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Foesleitner O, Knop KC, Lindenau M, Preisner F, Bäumer P, Heiland S, Bendszus M, Kronlage M. Quantitative MR Neurography in Multifocal Motor Neuropathy and Amyotrophic Lateral Sclerosis. Diagnostics (Basel) 2023; 13:diagnostics13071237. [PMID: 37046455 PMCID: PMC10093201 DOI: 10.3390/diagnostics13071237] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 03/19/2023] [Indexed: 03/29/2023] Open
Abstract
Background: The aim of this study was to assess the phenotype of multifocal motor neuropathy (MMN) and amyotrophic lateral sclerosis (ALS) in quantitative MR neurography. Methods: In this prospective study, 22 patients with ALS, 8 patients with MMN, and 10 healthy volunteers were examined with 3T MR neurography, using a high-resolution fat-saturated T2-weighted sequence, diffusion-tensor imaging (DTI), and a multi-echo T2-relaxometry sequence. The quantitative biomarkers fractional anisotropy (FA), radial and axial diffusivity (RD, AD), mean diffusivity (MD), cross-sectional area (CSA), T2-relaxation time, and proton spin density (PSD) were measured in the tibial nerve at the thigh and calf, and in the median, radial, and ulnar nerves at the mid-upper arm. Results: MMN showed a characteristic imaging pattern of decreased FA (p = 0.018), increased RD (p = 0.014), increased CSA (p < 0.001), increased T2-relaxation time (p < 0.001), and increased PSD (p = 0.025) in the upper arm nerves compared to ALS and controls. ALS patients did not differ from controls in any imaging marker, nor were there any group differences in the tibial nerve (p > 0.05). Conclusions: MMN shows a characteristic pattern of quantitative DTI and T2-relaxometry parameters in the upper-arm nerves, primarily indicating demyelination. Peripheral nerve changes in ALS seem to be below the detection level of current state-of-the-art quantitative MR neurography.
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van Rosmalen MHJ, Goedee HS, Derks R, Asselman F, Verhamme C, de Luca A, Hendrikse J, van der Pol WL, Froeling M. Quantitative magnetic resonance imaging of the brachial plexus shows specific changes in nerve architecture in chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy and motor neuron disease. Eur J Neurol 2021; 28:2716-2726. [PMID: 33934438 PMCID: PMC8362016 DOI: 10.1111/ene.14896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/12/2021] [Accepted: 04/28/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND The immunological pathophysiologies of chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) differ considerably, but neither has been elucidated completely. Quantitative magnetic resonance imaging (MRI) techniques such as diffusion tensor imaging, T2 mapping, and fat fraction analysis may indicate in vivo pathophysiological changes in nerve architecture. Our study aimed to systematically study nerve architecture of the brachial plexus in patients with CIDP, MMN, motor neuron disease (MND) and healthy controls using these quantitative MRI techniques. METHODS We enrolled patients with CIDP (n = 47), MMN (n = 29), MND (n = 40) and healthy controls (n = 10). All patients underwent MRI of the brachial plexus and we obtained diffusion parameters, T2 relaxation times and fat fraction using an automated processing pipeline. We compared these parameters between groups using a univariate general linear model. RESULTS Fractional anisotropy was lower in patients with CIDP compared to healthy controls (p < 0.001), patients with MND (p = 0.010) and MMN (p < 0.001). Radial diffusivity was higher in patients with CIDP compared to healthy controls (p = 0.015) and patients with MND (p = 0.001) and MMN (p < 0.001). T2 relaxation time was elevated in patients with CIDP compared to patients with MND (p = 0.023). Fat fraction was lower in patients with CIDP and MMN compared to patients with MND (both p < 0.001). CONCLUSION Our results show that quantitative MRI parameters differ between CIDP, MMN and MND, which may reflect differences in underlying pathophysiological mechanisms.
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Affiliation(s)
- Marieke H. J. van Rosmalen
- Department of Neurology and NeurosurgeryBrain Center Rudolf MagnusUniversity Medical Center UtrechtUtrechtThe Netherlands
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - H. Stephan Goedee
- Department of Neurology and NeurosurgeryBrain Center Rudolf MagnusUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Rosina Derks
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Fay‐Lynn Asselman
- Department of Neurology and NeurosurgeryBrain Center Rudolf MagnusUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Camiel Verhamme
- Department of NeurologyAmsterdam NeuroscienceAmsterdam University Medical CentersUniversity of AmsterdamAmsterdamThe Netherlands
| | - Alberto de Luca
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - J. Hendrikse
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - W. Ludo van der Pol
- Department of Neurology and NeurosurgeryBrain Center Rudolf MagnusUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Martijn Froeling
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
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Nerve Pathology Distinguishes Focal Motor Chronic Inflammatory Demyelinating Polyradiculoneuropathy From Multifocal Motor Neuropathy. J Clin Neuromuscul Dis 2021; 22:1-10. [PMID: 32833719 DOI: 10.1097/cnd.0000000000000279] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The objective of the study is to distinguish the mechanisms of disease for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN), which we believe to be fundamentally different. However, distinguishing the mechanisms is more difficult when the presentation of CIDP is motor-predominant, focal, or asymmetric. METHODS We describe 3 focal, motor-predominant, representative cases that could be interpreted on clinical and/or electrophysiological grounds as either MMN or focal CIDP, and present pathological findings. RESULTS We highlight pathological differences in these cases, and provide an argument that CIDP and MMN are distinct entities with different pathophysiological mechanisms-chronic demyelination for CIDP, and an immune-mediated attack on paranodal motor axons for MMN. CONCLUSIONS Based on clinical evaluation, electrophysiology, and nerve biopsy pathology, we can divide the conditions into inflammatory demyelinating neuropathy (focal CIDP) versus chronic axonal neuropathy (MMN). The divergent pathological findings provide further evidence that CIDP and MMN are fundamentally different disorders.
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Yeh WZ, Dyck PJ, van den Berg LH, Kiernan MC, Taylor BV. Multifocal motor neuropathy: controversies and priorities. J Neurol Neurosurg Psychiatry 2020; 91:140-148. [PMID: 31511307 DOI: 10.1136/jnnp-2019-321532] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/14/2019] [Accepted: 08/31/2019] [Indexed: 12/11/2022]
Abstract
Despite 30 years of research there are still significant unknowns and controversies associated with multifocal motor neuropathy (MMN) including disease pathophysiology, diagnostic criteria and treatment. Foremost relates to the underlying pathophysiology, specifically whether MMN represents an axonal or demyelinating neuropathy and whether the underlying pathophysiology is focused at the node of Ranvier. In turn, this discussion promotes consideration of therapeutic approaches, an issue that becomes more directed in this evolving era of precision medicine. It is generally accepted that MMN represents a chronic progressive immune-mediated motor neuropathy clinically characterised by progressive asymmetric weakness and electrophysiologically by partial motor conduction block. Anti-GM1 IgM antibodies are identified in at least 40% of patients. There have been recent developments in the use of neuromuscular ultrasound and MRI to aid in diagnosing MMN and in further elucidation of its pathophysiological mechanisms. The present Review will critically analyse the knowledge accumulated about MMN over the past 30 years, culminating in a state-of-the-art approach to therapy.
