Lack of Efficacy of High-Titered Immunoglobulin in Patients with West Nile Virus Central Nervous System Disease

George K, Hoang HE, Thakur KT. Clinical and Diagnostic Features of West Nile Virus Neuroinvasive Disease in New York City

West Nile virus (WNV) neuroinvasive disease (WNND) occurs in approximately 1 percent of WNV-infected patients and typically presents as encephalitis, meningitis, or acute flaccid paralysis (AFP). WNND remains a difficult inpatient diagnosis, creating significant challenges for prognostication and therapy selection. We characterized the clinical and diagnostic features of WNND cases at two major academic medical centers in New York City in routine clinical practice. We retrospectively reviewed the charts of thirty-six patients with WNND, including twenty-six encephalitis, four meningitis, and six AFP cases. The most common presenting symptoms were fever (86.1%) and gastrointestinal symptoms (38.9%) in addition to altered mental status (72.2%), lethargy (63.9%), gait disturbances (46.2%), and headache (44.4%). Fourteen (48.3%) patients displayed acute magnetic resonance imaging (MRI) findings, particularly T2 hyperintensities in the bilateral thalami, brainstem, and deep white matter. New York State Department of Health WNV CSF IgM testing was utilized for diagnosis in 58.3% of patients; however, just 38.1% had the result by discharge, compared to 85.6% of those who underwent serum IgM testing. The median length of stay was 13.5 days, 38.9% were intubated, and three patients (8.9%) died during acute hospitalization. Our findings underscore the morbidity, mortality, and diagnostic challenges of WNND, suggesting the potential utility of serum IgM testing in combination with confirmatory CSF testing to expedite diagnosis in the acute setting.

Neuroinvasive West Nile Virus Infection in Immunosuppressed and Immunocompetent Adults

Importance

West Nile virus (WNV) is the leading cause of human arboviral disease in the US, peaking during summer. The incidence of WNV, including its neuroinvasive form (NWNV), is increasing, largely due to the expanding distribution of its vector, the Culex mosquito, and climatic changes causing heavy monsoon rains. However, the distinct characteristics and outcomes of NWNV in individuals who are immunosuppressed (IS) and individuals who are not IS remain underexplored.

Objective

To describe and compare clinical and radiographic features, treatment responses, and outcomes of NWNV infection in individuals who are IS and those who are not IS.

Design, Setting, and Participants

This retrospective cohort study used data from the Mayo Clinic Hospital system collected from July 2006 to December 2021. Participants were adult patients (age ≥18 years) with established diagnosis of NWNV infection. Data were analyzed from May 12, 2020, to July 20, 2023.

Exposure

Immunosuppresion.

Main Outcomes and Measures

Outcomes of interest were clinical and radiographic features and 90-day mortality among patients with and without IS.

Results

Of 115 participants with NWNV infection (mean [SD] age, 64 [16] years; 75 [66%] male) enrolled, 72 (63%) were not IS and 43 (37%) were IS. Neurologic manifestations were meningoencephalitis (98 patients [85%]), encephalitis (10 patients [9%]), and myeloradiculitis (7 patients [6%]). Patients without IS, compared with those with IS, more frequently reported headache (45 patients [63%] vs 18 patients [42%]) and myalgias (32 patients [44%] vs 9 patients [21%]). In contrast, patients with IS, compared with those without, had higher rates of altered mental status (33 patients [77%] vs 41 patients [57%]) and myoclonus (8 patients [19%] vs 8 patients [4%]). Magnetic resonance imaging revealed more frequent thalamic T2 fluid-attenuated inversion recovery hyperintensities in individuals with IS than those without (4 patients [11%] vs 0 patients). Individuals with IS had more severe disease requiring higher rates of intensive care unit admission (26 patients [61%] vs 24 patients [33%]) and mechanical ventilation (24 patients [56%] vs 22 patients [31%]). The 90-day all-cause mortality rate was higher in the patients with IS compared with patients without IS (12 patients [28%] vs 5 patients [7%]), and this difference in mortality persisted after adjusting for Glasgow Coma Scale score (adjusted hazard ratio, 2.22; 95% CI, 1.07-4.27; P = .03). Individuals with IS were more likely to receive intravenous immunoglobulin than individuals without IS (12 individuals [17%] vs 24 individuals [56%]), but its use was not associated with survival (hazard ratio, 1.24; 95% CI, 0.50-3.09; P = .64).

