Acute cerebellar ataxia with human parvovirus B19 infection

Neurological Manifestations Associated with Parvovirus B19 Infection in Immunocompetent Children: Case Series and Systematic Review

An increasing number of reports have described human parvovirus B19 infection in association with a variety of neurological manifestations, especially in children. This study assessed the clinical and laboratory outcomes found in a case series of immunocompetent children who tested positive for parvovirus B19 by qualitative polymerase chain reaction assays of cerebrospinal fluid, in a tertiary referral center in the western Brazilian Amazon. We screened 178 children with clinically diagnosed central nervous system infections (meningoencephalitis). Of these, five (2.8%) were positive for parvovirus B19. A literature review also presented herein identified a further 50 cases of parvovirus B19 with neurological manifestations. Thus, even if the classic signs of parvovirus B19 infection are absent, such as the well-known rash, children with signs of neurological infection should also be evaluated for parvovirus B19 infection.

Acute ataxia in children: Common causes and yield of diagnostic work-up in the era of varicella vaccination

We aimed to identify the most common causes of acute ataxia in children in the era of widespread varicella vaccination and the yield of commonly used diagnostic work-up. This retrospective study reviewed the medical records of children who presented with ataxia of less than 72 h duration, over the last 12 years. Associated signs and symptoms, laboratory, EEG and neuroimaging studies, final diagnosis and clinical findings at discharge and during follow-up were studied. A total of 58 patients (35 boys, 23 girls), mean age 4.9 ± 3.8 years, were enrolled. The most common etiology of acute ataxia in our study was post-infectious acute cerebellar ataxia (50%). Children diagnosed with post-infectious acute cerebellar ataxia were significantly younger (3.48 ± 2.23 vs. 6.5 ± 3.1 years, p = 0.01), as compared with children diagnosed with infection and acute disseminated encephalomyelitis. 86% of children with post-infectious cerebellar ataxia were younger than 5 years of age. The abnormality yield of work-up studies performed in our cohort was 39% for lumbar puncture, 36% for EEG, 7% for CT scan. MRI was done in children who showed extra cerebellar signs, when vascular or demyelinating diseases were suspected and in children with prolonged symptoms and was abnormal in 8 (14%) children. We conclude that post-infectious acute cerebellar ataxia remains the most common cause of acute ataxia in children. Although lumbar puncture and neuroimaging should be considered in all children with acute cerebellar ataxia, younger children with a history of previous viral illness and no extra cerebellar signs and symptoms may benefit from watchful waiting.

Acute Ataxia in Childhood: 11-Year Experience at a Major Pediatric Neurology Referral Center

We categorized the causes of acute ataxia in the pediatric population-referred to the Division of Neurology-at a large, urban pediatric medical center. Of the 120 cases identified over the past 11 years, post-infectious cerebellar ataxia was the most commonly diagnosed (59%), followed by drug intoxication, opsoclonus-myoclonus ataxia syndrome, episodic ataxia, acute cerebellitis, cerebellar stroke, ADEM, meningitis, cerebral vein thrombosis, Leigh's disease, Miller-Fisher syndrome, and concussion. Among the patients with post-infectious cerebellar ataxia, 85% were 1-6 years old and all had a history of antecedent viral illness. CSF pleocytosis was present in 40% of patients; all had normal brain MRIs. The majority (91%) recovered within 30 days. We conclude that post-infectious cerebellar ataxia remains the most common cause of acute ataxia in childhood and that it carries a good prognosis. We also differentiate acute post-infectious cerebellar ataxia from other causes with similar presentations.

The role of parvovirus B19 in the pathogenesis of autoimmunity and autoimmune disease

Human parvovirus B19 is a single-stranded DNA virus which preferentially targets the erythroblasts in the bone marrow. B19 infection commonly causes erythema infectiosum, arthralgia, fetal death, transient aplastic crisis in patients with shortened red cell survival, and persistent infection in people who are immunocompromised. Less common clinical manifestations include atypical skin rashes, neurological syndromes, cardiac syndromes, and various cytopenias. B19 infection has also been associated with development of a variety of different autoimmune diseases, including rheumatological, neurological, neuromuscular, cardiovascular, haematological, nephrological and metabolic. Production of a variety of autoantibodies has been demonstrated to occur during B19 infection and these have been shown to be key to the pathogenesis of the particular disease process in a significant number of cases, for example, production of rheumatoid factor in cases of B19-associated rheumatoid arthritis and production of anti-glutamic acid decarboxylase (GAD) in patients with B19-associated type 1 diabetes mellitus. B19 infection has also been associated with the development of multiple autoimmune diseases in 12 individuals. Documented mechanisms in B19-associated autoimmunity include molecular mimicry (IgG antibody to B19 proteins has been shown to cross react with a variety of recognised human autoantigens, including collagen II, keratin, angiotensin II type 1 receptor, myelin basic protein, cardiolipin, and platelet membrane glycoprotein IIb/IIIa), B19-induced apoptosis with presentation of self-antigens to T lymphocytes, and the phospholipase activity of the B19 unique VP1 protein.

