Chikungunya encephalomyeloradiculitis: report of 2 cases with neuroimaging and 1 case with autopsy findings

Neuropathogenesis of Old World Alphaviruses: Considerations for the Development of Medical Countermeasures

Chikungunya virus (CHIKV) and other alphaviruses that primarily induce arthritogenic disease in humans, known as "Old World" alphaviruses, present an emerging public health concern as geographic ranges of mosquito vectors expand due to climate change. While a vaccine against CHIKV has recently been approved by several countries in North America and Europe, access to effective preventative countermeasures against disease induced by Old World alphaviruses remains elusive for the most vulnerable populations. Furthermore, treatment options continue to be limited to supportive care. Atypical neurological disease manifestations caused by Old World alphaviruses, which make up as many as 25% of the cases in some CHIKV outbreaks, present special challenges when considering strategies for developing effective countermeasures. This review focuses on Old World alphaviruses, specifically CHIKV, Ross River virus, O'nyoug-nyoug virus, and Mayaro virus, concentrating on the atypical neurological disease manifestations they may cause. Our current understanding of Old World alphavirus neuropathogenesis, gained from human cases and preclinical animal models, is discussed, including viral and host factors' roles in disease development. The current state of alphavirus preventatives and treatments, both virus-targeting and host-directed therapies, is then summarized and discussed in the context of addressing neurological disease induced by Old World alphaviruses.

Herpes simplex encephalomyeloradiculitis initially presents with urinary retention

Herpes simplex virus (HSV) infections necessitate careful management of urinary dysfunction and retention, which are underestimated conditions. Here, we present a rare case of HSV encephalomyeloradiculitis in a 76-year-old man, whose initial symptoms included urinary dysfunction and retention that alone lasted for approximately 1 week. Unlike in meningoencephalitis, high fever and headache were absent; however, the patient subsequently developed cauda equina syndrome and consciousness disturbance. Gadolinium-enhanced spinal MRI suggested enhanced cauda equina at the L2/3 level. Upon admission, he was treated for meningoencephalitis with acyclovir and steroid pulse therapy. Subsequent cerebrospinal fluid analysis result was positive for HSV DNA. A ‍brain MRI conducted 1 week after admission displayed high-intensity lesions in the white matter of the right temporal lobe, confirming HSV encephalomyeloradiculitis. These treatments were highly effective and gradually improved the patient's condition. He was discharged 1 month after hospitalization, and the urinary catheter was removed 2 weeks later. HSV infections can cause life-threatening encephalomyeloradiculitis. Therefore, both neurologists and urologists must pay attention to their occurrence and characteristics in clinical settings.

A case series of post-infectious chikungunya myeloradiculoneuropathy

Chikungunya fever is an arboviral illness caused by chikungunya virus (CHIKV) and transmitted by the bite of Aedes aegypti and Aedes albopictus. It is an RNA virus belonging to the genus Alphavirus and family Togaviridae. We present a case series of three patients with chikungunya illness developing para/post-infectious myeloradiculoneuropathy.These patients developed neurological symptoms in the form of bilateral lower limb weakness with sensory and bowel involvement after the recovery from the initial acute episode of chikungunya fever. Clinical examination findings suggested myeloradiculoneuropathy with normal Magnetic Resonance Imaging of the Spine, with the nerve conduction study showing sensorimotor axonal polyneuropathy. All the patients were treated with 1 g of methylprednisolone once a day for five days, and case 2 was given intravenous immunoglobulin also. In the follow-up, cases 1 and 2 showed complete recovery without recurrence, and case 3 did not show improvement at one month.

A rare case of chikungunya encephalitis and its management: A case report and literature review

Key Clinical Message

Chikungunya encephalitis, though rare, warrants clinical attention due to its severe complications. Early identification and appropriate management are crucial for improved outcomes in patients with this rare manifestation of chikungunya virus (CHIKV) infection.

Abstract

CHIKV infection is commonly associated with fever and joint pains, but neurological complications such as encephalitis are rare. Here, we present a unique case of confirmed chikungunya encephalitis in a 12-year-old male exhibiting atypical neurological symptoms. The diagnostic journey involved comprehensive neuroimaging and serological investigations, revealing intriguing findings on magnetic resonance imaging and positive CHIKV RNA in serum and cerebrospinal fluid. We discuss the clinical presentation, radiological characteristics, and management strategies, emphasizing the importance of recognizing this uncommon neurological manifestation of CHIKV infection.

"Clock dial pattern", a radiologic clue to neuro-chikungunya diagnosis: a case series

BACKGROUND

 Chikungunya is a mosquito-borne disease caused by the chikungunya virus (CHIKV) and can lead to neurological complications in severe cases.

OBJECTIVE

 This study examined neuroimaging patterns in chikungunya cases during two outbreaks in Brazil to identify specific patterns for diagnosis and treatment of neuro-chikungunya.

METHODS

 Eight patients with confirmed chikungunya and neurological involvement were included. Clinical examinations and MRI scans were performed, and findings were analyzed by neuroradiologists. Data on age, sex, neurological symptoms, diagnostic tests, MRI findings, and clinical outcomes were recorded.

RESULTS

 Patients showed different neuroimaging patterns. Six patients exhibited a "clock dial pattern" with hyperintense dotted lesions in the spinal cord periphery. One patient had thickening and enhancement of anterior nerve roots. Brain MRI revealed multiple hyperintense lesions in the white matter, particularly in the medulla oblongata, in six patients. One patient had a normal brain MRI.

CONCLUSION

 The "clock dial pattern" observed in spinal cord MRI may be indicative of chikungunya-related nervous system lesions. Isolated involvement of spinal cord white matter in chikungunya can help differentiate it from other viral infections. Additionally, distinct brainstem involvement in chikungunya-associated encephalitis, particularly in the rostral region, sets it apart from other arboviral infections. Recognizing these neuroimaging patterns can contribute to early diagnosis and appropriate management of neuro-chikungunya.