Conclusions and Relevance

In this cohort study of individuals with NWNV infection, individuals with IS had a higher risk of disease complications and poor outcomes than individuals without IS, highlighting the need for innovative and effective therapies to improve outcomes in this high-risk population.

Infectious Myelopathies

OBJECTIVE

Infectious myelopathy of any stage and etiology carries the potential for significant morbidity and mortality. This article details the clinical presentation, risk factors, and key diagnostic components of infectious myelopathies with the goal of improving the recognition of these disorders and guiding subsequent management.

LATEST DEVELOPMENTS

Despite our era of advanced multimodal imaging and laboratory diagnostic technology, a causative organism often remains unidentified in suspected infectious and parainfectious myelopathy cases. To improve diagnostic capability, newer technologies such as metagenomics are being harnessed to develop diagnostic assays with a greater breadth of data from each specimen and improvements in infection identification. Conventional assays have been optimized for improved sensitivity and specificity.

ESSENTIAL POINTS

Prompt recognition and treatment of infectious myelopathy decreases morbidity and mortality. The key diagnostic tools include serologies, CSF analysis, and imaging; however clinical presentation, epidemiologic risk factors, and history of recent illness are all vital to making the proper diagnosis because current laboratory and imaging modalities are often inconclusive. The cornerstone of recommended treatment is targeted antimicrobials with appropriate immune modulation, surgical intervention, supportive care, and interdisciplinary involvement, all of which further improve outcomes for patients with infectious myelopathy.

Clinical efficacy of immunoglobulin on the treatment of severe fever with thrombocytopenia syndrome: a retrospective cohort study

BACKGROUND

Optimal treatment strategy for severe fever with thrombocytopenia syndrome (SFTS) remained unknown. We aimed to evaluate the efficacy of intravenous immunoglobulin (IVIG) on SFTS.

METHODS

A retrospective cohort study was conducted based on medical records of the laboratory-confirmed SFTS patients hospitalized during 2010-2020 in the 154th hospital, China. A 1:1 propensity score matching with age, sex, the interval from symptom onset to admission, presence of chronic viral hepatitis, diabetes and disease severity was performed between Non-IVIG group (supportive therapy) and IVIG group (IVIG plus supportive therapy). The matching variables were adjusted to compare the case fatality rates (CFRs), viral load and laboratory parameters between the two groups. Risk ratio (RR) and 95% confidence interval (CI) were reported.

FINDINGS

Totally 2219 SFTS patients were recruited. CFRs were significantly higher in 1051 patients in IVIG group than 1168 patients in Non-IVIG group (19.0% vs. 4.6%, RR = 4.30, 95% CI 3.12-5.93). The difference remained significant after matching (17.2% vs. 5.1%, RR = 4.02, 95% CI 2.71-5.97). The CFR of IVIG group was significantly higher in all age groups, two IVIG therapy delay groups and two therapy duration groups compared to that of Non-IVIG group (all P < 0.05). IVIG therapy was related to higher viral loads and reduced counts of lymphocytes, T cells, CD4+ T cells and natural killer cells in the blood (all P < 0.05).

INTERPRETATION

No obvious efficacy of IVIG in saving life or improving outcome of SFTS was observed. Caution is needed for clinical physicians to continue prescribing IVIG for SFTS patients.

FUNDING

Natural Science Foundation of China.

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.

