Acute cerebellar ataxia due to Epstein-Barr virus

Acute cerebellar ataxia due to Epstein-Barr virus under administration of an immune checkpoint inhibitor

A 71-year-old male patient with adenocarcinoma of the lung and contralateral lung metastasis under administration of pembrolizumab had symptoms of cerebellar ataxia. We suspected that the symptoms were immune-related adverse events (irAE), but the patient was subsequently diagnosed as cerebellitis due to Epstein-Barr virus (EBV) infection. After steroid pulse therapy, the symptoms of cerebellar ataxia improved immediately. Immune checkpoint inhibitors (ICI) can induce neurological adverse events and cause acute cerebellar ataxia. Initially, irAEs were suspected in this case. His clinical data suggested that reactivation of the virus had occurred because the ICI affected his immune system. This is the first report of a case of acute cerebellar ataxia due to EBV under administration of an ICI.

Barr humbug: acute cerebellar ataxia due to Epstein-Barr virus

Epstein-Barr virus (EBV) infection is associated with neurological sequellae, but rarely there is acute cerebellar ataxia (ACA) in an adult. We present a novel case of a 26-year-old man, who presented with ACA. He had normal MRI and CSF analysis. Serum testing confirmed active EBV. A course of oral prednisolone 1 mg/kg for 4 weeks, with a subsequent taper was started. He made a full recovery within 3 weeks of presentation.

Gammaherpesvirus Infection of Human Neuronal Cells

Gammaherpesviruses human herpesvirus 4 (HHV4) and HHV8 are two prominent members of the herpesvirus family associated with a number of human cancers. HHV4, also known as Epstein-Barr virus (EBV), a ubiquitous gammaherpesvirus prevalent in 90 to 95% of the human population, is clinically associated with various neurological diseases such as primary central nervous system lymphoma, multiple sclerosis, Alzheimer's disease, cerebellar ataxia, and encephalitis. However, the possibility that EBV and Kaposi's sarcoma-associated herpesvirus (KSHV) can directly infect neurons has been largely overlooked. This study has, for the first time, characterized EBV infection in neural cell backgrounds by using the Sh-Sy5y neuroblastoma cell line, teratocarcinoma Ntera2 neurons, and primary human fetal neurons. Furthermore, we also demonstrated KSHV infection of neural Sh-Sy5y cells. These neuronal cells were infected with green fluorescent protein-expressing recombinant EBV or KSHV. Microscopy, genetic analysis, immunofluorescence, and Western blot analyses for specific viral antigens supported and validated the infection of these cells by EBV and KSHV and showed that the infection was efficient and productive. Progeny virus produced from infected neuronal cells efficiently infected fresh neuronal cells, as well as peripheral blood mononuclear cells. Furthermore, acyclovir was effective at inhibiting the production of virus from neuronal cells similar to lymphoblastoid cell lines; this suggests active lytic replication in infected neurons in vitro. These studies represent a potentially new in vitro model of EBV- and KSHV-associated neuronal disease development and pathogenesis.

IMPORTANCE

To date, no in vitro study has demonstrated gammaherpesvirus infection of neuronal cells. Moreover, worldwide clinical findings have linked EBV to neuronal pathologies, including multiple sclerosis, primary central nervous system lymphoma, and Alzheimer's disease. In this study, for the first time, we have successfully demonstrated the in vitro infection of Sh-Sy5y and Ntera2 cells, as well as human primary neurons. We have also determined that the infection is predominately lytic. Additionally, we also report infection of neuronal cells by KSHV in vitro similar to that by EBV. These findings may open new avenues of consideration related to neuronal pathologies and infection with these viruses. Furthermore, their contribution to chronic infection linked to neuronal disease will provide new clues to potential new therapies.

Multiple system atrophy of the cerebellar type: clinical state of the art

Multiple system atrophy (MSA) is a late-onset, sporadic neurodegenerative disorder clinically characterized by autonomic failure and either poorly levodopa-responsive parkinsonism or cerebellar ataxia. It is neuropathologically defined by widespread and abundant central nervous system α-synuclein-positive glial cytoplasmic inclusions and striatonigral and/or olivopontocerebellar neurodegeneration. There are two clinical subtypes of MSA distinguished by the predominant motor features: the parkinsonian variant (MSA-P) and the cerebellar variant (MSA-C). Despite recent progress in understanding the pathobiology of MSA, investigations into the symptomatology and natural history of the cerebellar variant of the disease have been limited. MSA-C presents a unique challenge to both clinicians and researchers alike. A key question is how to distinguish early in the disease course between MSA-C and other causes of adult-onset cerebellar ataxia. This is a particularly difficult question, because the clinical framework for conceptualizing and studying sporadic adult-onset ataxias continues to undergo flux. To date, several investigations have attempted to identify clinical features, imaging, and other biomarkers that may be predictive of MSA-C. This review presents a clinically oriented overview of our current understanding of MSA-C with a focus on evidence for distinguishing MSA-C from other sporadic, adult-onset ataxias.

Ataxia and Encephalitis in a Young Adult with EBV Mononucleosis: A Case Report

Neurological manifestations of mononucleosis are extremely rare, occurring in about 1% of all cases. However, when they occur, appropriate treatment must be undertaken to ensure appropriate symptomatic management and reduce morbidity. We present the case of a 25-year-old graduate student with weeklong complaints of fever, sore throat, fatigue, nausea, and "dizziness." She later developed increased sleep requirements, ataxia, vertigo, and nystagmus with a positive EBV IgM titer confirming acute infectious mononucleosis. The patient was clinically diagnosed with EBV-associated cerebellitis and encephalitis, displaying neurological and psychiatric impairment commonly seen in postconcussion syndrome. MRI showed no acute changes. She was started on valacyclovir and a prednisone taper, recovering by the end of twelve weeks. Though corticosteroids and acyclovir are not recommended therapy in patients presenting with EBV-associated ataxia, clinicians may want to keep a low threshold to start these medications in case more serious neurological sequelae develop.

Epstein-Barr virus-associated cerebellar ataxia

Cerebellar ataxia is a common neurological presentation. It can be acute, subacute or chronic. Neurological complications of Epstein-Barr virus (EBV) are well-recognised with a variety of presentations. Acute cerebellar ataxia is a rare, but an established complication. It has been described as the sole manifestation of EBV infection without the systemic features of infectious mononucleosis. The pathophysiology is not clear. The course of the illness may last for a few months with a benign outcome, though serious complications can happen. We present a case of a 38-year-old man who presented with an acute cerebellar ataxia owing to EBV infection, along with a review of the literature.