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.

Chikungunya fever

Chikungunya virus is widespread throughout the tropics, where it causes recurrent outbreaks of chikungunya fever. In recent years, outbreaks have afflicted populations in East and Central Africa, South America and Southeast Asia. The virus is transmitted by Aedes aegypti and Aedes albopictus mosquitoes. Chikungunya fever is characterized by severe arthralgia and myalgia that can persist for years and have considerable detrimental effects on health, quality of life and economic productivity. The effects of climate change as well as increased globalization of commerce and travel have led to growth of the habitat of Aedes mosquitoes. As a result, increasing numbers of people will be at risk of chikungunya fever in the coming years. In the absence of specific antiviral treatments and with vaccines still in development, surveillance and vector control are essential to suppress re-emergence and epidemics.

The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis)

BACKGROUND & IMPORTANCE

This patient and public-involved systematic review originally focused on arachnoiditis, a supposedly rare "iatrogenic chronic meningitis" causing permanent neurologic damage and intractable pain. We sought to prove disease existence, causation, symptoms, and inform future directions. After 63 terms for the same pathology were found, the study was renamed Diseases of the Leptomeninges (DLMs). We present results that nullify traditional clinical thinking about DLMs, answer study questions, and create a unified path forward.

METHODS

The prospective PRISMA protocol is published at Arcsology.org. We used four platforms, 10 sources, extraction software, and critical review with ≥2 researchers at each phase. All human sources to 12/6/2020 were eligible for qualitative synthesis utilizing R. Weekly updates since cutoff strengthen conclusions.

RESULTS

Included were 887/14286 sources containing 12721 DLMs patients. Pathology involves the subarachnoid space (SAS) and pia. DLMs occurred in all countries as a contributor to the top 10 causes of disability-adjusted life years lost, with communicable diseases (CDs) predominating. In the USA, the ratio of CDs to iatrogenic causes is 2.4:1, contradicting arachnoiditis literature. Spinal fusion surgery comprised 54.7% of the iatrogenic category, with rhBMP-2 resulting in 2.4x more DLMs than no use (p<0.0001). Spinal injections and neuraxial anesthesia procedures cause 1.1%, and 0.2% permanent DLMs, respectively. Syringomyelia, hydrocephalus, and arachnoid cysts are complications caused by blocked CSF flow. CNS neuron death occurs due to insufficient arterial supply from compromised vasculature and nerves traversing the SAS. Contrast MRI is currently the diagnostic test of choice. Lack of radiologist recognition is problematic.

DISCUSSION & CONCLUSION

DLMs are common. The LM clinically functions as an organ with critical CNS-sustaining roles involving the SAS-pia structure, enclosed cells, lymphatics, and biologic pathways. Cases involve all specialties. Causes are numerous, symptoms predictable, and outcomes dependent on time to treatment and extent of residual SAS damage. An international disease classification and possible treatment trials are proposed.

Pharmacological Potential of Flavonoids against Neurotropic Viruses

Flavonoids are a group of natural compounds that have been described in the literature as having anti-inflammatory, antioxidant, and neuroprotective compounds. Although they are considered versatile molecules, little has been discussed about their antiviral activities for neurotropic viruses. Hence, the present study aimed to investigate the pharmacological potential of flavonoids in the face of viruses that can affect the central nervous system (CNS). We carried out research from 2011 to 2021 using the Pubmed platform. The following were excluded: articles not in the English language, letters to editors, review articles and papers that did not include any experimental or clinical tests, and papers that showed antiviral activities against viruses that do not infect human beings. The inclusion criteria were in silico predictions and preclinical pharmacological studies, in vitro, in vivo and ex vivo, and clinical studies with flavonoids, flavonoid fractions and extracts that were active against neurotropic viruses. The search resulted in 205 articles that were sorted per virus type and discussed, considering the most cited antiviral activities. Our investigation shows the latest relevant data about flavonoids that have presented a wide range of actions against viruses that affect the CNS, mainly influenza, hepatitis C and others, such as the coronavirus, enterovirus, and arbovirus. Considering that these molecules present well-known anti-inflammatory and neuroprotective activities, using flavonoids that have demonstrated both neuroprotective and antiviral effects could be viewed as an alternative for therapy in the course of CNS infections.

Neuroimaging features of arboviral infections in the Americas

Arboviruses are zoonotic RNA viruses maintained in nature in cycles that involve arthropod vectors. The arboviruses that cause disease in humans are members of the Bunyaviridae, Togaviridae, Flaviviridae, and Reoviridae families. These viral species have geographically and climatically restricted distributions due to particular ecological and vector features. The main emerging arboviruses in the Americas are dengue, zika, yellow fever (Flaviviridae), and chikungunya (Togaviridae). All of these viruses can be transmitted by the Aedes aegypti and Aedes albopictus mosquitoes. Although not commonly, these infections are associated with neurological complications, characterized mainly by hemorrhage, encephalitis, myelitis, acute disseminated encephalomyelitis, Guillain-Barré syndrome, and/or congenital malformations. This review describes the imaging features of the neurological complications of these emerging arbovirus infections.

