospinal fluid total protein (CSF-TP) in identifying clinically relevant causes of albuminocytological dissociation (ACD).

METHODS

We reviewed the charts of 2627 patients who underwent a lumbar puncture at a tertiary care centre over a 20-year period. Samples with CSF-TP above 45 mg/dL (0.45 g/L) were included. Samples with white cell count >5×10⁹/L, red cell count >50×10⁹/L and glucose <2.5 mmol/L (45 mg/dL) were excluded as were samples with incomplete data and those taken from paediatric patients (ie, age <18 years old). Patients with CSF-TP elevated above 45 mg/dL were considered to have 'pseudo' ACD unless their CSF-TP was in excess of age-adjusted norms in which case they were considered to have 'true' ACD. Adjustment for sex was not applied to the age-adjusted norms although the importance of gender has been previously described.

RESULTS

The presence of ACD was associated with a broad range of neurological diagnoses. Among all 2627 patients with ACD, a clinical diagnosis explaining CSF-TP elevation was identified in 57% of cases. 'True' ACD was associated with a suitable diagnosis in 75% of cases, whereas patients with 'pseudo' ACD showed an appropriate diagnosis in only 51% of cases. Use of an age-adjusted upper reference limit favoured the detection of polyneuropathy patients (13.5% proportionate increase) and excluded a larger number of patients with isolated headache (10.7% proportionate decrease; p<0.0001).

CONCLUSIONS

Elevated CSF-TP is a common finding, with a range of underlying causes. Use of an age-adjusted upper reference limit for the CSF-TP value improves diagnostic specificity and helps to avoid overdiagnosis of ACD.

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.

Missing Cases of Herpes Simplex Virus (HSV) Infection of the Central Nervous System When the Reller Criteria Are Applied for HSV PCR Testing: a Multicenter Study

Previous studies suggested that herpes simplex virus (HSV) PCR testing can be safely deferred in patients with normal cerebrospinal fluid (CSF) white blood cell (WBC) counts and protein levels as long as they are older than 2 years of age and are not immunocompromised, the so-called Reller criteria. In this multicenter study, we retrospectively assessed the validity of these screening criteria in our setting. A total of 4,404 CSF specimens submitted for HSV PCR testing to the respective microbiology laboratories at the participating hospitals between 2012 and 2018 were included. Six commercially available HSV PCR assays were used across the participating centers. Ninety-one of the 4,404 CSF specimens (2.1%) tested were positive for HSV DNA (75 samples for HSV-1 and 16 for HSV-2). Nine patients failed to meet the Reller criteria, of whom seven were deemed to truly have HSV encephalitis. Overall, no significant correlation between HSV PCR cycle threshold (C_T ) values and WBC counts or total protein levels was found. In addition, median HSV PCR C_T s were comparable between patients who met the Reller criteria and those who did not (P = 0.531). In summary, we show that HSV DNA may be detected in CSF specimens with normal WBC and protein levels collected from immunocompetent individuals older than 2 years with HSV encephalitis. Nevertheless, the data also indicate that the number of cases detected could be lowered at least by half if CSF specimens with borderline WBC counts (4 cells/mm³) as well as children of any age are systematically tested.

Challenges in HSV encephalitis: normocellular CSF, unremarkable CCT, and atypical MRI findings

PURPOSE

Herpes simplex virus (HSV) encephalitis continues to be the most common form of sporadic lethal encephalitis worldwide. The wide spectrum of clinical presentations and laboratory findings often poses a diagnostic challenge for physicians which might delay administration of life-saving therapy with acyclovir. Atypical presentations of HSV encephalitis have become increasingly prevalent with better diagnostic techniques and have not been well studied.

METHODS

We retrospectively evaluated all consecutive PCR-proven HSV encephalitis cases treated at the Hospital of the Ludwig-Maximilians-University in Munich, Germany from January 1, 2013 to February 28, 2018.