Arthropod-borne encephalitis: an overview for the clinician and emerging considerations

The rapid spread of arboviral infections in recent years has continually established arthropod-borne encephalitis to be a pressing global health concern. Causing a wide range of clinical presentations ranging from asymptomatic infection to fulminant neurological disease, the hallmark features of arboviral infection are important to clinically recognise. Arboviral infections may cause severe neurological presentations such as meningoencephalitis, epilepsy, acute flaccid paralysis and stroke. While the pathogenesis of arboviral infections is still being investigated, shared neuroanatomical pathways among these viruses may give insight into future therapeutic targets. The shifting infection transmission patterns and evolving distribution of arboviral vectors are heavily influenced by global climate change and human environmental disruption, therefore it is of utmost importance to consider this potential aetiology when assessing patients with encephalitic presentations.

Treating cognitive impairments in primary central nervous system infections: A systematic review of pharmacological interventions

BACKGROUND

This research synthesized scientific evidence on the use of pharmacotherapy as intervention to reduce cognitive impairments in adult patients with primary central nervous system (CNS) infections.

METHODS

We searched for experimental studies published in English prior to October 2021 in MEDLINE, Embase and Cochrane databases. We included non-randomized studies (NRS) and randomized control trials (RCT) of pharmacotherapy versus placebo, drug, or a combination of drugs in adults with primary CNS infection. The certainty of the evidence was rated according to GRADE guidelines.

RESULTS

We included 8 RCTs and 1 NRS, involving a total of 805 patients (50.77% male patients; mean age 42.67 ± 10.58) with Lyme disease (LD), herpes simplex virus type 1 (HSV-1), or Creutzfeldt-Jakob disease (CJD) studying the efficacy of antibiotics, antiviral, and non-opioid analgesic drugs, respectively. In patients with LD, antibiotics alone or in combination with other drugs enhanced certain cognitive domains relative to placebo. In patients with HSV-1, the results were inconsistent. In patients with CJD, flupirtine maleate enhanced baseline cognitive scores. The quality of RCT studies was low, and the quality of NRS of intervention was very low, suggesting low and very low certainty in the reported results.

CONCLUSION

There is limited evidence and low certainty regarding the efficacy of antimicrobials and analgesics in reducing cognitive impairments in patients with LD, HSV-1, and CJD. Future efforts must be aimed at enhancing attention to clinical trial methodology and reporting, as well as reaching a consensus on outcome measures and the endpoint of clinical trials relevant to patients.

Is Intravenous Immunoglobulin Effective in Reducing the Risk of Mortality and Morbidity in Neuroinvasive West Nile Virus Infection?: A Critically Appraised Topic

BACKGROUND

The clinical benefit of intravenous immunoglobulin (IVIG) in adult individuals with neuroinvasive West Nile virus (niWNV) infection is not well substantiated. We sought to critically assess current evidence regarding the efficacy of IVIG in treating patients with niWNV.

METHODS

The objective was addressed through the development of a critically appraised topic that included a clinical scenario, structured question, literature search strategy, critical appraisal, assessment of results, evidence summary, commentary, and bottom-line conclusions. Participants included consultant and resident neurologists, a medical librarian, clinical epidemiologists, and a content expert in the field of neuro-infectious diseases.

RESULTS

The appraised study enrolled 62 participants with suspected niWNV, randomized into 3 different arms [37 participants in the Omr-IgG-am group, 12 in the Polygam group, and 13 in the normal saline (NS) group]. Omr-IgG-am and Polygam are different formulations of IVIG. IVIG safety, measured as rates of serious adverse events, was the primary study outcome while IVIG efficacy, measured as rates of unfavorable outcomes, was a secondary endpoint. The estimated rates of SAE were statistically similar in all groups (51.4% Omr-IgG-am, 58.3% Polygam, and 23.1% NS groups). Unfavorable outcomes also occurred at a similar rate between all the groups (51.5% Omr-IgG-am, 54.5% Polygam, and 27.3% NS).

CONCLUSIONS

The appraised trial showed that Omr-IgG-am and Polygam are as safe as NS. Data on efficacy from this trial were limited by a small sample size. Phase III clinical trials on IVIG efficacy in NiWNV infection are needed.