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Affiliation(s)
- Wei Zhen Yeh
- Department of Neurology, Royal Hobart Hospital, Hobart, Tasmania, Australia.,Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - P James Dyck
- Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - Leonard H van den Berg
- UMC Utrecht Brain Center, Department of Neurology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Matthew C Kiernan
- Bushell Chair of Neurology, Brain and Mind Centre, University of Sydney, Sydney, New South Wales, Australia.,Department of Neurology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Bruce V Taylor
- Department of Neurology, Royal Hobart Hospital, Hobart, Tasmania, Australia .,Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
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Haakma W, Jongbloed BA, Froeling M, Goedee HS, Bos C, Leemans A, van den Berg LH, Hendrikse J, van der Pol WL. MRI shows thickening and altered diffusion in the median and ulnar nerves in multifocal motor neuropathy. Eur Radiol 2016; 27:2216-2224. [PMID: 27655303 PMCID: PMC5374174 DOI: 10.1007/s00330-016-4575-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/09/2016] [Accepted: 08/22/2016] [Indexed: 12/13/2022]
Abstract
Objectives To study disease mechanisms in multifocal motor neuropathy (MMN) with magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) of the median and ulnar nerves. Methods We enrolled ten MMN patients, ten patients with amyotrophic lateral sclerosis (ALS) and ten healthy controls (HCs). Patients underwent MRI (in a prone position) and nerve conduction studies. DTI and fat-suppressed T2-weighted scans of the forearms were performed on a 3.0T MRI scanner. Fibre tractography of the median and ulnar nerves was performed to extract diffusion parameters: fractional anisotropy (FA), mean (MD), axial (AD) and radial (RD) diffusivity. Cross-sectional areas (CSA) were measured on T2-weighted scans. Results Forty-five out of 60 arms were included in the analysis. AD was significantly lower in MMN patients (2.20 ± 0.12 × 10-3 mm2/s) compared to ALS patients (2.31 ± 0.17 × 10-3 mm2/s; p < 0.05) and HCs (2.31± 0.17 × 10-3 mm2/s; p < 0.05). Segmental analysis showed significant restriction of AD, RD and MD (p < 0.005) in the proximal third of the nerves. CSA was significantly larger in MMN patients compared to ALS patients and HCs (p < 0.01). Conclusions Thickening of nerves is compatible with changes in the myelin sheath structure, whereas lowered AD values suggest axonal dysfunction. These findings suggest that myelin and axons are diffusely involved in MMN pathogenesis. Key Points • Diffusion magnetic resonance imaging provides quantitative information about multifocal motor neuropathy (MMN). • Diffusion tensor imaging allows non-invasive evaluation of the forearm nerves in MMN. • Nerve thickening and lowered diffusion parameters suggests myelin and axonal changes. • This study can help to provide insight into pathological mechanisms of MMN. Electronic supplementary material The online version of this article (doi:10.1007/s00330-016-4575-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wieke Haakma
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands. .,Department of Forensic Medicine and Comparative Medicine Lab, Aarhus University, Aarhus, Denmark.
| | - Bas A Jongbloed
- Brain Centre Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Martijn Froeling
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - H Stephan Goedee
- Brain Centre Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Clemens Bos
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Alexander Leemans
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Leonard H van den Berg
- Brain Centre Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - W Ludo van der Pol
- Brain Centre Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands
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Jovanovich E, Karam C. Human immune globulin infusion in the management of multifocal motor neuropathy. Degener Neurol Neuromuscul Dis 2015; 6:1-12. [PMID: 30050363 PMCID: PMC6053084 DOI: 10.2147/dnnd.s96258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Multifocal motor neuropathy (MMN) is a debilitating and rare disease causing profound weakness with minimal to no sensory symptoms. Conduction block is frequently seen on electrodiagnostic testing. An immune-mediated pathology is suspected though the exact underlying pathophysiology has yet to be elucidated. The presence of anti-GM1 ganglioside IgM antibodies coupled with favorable response to intravenous and subcutaneous immunoglobulins supports a complement-mediated mechanism which leads to destruction of nerve tissue with probable predilection to the nodes of Ranvier. High-dose immunoglobulin currently is the only treatment with proven efficacy for MMN patients. Unfortunately, many patients experience decreased responsiveness to immunoglobulins over time, requiring higher and more frequent dosing. In this review, we will focus on the pharmacology, efficacy, safety, and tolerability of intravenous and subcutaneous immune globulin infusion for treatment of MMN.
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Affiliation(s)
| | - Chafic Karam
- Department of Neurology, The University of North Carolina, Chapel Hill, NC, USA,
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Abstract
ABSTRACT:The essential function of a nerve fiber centers on the transmission of impulses. Slowing of conduction velocities merely delays conveyance of information but failure of conduction abolishes the function. Rate-dependent block may falsify input by disturbing the neural coding. The diagnosis of conduction block is complicated by phase cancellation and many other physiologic and technical factors, which may mimic the condition. The conduction block may be reversed by increasing action current with such agents as 4-aminopirizine as well as by reducing the threshold for excitation with a sodium - potassium pump inhibitor such as digitalis. Although their mechanisms of action are poorly understood, imunogloblin and imunosuppressive agents are also effective in some clinical entities like multifocal motor neuropathy with persistent conduction block.
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Plasmacytosis is a common immune signature in patients with MMN and CIDP and responds to treatment with IVIg. J Neuroimmunol 2015; 278:60-8. [DOI: 10.1016/j.jneuroim.2014.11.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/08/2014] [Accepted: 11/10/2014] [Indexed: 11/21/2022]
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Abstract
Chronic neuropathies are operationally classified as primarily demyelinating or axonal, on the basis of electrodiagnostic or pathological criteria. Demyelinating neuropathies are further classified as hereditary or acquired-this distinction is important, because the acquired neuropathies are immune-mediated and, thus, amenable to treatment. The acquired chronic demyelinating neuropathies include chronic inflammatory demyelinating polyneuropathy (CIDP), neuropathy associated with monoclonal IgM antibodies to myelin-associated glycoprotein (MAG; anti-MAG neuropathy), multifocal motor neuropathy (MMN), and POEMS syndrome. They have characteristic--though overlapping--clinical presentations, are mediated by distinct immune mechanisms, and respond to different therapies. CIDP is the default diagnosis if the neuropathy is demyelinating and no other cause is found. Anti-MAG neuropathy is diagnosed on the basis of the presence of anti-MAG antibodies, MMN is characterized by multifocal weakness and motor conduction blocks, and POEMS syndrome is associated with IgG or IgA λ-type monoclonal gammopathy and osteosclerotic myeloma. The correct diagnosis, however, can be difficult to make in patients with atypical or overlapping presentations, or nondefinitive laboratory studies. First-line treatments include intravenous immunoglobulin (IVIg), corticosteroids or plasmapheresis for CIDP; IVIg for MMN; rituximab for anti-MAG neuropathy; and irradiation or chemotherapy for POEMS syndrome. A correct diagnosis is required for choosing the appropriate treatment, with the aim of preventing progressive neuropathy.
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Affiliation(s)
- Norman Latov
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, 1305 York Avenue, Suite 217, New York, NY 10021, USA
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10
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Harschnitz O, Jongbloed BA, Franssen H, Straver DCG, van der Pol WL, van den Berg LH. MMN: from immunological cross-talk to conduction block. J Clin Immunol 2014; 34 Suppl 1:S112-9. [PMID: 24728842 PMCID: PMC4050293 DOI: 10.1007/s10875-014-0026-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 03/19/2014] [Indexed: 12/11/2022]
Abstract
Multifocal motor neuropathy (MMN) is a rare inflammatory neuropathy characterized by progressive, asymmetric distal limb weakness and conduction block (CB). Clinically MMN is a pure motor neuropathy, which as such can mimic motor neuron disease. GM1-specific IgM antibodies are present in the serum of approximately half of all MMN patients, and are thought to play a key role in the immune pathophysiology. Intravenous immunoglobulin (IVIg) treatment has been shown to be effective in MMN in five randomized placebo-controlled trials. Despite long-term treatment with intravenous immunoglobulin (IVIg), which is efficient in the majority of patients, slowly progressive axonal degeneration and subsequent muscle weakness cannot be fully prevented. In this review, we will discuss the current understanding of the immune pathogenesis underlying MMN and how this may cause CB, available treatment strategies and future therapeutic targets.