Neurological aspects of human parvovirus B19 infection: a systematic review

Parvovirus B19 has been linked with various clinical syndromes including neurological manifestations. However, its role in the latter remains not completely understood. Although the last 10 years witnessed a surge of case reports on B19-associated neurological aspects, the literature data remains scattered and heterogeneous, and epidemiological information on the incidence of B19-associated neurological aspects cannot be accurately extrapolated. The aim of this review is to identify the characteristics of cases of B19-associated neurological manifestations. A computerized systematic review of existing literature concerning cases of B19-related neurological aspects revealed 89 articles describing 129 patients; 79 (61.2%) were associated with CNS manifestations, 41 (31.8%) were associated with peripheral nervous system manifestations, and 9 (7.0%) were linked with myalgic encephalomyelitis. The majority of the cases (50/129) had encephalitis. Clinical characteristic features of these cases were analyzed, and possible pathological mechanisms were also described. In conclusion, B19 should be included in differential diagnosis of encephalitic syndromes of unknown etiology in all age groups. Diagnosis should rely on investigation of anti-B19 IgM antibodies and detection of B19 DNA in serum or CSF. Treatment of severe cases might benefit from a combined regime of intravenous immunoglobulins and steroids. To confirm these outcomes, goal-targeted studies are recommended to exactly identify epidemiological scenarios and explore potential pathogenic mechanisms of these complications. Performing retrospective and prospective and multicenter studies concerning B19 and neurological aspects in general, and B19 and encephalitic syndromes in particular, are required. © 2014 The Authors. Reviews in Medical Virology published by John Wiley & Sons, Ltd.

Acute cerebellar ataxia, acute cerebellitis, and opsoclonus-myoclonus syndrome

Acute cerebellar ataxia and acute cerebellitis represent a process characterized by parainfectious, postinfectious, or postvaccination cerebellar inflammation. There is considerable overlap between these entities. The mildest cases of acute cerebellar ataxia represent a benign condition that is characterized by acute truncal and gait ataxia, variably with appendicular ataxia, nystagmus, dysarthria, and hypotonia. It occurs mostly in young children, presents abruptly, and recovers over weeks. Neuroimaging is normal. Severe cases of cerebellitis represent the other end of the spectrum, presenting with acute cerebellar signs often overshadowed by alteration of consciousness, focal neurological deficits, raised intracranial pressure, hydrocephalus, and even herniation. Neuroimaging is abnormal and the prognosis is less favorable than in acute cerebellar ataxia. Acute disseminated encephalomyelitis may be confused with acute cerebellitis when the clinical findings are predominantly cerebellar, but lesions on neuroimaging are usually widespread. Paraneoplastic opsoclonus-myoclonus syndrome is often initially misdiagnosed as acute cerebellar ataxia, but has very specific features, course, and etiopathogensis.

Persistent adeno-associated virus 2 and parvovirus B19 sequences in post-mortem human cerebellum

We previously reported in a large cohort (N = 104) of post-mortem tissues the detection of both the non-pathogenic adeno-associated virus (AAV2) in approximately 13% and the pathogenic human parvovirus B19 (B19) in approximately 42% of human brains, particularly the dorsolateral prefrontal cortex. Multiple animal parvoviruses target the developing cerebellum (CBLM) resulting in hypoplasia and ataxia, but very little is known about the human parvoviruses and their ability to infect or cause disease in the CBLM. We have now confirmed in the above cohort the presence of AAV2 and B19 sequences in the CBLM. Our results show that approximately 27% and approximately 70% of human CBLM are positive by nested polymerase chain reaction for AAV2 and B19 sequences, respectively. We also document in a second cohort (N = 10) the presence of AAV2 (50%) and B19 (100%) sequences in the CBLM and correlate our results for B19 with studies from matched sera. Eighty percent (80%) of this cohort was positive for anti-B19 IgG, while none were IgM+, suggesting that most individuals had been previously infected with B19 but none acutely. To our knowledge, this study is the first to demonstrate that both AAV2 and B19 sequences are present at relatively high frequencies in the CBLM and are likely due to persistent rather than acute infection. Further studies will lead to insights into AAV2- and/or B19-CBLM interactions including mechanisms of infection, persistence, and possibly neuropathology, including cerebellar hypoplasia and ataxia.

