A Case Report of NMO Transverse Myelitis

BACKGROUND

Transverse myelitis is considered one of the cardinal features of neuromyelitis optica spectrum disorder (NMOSD), an immune-mediated inflammatory condition of the CNS characterized by severe, immune-mediated demyelination and axonal damage predominantly targeting optic nerves and spinal cord. We describe a case in which a diagnosis of NMOSD was established, associated with West Nile Virus (WNV) infection.

CASE PRESENTATION

A healthy 18-year-old female presented with intractable hiccups and rapidly progressing paraparesis. MRI demonstrated T2 edema extending from the medulla to the conus, consistent with longitudinally extensive transverse myelitis. Serum and CSF Aquaporin-4 IgG (AQP4) were both positive with high titers. In conjunction with antiviral therapy, immunomodulatory treatment was initiated using pulse methylprednisolone, plasmapheresis and Rituximab. A month and a half after admission, the patient was fully ambulatory with no residual symptoms. On her rheumatology follow-up visit, West Nile Virus-specific IgM in CSF was found to be positive from the patient's initial presentation.

CONCLUSION

We propose that West Nile Virus may have been the autoimmune trigger to the patient's development of NMOSD, highlighting the importance of evaluating viral triggers in autoimmune diseases.

Tumefactive demyelination in pediatrics: An unusual late neurological complication of hematopoietic stem cell transplant

Immune-mediated demyelination is a rare posttransplant complication. Here, we report an 8.5-year-old boy who developed left hemiparesis, 18 months post matched sibling donor hematopoietic stem cell transplant (HSCT) for relapsed acute myeloid leukemia and was diagnosed to have tumefactive demyelination. The diagnosis was established based on clinical and radiological features. The complete resolution of the lesions with steroids further established the immune-mediated pathophysiology.

Cortical grey matter demyelination can be induced by elevated pro-inflammatory cytokines in the subarachnoid space of MOG-immunized rats

A substantial proportion of cases with secondary progressive multiple sclerosis have extensive inflammation in the leptomeninges that is associated with increased subpial demyelination, neuronal loss and an exacerbated disease course. However, the mechanisms underlying this extensive subpial pathology are poorly understood. We hypothesize that pro-inflammatory cytokine production within the meninges may be a key to this process. Post-mortem cerebrospinal fluid and dissected cerebral leptomeningeal tissue from patients with multiple sclerosis were used to study the presence of tumour necrosis factor and interferon gamma protein and messenger RNA levels. A novel model of subpial cortical grey matter demyelination was set up in Dark Agouti rats and analysed using quantitative immunohistochemistry. Increased expression of the pro-inflammatory cytokines tumour necrosis factor and interferon gamma was found in the meninges of cases with secondary progressive multiple sclerosis exhibiting tertiary lymphoid-like structures. Injection of tumour necrosis factor and interferon gamma into the subarachnoid space of female Dark Agouti rats pre-immunized with a subclinical dose of myelin oligodendrocyte glycoprotein mimicked the pathology seen in multiple sclerosis, including infiltration of lymphocytes (CD4+ and CD8+ T cells and CD79+ B cells) into the meninges and extensive subpial demyelination. Extensive microglial/macrophage activation was present in a gradient from the pial surface to deeper cortical layers. Demyelination did not occur in control animals immunized with incomplete Freund's adjuvant and injected with cytokines. These results support the hypothesis that pro-inflammatory molecules produced in the meninges play a major role in cortical demyelination in multiple sclerosis, but also emphasize the involvement of an anti-myelin immune response.