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Affiliation(s)
- Oliver Harschnitz
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center Rudolf Magnus, Utrecht, 3584 CG The Netherlands
- Department of Translational Neuroscience, UMC Utrecht Brain Center Rudolf Magnus, Utrecht, 3584 CG The Netherlands
| | - Bas A. Jongbloed
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center Rudolf Magnus, Utrecht, 3584 CG The Netherlands
- Department of Neurology, St. Elisabeth Hospital, Tilburg, 5000 LC The Netherlands
| | - Hessel Franssen
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center Rudolf Magnus, Utrecht, 3584 CG The Netherlands
| | - Dirk C. G Straver
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center Rudolf Magnus, Utrecht, 3584 CG The Netherlands
| | - W. Ludo van der Pol
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center Rudolf Magnus, Utrecht, 3584 CG The Netherlands
| | - Leonard H. van den Berg
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center Rudolf Magnus, Utrecht, 3584 CG The Netherlands
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Buttmann M, Kaveri S, Hartung HP. Polyclonal immunoglobulin G for autoimmune demyelinating nervous system disorders. Trends Pharmacol Sci 2013; 34:445-57. [PMID: 23791035 DOI: 10.1016/j.tips.2013.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 05/08/2013] [Accepted: 05/22/2013] [Indexed: 12/13/2022]
Abstract
Demyelinating diseases with presumed autoimmune pathogenesis are characterised by direct or indirect immune-mediated damage to myelin sheaths, which normally surround nerve fibres to ensure proper electrical nerve conduction. Parenteral administration of polyclonal IgG purified from multi-donor human plasma pools may beneficially modulate these misguided immune reactions via several mechanisms that are outlined in this review. Convincing therapeutic evidence from controlled trials now exists for certain disorders of the peripheral nervous system, including Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, and multifocal motor neuropathy. In addition, there is evidence for potential therapeutic benefits of IgG in patients with chronic inflammatory demyelinating diseases of the central nervous system, including multiple sclerosis and neuromyelitis optica. This review introduces these disorders, briefly summarises the established treatment options, and discusses therapeutic evidence for the use of polyclonal immunoglobulins with a particular emphasis on recent clinical trials and meta-analyses.
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Affiliation(s)
- Mathias Buttmann
- Department of Neurology, University of Würzburg, Josef-Schneider-Str. 11, D-97080 Würzburg, Germany
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12
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Hobson-Webb LD. Neuromuscular ultrasound in polyneuropathies and motor neuron disease. Muscle Nerve 2013; 47:790-804. [DOI: 10.1002/mus.23737] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2012] [Indexed: 12/12/2022]
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Multifocal motor neuropathy, multifocal acquired demyelinating sensory and motor neuropathy, and other chronic acquired demyelinating polyneuropathy variants. Neurol Clin 2013; 31:533-55. [PMID: 23642723 DOI: 10.1016/j.ncl.2013.01.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chronic acquired demyelinating neuropathies (CADP) constitute an important group of immune neuromuscular disorders affecting myelin. This article discusses CADP with emphasis on multifocal motor neuropathy, multifocal acquired demyelinating sensory and motor neuropathy, distal acquired demyelinating symmetric neuropathy, and less common variants. Although each of these entities has distinctive laboratory and electrodiagnostic features that aid in their diagnosis, clinical characteristics are of paramount importance in diagnosing specific conditions and determining the most appropriate therapies. Knowledge regarding pathogenesis, diagnosis, and management of these disorders continues to expand, resulting in improved opportunities for identification and treatment.
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Abstract
Multifocal motor neuropathy (MMN) is a rare disorder in which the symptoms are caused by persistent conduction block lesions. The mononeuropathy multiplex progresses over time with increasing axonal loss. The cause of the conduction blocks and axonal loss are not completely understood but immune mechanisms are involved and response to intravenous immunoglobulin has been established. The importance of MMN goes beyond its clinical incidence as the increasing understanding of the pathogenesis of this disorder has implications for other peripheral nerve diseases and for our knowledge of peripheral nerve biology.
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Affiliation(s)
- Ximena Arcila-Londono
- Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan, USA
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15
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Multifocal motor neuropathy. J Clin Neurosci 2012; 19:1201-9. [PMID: 22743043 DOI: 10.1016/j.jocn.2012.02.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 02/06/2012] [Accepted: 02/13/2012] [Indexed: 11/22/2022]
Abstract
Multifocal motor neuropathy (MMN) was first described in 1988 as a purely motor neuropathy affecting multiple motor nerves. The diagnosis was based entirely on demonstrating electrophysiological evidence of a conduction block (CB) that selectively affected motor axons, with sparing of sensory axons even through the site of motor CB. Subsequently, a similar disorder was reported but with absence of demonstrable CB on routine nerve conduction studies and there is still some debate as to whether MMN without CB is related to MMN. MMN is thought to be an inflammatory neuropathy related to an immune attack on motor nerves. The conventional hypothesis is that the primary pathology is segmental demyelination, but recent research raises the possibility of a primary axonopathy. Anti-GM1 antibodies can be found in some patients but it is unclear whether these antibodies are pathogenic. Intravenous immunoglobulin is the mainstay of treatment but other immunosuppressive treatments can also be effective.
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16
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Hobson-Webb LD, Padua L, Martinoli C. Ultrasonography in the diagnosis of peripheral nerve disease. ACTA ACUST UNITED AC 2012; 6:457-71. [PMID: 23480810 DOI: 10.1517/17530059.2012.692904] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION High-resolution ultrasound (US) of the peripheral nerves is now a standard means of assessing neuromuscular disorders in many centers. Currently used in conjunction with electrodiagnostic (EDX) studies, nerve US is especially effective in the diagnosis of entrapment neuropathies. AREAS COVERED This article reviews the basic physics of peripheral nerve US, guidelines for its current use and future directions. Advantages of using nerve US alongside EDX studies are outlined along with current limitations of testing. The role of US in the diagnosis of entrapment neuropathy is emphasized, particularly in carpal tunnel syndrome (CTS). US assisted diagnosis of peripheral nerve tumors, hereditary neuropathy and dysimmune neuropathy and traumatic injuries is also described. EXPERT OPINION US is a powerful tool in the assessment of peripheral nerve disease. Nerve US is an evolving, young discipline. There is still much to learn, but current evidence supports US imaging of all patients presenting for evaluation of possible mononeuropathy. With improvements in resolution, the introduction of US contrast agents and objective measures of nerve echogenicity, there is promise for further expanding its role in the diagnosis of all peripheral neuropathies.
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Affiliation(s)
- Lisa D Hobson-Webb
- Duke University Medical Center, Department of Neurology , Durham, NC 27710 , USA +1 919 668 2277 ; +1 919 660 3853 ;
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Uncini A. A common mechanism and a new categorization for anti-ganglioside antibody-mediated neuropathies. Exp Neurol 2012; 235:513-6. [DOI: 10.1016/j.expneurol.2012.03.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 03/24/2012] [Accepted: 03/29/2012] [Indexed: 11/30/2022]
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Riva N, Gallia F, Iannaccone S, Corbo M, Terenghi F, Lazzerini A, Cerri F, Comi G, Quattrini A, Nobile-Orazio E. Chronic motor axonal neuropathy. J Peripher Nerv Syst 2011; 16:341-6. [DOI: 10.1111/j.1529-8027.2011.00366.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Vlam L, van der Pol WL, Cats EA, Straver DC, Piepers S, Franssen H, van den Berg LH. Multifocal motor neuropathy: diagnosis, pathogenesis and treatment strategies. Nat Rev Neurol 2011; 8:48-58. [PMID: 22105211 DOI: 10.1038/nrneurol.2011.175] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lehmann HC, Meyer Zu Horste G, Kieseier BC, Hartung HP. Pathogenesis and treatment of immune-mediated neuropathies. Ther Adv Neurol Disord 2011; 2:261-81. [PMID: 21179533 DOI: 10.1177/1756285609104792] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Immune-mediated neuropathies represent a heterogeneous spectrum of peripheral nerve disorders that can be classified according to time course, predominant involvement of motor/sensory fibers, distribution of deficits and paraclinical parameters such as electrophysiology and serum antibodies. In the last few years, significant advances have been achieved in elucidating underlying pathomechanisms, which made it possible to identify potential therapeutic targets. In this review, we discuss the latest development in pathogenesis and treatment of immune-mediated neuropathies.
