Delayed-onset and recurrent limb weakness associated with West Nile virus infection

Primary, secondary or less frequent causes of immune thrombocytopenia: A case report

Primary immune thrombocytopenia (ITP) is characterized by isolated low platelet count and it is a diagnosis of exclusion, contrasting to secondary ITP. Therefore, a positive diagnosis is difficult and requires extensive investigation. Some of the underlying conditions that are associated with ITP are lymphoproliferative disorders and infections, especially viral ones. In the present study, the case of a patient diagnosed with diffuse large B-cell lymphoma, who received chemotherapy and autologous hematopoietic stem cell transplantation is presented. After a complete remission of four years, the patient presented with sudden intense hemorrhagic syndrome and severely decreased platelet count. The most frequent causes of secondary ITP were excluded, including lymphoma relapse, and intravenous corticosteroids were started. However, shortly after hospital admission, the patient developed neuro-psychiatric anomalies, fever and pancytopenia, and West-Nile encephalitis was diagnosed. Although the initial development was favorable, he started to complain of progressive severe muscle weakness and eventually succumbed to infectious complications in the setting of prolonged hospitalization, corticotherapy, and immobilization.

Long-term, West Nile virus-induced neurological changes: A comparison of patients and rodent models

West Nile virus (WNV) is a mosquito-borne virus that can cause severe neurological disease in those infected. Those surviving infection often present with long-lasting neurological changes that can severely impede their lives. The most common reported symptoms are depression, memory loss, and motor dysfunction. These sequelae can persist for the rest of the patients’ lives. The pathogenesis behind these changes is still being determined. Here, we summarize current findings in human cases and rodent models, and discuss how these findings indicate that WNV induces a state in the brain similar neurodegenerative diseases. Rodent models have shown that infection leads to persistent virus and inflammation. Initial infection in the hippocampus leads to neuronal dysfunction, synapse elimination, and astrocytosis, all of which contribute to memory loss, mimicking findings in neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). WNV infection acts on pathways, such as ubiquitin-signaled protein degradation, and induces the production of molecules, including IL-1β, IFN-γ, and α-synuclein, that are associated with neurodegenerative diseases. These findings indicate that WNV induces neurological damage through similar mechanisms as neurodegenerative diseases, and that pursuing research into the similarities will help advance our understanding of the pathogenesis of WNV-induced neurological sequelae.

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In patients with and without diagnosed WNND, there are long-lasting neurological sequelae that can mimic neurodegenerative diseases.

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Some rodent models of WNV reproduce some of these changes with mechanisms similar to neurodegenerative diseases.

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There is significant overlap between WNV and ND pathogenesis and this has been understudied.

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Further research needs to be done to determine accuracy of animal models compared to human patients.

Acute Flaccid Myelitis: Current Status and Diagnostic Challenges

Acute flaccid myelitis (AFM) is a sudden-onset polio-like neuromuscular disability found commonly in young children. There is an increasing incidence of confirmed AFM cases in the USA and other countries in recent years, and in association with nonpolio enterovirus infection. This represents a significant challenge to clinicians and causes significant concern to the general public. Acute flaccid paralysis (AFP) is the long-known limb paralytic syndrome caused by a viral pathogen. AFM is a subset of AFP that is also characterized by a limb paralytic condition, but it has certain distinct features such as lesions in magnetic resonance imaging of the spinal cord gray matter. AFM leads to spinal cord, brainstem, or motor neuron dysfunction. The clinical phenotypes, pathology, and patient presentation of AFM closely mimic AFP. This article provides a concise overview of our current understanding of AFM and the clinical features that distinguish AFM from AFP and similar other neurological infectious and autoimmune diseases or disorders. We also discuss the diagnosis, clinical pathology, possible pathogenetic mechanisms, and currently available therapies.

Acute Flaccid Myelitis: Characteristics and Outcomes of 2014 and 2016 Cases at a Single Center

Acute flaccid myelitis (AFM) is a rare condition associated with spinal cord gray matter abnormalities and frequent persistent motor deficits in the limbs. We present our experience with the diagnosis, management, and outcomes of affected children in 2014 and 2016, emphasizing features that should trigger early consideration of AFM. Early viral testing may increase the rate of detecting associated viruses.