Severe ataxia as a complication of human parvovirus B19 acute encephalitis in a child

Human parvovirus B19 generally causes erythema infectiosum in childhood, but it can be associated with unusual findings, particularly in immunocompromised patients. This is a report about an immunocompetent 4-year-old female child affected with acute encephalitis by parvovirus B19, documented by polymerase chain reaction performed on cerebrospinal fluid, who was treated with intravenous immunoglobulins and dexamethasone and who developed a cerebellar syndrome with ataxia, dysmetria, and dysarthria. To the best of the authors' knowledge, this may be the first report of human parvovirus B19 encephalitis complicated by severe ataxia in childhood.

Detection of adeno-associated virus 2 and parvovirus B19 in the human dorsolateral prefrontal cortex

Although animal parvoviruses have long been recognized as causes of brain pathology in multiple animal models, especially during early development, human parvoviruses are rarely thought of as neurotropic or causes of neuropathology in humans. However, several recent case reports have suggested possible associations of parvovirus B19 (B19) infection with various neurological and neuropsychiatric symptoms. Adeno-associated virus 2 (AAV2) is related to B19 but has thus far not been shown to be associated with any human disease but is of clinical interest because of the recent use of recombinant AAV vectors in human gene therapy, including gene delivery to the brain. To date, there have been no large-scale studies of the propensity of wild-type human parvoviruses to infect the brain. The Stanley Medical Research Institute Brain Collection offered a unique opportunity to study a large sample (n = 104) of dorsolateral prefrontal cortex (DLPC) DNAs isolated from unaffected control, schizophrenic, and bipolar disorder brains for the presence of parvoviral sequences. This is the first investigator-blinded study to document the presence of parvoviral sequences in the DLPC by utilizing highly sensitive nested polymerase chain reaction (nPCR) and DNA sequencing. Of the overall sample, 6.7% to 12.5% were positive for AAV2, and 14.4% to 42.3% were positive for B19 sequences, with no statistical differences among subgroups. This is the first report to demonstrate the presence of human parvoviruses in a large cohort of adult DLPC, which underscores the need to gain a better insight into the basic biology of parvovirus-brain interactions, including mechanisms of infection and persistence.

Post-infectious acute cerebellar ataxia in children

Acute cerebellar ataxia is a relatively common neurologic disorder among children. Our aim was to characterize the clinical picture, etiology, and prognosis of acute cerebellar ataxia. The medical records of all children with a diagnosis of acute cerebellar ataxia hospitalized in our center and Hasharon Medical Center from 1990 to 2001 were reviewed. The diagnosis of acute cerebellar ataxia was based on the following criteria: acute onset of ataxia with or without nystagmus; absence of known genetic predisposing factors, such as familial degenerative disorders; and absence of drug intoxication, bacterial meningitis, and metabolic disorders. Thirty-nine children were identified; 54% were male; mean age at presentation was 4.8 +/- 3.8 years. All patients were observed for at least 1 year. A prodromal febrile illness was noted in 74.4%: varicella, 31%; mumps, 20%; nonspecific viral infection, 15.4%; mycoplasma, 5%; Epstein Barr virus, 3%. Latency from the prodromal illness to the onset of ataxia was 8.8 +/- 7.4 days. The most common associated neurologic findings were nystagmus and dysmetria. Full gait recovery took less than 2 weeks on average, and the longest duration of neurologic signs was 24 days (mumps-related). Acute cerebellar ataxia in childhood is a self-limited disease. The recovery was faster than that reported in previous publications and was complete in all children without any neurologic sequelae. Imaging studies are needed only in atypical presentation or if there is no spontaneous improvement after 1 to 2 weeks.

