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Therapeutic Outcomes and Electrophysiological Biomarkers in Anti-Myelin-Associated Glycoprotein Neuropathy: A Multicenter Cohort Study in South Korea. J Clin Neurol 2024; 20:50-58. [PMID: 38179632 PMCID: PMC10782088 DOI: 10.3988/jcn.2023.0127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/04/2023] [Accepted: 06/07/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND AND PURPOSE Unlike other immune-mediated neuropathies, anti-myelin-associated glycoprotein (MAG) neuropathy is often refractory to immunotherapy. It is necessary to compare the relative efficacies of various immunotherapies and develop objective biomarkers in order to optimize its clinical management. METHODS This study recruited 91 patients with high anti-MAG antibody titers from 7 tertiary hospitals in South Korea. We analyzed the baseline characteristics, therapeutic outcomes, and nerve conduction study (NCS) findings of 68 patients and excluded 23 false positive cases. RESULTS The rate of positive responses to treatment was highest using zanubrutinib (50%) and rituximab (36.4%), followed by corticosteroids (16.7%), immunosuppressants (9.5%), intravenous immunoglobulin (5%), and plasma exchange (0%). Disability and weakness were significantly associated with multiple NCS parameters at the time of diagnosis, especially distal compound muscle action potential (CMAP) amplitudes. Moreover, the longitudinal trajectory of the average CMAP amplitudes paralleled the clinical courses, with a 16.2 percentile decrease as an optimal cutoff for predicting a clinical exacerbation (area under the receiver operating characteristic curve=0.792). CONCLUSIONS Our study supports the use of NCS as an objective marker for estimating disease burden and tracking clinical changes in patients with anti-MAG neuropathy. We have described the beneficial effects of rituximab and a new drug, zanubrutinib, compared with conventional immunotherapies.
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Anti-myelin-associated glycoprotein neuropathy: Where do we stand? Muscle Nerve 2023; 68:823-832. [PMID: 37602932 DOI: 10.1002/mus.27954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/19/2023] [Accepted: 07/22/2023] [Indexed: 08/22/2023]
Abstract
Myelin-associated glycoprotein (MAG) is a transmembrane glycoprotein concentrated in periaxonal Schwann cell and oligodendroglial membranes of myelin sheaths that serves as an antigen for immunoglobulin M (IgM) monoclonal antibodies. Individuals who harbor anti-MAG antibodies classically develop a progressive autoimmune peripheral neuropathy characterized clinically by ataxia, distal sensory loss, and gait instability, and electrophysiologically by distally accentuated conduction velocity slowing. Although off-label immunotherapy is common, there are currently no proven effective disease-modifying therapeutics, and most patients experience slow accumulation of disability over years and decades. The typically slowly progressive nature of this neuropathy presents unique challenges when trying to find effective anti-MAG therapeutic agents. Drug development has also been hampered by the lack of validated outcome measures that can detect clinically meaningful changes in a reasonable amount of time as well as by the lack of disease activity biomarkers. In this invited review, we provide an update on the state of clinicometric outcome measures and disease activity biomarkers in anti-MAG neuropathy. We highlight the insensitivity of widely used existing clinicometric outcome measures such as the Inflammatory Neuropathy Cause and Treatment (INCAT) disability score as well as the INCAT sensory subscore in anti-MAG neuropathy, referencing the two previous negative randomized controlled clinical trials evaluating rituximab. We then discuss newly emerging candidate therapeutic agents, including tyrosine kinase inhibitors and enhanced B-cell-depleting agents, among others. We conclude with a practical approach to the evaluation and management of anti-MAG neuropathy patients.