Changing spectrum of acute encephalitis syndrome in India and a syndromic approach

Acute encephalitis syndrome (AES) refers to an acute onset of fever and clinical neurological manifestation that includes mental confusion, disorientation, delirium, or coma, which may occur because of infectious or non-infectious causes. Cerebrospinal fluid (CSF) pleocytosis generally favors infectious etiology, and a normal CSF favors an encephalopathy or non-infectious AES. Among the infectious AES, viral, bacterial, rickettsial, fungal, and parasitic causes are the commonest. Geographical and seasonal clustering and other epidemiological characteristics are important in clinical decision making. Clinical markers like eschar, skin rash, myalgia, hepatosplenomegaly, thrombocytopenia, liver and kidney dysfunction, elevated serum CK, fronto-temporal or thalamic involvement on MRI, and anterior horn cell involvement are invaluable clues for the etiological diagnosis. Categorizing the AES cases into neurologic [Herpes simplex encephalitis (HSE), Japanese encephalitis (JE), and West Nile encephalitis (WNE)] and systemic (scrub typhus, malaria, dengue, and Chikungunya) helps in rational utilization of diagnostic and management resources. In neurological AES, cranial CT/MRI revealing frontotemporal lesion is consistent with HSE, and thalamic and basal ganglia lesions are consistent with JE. Cerebrospinal fluid nucleic acid detection test or IgM antibody for JE and HSE are confirmatory. Presence of frontotemporal involvement on MRI indicates acyclovir treatment pending virological confirmation. In systemic AES, CT/MRI, PCR for HSE and JE, and acyclovir therapy may not be useful, rather treatable etiologies such as malaria, scrub typhus, and leptospirosis should be looked for. If smear or antigen for malaria is positive, should receive antimalarial, if negative doxycycline and ceftriaxone should be started pending serological confirmation of scrub typhus, leptospira, or dengue. A syndromic approach of AES based on the prevalent infection in a geographical region may be developed, which may be cost-effective.

MRI features in dengue encephalitis: A case series in South Indian tertiary care hospital

Dengue virus, a RNA virus of family Flaviviradae is considered non-neurotropic. Increasing studies and case reports reveal neurological manifestations of dengue virus. In our case series, we have evaluated magnetic resonance imaging (MRI) findings of 3 patients with dengue fever diagnosed by positive dengue NS1 antigen with neurological symptoms, which revealed nonspecific imaging features of dengue encephalitis in two cases and dengue meningoencephalitis in one case. Autopsy findings are also correlated in 2 patients who succumbed to their disease. This case series underlines the consideration of dengue encephalitis in patients of dengue fever with neurological symptoms and relevant imaging findings.

Clinical and magnetic resonance imaging patterns of extensive Chikungunya virus-associated myelitis

Chikungunya fever is an arbovirus infection transmitted by the same mosquito vector of dengue and Zika virus. Besides high fever, common clinical symptoms include articular pain and general malaise. Neurological involvement is unusual, but some patients may develop peripheral and central nervous system involvement, including meningoencephalitis, myelitis, Guillain-Barré syndrome, and acute disseminated encephalomyelitis. We present three cases of Chikungunya fever complicated with extensive myelitis. The spinal cord magnetic resonance imaging (MRI) pattern is characterized by multiple dotted-like and longitudinal hyperintense lesions, with contrast enhancement, mostly distributed in the peripheral regions of the spinal cord. It seems that these lesions are mostly located in the perivascular spaces (PVS), related or not to virus attack. Involvement of brain PVS can also be demonstrated, as shown in two of the cases described. Considering the MRI pattern, extensive spinal cord lesion should include Chikungunya as a differential diagnosis, especially during an outbreak.

Exome-Wide Search for Genes Associated With Central Nervous System Inflammatory Demyelinating Diseases Following CHIKV Infection: The Tip of the Iceberg

Chikungunya virus (CHIKV) is a re-emergent arbovirus that causes a disease characterized primarily by fever, rash and severe persistent polyarthralgia, although <1% of cases develop severe neurological manifestations such as inflammatory demyelinating diseases (IDD) of the central nervous system (CNS) like acute disseminated encephalomyelitis (ADEM) and extensive transverse myelitis. Genetic factors associated with host response and disease severity are still poorly understood. In this study, we performed whole-exome sequencing (WES) to identify HLA alleles, genes and cellular pathways associated with CNS IDD clinical phenotype outcomes following CHIKV infection. The cohort includes 345 patients of which 160 were confirmed for CHIKV. Six cases presented neurological manifestation mimetizing CNS IDD. WES data analysis was performed for 12 patients, including the CNS IDD cases and 6 CHIKV patients without any neurological manifestation. We identified 29 candidate genes harboring rare, pathogenic, or probably pathogenic variants in all exomes analyzed. HLA alleles were also determined and patients who developed CNS IDD shared a common signature with diseases such as Multiple sclerosis (MS) and Neuromyelitis Optica Spectrum Disorders (NMOSD). When these genes were included in Gene Ontology analyses, pathways associated with CNS IDD syndromes were retrieved, suggesting that CHIKV-induced CNS outcomesmay share a genetic background with other neurological disorders. To our knowledge, this study was the first genome-wide investigation of genetic risk factors for CNS phenotypes in CHIKV infection. Our data suggest that HLA-DRB1 alleles associated with demyelinating diseases may also confer risk of CNS IDD outcomes in patients with CHIKV infection.

Chikungunya encephalitis, a case series from an endemic country

BACKGROUND

The Chikungunya Virus (CHIKV) was introduced into Honduras in 2015. Since then the WHO has reported more than 14,000 suspected cases in the country.

OBJECTIVE

To describe the clinical, laboratory, neuroimaging, and pathological features of CHIKV encephalitis.

PATIENTS AND METHODS

We evaluated all consecutive cases of CHIKV infection meeting encephalitis criteria at Hospital Escuela Universitario at Tegucigalpa, Honduras, during 2015. Who case definition was used: patient with neurological manifestations meeting clinical criteria (fever >38.5 °C, joint pain); resident/visitor in the last 15 days to an endemic area; laboratory confirmation with IgM/ELISA. Other etiologies were excluded by ancillary studies.

