SIADH in a patient with sensory ataxic neuropathy with anti-disialosyl antibodies (CANOMAD)

A Case of Miller-Fisher Syndrome with Syndrome of Inappropriate Secretion of Antidiuretic Hormone

We report a 72-year-old woman with Miller-Fisher syndrome (MFS) with syndrome of inappropriate secretion of antidiuretic hormone (SIADH). She developed diplopia and unsteady gait a week after an upper respiratory infection. Neurologic examination revealed ophthalmoplegia, ataxia, symmetrical weakness, numbness, and areflexia. She underwent intravenous immunoglobulin therapy. Her serum sodium concentration decreased to 119 mEq/L on day 12. She had low plasma osmolarity (254 mosm/kg), high urine osmolarity (457 mosm/kg), and high urine sodium level (73 mEq/L), while the blood level of antidiuretic hormone was normal. Anti-GD1b immunoglobulin G (IgG), -GQ1b IgG, -GT1a IgG, and -Gal-C IgM antibodies were positive. We diagnosed her with MFS overlapping with SIADH. Four weeks after onset, her symptoms recovered. The elevation of anti-GD1b, -GQ1b, and -GT1a antibodies that recognize disialosyl residue may be pathologically related to SIADH.

Sustained response to subcutaneous immunoglobulins in chronic ataxic neuropathy with anti-disialosyl IgM antibodies (CANDA): report of two cases and review of the literature

INTRODUCTION

Chronic ataxic neuropathy with anti-disialosyl IgM antibodies (CANDA) is a rare disorder for which the pathological, neurophysiological, and therapeutic evidence remains anecdotal and controversial.

METHODS

This report on CANDA focuses on the neurophysiological patterns and treatment responses shared by two cases. One patient underwent nerve ultrasound follow-up. A comprehensive review of the literature highlighted the diverse experiences with different treatment options.

RESULTS

Response to different therapies was similar in both patients: intravenous immunoglobulins achieved a favorable response albeit with significant wearing-off fluctuations; treatment with subcutaneous immunoglobulins (SCIg) was an effective alternative leading to a clinical response for at least 2 years. Rituximab, which was trialed in both patients, was not continued long enough to determine its efficacy in modifying the disease course and/or modulating responsiveness to immunoglobulins. Steroids caused clinical worsening in both patients.

CONCLUSIONS

Immunoglobulin therapy appeared as the most effective in the treatment of these two patients. SCIg provided an effective treatment option for the long-term management of CANDA.

Clinical phenotype of patients with neuropathy associated with monoclonal gammopathy: a comparative study and a review of the literature

The objective of this study was to investigate if the clinical and electrophysiological phenotype of patients with polyneuropathy associated with IgM monoclonal gammopathy (IgM-PNP) is related to the presence of antibodies against gangliosides or myelin-associated glycoprotein (MAG). We compared clinical and nerve conduction study (NCS) characteristics of 11 IgM-PNP patients with antibodies against asialo-GM1 or gangliosides (GM1, GD1a, GD1b, GM2 or GQ1b) to 11 consecutive IgM-PNP patients with anti-MAG neuropathy and to 9 IgM-PNP patients without antibodies against either MAG or gangliosides. Patients with anti-ganglioside antibodies could not be differentiated from those with anti-MAG antibodies based on clinical characteristics. However, within the group of anti-ganglioside antibody positive patients, antibodies against GD1b and GQ1b were associated with a purely sensory neuropathy (p = 0.002), while asymmetric weakness with symmetric sensory loss was associated with anti-asialo-GM1 antibodies. In conclusion, polyneuropathy associated with IgM monoclonal gammopathy and anti-ganglioside antibodies clinically resembles anti-MAG neuropathy. Pure sensory neuropathy and marked asymmetry may suggest the presence of anti-ganglioside rather than anti-MAG antibodies.

Paraproteinemic neuropathies

The term paraproteinemic neuropathy refers to a heterogeneous group of neuropathies, which share the common feature of a homogeneous immunoglobulin in the serum. The presence of a monoclonal gammopathy indicates an underlying clonal B-cell expansion, which may appear in the context of a lymphoproliferative disorder. If a neoplastic origin of the gammopathy is identified, the treatment should be targeted to the neoplasm. In most patients, however, the monoclonal gammopathy is not associated with malignant haematological disorders, and is defined as monoclonal gammopathy of undetermined significance.

Clinicopathological features of acute autonomic and sensory neuropathy

Acute autonomic and sensory neuropathy is a rare disorder that has been only anecdotally reported. We characterized the clinical, electrophysiological, pathological and prognostic features of 21 patients with acute autonomic and sensory neuropathy. An antecedent event, mostly an upper respiratory tract or gastrointestinal tract infection, was reported in two-thirds of patients. Profound autonomic failure with various degrees of sensory impairment characterized the neuropathic features in all patients. The initial symptoms were those related to autonomic disturbance or superficial sensory impairment in all patients, while deep sensory impairment accompanied by sensory ataxia subsequently appeared in 12 patients. The severity of sensory ataxia tended to become worse as the duration from the onset to the peak phase of neuropathy became longer (P<0.001). The distribution of sensory manifestations included the proximal regions of the limbs, face, scalp and trunk in most patients. It tended to be asymmetrical and segmental, rather than presenting as a symmetric polyneuropathy. Pain of the involved region was a common and serious symptom. In addition to autonomic and sensory symptoms, coughing episodes, psychiatric symptoms, sleep apnoea and aspiration, pneumonia made it difficult to manage the clinical condition. Nerve conduction studies revealed the reduction of sensory nerve action potentials in patients with sensory ataxia, while it was relatively preserved in patients without sensory ataxia. Magnetic resonance imaging of the spinal cord revealed a high-intensity area in the posterior column on T(2)*-weighted gradient echo image in patients with sensory ataxia but not in those without it. Sural nerve biopsy revealed small-fibre predominant axonal loss without evidence of nerve regeneration. In an autopsy case with impairment of both superficial and deep sensations, we observed severe neuronal cell loss in the thoracic sympathetic and dorsal root ganglia, and Auerbach's plexus with well preserved anterior hone cells. Myelinated fibres in the anterior spinal root were preserved, while those in the posterior spinal root and the posterior column of the spinal cord were depleted. Although recovery of sensory impairment was poor, autonomic dysfunction was ameliorated to some degree within several months in most patients. In conclusion, an immune-mediated mechanism may be associated with acute autonomic and sensory neuropathy. Small neuronal cells in the autonomic and sensory ganglia may be affected in the initial phase, and subsequently, large neuronal cells in the sensory ganglia are damaged.