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Clinical Reasoning: A 67-Year-Old Woman With Progressive Tingling Sensations and Imbalance. Neurology 2023; 100:151-157. [PMID: 36302667 DOI: 10.1212/wnl.0000000000201624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 10/12/2022] [Indexed: 02/05/2023] Open
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Autoimmune polyneuropathies. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:587-608. [PMID: 37562888 DOI: 10.1016/b978-0-323-98818-6.00004-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
The autoimmune peripheral neuropathies with prominent motor manifestations are a diverse collection of unusual peripheral neuropathies that are appreciated in vast clinical settings. This chapter highlights the most common immune-mediated, motor predominant neuropathies excluding acute, and chronic inflammatory demyelinating polyradiculoneuropathy (AIDP and CIDP, respectively). Other acquired demyelinating neuropathies such as distal CIDP and multifocal motor neuropathy will be covered. Additionally, the radiculoplexus neuropathies, resulting from microvasculitis-induced injury to nerve roots, plexuses, and nerves, including diabetic and nondiabetic lumbosacral radiculoplexus neuropathy and neuralgic amyotrophy (i.e., Parsonage-Turner syndrome), will be included. Finally, the motor predominant peripheral neuropathies encountered in association with rheumatological disease, particularly Sjögren's syndrome and rheumatoid arthritis, are covered. Early recognition of these distinct motor predominant autoimmune neuropathies and initiation of immunomodulatory and immunosuppressant treatment likely result in improved outcomes.
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Value of Antibody Determinations in Chronic Dysimmune Neuropathies. Brain Sci 2022; 13:brainsci13010037. [PMID: 36672019 PMCID: PMC9856104 DOI: 10.3390/brainsci13010037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/12/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
Chronic dysimmune neuropathies encompass a group of neuropathies that share immune-mediated pathomechanism. Chronic dysimmune antibody-related neuropathies include anti-MAG neuropathy, multifocal motor neuropathy, and neuropathies related to immune attack against paranodal antigens. Such neuropathies exhibit distinguishing pathomechanism, clinical and response to therapy features with respect to chronic inflammatory demyelinating polyradiculoneuropathy and its variants, which represent the most frequent form of chronic dysimmune neuropathy. This narrative review provides an overview of pathomechanism; clinical, electrophysiological, and biochemical features; and treatment response of the antibody-mediated neuropathies, aiming to establish when and why to look for antibodies in chronic dysimmune neuropathies.
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Efficacy of rituximab in anti-myelin-associated glycoprotein demyelinating polyneuropathy: Clinical, hematological and neurophysiological correlations during 2 years of follow-up. Eur J Neurol 2022; 29:3611-3622. [PMID: 36083713 PMCID: PMC9825860 DOI: 10.1111/ene.15553] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/11/2022] [Accepted: 08/31/2022] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND PURPOSE We evaluated the clinical and neurophysiological efficacy of rituximab (RTX) in a neurophysiologically homogeneous group of patients with monoclonal gammopathy and immunoglobulin M (IgM) anti-myelin-associated glycoprotein antibody (anti-MAG) demyelinating polyneuropathy. METHODS Twenty three anti-MAG-positive polyneuropathic patients were prospectively evaluated before and for 2 years after treatment with RTX 375 mg/m2 . The Inflammatory Neuropathy Cause and Treatment (INCAT) disability scale (INCAT-ds), modified INCAT sensory score (mISS), Medical Research Council sum score, Patients' Global Impression of Change scale were used, IgM levels were assessed and extensive electrophysiological examinations were performed before (T0) and 1 year (T1) and 2 years (T2) after RTX treatment. RESULTS At T1 and T2 there was a significant reduction from T0 both in mISS and in INCAT-ds, with a p value < 0.001 in the inferential Friedman's test overall analysis. Ulnar nerve Terminal Latency Index and distal motor latency significantly changed from T0 to T1 and in the overall analysis (p = 0.001 and p = 0.002), and ulnar nerve sensory nerve action potential (SNAP) amplitude was significantly increased at T2 from T1, with a p value < 0.001 in the overall analysis. Analysis of the receiver-operating characteristic curves showed that a 41.8% increase in SNAP amplitude in the ulnar nerve at T2 from T0 was a fair predictor of a mISS reduction of ≥2 points (area under the curve 0.85; p = 0.005; sensitivity: 90.9%, specificity: 83.3%). CONCLUSIONS This study suggests that RTX is effective in patients with clinically active demyelinating anti-MAG neuropathy over 2 years of follow-up, and that some neurophysiological variables might be useful for monitoring this efficacy.
