Magnetic resonance imaging of the spinal cord in the evaluation of 3 patients with sensory neuronopathies: Diagnostic assessment, indications of treatment response, and impact of autoimmunity: A case report

Rationale: Sensory neuronopathy can be a devastating peripheral nervous system disorder. Profound loss in joint position is associated with sensory ataxia, and reflects degeneration of large-sized dorsal root ganglia. Prompt recognition of sensory neuronopathies may constitute a therapeutic window to intervene before there are irreversible deficits. However, nerve-conduction studies may be unrevealing early in the disease course. In such cases, the appearance of dorsal column lesions on spinal-cord MRI can help in the diagnosis. However, most studies have not defined whether such dorsal column lesions may occur within earlier as well as chronic stages of sensory neuronopathies, and whether serial MRI studies can be used to help assess treatment efficacy. In this case-series of three sensory neuronopathy patients, we report clinical characteristics, immunological markers, nerve-conduction and skin-biopsy studies, and neuroimaging features. Patient concerns: All three patients presented with characteristic features of sensory neuronopathy with abnormal spinal-cord MRI studies. Radiographic findings included non-enhancing lesions in the dorsal columns that were longitudinally extensive (spanning-≥-3 vertebral segments). Diagnoses: All patients had anti-Ro/SS-A and/or anti-La/SS-B antibodies, with patients one and two having Sjögren's syndrome. MRI findings were similar when performed in the earlier stages of a sensory neuronopathy (patient one, after four months) and chronic stages (patients two and three, after five and three years, respectively). Interventions: Patient one was treated with rituximab combined with intravenous immunoglobulin therapy. Outcomes: Patient one was initially wheelchair-bound and had improved ambulation after treatment. In this patient, serial MRI studies revealed partial resolution of dorsal column lesions, associated with decreased sensory ataxia and improved nerve-conduction studies. Lessons: In addition to vitamin B12 and copper deficiency, it is important to include sensory neuronopathies in the differential diagnosis of dorsal column lesions. MRI spinal-cord lesions have similar appearances in the earlier as well as chronic phases of a sensory neuronopathy, and therefore suggest that such dorsal column lesions may reflect inflammatory as well as a gliotic burden of injury. MRI may also be a useful longitudinal indicator of treatment response.