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.

Cerebellar ataxia and sensory ganglionopathy associated with light-chain myeloma

Background

Cerebellar ataxia with sensory ganglionopathy is a rare neurological combination that can occur in some hereditary ataxias including mitochondrial diseases and in gluten sensitivity. Individually each condition can be a classic paraneoplastic neurological syndrome. We report a patient with this combination who was diagnosed with light-chain myeloma ten years after initial presentation.

Case presentation

A 65-year-old Caucasian lady was referred to our Ataxia Clinic because of a 6-year history of progressive unsteadiness and a 2-year history of slurred speech. Past medical history included arterial hypertension. The patient was a non-smoker was not consuming alcohol excessively. There was no family history of ataxia.

Neurological examination revealed prominent gaze-evoked nystagmus, heel to shin ataxia, gait ataxia, reduced reflexes and loss of vibration sensation in the legs.

Cerebellar ataxia was confirmed using magnetic resonance spectroscopy of the cerebellum and sensory ganglionopathy using neurophysiological assessments including blink reflex study. A muscle biopsy that was arranged to explore the possibility of mitochondrial disease revealed amyloidosis. Urinalysis confirmed the presence of light chains. A bone marrow biopsy confirmed the diagnosis of light chain multiple myeloma.

Conclusions

Whilst it could be argued that this could simply be a coincidence, the rarity of these conditions and the absence of an alternative aetiology for the neurological dysfunction argue in favour of a paraneoplastic phenomenon.

Electronic supplementary material

The online version of this article (doi:10.1186/s40673-016-0060-4) contains supplementary material, which is available to authorized users.

Sweat Gland Denervation in Cerebellar Ataxia with Neuropathy and Vestibular Areflexia Syndrome (CANVAS)

Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a newly recognized disorder characterized by cerebellar ataxia, nonlength-dependent sensory impairment, and bilateral vestibular loss. Sudomotor dysfunction has been described in CANVAS; however, the underlying pathology is not well characterized. To describe novel histopathological features of this syndrome, 2 siblings are presented who had CANVAS with unique findings of sweat gland denervation. Skin biopsy testing was performed to assess sudomotor structure and revealed markedly reduced sweat gland nerve fiber density below the 2.5th percentile in both patients. These histopathological findings suggest that postganglionic sudomotor dysfunction is an additional feature of CANVAS.