RESULTS

Out of 95 cases with suspected CHIKV infection, 7 (7%) cases with CHIKV encephalitis were identified; mean age was 56 years and four were men. The mean latency from onset of symptoms to diagnosis was 5 five days. Clinical manifestations were: fever/arthralgia, headache/alteration of consciousness and status epilepticus. The EEG demonstrated slow background activity and generalized epileptiform discharges in three patients. Brain MRI showed bilateral white matter hyperintensities and one with focal encephalitis; CSF analysis demonstrated lymphocytic pleocytosis and hyperproteinorrachia. Two patients died. Postmortem brain examination of one patient revealed lymphocytic infiltrates with focal necrosis in hippocampus, frontal lobes and medulla oblongata.

CONCLUSIONS

Neurological complications of CHIKV are infrequent, but may be severe. In this case series, the neurological manifestation was encephalitis. Predominant symptoms and signs were fever, behavioral abnormalities, headache and seizures. Because of the potential morbidity and mortality of CHIKV encephalitis, these patients should be admitted to hospital urgently.

Fatal Outcome of Chikungunya Virus Infection in Brazil

BACKGROUND

Chikungunya virus (CHIKV) emerged in the Americas in 2013 and has caused approximately 2.1 million cases and >600 deaths. A retrospective investigation was undertaken to describe clinical, epidemiological, and viral genomic features associated with deaths caused by CHIKV in Ceará state, northeast Brazil.

METHODS

Sera, cerebrospinal fluid (CSF), and tissue samples from 100 fatal cases with suspected arbovirus infection were tested for CHIKV, dengue virus (DENV), and Zika virus (ZIKV). Clinical, epidemiological, and death reports were obtained for patients with confirmed CHIKV infection. Logistic regression analysis was undertaken to identify independent factors associated with risk of death during CHIKV infection. Phylogenetic analysis was conducted using whole genomes from a subset of cases.

RESULTS

Sixty-eight fatal cases had CHIKV infection confirmed by reverse-transcription quantitative polymerase chain reaction (52.9%), viral antigen (41.1%), and/or specific immunoglobulin M (63.2%). Co-detection of CHIKV with DENV was found in 22% of fatal cases, ZIKV in 2.9%, and DENV and ZIKV in 1.5%. A total of 39 CHIKV deaths presented with neurological signs and symptoms, and CHIKV-RNA was found in the CSF of 92.3% of these patients. Fatal outcomes were associated with irreversible multiple organ dysfunction syndrome. Patients with diabetes appear to die at a higher frequency during the subacute phase. Genetic analysis showed circulation of 2 CHIKV East-Central-South African (ECSA) lineages in Ceará and revealed no unique virus genomic mutation associated with fatal outcome.

CONCLUSIONS

The investigation of the largest cross-sectional cohort of CHIKV deaths to date reveals that CHIKV-ECSA strains can cause death in individuals from both risk and nonrisk groups, including young adults.

Neuroimaging of Emergent and Reemergent Infections

Infectious diseases emerge and reemerge over the years, and many of them can cause neurologic disease. Several factors contribute to the emergence and reemergence of these conditions, including human population growth, an increase in international travel, the geographic expansion of recognized pathogens to areas where they were previously nonendemic, and greater contact with wild animal reservoirs. The antivaccination social movement has played an important role in the reemergence of infectious diseases, especially some viral conditions. The authors review different viral (arboviruses such as dengue, chikungunya, and Zika virus; enterovirus 71; measles; and influenza), bacterial (syphilis, Lyme disease, and listeriosis), and parasitic (Chagas disease) diseases, focusing primarily on their neurologic complications. Although there are several additional infectious diseases with central nervous system manifestations that could be classified as emergent or reemergent, those listed here are the most relevant from an epidemiologic standpoint and are representative of important public health issues on all continents. The infections caused by these pathogens often show a variety of neuroimaging patterns that can be identified at CT and MRI, and radiology is central to the diagnosis and follow-up of such conditions. Given the increasing relevance of emerging and reemerging infections in clinical practice and public health scenarios, radiologists should be familiar with these infections. Online supplemental material is available for this article. ^©RSNA, 2019.

Immunopathogenesis of alphaviruses

Alphaviruses, members of the enveloped, positive-sense, single-stranded RNA Togaviridae family, represent a reemerging public health threat as mosquito vectors expand into new geographic territories. The Old World alphaviruses, which include chikungunya virus, Ross River virus, and Sindbis virus, tend to cause a clinical syndrome characterized by fever, rash, and arthritis, whereas the New World alphaviruses, which consist of Venezuelan equine encephalitis virus, eastern equine encephalitis virus, and western equine encephalitis virus, induce encephalomyelitis. Following recovery from the acute phase of infection, many patients are left with debilitating persistent joint and neurological complications that can last for years. Clues from human cases and studies using animal models strongly suggest that much of the disease and pathology induced by alphavirus infection, particularly atypical and chronic manifestations, is mediated by the immune system rather than directly by the virus. This review discusses the current understanding of the immunopathogenesis of the arthritogenic and neurotropic alphaviruses accumulated through both natural infection of humans and experimental infection of animals, particularly mice. As treatment following alphavirus infection is currently limited to supportive care, understanding the contribution of the immune system to the disease process is critical to developing safe and effective therapies.