Arthropod-Borne Flaviviruses in Pregnancy

Flaviviruses are a diverse group of enveloped RNA viruses that cause significant clinical manifestations in the pregnancy and postpartum periods. This review highlights the epidemiology, pathophysiology, clinical features, diagnosis, and prevention of the key arthropod-borne flaviviruses of concern in pregnancy and the neonatal period-Zika, Dengue, Japanese encephalitis, West Nile, and Yellow fever viruses. Increased disease severity during pregnancy, risk of congenital malformations, and manifestations of postnatal infection vary widely amongst this virus family and may be quite marked. Laboratory confirmation of infection is complex, especially due to the reliance on serology for which flavivirus cross-reactivity challenges diagnostic specificity. As such, a thorough clinical history including relevant geographic exposures and prior vaccinations is paramount for accurate diagnosis. Novel vaccines are eagerly anticipated to ameliorate the impact of these flaviviruses, particularly neuroinvasive disease manifestations and congenital infection, with consideration of vaccine safety in pregnant women and children pivotal. Moving forward, the geographical spread of flaviviruses, as for other zoonoses, will be heavily influenced by climate change due to the potential expansion of vector and reservoir host habitats. Ongoing 'One Health' engagement across the human-animal-environment interface is critical to detect and responding to emergent flavivirus epidemics.

Neuroinvasive West Nile virus infection in solid organ transplant recipients

BACKGROUND

Literature on the natural course of neuroinvasive West Nile virus (WNV) infection in solid organ transplant (SOT) recipients is sparse. In the setting of a 2021 WNV outbreak in Arizona, we reviewed our institution's experience with neuroinvasive WNV infection in patients with SOT.

METHODS

We retrospectively identified SOT recipients treated for neuroinvasive WNV at Mayo Clinic in Arizona from 2007 through 2021. Clinical manifestations, disease course, and outcomes were analyzed.

RESULTS

Among 24 SOT recipients with WNV infection identified during the study period, 13 infections occurred in 2021. Most patients had gastrointestinal tract symptoms and fever at disease presentation. Five patients had cognitive impairment, and 14 initially or eventually had acute flaccid paralysis. Clinically significant deterioration occurred at a median of 4 (range, 1-11) days after hospital admission. Seventeen patients (71%) were transferred to the intensive care unit, with 15 requiring mechanical ventilation. Initial cerebrospinal fluid analysis mainly demonstrated a neutrophil-predominant pleocytosis. Almost all patients (n = 23) were treated with intravenous immunoglobulin alone or in combination with interferon alfa-2b. Sixteen patients had clinical improvement, 4 of whom recovered completely. Six patients died during hospitalization due to complications of neuroinvasive WNV infection. Two patients were discharged to hospice without clinical recovery. The overall 30-day mortality rate was 36%.

CONCLUSION

Despite advances in supportive care, neuroinvasive WNV infection is associated with substantial morbidity and mortality in SOT recipients. Flaccid paralysis is an indicator of poor prognosis.

West Nile virus: another emerging arboviral risk for travelers?

Purpose of Review

West Nile virus (WNV) is an arbovirus transmitted by mosquitos of the genus Culex. Manifestations of WNV infection range from asymptomatic to devastating neuroinvasive disease leading to flaccid paralysis and death. This review examines WNV epidemiology and ecology, with an emphasis on travel-associated infection.

Recent Findings

WNV is widespread, including North America and Europe, where its range has expanded in the past decade. Rising temperatures in temperate regions are predicted to lead to an increased abundance of Culex mosquitoes and an increase in their ability to transmit WNV. Although the epidemiologic patterns of WNV appear variable, its geographic distribution most certainly will continue to increase. Travelers are at risk for WNV infection and its complications. Literature review identified 39 cases of documented travel-related WNV disease, the majority of which resulted in adverse outcomes, such as neuroinvasive disease, prolonged recovery period, or death.