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Lehmann HC, Hartung HP. Plasma exchange and intravenous immunoglobulins: mechanism of action in immune-mediated neuropathies. J Neuroimmunol 2010; 231:61-9. [PMID: 21056913 DOI: 10.1016/j.jneuroim.2010.09.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Immune-mediated neuropathies are a heterogeneous group of peripheral nerve disorders, which are classified by time course, clinical pattern, affected nerves and pathological features. Plasma exchange (PE) and intravenous immunoglobulins (IVIg) are mainstays in the treatment of immune-mediated neuropathies. Of all treatments currently used, IVIg has probably the widest application range in immune-mediated neuropathies and efficacy has been well documented in several randomized controlled trials for Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy (CIDP). Beneficial effects of IVIg have also been proven for multifocal motor neuropathy (MMN). Likewise, PE is an established treatment for GBS and CIDP, whereas it is considered to be ineffective in MMN. Different mechanisms of action are sought to be responsible for the immunemodulatory effect of PE and IVIg in autoimmune disorders. Some of those might be important for immune-mediated neuropathies, while others are probably negligible. The aim of this review is to summarize the recent advances in elucidating disease-specific mechanisms of actions of PE and IVIg in the treatment of immune-mediated neuropathies.
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Affiliation(s)
- Helmar C Lehmann
- Medical Faculty, Department of Neurology, Heinrich-Heine-University, Moorenstrasse 5, 40225 Düsseldorf, Germany.
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22
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Straver DCG, van Asseldonk JTH, Notermans NC, Wokke JHJ, van den Berg LH, Franssen H. Cold paresis in multifocal motor neuropathy. J Neurol 2010; 258:212-7. [PMID: 20803025 PMCID: PMC3036831 DOI: 10.1007/s00415-010-5712-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 08/09/2010] [Accepted: 08/11/2010] [Indexed: 10/25/2022]
Abstract
Increased weakness during cold (cold paresis) was reported in single cases of multifocal motor neuropathy (MMN). This was unexpected because demyelination is a feature of MMN and symptoms of demyelination improve, rather than worsen, in cold. It was hypothesized that cold paresis in MMN does not reflect demyelination only, but may indicate the existence of inflammatory nerve lesions with permanently depolarized axons that only just conduct at normal temperature, but fail at lower temperatures. We investigated symptoms of cold paresis in 50 MMN patients, 48 chronic inflammatory demyelinating polyneuropathy (CIDP) patients, 35 progressive spinal muscular atrophy (PSMA) patients, and 25 chronic idiopathic axonal polyneuropathy patients. We also investigated symptoms of increased weakness during warmth (heat paresis). Cold paresis was reported more often than heat paresis. Cold paresis was most frequently reported in MMN. Multivariate analysis indicated that MMN patients had a 4- to 6-fold higher risk of reporting cold paresis than CIDP or PSMA patients. Because cold paresis is not consistent with demyelination, the lesions in MMN may involve other mechanisms than demyelination only. In conclusion, symptoms of cold paresis are common in peripheral nervous system disorders, particularly in MMN. This supports the above-described hypothesis.
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Affiliation(s)
- Dirk C G Straver
- Neuromuscular Disease Group, Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
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23
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Van Den Berg LH, Franssen H, Van Asseldonk JTH, Van Den Berg-Vos RM, Wokke JHJ. Chapter 12 Multifocal and other motor neuropathies. HANDBOOK OF CLINICAL NEUROLOGY 2007; 82:229-245. [PMID: 18808897 DOI: 10.1016/s0072-9752(07)80015-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Leonard H Van Den Berg
- Neuromuscular Research Group, Rudolf Magnus Institute of Neuroscience, Department of Neurology, University Medical Center Utrecht, The Netherlands
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24
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Abstract
Multifocal motor neuropathy with persistent conduction blocks was first specifically identified in 1986. Its major criterion is conduction blocks in motor nerves only. Clinically, this is a multifocal, thus asymmetric, neuropathy that begins and predominant touches upper limbs; it especially affects men after the age of 50 years and has a chronic course with relapses. Approximately 40-50% of patients also have IgM serum antibodies directed against GM1 ganglioside. There are no other laboratory criteria, although moderately high protein levels are found in cerebrospinal fluid. Its course is unpredictable, because the neuropathy may remain limited to one or two motor nerves or extend progressively to all the motor nerves of all four limbs. In general, there is no damage to sensory or cranial nerves or to the autonomic or central nervous systems. Intravenous polyvalent immunoglobulins at high doses are remarkably effective in the short term in 70 to 80% of cases. Corticosteroids and plasma exchange are generally ineffective and may aggravate the neuropathy. The long-term efficacy of intravenous immunoglobulins in delaying motor decline and axon loss in the affected motor nerves is controversial. No information is currently available about the long-term efficacy of other immunomodulatory treatment.
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Affiliation(s)
- Jean-Marc Léger
- Centre de Référence Maladies Neuromusculaires Rares, CHU Pitié-Salpêtrière, Paris.
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25
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Nobile-Orazio E, Cappellari A, Priori A. Multifocal motor neuropathy: current concepts and controversies. Muscle Nerve 2005; 31:663-80. [PMID: 15770650 DOI: 10.1002/mus.20296] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Multifocal motor neuropathy (MMN) is now a well-defined purely motor multineuropathy characterized by the presence of multifocal partial motor conduction blocks (CB), frequent association with anti-GM1 IgM antibodies, and usually a good response to high-dose intravenous immunoglobulin (IVIg) therapy. However, several issues remain to be clarified in the diagnosis, pathogenesis, and therapy of this condition including its nosological position and its relation to other chronic dysimmune neuropathies; the degree of CB necessary for the diagnosis of MMN; the existence of an axonal form of MMN; the pathophysiological basis of CB; the pathogenetic role of antiganglioside antibodies; the mechanism of action of IVIg treatments in MMN and the most effective regimen; and the treatment to be used in unresponsive patients. These issues are addressed in this review of the main clinical, electrophysiological, immunological, and therapeutic features of this neuropathy.
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Affiliation(s)
- Eduardo Nobile-Orazio
- Dino Ferrari Centre and Centre of Excellence for Neurodegenerative Diseases, Department of Neurological Sciences, Milan University, IRCCS Ospedale Maggiore Policlinico, and Humanitas Clinical Institute, Milan, Italy.
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26
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Van Asseldonk JTH, Franssen H, Van den Berg-Vos RM, Wokke JHJ, Van den Berg LH. Multifocal motor neuropathy. Lancet Neurol 2005; 4:309-19. [PMID: 15847844 DOI: 10.1016/s1474-4422(05)70074-0] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Multifocal motor neuropathy (MMN) is an immune-mediated disorder characterised by slowly progressive, asymmetrical weakness of limbs without sensory loss. The clinical presentation of MMN mimics that of lower-motor-neuron disease, but in nerve-conduction studies of patients with MMN motor-conduction block has been found. By contrast with chronic inflammatory demyelinating polyneuropathy, treatment with prednisolone and plasma exchange is generally ineffective in MMN and even associated with clinical worsening in some patients. Of the immunosuppressants, cyclophosphamide has been reported as effective but only anecdotally. Various open trials and four placebo-controlled trials have shown that treatment with high-dose intravenous immunoglobulin leads to improvement of muscle strength in patients with MMN. Although clinical, pathological, imaging, immunological, and electrophysiological studies have improved our understanding of MMN over the past 15 years, further research is needed to elucidate pathogenetic disease mechanisms in the disorder.