Neurological manifestations of human parvovirus B19 infection

Since its discovery, human parvovirus B19 has been linked with a broad spectrum of clinical syndromes. An aetiological role for the virus has been confirmed in erythema infectiosum, transient aplastic crisis, persistent infection manifesting as pure red cell aplasia in immunocompromised persons, non-immune hydrops fetalis and arthritis. Less commonly recognised, but receiving increasing attention recently, are the neurological manifestations, a variety of which have been described in patients with either clinically diagnosed or laboratory confirmed B19 infection. The purpose of this review is to summarise present knowledge of B19, its known and potential pathogenic mechanisms and its association with human diseases, particularly those with neurological manifestations. The outcome of the review supports an aetiological role of the virus in neurological disease. However, the pathogenesis remains unknown and elucidating this is a priority.

Acute cerebellar ataxia in a toddler: case report and literature review

Acute cerebellar ataxia (ACA) is an inflammatory CNS disease that is characterized by rapid onset of ataxia in a child under 6 years of age. Symptoms typically occur in association with a relatively benign viral illness and have been reported after vaccination as well. Immunological studies suggest that both involve autoimmune destruction of axon tracts, with pathological and radiographic evidence of a link with multiple sclerosis. The emergency approach should be focused on excluding more significant illnesses, such as meningitis or an intracranial mass lesion. Here we present a case of a young girl with ACA and review the relevant literature.

Evidence for the role of demyelination, HLA-DR alleles, and cytokines in the pathogenesis of parvovirus B19 meningoencephalitis and its sequelae

OBJECTIVE

To review the clinical and pathological features of parvovirus B19 meningoencephalitis and its sequelae in 12 previously published cases, and to perform additional tests to determine the pathogenesis of the disease.

METHODS

Cases were reviewed and available serum and cerebrospinal fluid (CSF) tested for antiganglioside antibodies and a range of cytokines. In situ hybridisation for parvovirus B19 DNA was performed on postmortem brain tissue in two cases. HLA-DRB1 typing was undertaken on genomic DNA extracted from peripheral blood leucocytes.

RESULTS

Cerebellar involvement was suggested either clinically or pathologically in four cases. In the two cases with postmortem histology, there was marked atrophy of the molecular and granular layers of the cerebellum with focal loss of Purkinje cells. Brain scanning by MRI or CT was done in six cases during the acute phase. Three were abnormal with evidence of demyelination. Three had markedly enlarged ventricles, in two of which there was high signal intensity from the white matter on both T1 and T2 weighted images. The three cases with abnormal brain scans had long term neurological sequelae (mental retardation, personality change, altered affect). In situ hybridisation on available postmortem brain tissue was negative in the two cases tested. All cases in which HLA-DR alleles were determined carried at least one of the following alleles: HLA-DRB1*01, *04, *07, *09, *15, *16. Available serum and CSF was tested for antiganglioside antibodies (all negative) and for a panel of cytokines, which had a similar profile in both serum (n = 5) and CSF (n = 1) during the acute phase. Cytokines that were consistently detectable were IL-6 (mean 726.20 pg/ml), TNFalpha (50.64 pg/ml), IFNgamma (39.64 pg/ml), GM-CSF (216.12 pg/ml), and MCP-1 (154.43 pg/ml); IL-1beta, IL-5, and IL-13 were undetectable.

CONCLUSIONS

HLA-DR associations, an increased cytokine response, and benefit from immunomodulatory treatment (in one case) support a role for the immune response in the pathogenesis of parvovirus B19 meningoencephalitis.

Parvovirus B19 nonstructural (NS1) protein as a transactivator of interleukin-6 synthesis: common pathway in inflammatory sequelae of human parvovirus infections?

This review focuses on the role that human parvovirus B19 nonstructural (NS1) protein as a transactivator of the proinflammatory cytokine, interleukin-6 (IL-6), might play in triggering the multiparametric inflammatory outcomes of B19 infection. Parvovirus B19 is a ubiquitous virus, and it is often expressed during conditions of immunodepression including that induced by long-term chemotherapy, viral infection (HIV, HTLV-1), or genetic immunodeficiency disorders. Through NS1 expression, B19 may contribute to the immune dysregulation associated with these disorders, or serve as a cofactor in enhancing retroviral replication. Hence, NS1 transactivation of proinflammatory cytokine promoters such as IL-6 may be pivotal in triggering the various inflammatory and autoimmune disorders that have been linked to parvovirus B19 infections.