Chikungunya encephalitis: report of a fatal case in Northeastern Brazil

Chikungunya, a viral infection that presents with fever, rash and polyarthritis, is usually an acute febrile illness. Uncommon neurological manifestations include meningoencephalitis, encephalitis, myelitis, Guillain-Barre syndrome, myelopathy and neuropathy. During an outbreak of the disease in La Reunion Island, abnormalities were observed in the magnetic resonance imaging (MRI) of patients with encephalitis and acute disseminated encephalomyelitis, showing bilateral, frontoparietal, white matter lesions with restricted diffusion, similar to our case. We report a 57-year-old male patient with comorbidities, admitted with high fever, arthralgia, asthenia, vomiting, psychomotor agitation, behavioral changes and seizures. Cerebrospinal fluid (CSF) values revealed pleocytosis (98 cells/mm3 with 68% lymphocytes and 12% monocytes) and high levels of protein (161 mg%). Brain MRI showed hyperintense lesions in the temporal and frontal lobes and bilaterally in the posterior thalamus. CSF serology was positive for IgM antibodies to Chikungunya virus. Encephalitis due to an acute viral infection by Chikungunya was diagnosed. The patient’s clinical condition worsened and he died on the twenty-fourth day of admission to our hospital.

Events preceding death among chikungunya virus infected patients: a systematic review

Since its re-emergence in the late 1990s, there have been reports of Chikungunya fever (CHIK-F) presenting with severe or atypical findings. There is little knowledge regarding the clinical events leading to the death of patients with CHIK-F. This study aimed to systematically review the literature regarding CHIK-F and identify clinical features preceding death. We searched PubMed, Scopus, Embase, Lilacs, and IsiWeb for case-reports, case-series, or cohorts of CHIK-F reporting at least one death, up to December 2019. Fifty-seven reports were analyzed, including 2140 deaths. Data about specific clinical events that precede death are scarce. The central tendency of time between disease onset and death ranged from 2 days to 150 days. The most common clinical findings among decedents were fever (22.0%), arthralgia (15.7%), myalgia (10.7%), and headache (8.2%). Excluding pediatric populations, the reported central tendency of age among the decedents was 53 or older, with a non-weighted median of 67, ranging up to 80 years old. Authors mentioned organic dysfunction in 91.2% reports. Among all the 2140 decedents, the most common dysfunctions were cardiovascular (7.2%), respiratory (6.4%), neurological (5.4%), renal (4.2%), liver (3.0%), and hematological (1.3%) dysfunction. Exacerbation of previous diabetes (5.6%) or hypertension (6.9%) was mentioned as conditions preceding death. Currently, older age, primary neurological, cardiovascular, or respiratory dysfunction and a previous diagnosis of diabetes or hypertension are the main clinical events preceding death.

Brain MR Imaging of Patients with Perinatal Chikungunya Virus Infection

Since 2005, it has been known that mother-to-child transmission of the chikungunya virus is possible. Transmission generally occurs in the perinatal period. In the present study, we describe the brain lesions seen on MR imaging of 6 cases of perinatal chikungunya infection. Patients who underwent brain MR imaging in the acute phase presented with areas of restricted diffusion in the white matter, suggesting a perivascular distribution, whereas those in the subacute/late phase showed cystic lesions, also with a perivascular distribution, with or without brain atrophy. One patient also presented with scattered hemorrhages in the frontal and parietal lobes. Important differential diagnoses include rotavirus, Parechovirus, herpes simplex infection, and hypoxic-ischemic encephalopathy, depending on the disease phase.

Human Parechovirus Meningoencephalitis: Neuroimaging in the Era of Polymerase Chain Reaction-Based Testing

Human parechovirus infection is an increasingly recognized cause of neonatal meningoencephalitis. We describe characteristic clinical features and brain MR imaging abnormalities of human parechovirus meningoencephalitis in 6 infants. When corroborated by increasingly available polymerase chain reaction-based testing of the CSF, the distinctive MR imaging appearance may yield a specific diagnosis that obviates costly and time-consuming further clinical evaluation. In our study, infants with human parechovirus presented in the first 35 days of life with seizures, irritability, and sepsis. MR imaging consistently demonstrated low diffusivity within the thalami, corpus callosum, and subcortical white matter with a frontoparietal predominance. T1 and T2 shortening connoting white matter injury along the deep medullary veins suggests venous ischemia as an alternative potential pathogenetic mechanism to direct neuroaxonal injury.

Imaging of Emerging Infectious Diseases

Purpose of Review

Emerging infectious diseases have seen a record increase in prevalence, and understanding their management is critical in an increasingly global community. In this paper, we review current literature detailing the role of radiology in the diagnosis and treatment of the Ebola (EVD), Zika (ZVD), Chikungunya (CHIKF), H1N1, Middle East Respiratory (MERS), and Severe Acute Respiratory Syndrome (SARS) viruses.

Recent Findings

Complex protocols are required to safely use portable imaging in EVD to prevent nosocomial spread of disease. In ZVD, antenatal ultrasound can detect fetal abnormalities early, allowing implementation of care and support to affected families. Imaging is useful in assessing the extent of involvement of chronic CHIKF and monitoring treatment effect. Chest radiography and CT play a more direct role in the diagnosis and monitoring of the viral infections with primarily respiratory manifestations (H1N1, MERS, and SARS).

Summary

Radiology plays a variable role in emerging infectious diseases, requiring an understanding of disease transmission and safe imaging practices, as well as imaging features that affect clinical management.

Pediatric West Nile Virus-Associated Neuroinvasive Disease: A Review of the Literature

Over the past two decades, West Nile virus has become the most common arbovirus in North America, leading to several outbreaks and infecting thousands of people. Mosquitos help transmit the virus in the majority of cases, but transmission occurs via blood transfusions, organ transplantation, and possibly pregnancy and breastfeeding. While most infected patients experience mild to no symptoms, thousands of West Nile virus-associated neuroinvasive cases have been reported in the United States, with over 700 cases occurring in children from 2003 to 2016. Neuroinvasive disease presents as meningitis, encephalitis, or acute flaccid paralysis, and carries a high likelihood of poor outcome, including severe neurological disability or death. To date, no pharmacologic treatment has proven effective. Therapeutic clinical trials have not been successfully completed due to the sporadic nature of viral outbreaks and resultant poor study enrollment. Although older age and chronic disease are risk factors for neuroinvasive West Nile virus disease in adults, the specific factors that influence the risk in pediatric populations have not been fully elucidated. This review summarizes the most recent literature regarding West Nile virus-associated neuroinvasive disease, especially as it pertains to the pediatric population. Moreover, the review describes the epidemiology, clinical, laboratory, and radiographic findings, and outlines the various therapies that have been trialed and potential future research directions.