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Affiliation(s)
- Jan-Thies H Van Asseldonk
- Department of Clinical Neurophysiology, Neuromuscular Research Group, Rudolf Magnus Institute of Neuroscience, University Medical Centre Utrecht, Netherlands
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27
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Léger JM. Neuropathies motrices multifocales avec blocs de conduction persistants : 18 ans après. Rev Neurol (Paris) 2004; 160:889-98. [PMID: 15492715 DOI: 10.1016/s0035-3787(04)71070-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Multifocal motor neuropathy with persistent conduction blocks was firstly reported in 1986 and outlined from the group of purely motor diseases of the peripheral nervous system. The main criterion is the presence of conduction blocks located only on the motor nerves; additionally 30 percent of patients have IgM subclass serum antibodies directed against GM1 ganglioside. The clinical picture is a multifocal, asymmetrical, neuropathy, starting and predominant in the upper limbs, occurring in males aged 50 years and more, and having a progressive course. There is no biological sign besides elevated anti-GM1 antibodies. CSF analysis discloses mild increased protein count. The course is unpredictable, the neuropathy may be strictly limited to one or two motor nerves, or spread to other motor nerves in the four limbs. There is no involvement of the sensory and the cranial nerves, no involvement of the autonomic and the central nervous system. The pathophysiology is unknown, animal models do not allow to confirm the role of humoral immunity, and the role of anti-GM1 antibodies is controversial. Randomized controlled trials have assessed the efficacy of intravenous immunoglobulins which dramatically improve strength in 70-80 percent of patients in the short term, but remain unable to prevent motor deterioration in most patients, together with the occurrence of new conduction blocks. Corticosteroids and plasma exchanges do not improve the patients and may be followed by transient worsening. Long-term efficacy of immunosuppressive agents is not known.
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Affiliation(s)
- J-M Léger
- Groupe Neuropathies Périphériques Pitié-Salpêtrière, Hôpital Pitié-Salpêtrière, Paris.
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28
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Taylor BV, Dyck PJB, Engelstad J, Gruener G, Grant I, Dyck PJ. Multifocal motor neuropathy: pathologic alterations at the site of conduction block. J Neuropathol Exp Neurol 2004; 63:129-37. [PMID: 14989599 DOI: 10.1093/jnen/63.2.129] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The pathologic changes of nerves in multifocal motor neuropathy (MMN), a rare neuropathy with selective focal conduction block of motor fibers in mixed nerves, remain essentially unstudied. Fascicular nerve biopsy of 8 forearm or arm nerves in 7 patients with typical MMN was undertaken for diagnostic reasons at the site of the conduction block. Abnormalities were seen in 7 of 8 nerves, including a varying degree of multifocal fiber degeneration and loss, an altered fiber size distribution with fewer large fibers, an increased frequency of remyelinated fiber profiles, and frequent and prominent regenerating fiber clusters. Small epineurial perivascular inflammatory infiltrates were observed in 2 nerves. We did not observe overt segmental demyelination or onion bulb formation. We hypothesize that an antibody-mediated attack directed against components of axolemma at nodes of Ranvier could cause conduction block, transitory paranodal demyelination and remyelination, and axonal degeneration and regeneration. Alternatively, the antibody attack could be directed at components of paranodal myelin. We favor the first hypothesis because in nerves studied by us, axonal pathological alteration predominated over myelin pathology. Irrespective of which mechanism is involved, we conclude that the unequivocal multifocal fiber degeneration and loss and regenerative clusters at sites of conduction block explains the observed clinical muscle weakness and atrophy and alterations of motor unit potentials. The occurrence of conduction block and multifocal fiber degeneration and regeneration at the same sites suggests that the processes of conduction block and fiber degeneration and regeneration are linked. Finding discrete multifocal fiber degeneration may also provide an explanation for why the functional abnormalities remain unchanged over long periods of time at discrete proximal to distal levels of nerve and may emphasize a need for early intervention (assuming that efficacious treatment is available).
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Affiliation(s)
- Bruce V Taylor
- Department of Neurology, Royal Hobart Hospital, Hobart Tasmania, Australia
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29
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Van Asseldonk JTH, Van den Berg LH, Van den Berg-Vos RM, Wieneke GH, Wokke JHJ, Franssen H. Demyelination and axonal loss in multifocal motor neuropathy: distribution and relation to weakness. Brain 2003; 126:186-98. [PMID: 12477706 DOI: 10.1093/brain/awg019] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Multifocal motor neuropathy (MMN) is characterized by a slowly progressive, asymmetric weakness of the limbs without sensory loss. The arms are usually affected to a greater extent than the legs, and distal muscles more than proximal muscles. The distribution of electrophysiological abnormalities and its correlation with weak muscle groups in MMN have not been investigated systematically. The aim of the present study was to assess whether electrophysiological abnormalities have a preferential or random distribution, whether electrophysiological abnormalities in a nerve correlate with weakness in the innervated muscles, and whether these results are relevant for the development of optimal electrodiagnostic protocols. We compared the pattern of weakness and electrophysiological abnormalities in 39 patients with a lower motoneuron syndrome and a positive response to intravenous immunoglobulins. All patients underwent an extensive standardized electrophysiological examination. Electrophysiological evidence of demyelination was found more often in the nerves of the arms and was distributed randomly over lower arm, upper arm and shoulder segments. Electrophysiological evidence of axonal loss presented more frequently in longer nerves, occurring most often in the leg nerves. For the arm nerves, it is possible that the length dependence of axonal loss is due to the random distribution of demyelinating lesions that lead to axonal degeneration. Weakness was associated with features of demyelination and axonal loss in the nerves of the arm, and with features of axonal loss in leg nerves. However, a substantial number (approximately one-third) of electrophysiological abnormalities were found in nerves innervating non-weakened muscles. These results imply that in MMN, conduction block is most likely to be found in long arm nerves innervating weakened muscles, but if conduction block cannot be detected in these nerves, the electrophysiological examination should be extended to other arm nerves including those innervating non-weakened muscles.
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Affiliation(s)
- J T H Van Asseldonk
- Department of Neurology, Rudolf Magnus Institute for Neurosciences, University Medical Centre Utrecht, The Netherlands
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30
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Cappelen-Smith C, Kuwabara S, Lin CSY, Burke D. Abnormalities of axonal excitability are not generalized in early multifocal motor neuropathy. Muscle Nerve 2002; 26:769-76. [PMID: 12451600 DOI: 10.1002/mus.10262] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The clinical and neurophysiological features of multifocal motor neuropathy (MMN) indicate selective involvement of motor axons, but pathological abnormalities in sensory axons suggest a more widespread disease process. The present study was undertaken to determine whether the focal abnormalities are associated with widespread subclinical abnormalities in motor axons. Threshold tracking was used to measure excitability properties (stimulus-response curves, strength-duration properties, recovery cycle, and threshold electrotonus) of the median nerve in five patients with MMN with lesions proximal to the site of testing. Patients were compared with 25 healthy controls. The changes in excitability indices were similar to those in controls, and in one patient there was no alteration after treatment with intravenous gammaglobulin. In this patient, indices of axonal excitability were also measured before, during, and after ischemia of the arm for 10 min. Again no differences were detected. This study provides no evidence for a generalized subclinical abnormality in MMN, at least when disease duration is less than 6 years.
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Affiliation(s)
- Cecilia Cappelen-Smith
- Department of Clinical Neurophysiology, Prince of Wales Hospital and Prince of Wales Medical Research Institute, University of New South Wales, Barker Street, Randwick, Sydney, New South Wales 2031, Australia
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31
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Beydoun SR, Rison RA, Commins D. Secondary amyloidosis as a life-ending event in multifocal motor neuropathy. Muscle Nerve 2001; 24:1396-402. [PMID: 11562923 DOI: 10.1002/mus.1162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Multifocal motor neuropathy (MMN) is a disorder of peripheral nerve often associated with a high monosialoganglioside (GM1) antibody and multifocal conduction block. It has a chronic, indolent course with involvement of predominantly peripheral motor nerves, usually in an asymmetric fashion. There have been few reported cases of progression to frank quadriplegia. Secondary amyloidosis refers to the deposition of amyloid in various tissues due to an underlying chronic inflammatory state. We report the first case, to our knowledge, of a patient with MMN associated with high titer of GM1 antibody who developed acute paraplegia with both cranial nerve and worsening sensory involvement associated with multiorgan compromise due to a secondary amyloidosis involving the myocardium.