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Anti-MAG neuropathy: From biology to clinical management. J Neuroimmunol 2021; 361:577725. [PMID: 34610502 DOI: 10.1016/j.jneuroim.2021.577725] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 09/20/2021] [Indexed: 12/19/2022]
Abstract
The acquired chronic demyelinating neuropathies include a growing number of disease entities that have characteristic, often overlapping, clinical presentations, mediated by distinct immune mechanisms, and responding to different therapies. After the discovery in the early 1980s, that the myelin associated glycoprotein (MAG) is a target antigen in an autoimmune demyelinating neuropathy, assays to measure the presence of anti-MAG antibodies were used as the basis to diagnose the anti-MAG neuropathy. The route was open for describing the clinical characteristics of this new entity as a chronic distal large fiber sensorimotor neuropathy, for studying its pathogenesis and devising specific treatment strategies. The initial use of chemotherapeutic agents was replaced by the introduction in the late 1990s of rituximab, a monoclonal antibody against CD20+ B-cells. Since then, other anti-B cells agents have been introduced. Recently a novel antigen-specific immunotherapy neutralizing the anti-MAG antibodies with a carbohydrate-based ligand mimicking the natural HNK-1 glycoepitope has been described.
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Abstract
Paraproteinemia is associated with different peripheral neuropathies. The major causes of neuropathy correlated with paraproteinemia are the deposition of immunoglobulin in the myelin, represented by anti-myelin-associated glycoprotein (MAG) neuropathy; deposition of immunoglobulin or its fragment in the interstitium, represented by immunoglobulin light chain amyloidosis (AL amyloidosis); and paraneoplastic mechanisms that cannot be solely attributed to the deposition of immunoglobulin or its fragment, represented by polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin change (POEMS) syndrome. Patients with anti-MAG neuropathy and POEMS syndrome present with slowing of nerve conduction parameters. This characteristic fulfills the electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP) defined by the European Academy of Neurology and Peripheral Nerve Society (EAN/PNS). Although direct damage caused by the deposition of amyloid can induce axonal damage in AL amyloidosis, some patients with this condition have features fulfilling the EAN/PNS electrodiagnostic criteria for CIDP. Conventional immunotherapies for CIDP, such as steroids, intravenous immunoglobulin, and plasma exchange, offer no or only minimal-to-modest benefit. Although rituximab can reduce the level of circulating autoantibodies, it may only be effective in some patients with anti-MAG neuropathy. Drugs including melphalan, thalidomide, lenalidomide, and bortezomib for POEMS syndrome and those including melphalan, thalidomide, lenalidomide, pomalidomide, bortezomib, ixazomib, and daratumumab for AL amyloidosis are considered. Since there will be more therapeutic options in the future, thereby enabling appropriate treatments for individual neuropathies, there is an increasing need for early diagnosis.
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Severe Paraproteinemic Demyelinating Neuropathy With Impaired Excitability of the Distal Segments of the Peripheral Nerves. J Clin Neuromuscul Dis 2021; 23:43-48. [PMID: 34431801 DOI: 10.1097/cnd.0000000000000357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
ABSTRACT We report clinical and detailed nerve conduction findings in case of polyneuropathy associated with kappa light chains monoclonal gammopathy of undetermined significance with progression to lymphoproliferative disorder. A 55-year-old man had a predominantly distal, chronic (5 years duration), slowly progressive, symmetric, predominantly sensory impairment with sensory ataxia, and mild weakness. M protein was identified by serum protein electrophoresis. The kappa/lambda ratio of free light chains was significantly elevated to 11.96. The cerebrospinal fluid protein level was elevated at 3.5 g/L. This case study has revealed 2 unusual electrophysiological phenomena-a very unusual prolongation of distal motor latencies of compound muscle action potentials (CMAP) up to 86.5 ms and impaired excitability of the distal segments of the peripheral nerves. The distal CMAP areas were considerably lower compared with the proximal CMAP areas. Radiography of the skull revealed osteolytic lesions.
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Chronic Immune-Mediated Polyneuropathies. Clin Geriatr Med 2021; 37:327-345. [PMID: 33858614 DOI: 10.1016/j.cger.2021.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This article discusses the chronic immune-mediated polyneuropathies, a broad category of acquired polyneuropathies that encompasses chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), the most common immune-mediated neuropathy, the CIDP variants, and the vasculitic neuropathies. Polyneuropathies associated with rheumatological diseases and systemic inflammatory diseases, such as sarcoidosis, will also be briefly covered. These patients' history, examination, serum studies, and electrodiagnostic studies, as well as histopathological findings in the case of vasculitis, confirm the diagnosis and differentiate them from the more common length-dependent polyneuropathies. Prompt identification and initiation of treatment is imperative for these chronic immune-mediated polyneuropathies to prevent disability and even death.