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.

West Nile Virus Infection

Although long recognized as a human pathogen, West Nile virus (WNV) emerged as a significant public health problem following its introduction and spread across North America. Subsequent years have seen a greater understanding of all aspects of this viral infection. The North American epidemic resulted in a further understanding of the virology, pathogenesis, clinical features, and epidemiology of WNV infection. Approximately 80% of human WNV infections are asymptomatic. Most symptomatic people experience an acute systemic febrile illness; less than 1% of infected people develop neuroinvasive disease, which typically manifests as meningitis, encephalitis, or anterior myelitis resulting in acute flaccid paralysis. Older age is associated with more severe illness and higher mortality; other risk factors for poor outcome have been challenging to identify. In addition to natural infection through mosquito bites, transfusion- and organ transplant-associated infections have occurred. Since there is no definitive treatment for WNV infection, protection from mosquito bites and other preventative measures are critical. WNV has reached an endemic pattern in North America, but the future epidemiologic pattern is uncertain.

Primary Versus Nonprimary West Nile Virus Infection: A Cohort Study

BACKGROUND

Since 2001, we have observed patients with a clinical picture consistent with West Nile virus (WNV) infection, which was defined as nonprimary infection (NPI) owing to the presence of highly elevated serum immunoglobulin G antibody titers with a high avidity index (≥ 55%), absent or low titers of serum and cerebrospinal fluid (CSF) immunoglobulin M, and occasionally positive results of WNV-specific real-time reverse-transcription polymerase chain reaction analysis of CSF and/or blood specimens.

METHODS

We investigated 124 patients with a diagnosis of primary WNV infection (PI) or NPI during 2005-2007 at Sheba Medical Center (Tel-Hashomer, Israel). Logistic regression was used to evaluate the association of variables with PI and NPI and with in-hospital mortality.

RESULTS

A total of 68 and 50 patients with PI and NPI, respectively were included; 6 patients had incomplete data. In multivariate models, NPI was significantly associated with underlying psychiatric disorders (adjusted odds ratio [aOR], 13.73; 95% confidence interval [CI], 2.28-82.56; P = .004), hospitalization during winter and spring (aOR, 8.82; 95% CI, 1.59-48.87; P = .013), and fever (aOR, 0.61; 95% CI, .39-.95; P = .031). In-hospital mortality was significantly associated with NPI (aOR, 3.86; 95% CI, 1.12-13.28; P = .032) and a higher Charlson comorbidity index (aOR, 1.37; 95% CI, 1.03-1.83; P = .032).

CONCLUSIONS

The possibility that NPI may be an emerging clinical entity with a high mortality rate must be considered seriously.

Delayed-onset flaccid paralysis related to west Nile virus reactivation following treatment with rituximab: a case report

BACKGROUND

Neurological manifestations of West Nile virus infection include meningitis, encephalitis and acute flaccid paralysis. Typically, West Nile virus-associated acute flaccid paralysis is characterized by acute and rapidly progressing limb weakness, occurring early in the course of the disease.

CASE PRESENTATION

We report a patient of Yemenite descent who developed West Nile virus-encephalitis and poliomyelitis two weeks following treatment with rituximab for B cell lymphoma, and delayed encephalitis with ascending demyelinating polyneuropathy 6 months later. Diagnosis of the first episode was based on a high West Nile virus copy number in the blood polymerase chain reaction. During the second episode the patient developed encephalitis and flaccid asymmetric quadriparesis, accompanied by high IgM anti-West Nile virus titers in the blood and cerebrospinal fluid.

CONCLUSION

The delayed polyneuropathy post-West Nile virus infection and encephalitis/poliomyelitis may be related to reactivation of the virus or to a delayed autoimmune (post-infectious) process, possibly accelerated by the recovering B-cell humoral immunity, 6 months after treatment with rituximab. This case depicts the complexities of the immune responses and their reconstitution following monoclonal antibody treatment and the diversity of neurological syndromes associated with West Nile virus infection.

West Nile virus: should pediatricians care?