Cerebrospinal Fluid Immunoglobulins as Potential Biomarkers of Chikungunya Encephalitis

Chikungunya virus causes fever and severe polyarthritis or arthralgia and is associated with neurologic manifestations that are sometimes challenging to diagnose. We demonstrate intrathecal synthesis of chikungunya antibodies in a patient with a history of acute infection complicated by encephalitis. The specificity of the intracerebral immune response supports early chikungunya-associated encephalitis diagnosis.

Tropism of the Chikungunya Virus

Chikungunya virus (CHIKV) is a re-emerging mosquito-borne virus that displays a large cell and organ tropism, and causes a broad range of clinical symptoms in humans. It is maintained in nature through both urban and sylvatic cycles, involving mosquito vectors and human or vertebrate animal hosts. Although CHIKV was first isolated in 1953, its pathogenesis was only more extensively studied after its re-emergence in 2004. The unexpected spread of CHIKV to novel tropical and non-tropical areas, in some instances driven by newly competent vectors, evidenced the vulnerability of new territories to this infectious agent and its associated diseases. The comprehension of the exact CHIKV target cells and organs, mechanisms of pathogenesis, and spectrum of both competitive vectors and animal hosts is pivotal for the design of effective therapeutic strategies, vector control measures, and eradication actions.

Spectrum of neurological complications in chikungunya fever: experience at a tertiary care centre and review of literature

Chikungunya (CHIK) has re-emerged as a potential neurotropic virus, with outbreaks recently being reported from many parts of India. The present study was conducted to study the spectrum and outcome of neurological complications in patients of CHIK during the 2016 outbreak in Delhi. A total of 42 cases seropositive for IgM CHIK antibodies by MAC-ELISA and developing neurological complications were enrolled. The male:female ratio was 1:2 (age range = 18-90 years). The neurological manifestations observed were encephalitis (n = 12), bulbar palsy (n = 3), acute disseminated encephalomyelitis (n = 1), cerebellitis (n = 1), myelopathy (n = 1), radiculoneuropathy (n = 3), carpal tunnel syndrome (n = 9) and tremors (n = 1). Ten patients reported worsening of pre-existing neuropathic symptoms of diabetic peripheral neuropathy (n = 4) and carpal tunnel syndrome (n = 6). One patient had aggravation of myasthenia gravis leading to respiratory failure. The majority of patients (n = 32) showed a good outcome; ten had a poor prognosis, out of which four died, all from the encephalitis group, particularly the elderly with co-morbidities.

Genetic control of alphavirus pathogenesis

Alphaviruses, members of the positive-sense, single-stranded RNA virus family Togaviridae, represent a re-emerging public health concern worldwide as mosquito vectors expand into new geographic ranges. Members of the alphavirus genus tend to induce clinical disease characterized by rash, arthralgia, and arthritis (chikungunya virus, Ross River virus, and Semliki Forest virus) or encephalomyelitis (eastern equine encephalitis virus, western equine encephalitis virus, and Venezuelan equine encephalitis virus), though some patients who recover from the initial acute illness may develop long-term sequelae, regardless of the specific infecting virus. Studies examining the natural disease course in humans and experimental infection in cell culture and animal models reveal that host genetics play a major role in influencing susceptibility to infection and severity of clinical disease. Genome-wide genetic screens, including loss of function screens, microarrays, RNA-sequencing, and candidate gene studies, have further elucidated the role host genetics play in the response to virus infection, with the immune response being found in particular to majorly influence the outcome. This review describes the current knowledge of the mechanisms by which host genetic factors influence alphavirus pathogenesis and discusses emerging technologies that are poised to increase our understanding of the complex interplay between viral and host genetics on disease susceptibility and clinical outcome.

A Case Report on Chikungunya Virus-Associated Encephalomyelitis

Chikungunya is a rerising alphavirus infection that has resulted from enhanced vector competence. Alphaviruses are divided into arthritogenic viruses (old world) and encephalitogenic viruses (new world) including equine encephalitis viruses. Chikungunya is a dengue-like illness characterized by acute febrile polyarthralgia, arthritis, malaise, body ache, rash, headache, and nausea. The illness is self-limiting. The neurological manifestations are uncommon and incorporate meningoencephalitis, myelitis, Guillain–Barre syndrome, cranial nerve palsies, myelopathy, and neuropathy; MRI abnormalities in patients with encephalopathy from India have been reported in the form of multiple punctuate white matter lesions that are more prominent on diffusion-weighted MRI than on T2 or T1. Here, we present an intriguing case of chikungunya encephalomyelitis who presented to our tertiary care hospital with quadriparesis and urinary retention. He was treated with 5 doses of intravenous immunoglobulin along with supportive care with which he showed partial recovery.

Delayed central nervous system manifestation of Chikungunya virus with magnetic resonance T2 weighted imaging high signal changes-a case report

CHIKV is a relatively new virus and we are still learning about the illness. Very little is known about CNS its involvement and even less about its delayed or long-term manifestations if any. It therefore behoves us to consider delayed CNS involvement when assessing patients with CHIKV infections that may not have had an acute neurological manifestation at the time of diagnosis coupled with new onset neurological manifestations and MRI abnormalities. It seems likely that patients with CHIKV may experience delayed CNS manifestation of the viral infection. This report highlights the importance of a travel history when assessing patients with a neurological complaint. The pathway to best manage such cases is with repeated imaging to assess if the signal changes either progress, resolve or more importantly if there is any MRI correlation should changes in neurology develop during the surveillance period.