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Affiliation(s)
- S R Beydoun
- Keck University of Southern California School of Medicine, Department of Neurology, 1450 San Pablo Street, Suite 1900, Los Angeles, California 90033, USA.
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32
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Abstract
Multifocal motor neuropathy (MMN) is a recently identified peripheral nerve disorder characterized by progressive, predominantly distal, asymmetric limb weakness mostly affecting upper limbs, minimal or no sensory impairment, and by the presence on nerve conduction studies of multifocal persistent partial conduction blocks on motor but not sensory nerves. The etiopathogenesis of MMN is not known, but there is some evidence, based mostly on the clinical improvement after immunological therapies, that the disease has an immunological basis. Antibodies, mostly IgM, to the gangliosides GM1, and though less frequently, GM2 and GD1a, are frequently detected in patients' sera, helping in the diagnosis of this disease. Even if there is some experimental evidence that these antibodies may be pathogenic in vitro, their role in the neuropathy remains to be established. Patients with MMN do not usually respond to steroids or plasma exchange, which may occasionally worsen the symptoms, while the efficacy of cyclophosphamide is limited by its relevant side effects. More than 80% of MMN patients rapidly improve with high dose intravenous immunoglobulin therapy (IVIg). The effect of this therapy is, however, transient and improvement has to be maintained with periodic infusions. A positive response to interferon-beta has been recently reported in a minority of patients, some of whom were resistant to IVIg. Even if many progresses have been made on the diagnosis and therapy of MMN, there are still several issues on the nosological position, etiopathogenesis and long-term treatment of this neuropathy that need to be clarified.
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Affiliation(s)
- E Nobile-Orazio
- "Giorgio Spagnol" Service of Clinical Neuroimmunology, Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, IRCCS Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy.
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Katz JS, Saperstein DS. Asymmetric Acquired Demyelinating Polyneuropathies: MMN and MADSAM. Curr Treat Options Neurol 2001; 3:119-125. [PMID: 11180748 DOI: 10.1007/s11940-001-0046-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
More than a half a century after Austin's initial description of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), the clinical spectrum of chronic acquired demyelinating polyneuropathies has expanded. Currently there are a number of entities that can be put under the heading of chronic acquired demyelinating neuropathy (CADP) based on differing clinical presentations. In this scheme, CIDP is used only to refer to patients with demyelinating neuropathies and generalized symmetric weakness. In contrast, multifocal motor neuropathy (MMN) and multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) fall into the category of asymmetrical, multifocal forms of CADP. These are distinguished from each other only by the presence of sensory involvement. In our opinion, there are pragmatic reasons for splitting these clinical presentations into distinct entities. Although each of these clinical subtypes shares some basic similarities, there are important differences. MMN is usually considered resistant to corticosteroid therapy and the first line agent in this disorder is intravenous immunoglobulin (IVIg). MADSAM neuropathy can be responsive to prednisone or IVIg, and has a profile more analogous to classic CIDP with regards to its laboratory features and treatment response.
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Affiliation(s)
- Jonathan S. Katz
- Department of Neurology (127) and Department of Veterans Affairs, Palo Alto VA Medical Center, 3801 Miranda Avenue, Palo Alto, CA 94304, USA
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34
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Abstract
A number of presentations of chronic demyelinating polyneuropathy have been identified, each distinguished by its phenotypic pattern. In addition to classic chronic inflammatory demyelinating polyneuropathy (CIDP), which is characterized clinically by symmetric proximal and distal weakness and sensory loss, several regional variants can be recognized: multifocal motor neuropathy (MMN: asymmetric and pure motor), multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy (asymmetric, sensory, and motor), and distal acquired demyelinating symmetric (DADS) neuropathy (symmetric, distal, sensory, and motor). There are also temporal, pathological, and disease-associated variants. This review describes a clinical scheme for approaching the chronic acquired demyelinating polyneuropathies that leads to a rational use of supportive laboratory studies and treatment options. In addition, we propose new diagnostic criteria for CIDP that more accurately reflect current clinical practice.
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Affiliation(s)
- D S Saperstein
- Department of Neurology, Wilford Hall Medical Center, 2200 Bergquist Drive, Suite 1 (MMCN), San Antonio, Texas 78236-5300, USA.
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35
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Abstract
We studied a patient with polyradiculoneuropathy with anaplastic carcinoma of the thymus. Motor manifestations dominated. Postmortem examinations indicated that the primary changes were in the spinal nerve roots, peripheral nerves and, possibly, the spinal anterior horn cells. The posterior funiculi and posterior root ganglia were also affected, implying multifocal and multiphasic degeneration. This unusual polyradiculoneuropathy is a form of carcinomatous neuropathy.
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Affiliation(s)
- T Ohtake
- Department of Neurology, Tokyo Metropolitan Neurological Hospital, 2-6-1 Musashidai, Fuchu, Tokyo, Japan.
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Saperstein DS, Amato AA, Wolfe GI, Katz JS, Nations SP, Jackson CE, Bryan WW, Burns DK, Barohn RJ. Multifocal acquired demyelinating sensory and motor neuropathy: the Lewis-Sumner syndrome. Muscle Nerve 1999; 22:560-6. [PMID: 10331353 DOI: 10.1002/(sici)1097-4598(199905)22:5<560::aid-mus2>3.0.co;2-q] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We report 11 patients with multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy, defined clinically by a multifocal pattern of motor and sensory loss, with nerve conduction studies showing conduction block and other features of demyelination. The clinical, laboratory, and histological features of these patients were contrasted with those of 16 patients with multifocal motor neuropathy (MMN). Eighty-two percent of MADSAM neuropathy patients had elevated protein concentrations in the cerebrospinal fluid, compared with 9% of the MMN patients (P < 0.001). No MADSAM neuropathy patient had elevated anti-GM1 antibody titers, compared with 56% of MMN patients (P < 0.01). In contrast to the subtle abnormalities described for MMN, MADSAM neuropathy patients had prominent demyelination on sensory nerve biopsies. Response to intravenous immunoglobulin treatment was similar in both groups (P = 1.0). Multifocal motor neuropathy patients typically do not respond to prednisone, but 3 of 6 MADSAM neuropathy patients improved with prednisone. MADSAM neuropathy more closely resembles chronic inflammatory demyelinating polyneuropathy and probably represents an asymmetrical variant. Given their different clinical patterns and responses to treatment, it is important to distinguish between MADSAM neuropathy and MMN.
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Affiliation(s)
- D S Saperstein
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, USA
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Vagg R, Mogyoros I, Kiernan MC, Burke D. Activity-dependent hyperpolarization of human motor axons produced by natural activity. J Physiol 1998; 507 ( Pt 3):919-25. [PMID: 9508850 PMCID: PMC2230820 DOI: 10.1111/j.1469-7793.1998.919bs.x] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
1. The changes in excitability of motor axons produced by natural activity were measured in six healthy subjects using voluntary contractions lasting 15 s, 30 s and 1 min, by recording the changes in stimulus current required to produce a compound muscle action potential of approximately 60 % of maximum. 2. On cessation of the contractions there was a prominent increase in the current required to produce the target potential, accompanied by an increase in rheobase, a decrease in strength-duration time constant, and an increase in axonal supernormality. These changes indicate that the hypoexcitability was due to axonal hyperpolarization. 3. The activity-dependent hypoexcitability increased in depth and duration the longer the contraction. Following a 1 min contraction, it produced a 24 % increase in threshold, waning over 15 min. The hypoexcitability was greater than in cutaneous afferents tetanized to produce an equivalent rate-dependent stress. 4. It is concluded that natural activity results in substantial hyperpolarization of active axons and that, for similar discharge rates, the degree of hyperpolarization is greater in motor axons than cutaneous afferents. The greater effect of activity on the excitability of motor axons could be due to less inward rectification and less persistent Na+ conductance than in sensory axons. It is suggested that motor axons may therefore be more susceptible than cutaneous afferents to conduction block at sites of impaired safety margin for impulse conduction.