Given the recurrent serious outbreaks of West Nile Virus (WNV) in the United States over the past decade, the spread to Canada and South America, the recurrent outbreaks in Europe, and the potential for serious neurological disease even in children under 18 years, paediatricians in affected areas must consider WNV in the differential diagnosis of all children presenting with aseptic meningitis, encephalitis and acute flaccid paralysis. Additionally, given that WNV encephalitis can occur after WNV infection, suspicion for neurological WNV disease must remain high even after otherwise benign febrile illnesses if the child lives in or has traveled to an affected region. Under-diagnosis in the pediatric population is likely a serious problem, necessitating further educational efforts. More follow-up studies of WNV neurological disease in children and youth are needed to better understand the potential long-term sequelae during vulnerable times of neurodevelopment and neural remodeling. Similarly, more research is need on short and long-term fetal outcomes of maternal WNV infection.

Clinical manifestations and outcomes of West Nile virus infection

Since the emergence of West Nile virus (WNV) in North America in 1999, understanding of the clinical features, spectrum of illness and eventual functional outcomes of human illness has increased tremendously. Most human infections with WNV remain clinically silent. Among those persons developing symptomatic illness, most develop a self-limited febrile illness. More severe illness with WNV (West Nile neuroinvasive disease, WNND) is manifested as meningitis, encephalitis or an acute anterior (polio) myelitis. These manifestations are generally more prevalent in older persons or those with immunosuppression. In the future, a more thorough understanding of the long-term physical, cognitive and functional outcomes of persons recovering from WNV illness will be important in understanding the overall illness burden.

Unusual case of West Nile Virus flaccid paralysis in a 10-year-old child

West Nile virus infection is asymptomatic in most cases. West Nile virus neuroinvasive disease includes encephalitis, meningitis, and/or acute flaccid paralysis. In children, acute flaccid paralysis as the solo presentation of West Nile virus disease is rare. It develops abruptly and progresses rapidly early in the disease course. We report on a 10-year-old child who presented with a slowly progressive left leg flaccid paralysis over 4 weeks. He tested positive for West Nile virus in both blood and cerebrospinal fluid. Spinal MRI showed enhancement of the ventral nerve roots. This was also supported by electrophysiological studies. One week after the plateauing of his left leg paralysis, he was readmitted to the hospital with left hand weakness. Complete recovery of his recurrent weakness was observed after prompt 5-day course of intravenous immunoglobulin G therapy. However, no improvement was noticed in the left foot drop. To our knowledge, this is the first case report of West Nile virus disease in children presented with a slowly progressive flaccid paralysis, and a recurrent weakness recovered after intravenous immunoglobulin G administration.

Immune responses to West Nile virus infection in the central nervous system

West Nile virus (WNV) continues to cause outbreaks of severe neuroinvasive disease in humans and other vertebrate animals in the United States, Europe, and other regions of the world. This review discusses our understanding of the interactions between virus and host that occur in the central nervous system (CNS), the outcome of which can be protection, viral pathogenesis, or immunopathogenesis. We will focus on defining the current state of knowledge of WNV entry, tropism, and host immune response in the CNS, all of which affect the balance between injury and successful clearance.

Hypothyroid myopathy mimicking postpolio syndrome

Hypothyroidism can have diverse neurological manifestations. Myopathy may rarely be the sole manifestation of autoimmune thyroiditis. We hereby report an atypical manifestation of severe hypothyroidism in a middle-aged woman with childhood onset of paralytic polio involving her right leg presenting with a recent onset of increased weakness in the right leg mimicking postpolio syndrome.

Neuroinvasive flavivirus infections

Flaviviruses, including Dengue, West Nile, Japanese encephalitis, and Tick-borne encephalitis virus, are major emerging human pathogens, affecting millions of individuals worldwide. Many clinically important flaviviruses elicit CNS diseases in infected hosts, including traditional "hemorrhagic" viruses, such as Dengue. This review focuses on the epidemiology, symptomatology, neuropathology, and, specifically, neuropathogenesis of flavivirus-induced human CNS disease. A detailed insight into specific factors priming towards neuroinvasive disease is of clear clinical significance, as well as importance to the development of antiviral therapies and identification of key mechanisms involved in the (re)emergence of specific flaviviruses, including potentially novel or previously unrecognized ones, as neuroinvasive pathogens.