RESULTS

We included 18 patients with PCR-proven HSV encephalitis. The most common clinical features were altered mental status (77.8%), focal neurologic deficits (72.2%) and fever (72.2%). Remarkably, four of these patients (22.2%) had a normocellular cerebrospinal fluid (CSF) on admission. Electroencephalography and magnetic resonance imaging abnormalities were highly sensitive for HSV encephalitis independent of CSF cell count. Striking atypical findings on MRI were extensive global brain swelling and severe brainstem involvement in single patients. Of note, initial CT scans were normal in 11 out of 16 patients (68.8%). All patients were treated with acyclovir. Three patients still developed a clinical deterioration under therapy with acyclovir with one patient requiring decompressive craniotomy due to bilateral space-occupying temporal lobe hemorrhage. 94.4% of the patients survived but only 38.9% were discharged with a good clinical outcome (Glasgow Outcome Score = 5).

CONCLUSION

Atypical presentations of HSV encephalitis seem to be more common than previously thought and physicians should apply a high level of clinical suspicion and a low threshold to initiate life-saving acyclovir therapy in suspected cases.

Mechanisms of Blood-Brain Barrier Disruption in Herpes Simplex Encephalitis

Herpes simplex encephalitis (HSE) is often caused by infection with herpes simplex virus 1 (HSV-1), a neurotropic double-stranded DNA virus. HSE infection always impacts the temporal and frontal lobes or limbic system, leading to edema, hemorrhage, and necrotic changes in the brain parenchyma. Additionally, patients often exhibit severe complications following antiviral treatment, including dementia and epilepsy. HSE is further associated with disruptions to the blood-brain barrier (BBB), which consists of microvascular endothelial cells, tight junctions, astrocytes, pericytes, and basement membranes. Following an HSV-1 infection, changes in BBB integrity and permeability can result in increased movement of viruses, immune cells, and/or cytokines into the brain parenchyma. This leads to an enhanced inflammatory response in the central nervous system and further damage to the brain. Thus, it is important to protect the BBB from pathogens to reduce brain damage from HSE. Here, we discuss HSE and the normal structure and function of the BBB. We also discuss growing evidence indicating an association between BBB breakdown and the pathogenesis of HSE, as well as future research directions and potential new therapeutic targets. Graphical Abstract During herpes simplex encephalitis, the functions and structures of each composition of BBB have been altered by different factors, thus the permeability and integrity of BBB have been broken. The review aim to explore the potential mechanisms and factors in the process, probe the next research targets and new therapeutic targets.

Acute encephalitis - diagnosis and management

Encephalitis, inflammation of the brain, is most commonly caused by a viral infection (especially herpes simplex virus [HSV] type 1 in the UK) although autoimmune causes, such as N-methyl D-aspartate receptor (NMDAR) antibody encephalitis, are increasingly recognised. Most patients present with a change in consciousness level and may have fever, seizures, movement disorder or focal neurological deficits. Diagnosis hinges crucially on lumbar puncture and cerebrospinal fluid (CSF) examination, but imaging and electroencephalography (EEG) may also be helpful. Treatment of HSV encephalitis with aciclovir dramatically improves outcome, but the optimal management of autoimmune encephalitis is still uncertain. Many patients with encephalitis are left with residual physical or neuropsychological deficits which require long-term multidisciplinary management. Here we review assessment of patients with suspected encephalitis, general aspects of management and areas of ongoing research.

HSV-1 Encephalitis: High Index of Clinical Suspicion, Prompt Diagnosis, and Early Therapeutic Intervention Are the Triptych of Success-Report of Two Cases and Comprehensive Review of the Literature