Summary

The prediction of WNV risk is challenging due to the complex interactions of vector, pathogen, host, and environment. Travelers planning to visit endemic areas should be advised regarding WNV risk and mosquito bite prevention. Evaluation of ill travelers with compatible symptoms should consider the diagnosis of WNV for those visiting in endemic areas as well as for those returning from destinations with known WNV circulation.

Neurology of Acute Viral Infections

As specialists in acute neurology, neurohospitalists are often called upon to diagnose and manage acute viral infections affecting the nervous system. In this broad review covering the neurology of several acute viral infections, our aim is to provide key diagnostic and therapeutic pearls of practical use to the busy neurohospitalist. We will review acute presentations, diagnosis, and treatment of human herpesviruses, arboviruses, enteroviruses, and some vaccine-preventable viruses. The neurological effects of coronaviruses, including COVID-19, are not covered in this review.

Polyclonal hyper immunoglobulin: A proven treatment and prophylaxis platform for passive immunization to address existing and emerging diseases

Passive immunization with polyclonal hyper immunoglobulin (HIG) therapy represents a proven strategy by transferring immunoglobulins to patients to confer immediate protection against a range of pathogens including infectious agents and toxins. Distinct from active immunization, the protection is passive and the immunoglobulins will clear from the system; therefore, administration of an effective dose must be maintained for prophylaxis or treatment until a natural adaptive immune response is mounted or the pathogen/agent is cleared. The current review provides an overview of this technology, key considerations to address different pathogens, and suggested improvements. The review will reflect on key learnings from development of HIGs in the response to public health threats due to Zika, influenza, and severe acute respiratory syndrome coronavirus 2.

An Atypical Presentation of West Nile Virus With Successful Treatment After Plasma Exchange and Intravenous Immunoglobulin

West Nile (WN) disease is a relatively rare arboviral virus. Neuroinvasive cases of WN account for less than 1% of the total cases. The case described had difficult symptomatology and radical presentation, which included ascending paralysis. To date, there have been very few reports of West Nile cases that present with ascending paralysis. We describe the case of a 63-year-old white male who presented with a fever and proximal muscle weakness in the thighs and legs that rapidly worsened and ascended, eventually resulting in diaphragmatic paralysis. He was intubated after respiratory failure and given intravenous immunoglobulin and plasma exchange. The patient remained ventilated with persistent weakness. However, this improved after intravenous immunoglobulin and plasma exchange therapy. This case serves as a reminder to keep the diagnosis of WN on the differential, a primer on advanced treatments in the setting of aggressive atypical WN, and a lesson on similarly presenting diseases and distinguishing characteristics that may help rule out these diseases from WN.

Encephalitis Caused by Jamestown Canyon Virus in a Liver Transplant Patient, North Carolina, USA, 2017

We describe the first documented case of Jamestown Canyon Virus (JCV) in North Carolina, which occurred in a liver transplant patient who presented acutely with headache, aphasia, and confusion. This is also the first report of recovery from JCV encephalitis following treatment with intravenous immune globulin.

Acute neurologic emerging flaviviruses

The COVID-19 pandemic has shed light on the challenges we face as a global society in preventing and containing emerging and re-emerging pathogens. Multiple intersecting factors, including environmental changes, host immunological factors, and pathogen dynamics, are intimately connected to the emergence and re-emergence of communicable diseases. There is a large and expanding list of communicable diseases that can cause neurological damage, either through direct or indirect routes. Novel pathogens of neurotropic potential have been identified through advanced diagnostic techniques, including metagenomic next-generation sequencing, but there are also known pathogens which have expanded their geographic distribution to infect non-immune individuals. Factors including population growth, climate change, the increase in animal and human interface, and an increase in international travel and trade are contributing to the expansion of emerging and re-emerging pathogens. Challenges exist around antimicrobial misuse giving rise to antimicrobial-resistant infectious neurotropic organisms and increased susceptibility to infection related to the expanded use of immunomodulatory treatments. In this article, we will review key concepts around emerging and re-emerging pathogens and discuss factors associated with neurotropism and neuroinvasion. We highlight several neurotropic pathogens of interest, including West Nile virus (WNV), Zika Virus, Japanese Encephalitis Virus (JEV), and Tick-Borne Encephalitis Virus (TBEV). We emphasize neuroinfectious diseases which impact the central nervous system (CNS) and focus on flaviviruses, a group of vector-borne pathogens that have expanded globally in recent years and have proven capable of widespread outbreak.