The neurological complications of chikungunya virus: A systematic review

We performed a systematic review on the neurological complications of chikungunya virus. Such complications are being reported increasingly, owing primarily to the scale of recent epidemics but also to a growing understanding of the virus' neurovirulence. We performed a thorough literature search using PubMed and Scopus databases, summating the data on all published reports of neurological disease associated with chikungunya virus. We appraised the data for each major condition in adults, children, and neonates, as well as evaluating the latest evidence on disease pathogenesis and management strategies. The review provides a comprehensive summary for clinicians, public health officials, and researchers tackling the challenges associated with this important emerging pathogen.

Nucleophosmin (NPM1)/B23 in the Proteome of Human Astrocytic Cells Restricts Chikungunya Virus Replication

Chikungunya virus (CHIKV), a positive-stranded RNA virus, can cause neurological complications by infecting the major parenchymal cells of the brain such as neurons and astrocytes. A proteomic analysis of CHIKV-infected human astrocytic cell line U-87 MG revealed tight functional associations among the modulated proteins. The predominant cellular pathways involved were of transcription-translation machinery, cytoskeletol reorganization, apoptosis, ubiquitination, and metabolism. In the proteome, we could also identify a few proteins that are reported to be involved in host-virus interactions. One such protein, Nucleophosmin (NPM1)/B23, a nucleolar protein, showed enhanced cytoplasmic aggregation in CHIKV-infected cells. NPM1 aggregation was predominantly localized in areas wherein CHIKV antigen could be detected. Furthermore, we observed that inhibition of this aggregation using a specific NPM1 oligomerization inhibitor, NSC348884, caused a significant dose-dependent enhancement in virus replication. There was a marked increase in the amount of intracellular viral RNA, and ∼10⁵-fold increase in progeny virions in infected cells. Our proteomic analysis provides a comprehensive spectrum of host proteins modulated in response to CHIKV infection in astrocytic cells. Our results also show that NPM1/B23, a multifunctional chaperone, plays a critical role in restricting CHIKV replication and is a possible target for antiviral strategies.

Viral and Prion Infections of the Central Nervous System: Radiologic-Pathologic Correlation: From the Radiologic Pathology Archives

Viral infections of the central nervous system (CNS) range in clinical severity, with the most severe proving fatal within a matter of days. Some of the more than 100 different viruses known to affect the brain and spinal cord are neurotropic with a predilection for producing CNS infection. The host response to viral infection of the CNS is responsible for the pathophysiology and imaging findings seen in affected patients. Viral CNS infections can take the form of meningitis, encephalitis, encephalomyelitis, or, when involving the spinal cord and nerve roots, encephalomyeloradiculitis. In 1982, an infectious particle termed a prion that lacked nucleic acid and therefore was not a virus was reported to produce the fatal neurodegenerative disease Creutzfeldt-Jakob disease and related disorders. These prion diseases produce characteristic neuroimaging findings that are distinct from those seen in most viral infections. The clinical and imaging findings associated with viral CNS infection are often nonspecific, with microbiologic analysis of cerebrospinal fluid the most useful single test allowing for diagnosis of a specific viral infection. This review details the spectrum of viral CNS infections and uses case material from the archives of the American Institute for Radiologic Pathology, with a focus on the specific clinical characteristics and magnetic resonance imaging features seen in these infections. Where possible, the imaging features that allow distinction of these infections from other CNS inflammatory conditions are highlighted.

Immunoglobulin-responsive chikungunya encephalitis: two case reports

Chikungunya virus is an alphavirus transmitted by the mosquito Aedes, mainly Aedes aegypti and Aedes albopictus, that can cause acute illness, mostly self-limited, characterized by fever, maculopapular rash, and disabling polyarthritis/arthralgia, with an incubation period of 1 to 12 days. Chikungunya was largely regarded as a non-fatal and self-limited disease, but recently, serious cases have been reported including some with severe involvement of the nervous system, such as meningoencephalitis, myelitis, polyradiculitis, and polyradiculoneuropathy. In this report, we describe the clinical and laboratory findings of two patients with encephalitis associated with chikungunya in a northeastern city in Brazil, who exhibited a good outcome, with improvement after treatment with i.v. immunoglobulin (IVIg).

MR imaging of adult acute infectious encephalitis

BACKGROUND

Imaging is a key tool for the diagnosis of acute encephalitis. Brain CT scan must be urgently performed to rule out a brain lesion with mass effect that would contraindicate lumbar puncture. Brain MRI is less accessible than CT scan, but can provide crucial information with patients presenting with acute encephalitis.

METHOD

We performed a literature review on PubMed on April 1, 2015 with the search terms "MRI" and "encephalitis".

RESULTS

We first described the various brain MRI abnormalities associated with each pathogen of acute encephalitis (HSV, VZV, other viral agents targeting immunocompromised patients or travelers; tuberculosis, listeriosis, other less frequent bacterial agents). Then, we identified specific patterns of brain MRI abnomalies that may suggest a particular pathogen. Limbic encephalitis is highly suggestive of HSV; it also occurs less frequently in encephalitis due to HHV6, syphillis, Whipple's disease and HIV primary infection. Rhombencephalitis is suggestive of tuberculosis and listeriosis. Acute ischemic lesions can occur in patients presenting with severe bacterial encephalitis, tuberculosis, VZV encephalitis, syphilis, and fungal infections.

CONCLUSION

Brain MRI plays a crucial role in the diagnosis of acute encephalitis. It detects brain signal changes that reinforce the clinical suspicion of encephalitis, especially when the causative agent is not identified by lumbar puncture; it can suggest a particular pathogen based on the pattern of brain abnormalities and it rules out important differential diagnosis (vascular, tumoral or inflammatory causes).