Herpes Simplex Virus (HSV) encephalitis is an acute infectious disease of the Central Nervous System (CNS), usually affecting the limbic structures, the median temporal cortex, and the orbitofrontal regions. Its annual incidence has significantly increased over the last 20 years and the mortality rate is 7%, if early diagnosed and treated, and 70%, if left untreated, while it is associated with high rates of morbidity. It should be noted that even when Cerebrospinal fluid (CSF) analysis seems normal, imaging studies are not specific and HSV Polymerase Chain Reaction (PCR) test is negative; the clinician should be more aggressive, if clinical presentation is indicative for HSV encephalitis, by administrating acyclovir early after patient's admission. The latter may be a vital intervention for the patient, modifying the patient's clinical course. Through the presentation of two cases of HSV-1 encephalitis that we managed in our department over the last 1 year and after systematic and comprehensive research of the relevant literature, we aim at showing the crucial role of medical history and physical examination, along with the high index of clinical suspicion, in order to make promptly the diagnosis and administer timely intravenous acyclovir, limiting the possibility of complications during the disease's course.

CSF in acute and chronic infectious diseases

Infections of the nervous system are an important and challenging aspect of clinical neurology. Immediate correct diagnosis enables to introduce effective therapy, in conditions that without diagnosis may leave the patient with severe neurological incapacitation and sometimes even death. The cerebrospinal fluid (CSF) is a mirror that reflects nervous system pathology and can promote early diagnosis and therapy. The present chapter focuses on the CSF findings in neuro-infections, mainly viral and bacterial. Opening pressure, protein and glucose levels, presence of cells and type of the cellular reaction should be monitored. Other tests can also shed light on the causative agent: serology, culture, staining, molecular techniques such as polymerase chain reaction. Specific examination such as panbacterial and panfungal examinations should be examined when relevant. Our chapter is a guide-text that combines clinical presentation and course with CSF findings as a usuaful tool in diagnosis of neuroinfections.

Epigenetic Treatment of Persistent Viral Infections

Preclinical Research Approximately 2,500 years ago, Hippocrates used the word herpes as a medical term to describe lesions that appeared to creep or crawl on the skin, advocating heat as a possible treatment. During the last 50 years, pharmaceutical research has made great strides, and therapeutic options have expanded to include small molecule antiviral agents, protease inhibitors, preventive vaccines for a handful of the papillomaviruses, and even cures for hepatitis C virus infections. However, effective treatments for persistent and recurrent viral infections, particularly the highly prevalent herpesviruses, continue to represent a significant unmet medical need, affecting the majority of the world's population. Exploring the population diversity of the human microbiome and the effects its compositional variances have on the immune system, health, and disease are the subjects of intense investigational research and study. Among the collection of viruses, bacteria, fungi, and single-cell eukaryotes that comprise the human microbiome, the virome has been grossly understudied relative to the influence it exerts on human pathophysiology, much as mitochondria have until recently failed to receive the attention they deserve, given their critical biomedical importance. Fortunately, cellular epigenetic machinery offers a wealth of druggable targets for therapeutic intervention in numerous disease indications, including those outlined above. With advances in synthetic biology, engineering our body's commensal microorganisms to seek out and destroy pathogenic species is clearly on the horizon. This is especially the case given recent breakthroughs in genetic manipulation with tools such as the CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated) gene-editing platforms. Tying these concepts together with our previous work on the microbiome and neurodegenerative and neuropsychiatric diseases, we suggest that, because mammalian cells respond to a viral infection by triggering a cascade of antiviral innate immune responses governed substantially by the cell's mitochondria, small molecule carnitinoids represent a new class of therapeutics with potential widespread utility against many infectious insults. Drug Dev Res 78 : 24-36, 2017.   © 2016 Wiley Periodicals, Inc.

Nosocomial herpes simplex encephalitis: A challenging diagnosis

Herpes simplex encephalitis (HSE) is a rare disease, but it is the most common form of sporadic encephalitis. HSE is transmitted through direct contact and developing nosocomial HSE is rarely reported in the literature. Nosocomial HSE is difficult to diagnose due to its non-specific clinical features. In this article, we present a case of nosocomial HSE that was responsible for grave consequence. We also explore its causes, outcome, and give recommendations to avoid such fatal occurrence. We stress on strict adherence to the standard precautions and preventive control measures.