Infectious Meningitis and Encephalitis

Infectious meningitis and encephalitis are associated with significant morbidity and mortality worldwide. Acute bacterial meningitis is rapidly fatal and early recognition and institution of therapy are imperative. Viral meningitis is typically a benign self-limited illness. Chronic meningitis (defined as presenting with >4 weeks of symptoms) is most often caused by tuberculosis and fungal infection. Because the diagnostic testing for tuberculous meningitis is insensitive and cultures often take weeks to grow, therapy is often initiated empirically when the diagnosis is suspected. Human simplex virus encephalitis is the most common cause of encephalitis and requires prompt treatment with intravenous acyclovir.

Update on Viral Infections Involving the Central Nervous System in Pediatric Patients

Infections of the central nervous system (CNS) are mainly caused by viruses, and these infections can be life-threatening in pediatric patients. Although the prognosis of CNS infections is often favorable, mortality and long-term sequelae can occur. The aims of this narrative review were to describe the specific microbiological and clinical features of the most frequent pathogens and to provide an update on the diagnostic approaches and treatment strategies for viral CNS infections in children. A literature analysis showed that the most common pathogens worldwide are enteroviruses, arboviruses, parechoviruses, and herpesviruses, with variable prevalence rates in different countries. Lumbar puncture (LP) should be performed as soon as possible when CNS infection is suspected, and cerebrospinal fluid (CSF) samples should always be sent for polymerase chain reaction (PCR) analysis. Due to the lack of specific therapies, the management of viral CNS infections is mainly based on supportive care, and empiric treatment against herpes simplex virus (HSV) infection should be started as soon as possible. Some researchers have questioned the role of acyclovir as an empiric antiviral in older children due to the low incidence of HSV infection in this population and observed that HSV encephalitis may be clinically recognizable beyond neonatal age. However, the real benefit-risk ratio of selective approaches is unclear, and further studies are needed to define appropriate indications for empiric acyclovir. Research is needed to find specific therapies for emerging pathogens. Moreover, the appropriate timing of monitoring neurological development, performing neuroimaging evaluations and investigating the effectiveness of rehabilitation during follow-up should be evaluated with long-term studies.

Central nervous system infections after solid organ transplantation

PURPOSE OF REVIEW

Significant advances to our understanding of several neuroinfectious complications after a solid organ transplant (SOT) have occurred in the last few years. Here, we review the central nervous system (CNS) infections that are relevant to SOT via a syndromic approach with a particular emphasis on recent updates in the field.

RECENT FINDINGS

A few key studies have advanced our understanding of the epidemiology and clinical characteristics of several CNS infections in SOT recipients. Risk factors for poor prognosis and protective effects of standard posttransplant prophylactic strategies have been better elucidated. Newer diagnostic modalities which have broad clinical applications like metagenomic next-generation sequencing, as well as those that help us better understand esoteric concepts of disease pathogenesis have been studied. Finally, several studies have provided newer insights into the treatment of these diseases.

SUMMARY

Recent findings reflect the steady progress in our understanding of CNS infections post SOT. They provide several avenues for improvement in the prevention, early recognition, and therapeutic outcomes of these diseases.

Encephalitis and Brain Abscess

PURPOSE OF REVIEW

This article reviews infections of the brain parenchyma and includes an overview of the epidemiology, pathogenesis, diagnostic approach, and management of infectious encephalitis and brain abscess.