Spectral characterisation, antiviral activities, in silico ADMET and molecular docking of the compounds isolated from Tectona grandis to chikungunya virus

Chikungunya infection is treated symptomatically with antipyretics and anti-inflammatory drugs without any specific antiviral drug till date. The lack of an approved antiviral drug and the emergence of virulent strains after 2006 epidemics emphasize the need for the development of potential antiviral drugs to Chikungunya virus. Hence, we studied the antiviral activity of the extracts and compounds isolated from Tectona grandis leaves to both the Asian and East central South African strains of Chikungunya virus. Five compounds were isolated from the ethanolic extract of Tectona grandis by bioactivity guided fractionation followed by Spectral Characterisation through GC-MS and NMR spectroscopy and investigated for the antiviral activity. Also in silico ADMET and Molecular Docking of the characterised compounds against the structural and non structural proteins of Chikungunya virus were performed. The characterised compound Benzene-1-carboxylic acid hexadeconate was effective at IC 50 3.036μg/ml (7.5μM) and 76.46μg/ml (189.02μM) to Asian and ECSA strain of CHIKV respectively. The compound showed desirable pharmacokinetic properties and significant molecular interactions with the E1 protein of Chikungunya virus by in silico analysis. Thus Benzene-1-carboxylic acid-2-hexadeconate isolated from Tectona grandis was found to be a promising drug candidate to both the Asian and ECSA strains of Chikungunya virus with high selectivity indices in comparison to the reference RNA antiviral drug Ribavirin.

Arbovirus Infections

PURPOSE OF REVIEW

Arbovirus (arthropod-borne virus) infections are increasingly important causes of neurologic disease in the United States through both endemic transmission and travel-associated infections. This article reviews the major arbovirus infections that can cause neurologic disease likely to be encountered in the United States.

RECENT FINDINGS

West Nile virus continues to be an important cause of epidemic encephalitis, while emerging arbovirus infections such as dengue and chikungunya have rapidly expanded their geographic distribution. As emerging arboviruses expand in new geographic regions, neurologic abnormalities are reported in new patient populations.

SUMMARY

Emerging arbovirus infections are increasingly important causes of neurologic disease throughout the world and in the United States. While no US Food and Drug Administration (FDA)-approved therapy is yet available for these infections, prompt recognition and diagnosis from the consulting neurologist will ensure appropriate supportive care for the patient.

Neonatal encephalitis due to Chikungunya vertical transmission: First report in Brazil

PURPOSE

To report the first case of Chikungunya encephalitis acquired in the perinatal period during the current outbreak in Brazil.

METHODS

Case report.

RESULTS

A male neonate with 3500 g developed macular erythematous rash, hypoactivity and fever progressing to generalized seizures. His mother had experienced a disseminated rash and fever before delivery. EEG showed diffuse slowing and cranial NMR was suggestive of encephalitis. Rt-PCR for Chikungunya virus (CHIKV) was positive in cerebrospinal fluid (CSF), blood, urine and saliva. The newborn was discharged home with neurological improvement.

CONCLUSION

We report the first case of a perinatal CHIKV infection associated with a rapidly evolving encephalitis and an extensive dissemination of the virus as documented by positive rt-PCR results in CSF, blood, urine and saliva in the present outbreak in Brazil. In countries experiencing outbreaks of CHIKV infections, clinicians and neonatologists must be familiar with the possibility of the occurrence of neurologic complications and its possible consequences.

Encephalitic Arboviruses: Emergence, Clinical Presentation, and Neuropathogenesis

Arboviruses are arthropod-borne viruses that exhibit worldwide distribution, contributing to systemic and neurologic infections in a variety of geographical locations. Arboviruses are transmitted to vertebral hosts during blood feedings by mosquitoes, ticks, biting flies, mites, and nits. While the majority of arboviral infections do not lead to neuroinvasive forms of disease, they are among the most severe infectious risks to the health of the human central nervous system. The neurologic diseases caused by arboviruses include meningitis, encephalitis, myelitis, encephalomyelitis, neuritis, and myositis in which virus- and immune-mediated injury may lead to severe, persisting neurologic deficits or death. Here we will review the major families of emerging arboviruses that cause neurologic infections, their neuropathogenesis and host neuroimmunologic responses, and current strategies for treatment and prevention of neurologic infections they cause.

The Multifactorial Background of Emerging Viral Infections with Neurological Manifestation

The events of the past year have highlighted the continuing importance of emerging virus infections on the diagnosis and treatment of neurological disease. This review focusses on clarifying the effects of the multiple overlapping factors that impact emergence, including viral richness, transmission opportunity, and establishment. Case studies of the West Nile, chikungunya, and Zika viruses are utilised to illustrate the dramatic effects of expansion in the range and geographical distribution of emerging infectious disease, the acquisition of new virus vectors, and of increasing human anthropogenic factors such as global transport, climate change, and mosquito abatement programmes on the regional spread and clinical consequences of emerging infectious disease.

Neurotropic virus infections as the cause of immediate and delayed neuropathology

A wide range of viruses from different virus families in different geographical areas, may cause immediate or delayed neuropathological changes and neurological manifestations in humans and animals. Infection by neurotropic viruses as well as the resulting immune response can irreversibly disrupt the complex structural and functional architecture of the central nervous system, frequently leaving the patient or affected animal with a poor or fatal prognosis. Mechanisms that govern neuropathogenesis and immunopathogenesis of viral infections are highlighted, using examples of well-studied virus infections that are associated with these alterations in different populations throughout the world. A better understanding of the molecular, epidemiological and biological characteristics of these infections and in particular of mechanisms that underlie their clinical manifestations may be expected to provide tools for the development of more effective intervention strategies and treatment regimens.