Multifocal motor neuropathy: Long-term treatment with subcutaneous immunoglobulin

AbstractMultifocal motor neuropathy (MMN) is a rare disease with a prevalence of less than 1 per 100,000 people. Intravenous immunoglobulin (IVIG) therapy, performed for a long-term period, has been demonstrated able to improve the clinical picture of MMN patients, ameliorating motor symptoms and/or preventing disease progression. Treatment with subcutaneous immunoglobulin (SCIg) has been shown to be as effective as IVIG. However, previously published data showed that follow-up of MMN patients in treatment with SCIg lasted no more than 56 months. We report herein the results of a long-term SCIg treatment follow up (up to 96 months) in a group of 8 MMN patients (6 M; 2F), previously stabilized with IVIG therapy. Clinical follow-up included the administration of Medical Research Council (MRC) sum-score, the Overall Neuropathy Limitation Scale (ONLS) and the Life Quality Index questionnaire (LQI) at baseline and then every 6 months. Once converted to SCIg, patients’ responsiveness was quite good. Strength and motor functions remained stable or even improved during this long-term follow-up with benefits on walking capability, resistance to physical efforts and ability in hand fine movements.

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Pure Motor Onset and IgM-Gammopathy Occurrence in Multifocal Acquired Demyelinating Sensory and Motor Neuropathy

Neurology ◽

10.1212/wnl.0000000000012618 ◽

2021 ◽

pp. 10.1212/WNL.0000000000012618

Author(s):

Grayson Beecher ◽

Shahar Shelly ◽

P. James B. Dyck ◽

Michelle L. Mauermann ◽

Jennifer M Martinez-Thompson ◽

...

Keyword(s):

Monoclonal Gammopathy ◽

Motor Nerve ◽

Multifocal Motor Neuropathy ◽

Term Treatment ◽

Motor Neuropathy ◽

Point Reduction ◽

Long Term Treatment ◽

Motor Onset ◽

Pure Motor

Objectives:To longitudinally investigate patients with multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy, quantifying timing and location of sensory involvements in motor-onset patients, along with clinico-histopathological and electrophysiological findings to ascertain differences in patients with and without monoclonal gammopathy of uncertain significance (MGUS).Methods:Patients with MADSAM neuropathy seen at Mayo Clinic and tested for monoclonal gammopathy and ganglioside antibodies, were retrospectively reviewed (January 1st, 2007-December 31st, 2018).Results:Of 76 patients with MADSAM, 53% had pure motor, 16% pure sensory, 30% sensorimotor and 1% cranial nerve onsets. Motor-onset patients were initially diagnosed as multifocal motor neuropathy (MMN). MGUS occurred in 25% (89% IgM subtype), associating with ganglioside autoantibodies (p<0.001) and higher IgM titers (p<0.04). Median time to sensory involvements (confirmed by electrophysiology) in motor-onset patients was 18 months (range: 6-180). Compared to initial motor nerve involvements, subsequent sensory findings were within the same territory 35% (14/40), outside 20% (8/40), or both 45% (18/40). Brachial and lumbosacral plexus MRI was abnormal in 87% (34/39) and 84% (21/25), respectively, identifying hypertrophy and increased T2 signal predominantly in brachial plexus trunks (64%), divisions (69%), and cords (69%), and intrapelvic sciatic (64%) and femoral (44%) nerves. Proximal fascicular nerve biopsies (n=9) more frequently demonstrated onion-bulb pathology (p=0.001) and endoneurial inflammation (p=0.01) than distal biopsies (n=17). MRI and biopsy findings were similar amongst patient subgroups. Initial Inflammatory Neuropathy Cause and Treatment (INCAT) disability scores were higher in patients with MGUS relative to without (p=0.02). Long-term treatment responsiveness by INCAT score reduction ≥1 or motor Neuropathy Impairment Score (mNIS) >8 point reduction occurred in 75% (49/65) irrespective of MGUS or motor-onsets. Most required ongoing immunotherapy (86%). Patients with MGUS more commonly required dual-agent immunotherapy for stability (p=0.02).Discussion:Pure motor-onsets are the most common MADSAM presentation. Long-term follow-up, repeat electrophysiology and nerve pathology help distinguish motor-onset MADSAM from MMN. Better long-term immunotherapy responsiveness occurs in motor-onset MADSAM compared to MMN reports. Patients having MGUS commonly require dual immunotherapy.Classification of Evidence:This study provides Class II evidence that most clinical, electrophysiological, and histopathological findings were similar between patients with MADSAM with and without monoclonal gammopathy of unknown significance.

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The Long-term Treatment of Multifocal Motor Neuropathy with Intravenous Immunoglobulin

European Neurological Review ◽

10.17925/enr.2012.07.02.128 ◽

2012 ◽

Vol 7 (2) ◽

pp. 128 ◽

Cited By ~ 1

Author(s):

Leonard H van den Berg ◽

Keyword(s):

Muscle Strength ◽

Intravenous Immunoglobulin ◽

Initial Response ◽

Multifocal Motor Neuropathy ◽

Term Treatment ◽

Response To Treatment ◽

Motor Neuropathy ◽

Double Blind ◽

Long Term Treatment

Multifocal motor neuropathy (MMN) is a rare, purely motor neuropathy. It is a progressive disorder, most patients eventually developing severe fatigue and weakness in the arm muscles that severely impair daily functioning and quality of life. Unlike other motor neuropathies such as motor neurone disease, MMN is treatable with regular infusions of intravenous immunoglobulin (IVIg). Four double-blind, randomised, placebo-controlled studies have shown that in the short term, IVIg significantly improves muscle strength and disability in more than 70 % of patients. The 11 observational studies reviewed in this article confirm that long-term maintenance treatment with IVIg maintains clinical improvement compared to pre-treatment baseline in most patients. Infusions are generally well tolerated, but regular monitoring and re-evaluation of the IVIg maintenance regimen is essential, as most patients need progressive increases in dosage or reduced intervals between infusions to maintain their response to treatment. In the absence of accepted predictive markers, maintenance IVIg should be individualised, based on each patient’s initial response, disability and the interval between the first infusion and decline in muscle strength.

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