RECENT FINDINGS

The epidemiology of infectious encephalitis and brain abscess has changed in recent years. Vaccination has reduced the incidence of certain viruses associated with encephalitis, while a decrease in fulminant otogenic infections has led to fewer brain abscesses associated with otitis media. However, changes in climate and human population density and distribution have enabled the emergence of newer pathogens and expanded the geographic range of others, and greater adoption of intensive immunosuppressive regimens for autoimmune conditions has increased the risk of opportunistic infections of the brain. The widespread use of early neuroimaging, along with improved diagnostic methodologies for pathogen detection, newer antimicrobial therapies with better brain penetration, and less invasive neurosurgical techniques, has resulted in better outcomes for patients with infectious encephalitis and brain abscess. Novel technologies including metagenomic next-generation sequencing are increasingly being applied to these conditions in an effort to improve diagnosis. Nevertheless, both infectious encephalitis and brain abscess continue to be associated with substantial mortality.

SUMMARY

Infectious encephalitis and brain abscess can present as neurologic emergencies and require rapid assessment, thorough and appropriate diagnostic testing, and early initiation of empiric therapies directed against infectious agents. Close clinical follow-up, proper interpretation of diagnostic results, and appropriate tailoring of therapeutic agents are essential to optimizing outcomes. Diagnosis and management of parenchymal brain infections are complex and often best achieved with a multidisciplinary care team involving neurologists, neurosurgeons, neuroradiologists, infectious disease physicians, and pathologists.

Meningitis

PURPOSE OF REVIEW

This article reviews the diagnosis and treatment of infectious meningitis, including updates on newer molecular diagnostic techniques for microbiological diagnosis.

RECENT FINDINGS

New polymerase chain reaction (PCR)-based molecular diagnostic techniques have improved the timeliness of microbiological diagnosis in meningitis, but clinicians must be aware of the limitations of such tests. Next-generation sequencing can now be applied to CSF, allowing for diagnosis of infections not identifiable by conventional means.

SUMMARY

Infectious meningitis can be caused by a broad range of organisms. The clinician must be aware of the test characteristics of new molecular techniques for microbiological diagnosis as well as traditional techniques to tailor antimicrobial therapy appropriately in patients with meningitis.

Unusual Movement Disorders and Atypical Magnetic Resonance Imaging (MRI) Findings in Patients with West Nile Encephalitis: Case Reports of 2 Patients with Evidence of Clinical and Imaging Resolution with IVIG

BACKGROUND West Nile virus (WNv) is the leading cause of epidemic arbovirus encephalitis in the continental United States. Movement disorders (MDs) have been reported in 20% to 40% of patients with WNv and about 37% of patients with WNv encephalitis have changes on magnetic resonance imaging (MRI). We report 2 unusual cases of neuroinvasive WNv in patients with unusual MDs and unreported MRI findings. CASE REPORT In the first case, a 34-year-old man presented with a 1-week history of disinhibition, agitation, opsoclonus-myoclonus and ataxia syndrome (OMAS), tremor, and facial agnosia. Evaluation of his cerebrospinal fluid (CSF) revealed elevated immunoglobulin (Ig)M against WNv, a high level of protein (98 mg/dL), and an elevated white blood cell (WBC) count (134, 37% lymphocytes). An MRI of the brain showed an area of diffusion restriction in the splenium of the corpus callosum. The patient's MRI findings and OMA improved significantly after 2 treatments with i.v. IG (IVIG). In the second case, a 57-year-old woman presented with fever, headaches, psychosis, and ataxia; she was subsequently intubated for airway protection. Analysis of her CSF showed elevated IgM against WNv, a high level of protein (79 mg/dL), and elevated WBC count (106, 90% lymphocytes). One week after the onset of symptoms, the patient experienced facial dyskinesia. Later, she developed proximal bilateral lower extremity weakness. An MRI of her lumbar spine showed evidence of myeloradiculitis with contrast enhancement of the conus medullaris and ventral nerve roots. After a single treatment with IVIG, she had partial improvement in weakness. CONCLUSIONS MDs and changes on MRI have been reported in patients with neuroinvasive WNv disease. Our patient with OMAS also had transient splenial diffusion restriction on imaging, which, to the best of our knowledge, has not been previously reported with WNv infection. In both patients, treatment with IVIG resulted in improvement in symptoms.