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Affiliation(s)
- R Vagg
- Department of Clinical Neurophysiology, Prince of Wales Hospital and Prince of Wales Medical Research Institute, Sydney, Australia
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38
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Abstract
One of the defining electrophysiological characteristics of multifocal motor neuropathy (MMN) is focal motor nerve conduction block. We have noted occasional patients with typical clinical features of MMN in whom there is no demonstrable conduction block. Upon review of 5 such cases, we conclude that otherwise typical MMN may present without overt conduction block. This subset of patients does not otherwise differ from patients with MMN in whom this hallmark electrodiagnostic feature is present.
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Affiliation(s)
- A S Pakiam
- Department of Neurology, University of Minnesota Hospitals and Clinics, Minneapolis 55455, USA
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39
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Dobigny-Roman N, Verny M, Bouche P, Léger JM. [Multifocal motor neuropathy: an individualized disease of the peripheral nervous system]. Rev Med Interne 1997; 18:618-25. [PMID: 9365736 DOI: 10.1016/s0248-8663(97)82463-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Multifocal motor neuropathy is a peripheral nervous system disease described among chronic inflammatory demyelinating polyneuropathies. It is characterized according to both clinical criteria, including chronic asymmetric and multifocal deficit which starts and remains prominent in the upper limbs, and electrophysiological criteria, including persistent multifocal motor conduction blocks in motor nerves. High titers of serum antiganglioside GM1 antibodies are discovered in nearly 40% of cases. Steroids and plasma exchange are not efficient. High doses of intravenous immunoglobulins (i.v.Ig) improved symptoms in the majority of open and controlled published studies. The quality of the response to i.v.Ig may worsen in some patients after a variable number of infusions, leading to immunosuppressive treatments mainly with oral or intravenous cyclophosphamide. Its etiology is unknown but the frequent presence of anti-GM1 antibody high serum titers, the pathological findings in some rare morphological studies, and the response to i.v.Ig favor the hypothesis of an autoimmune disorder.
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Affiliation(s)
- N Dobigny-Roman
- Service de gérontologie SPII, hôpital Sainte-Perine, Paris, France
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40
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Corbo M, Abouzahr MK, Latov N, Iannaccone S, Quattrini A, Nemni R, Canal N, Hays AP. Motor nerve biopsy studies in motor neuropathy and motor neuron disease. Muscle Nerve 1997; 20:15-21. [PMID: 8995578 DOI: 10.1002/(sici)1097-4598(199701)20:1<15::aid-mus2>3.0.co;2-k] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The clinical presentation of motor neuropathy often resembles that of motor neuron disease, sometimes leading to an erroneous diagnosis. Moreover, the underlying pathological process in motor neuropathy has been rarely investigated and there are no systematic studies of the affected motor nerves. We describe a new motor nerve biopsy procedure, performed in 15 patients: 6 with motor neuropathy and 9 with motor neuron disease. The motor branch from the anterior division of the obturator nerve to the gracilis muscle in the thigh was biopsied. In both groups of patients the motor nerves exhibited depletion of myelinated nerve fibers. In motor neuropathy there was a significantly higher density of regenerative clusters of small myelinated fibers in comparison to motor nerves from patients with motor neuron disease. In addition, in 3 patients with motor neuropathy there was evidence for demyelination with thinly myelinated axons and small onion bulb formations. These pathological studies of motor nerve biopsies can help to differentiate motor neuropathy from motor neuron disease.
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Affiliation(s)
- M Corbo
- Department of Neurology, University of Milan, Italy
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Yokota T, Saito Y, Yuki N, Tanaka H. Persistent increased threshold of electrical stimulation selective to motor nerve in multifocal motor neuropathy. Muscle Nerve 1996; 19:823-8. [PMID: 8965834 DOI: 10.1002/mus.880190702] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In multifocal motor neuropathy (MMN) the threshold of electrical stimulation showed a persistent, marked increase for the motor nerve which decreased after treatment with intravenous immunoglobulin or oral cyclophosphamide; whereas, the threshold was normal for the sensory nerve. This discrepancy of the thresholds for motor and sensory nerves indicates that the increased threshold for motor nerve is not caused by change in perineural capacitance, such as subperi- and endoneural edema or perineural thickening. Inching studies showed that the site of the elevated motor nerve threshold was closely associated with conduction slowing and block. For the cause of the increased threshold, therefore, we suppose the presence of a factor which interferes with reorganization of the nodal property in the remyelinative process or which directly blocks sodium channels where the blood-nerve barrier is impaired in MMN.
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Affiliation(s)
- T Yokota
- Department of Neurology, Tokyo Medical and Dental University, Japan
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Abstract
A 73-year-old man with a 16-year history of fasciculations and 15 years of weakness in his right arm was diagnosed with focal motor neuron disease. After 10 years of purely motor symptoms, he developed mild parasthesias although his sensory examination remained normal. Reflexes were reduced or absent in the weak muscles but were normal elsewhere. Nerve conduction was studied in nerves innervating weak muscles and showed severe motor conduction block. Sensory nerve conduction studies were minimally abnormal, showing reduced amplitudes with normal velocities. Based on the clinical picture and the presence of severe motor conduction block, the patient was diagnosed as multifocal motor neuropathy. Treatment with high-dose intravenous immunoglobulin was given with significant improvement in strength and partial resolution of the conduction block. As this case demonstrates, this treatable disorder may occasionally be mistaken for motor neuron disease although the resemblance is only superficial, and it should never be mistaken for amyotrophic lateral sclerosis. Multifocal motor neuropathy is an inflammatory, demyelinating neuropathy which, like chronic inflammatory demyelinating polyneuropathy (CIDP), is probably immune-mediated. It differs from typical CIDP by virtue of a marked predilection for motor axons, a strikingly restricted distribution, and a protracted course. Treatment with high-dose intravenous immunoglobulin is frequently helpful, but other forms of immune manipulation are less effective.
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Affiliation(s)
- G J Parry
- Department of Neurology, University of Minnesota, Minneapolis, USA
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44
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Veugelers B, Theys P, Lammens M, Van Hees J, Robberecht W. Pathological findings in a patient with amyotrophic lateral sclerosis and multifocal motor neuropathy with conduction block. J Neurol Sci 1996; 136:64-70. [PMID: 8815180 DOI: 10.1016/0022-510x(95)00295-d] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We studied a 53-year-old woman with progressive weakness of the left arm, gradually spreading to the other limbs. Neurological examination revealed a motor neuron syndrome with paresis, fasciculations and atrophy. Electrophysiological studies showed multiple motor conduction blocks. The anti-GM1 IgM titer was elevated. The patient was thought to have a multifocal motor neuropathy. Despite intravenous cyclophosphamide treatment, however, she died with respiratory insufficiency. On postmortem examination, the brachial plexus showed patches of demyelination underlying different areas of motor conduction block. The spinal cord, however, revealed severe neuronal loss in the ventral horn and axonal loss in the corticospinal tract, indicative of amyotrophic lateral sclerosis. Demyelination of peripheral nerves could have been responsible for the other conduction blocks in this patient. The prominent degeneration of motor neurons, however, must also have played a role in the clinical picture. Some patients with the syndrome of a multifocal motor neuropathy may have MND rather than, or in addition to, a demyelinating peripheral motor neuropathy.