A 20-year historical review of West Nile virus since its initial emergence in North America: Has West Nile virus become a neglected tropical disease?

After the unexpected arrival of West Nile virus (WNV) in the United States in 1999, the mosquito-borne virus quickly spread throughout North America. Over the past 20 years, WNV has become endemic, with sporadic epizootics. Concerns about the economic impact of infection in horses lead to the licensure of an equine vaccine as early as 2005, but few advances regarding human vaccines or treatments have since been made. There is a high level of virus transmission in hot/humid, subtropical climates, and high morbidity that may disproportionately affect vulnerable populations including the homeless, elderly, and those with underlying health conditions. Although WNV continues to cause significant morbidity and mortality at great cost, funding and research have declined in recent years. These factors, combined with neglect by policy makers and amenability of control measures, indicate that WNV has become a neglected tropical disease.

Efficacy and safety of intravenous immunoglobulins for the treatment of viral encephalitis: a systematic literature review

BACKGROUND

For most viral encephalitides, therapy is merely supportive. Intravenous immunoglobulins (IVIG) have been used as a prophylactic and therapeutic approach. We conduct a systematic review on the safety and efficacy of IVIG in viral encephalitis.

METHODS

We conducted a systematic review assessing PubMed, Cochrane Database, Biosis Previews and the ClinicalTrials.gov website to identify all reports on patients with viral encephalitis treated with IVIG as of May 31, 2019. The main outcomes assessed were therapeutic efficacy and safety. For an increased homogeneity of the population, atypical viral infections were excluded, as were reports on prophylactic IVIG use, intrathecal application of immunoglobulins, or use of antibody-enriched IVIG-preparations. Data were extracted from published studies. Descriptive statistics were used.

RESULTS

We included a total of 44 studies (39 case reports). The case reports cover a total of 53 patients. Our search retrieved two prospective and three retrospective studies. These show heterogeneous results as to the efficacy of IVIG therapy. Only one study reports a significant association between IVIG-use and death (odds ratio 0.032; 95% confidence interval 0.0033-0.3024; p = 0.0027). None of the studies report significant differences in the number of serious adverse events.

CONCLUSION

Data on the efficacy of IVIG-therapy is heterogeneous. While it seems generally safe, evident superiority compared to supportive treatment has not been demonstrated so far. Future trials should also investigate the optimal dosing and timing of IVIG and their benefit in the immunosuppressed.

Treatment of Viral Encephalitis

Viral encephalitis is difficult to treat. Herpes simplex encephalitis has been successfully treated with acyclovir, but is still a cause for significant morbidity even with that treatment. A rare form of autoimmune encephalitis related to NMDA receptor antibody after infection by herpes simplex can be treated with corticosteroid therapy. Arthropod-borne encephalitides, such as West Nile virus encephalitis and Eastern equine encephalitis, are primarily treated with supportive measures. Attempts have been made to use immunoglobulin therapy with limited effects. Progressive multifocal leukoencephalopathy has been treated with an emerging immune activation therapy in a limited number of patients with incomplete success.

Unexpected complete recovery of a patient with severe tick-borne encephalitis treated with favipiravir

We report a case of tick-borne encephalitis (TBE) in a 22-year-old man, who was admitted to the Medical University of Vienna hospital with severe meningoencephalitis, unresponsive and dependent on a respirator. He had given a history of a recent tick bite, but because he had previously received a full course of vaccination against TBE, West Nile virus infection was suspected. Because the antiviral drug favipiravir has been reported to be active against WNV, therapy was initiated, and continued even after a diagnosis of TBE was confirmed, due to significant improvement of symptoms. Within days, the patient's symptoms resolved, and he was discharged after complete recovery at 15 days after onset. Although this single case does not permit any conclusion as to the role of favipiravir in the favorable outcome, it suggests that the drug should be further evaluated in laboratory animal models and in appropriate clinical settings.