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Affiliation(s)
- B Veugelers
- Department of Neurology, University Hospital Gasthuisberg, Leuven, Belgium
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45
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Corse AM, Chaudhry V, Crawford TO, Cornblath DR, Kuncl RW, Griffin JW. Sensory nerve pathology in multifocal motor neuropathy. Ann Neurol 1996; 39:319-25. [PMID: 8602750 DOI: 10.1002/ana.410390308] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The nosological status of multifocal motor neuropathy remains controversial. The clinical and electrodiagnostic hallmarks suggest selective motor fiber involvement. In this study, we asked to what extent sensory nerves might be involved pathologically in multifocal motor neuropathy. Examination of sensory nerve biopsy specimens from 11 patients did reveal pathological findings in all, but they were very mild. An increased number of thinly myelinated, large-caliber fibers was the unifying feature common to each specimen. By electron microscopy, each biopsy specimen had thinly myelinated fibers surrounded by minor onion bulbs. Active demyelination, though scant, was seen in 3 nerves. Myelinated fiber density was normal. Subperineurial edema and inflammation were not present. We conclude that multifocal motor neuropathy is not an exclusively motor abnormality, although it appears to be so clinically and electrophysiologically. The frequent, albeit mild, pathological abnormalities in sensory fibers suggest that the demyelinating pathophysiology also affects sensory fibers, but to a lesser degree than motor fibers. Some investigators maintain that multifocal motor neuropathy is within the spectrum of chronic inflammatory demyelinating polyneuropathy. The very mild degree of sensory fiber involvement, the absence of inflammation or edema, and the distinctive clinical features support the concept of multifocal motor neuropathy as distinct from chronic inflammatory demyelinating polyneuropathy.
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Affiliation(s)
- A M Corse
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287-7519, USA
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46
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Bouche P, Moulonguet A, Younes-Chennoufi AB, Adams D, Baumann N, Meininger V, Léger JM, Said G. Multifocal motor neuropathy with conduction block: a study of 24 patients. J Neurol Neurosurg Psychiatry 1995; 59:38-44. [PMID: 7608707 PMCID: PMC1073599 DOI: 10.1136/jnnp.59.1.38] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Twenty four patients with pure motor neuropathy are reported. The chronic motor involvement associated with fasciculations and cramps, mainly in the arms, led, in most patients, to an initial diagnosis of motor neuron disease. In some patients (nine of 24), there was no appreciable muscle atrophy. Tendon reflexes were often absent or weak. The finding of persistent multifocal conduction block confined to motor nerve fibres raises questions about the nature and the importance of this syndrome. Segmental reduction of motor conduction velocity occurred at the site of the block, but significant slowing of motor nerve conduction was not found outside this site. The response to intravenous IVIg treatment seems to be correlated with the absence of amyotrophy. Patients with little or no amyotrophy had an initial and sustained response to IVIg, and did not develop amyotrophy during the follow up study. They could be considered to have a variant of chronic inflammatory demyelinating polyneuropathy. Patients with pronounced amyotrophy independent of the disease duration did not respond as well to IVIg treatment, suggesting the existence of a distinct entity. Among the patients treated about two thirds who had an initial good response to IVIg had high or significant antiganglioside GM1 (anti-GM1) antibody titres, but there was no correlation between the high titres before treatment and long lasting response to IVIg treatment.
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Affiliation(s)
- P Bouche
- Laboratoire d'Explorations Functionelles Neurologie, Hôpital de la Salpêtrieve, Paris, France
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Leger JM, Younes-Chennoufi AB, Chassande B, Davila G, Bouche P, Baumann N, Brunet P. Human immunoglobulin treatment of multifocal motor neuropathy and polyneuropathy associated with monoclonal gammopathy. J Neurol Neurosurg Psychiatry 1994; 57 Suppl:46-9. [PMID: 7964853 PMCID: PMC1016725 DOI: 10.1136/jnnp.57.suppl.46] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Intravenous human immune globulin (IVIg) has been proposed for the treatment of various peripheral neuropathies that are considered to be immunemediated. The results are reported of an open trial conducted in multifocal motor neuropathy and polyneuropathy associated with monoclonal gammopathy. Six cases with multifocal motor neuropathy, selected on clinical and electrophysiological criteria (four of six patients also had significantly high anti-GM1 titres), received IVIg monthly, at doses varying from 1.6 to 2.5 mg/kg, over three to 13 months. The initial response to treatment was dramatic in 3/6 cases (with improvement of at least two grades on the MRC scale in the five more severely affected muscles). The final evaluation showed a good result in 4/6 cases, but the conduction blocks were not significantly reduced. In 13 other cases with polyneuropathy associated with IgM monoclonal gammopathy of unknown significance, IVIg was of benefit, with improvement of at least one grade on the Prineas score, in 4/7 cases previously treated with immunosuppression and 2/3 cases not treated before IVIg. In the last group of four patients with polyneuropathy and IgG monoclonal gammopathy, IVIg was followed by clinical improvement in the two cases with a chronic demyelinating polyneuropathy.
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Affiliation(s)
- J M Leger
- Service de Neurologie, Hôpital de la Salpêtrière, Paris, France
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49
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Abstract
We studied the tendon reflex (T-reflex) in 26 patients with acquired chronic demyelinating polyneuropathy (CDN), including 22 with chronic inflammatory demyelinating polyneuropathy (CIDP). In 7 patients reflexes were brisk or normal on clinical testing. The height adjusted T-reflex was abnormal in 25 (96%) cases, including 6 of 7 patients with brisk or normal reflexes on clinical testing. Mean latency (P < 0.01) and duration (P < 0.05) of the ankle and patellar tendon reflexes were significantly prolonged in the CIDP patients when compared to the controls. Mean latency in the CIDP patients was 152% of normal means. In 7 CIDP patients, the T-reflex latencies were prolonged beyond 150% of normal means. Thus, the T-reflex test is abnormal in a majority of patients with CDN, even in the presence of well-preserved clinical reflexes, and the T-reflex latency is a useful indicator of the presence of a demyelinating peripheral neuropathy in some patients.
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Affiliation(s)
- H R Kuruoglu
- Department of Neurology, University of Alabama at Birmingham, Veterans Administration Medical Center 35294
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50
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Lange DJ, Trojaborg W, McDonald TD, Blake DM. Persistent and transient "conduction block" in motor neuron diseases. Muscle Nerve 1993; 16:896-903. [PMID: 8355720 DOI: 10.1002/mus.880160903] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Although conduction block indicates dysfunction of peripheral nerve, it may occur in patients with clinically typical motor neuron disease. There are no universally accepted criteria to identify conduction block, so diagnosis may be difficult. In some peripheral neuropathies, conduction block persists over long periods of time. If conduction block persists in motor neuron disease, then a more reproducible means for identification would be available. We repeatedly studied 9 patients with different forms of motor neuron diseases; conduction block was suspected because of excessive loss of the amplitude of motor evoked responses between distal and proximal stimulation sites. Five showed persistent amplitude loss at intervals between 12 and 36 months. All had focal loss of amplitude and area across a specific segment; all were men; none had definite upper motor neuron signs, 2 had probable and 3 had no upper motor neuron signs; 1 had IgM paraproteinemia, one elevated anti-GM1 titers; the duration of symptoms spanned 4-13 years. Four patients had transient loss of amplitude that was not reproduced in intervals between 3 and 13 months. None had focal loss of both amplitude and area; 2 were men; all had definite upper motor neuron signs and none had symptoms for more than 3-13 months; and none had immunological abnormalities. Thus, patients with persistent amplitude loss fulfill other criteria for conduction block, have prolonged survival but otherwise have clinical syndromes indistinguishable from ALS, except that definite upper motor neuron signs seem to be exceptional.
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Affiliation(s)
- D J Lange
- Department of Neurology, Columbia-Presbyterian Medical Center, New York, NY 10032-2603
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