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Monoclonal Gammopathies of 'Neurological Significance': Paraproteinemic Neuropathies. Can J Neurol Sci 2021; 48:616-625. [PMID: 33397535 DOI: 10.1017/cjn.2020.278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES To study the clinical profile and outcomes of patients with paraproteinemic neuropathy (PPN) and to explore the utility of nerve conduction studies (NCSs) to differentiate between the demyelinating subtypes. METHODS We did a retrospective analysis of patients diagnosed with PPN between January 2010 and December 2019 in an inpatient setting. The study population consisted of patients above 16 years of age presenting with clinical features suggestive of chronic peripheral neuropathy and on evaluation was found to have PPN. RESULTS A total of 74 patients were identified. The patients were predominantly in the 6th decade, and the majority were males. The subtypes of PPN were monoclonal gammopathy of undetermined significance (MGUS) (45.9%), POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes) (24.3%), solitary plasmacytoma (17.6%), multiple myeloma (8.1%), and AL amyloidosis (4.1%). There are specific features on NCS which can help in identifying POEMS syndrome and IgM MGUS. The majority of patients with PPN tend to stabilize or improve with treatment; however, many have a severe residual disability. New terminology and classification of these entities as 'monoclonal gammopathies of neurological significance' can aid in early diagnosis and the development of effective treatment, to prevent residual disability. CONCLUSION PPN has a heterogeneous spectrum of clinical, biochemical, and electrophysiological features. NCS can help distinguish POEMS syndrome and IgM MGUS from other demyelinating subtypes.
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Temporal evolution of nerve conduction study abnormalities in anti-myelin-associated glycoprotein neuropathy. Muscle Nerve 2020; 63:401-404. [PMID: 33290607 DOI: 10.1002/mus.27134] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 11/27/2020] [Accepted: 12/06/2020] [Indexed: 11/08/2022]
Abstract
BACKGROUND A distal-predominant demyelinating symmetric pattern is most frequent in patients with neuropathy associated with anti-myelin-associated glycoprotein (MAG) antibodies. The literature however lacks longitudinal data to describe whether this is consistent over time. METHODS From the Ottawa Neuromuscular Center database, we identified 23 patients with both immunoglobulin M gammopathy and anti-MAG antibodies. For median, ulnar and fibular motor conduction studies, we analyzed distal latency and amplitude, negative peak duration, terminal latency index (TLI), and conduction velocity. For median, ulnar, sural, and superficial fibular sensory conduction studies, we analyzed distal latency and amplitude. Results were compared for the earliest and the latest data sets. RESULTS The mean time interval between the two assessment points was 6.5 years. Median and ulnar motor nerve conduction studies did not show a significant change for any of the parameters tested. There was disproportionate prolongation of median distal motor latency and reduction in TLI, compared to the ulnar nerve. Deep fibular motor conduction studies showed a marked reduction in amplitudes over time. Sensory potentials were recordable in the upper limb in less than 50% at the first study and less than 25% on the most recent study. There was an even larger attrition of recordable sural and superficial fibular sensory potentials. CONCLUSIONS Our results highlight the stability of median and ulnar motor conduction study results over a mean observation period of 6.5 years. In contrast, lower limb motor and all sensory potentials show a marked trend toward becoming unrecordable.
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Proximal Nerve Root Involvement in immunoglobulin M Anti-Myelin-Associated Glycoprotein Neuropathy Presenting as Cauda Equina Syndrome. J Clin Neuromuscul Dis 2020; 22:109-113. [PMID: 33214398 DOI: 10.1097/cnd.0000000000000307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Typical distal symptoms in anti-myelin-associated glycoprotein (anti-MAG) neuropathy are believed to be due to the binding of immunoglobulin M to distal nerve terminals. We describe the case of a 56-year-old man diagnosed with immunoglobulin M anti-MAG neuropathy in the setting of Waldenström macroglobulinemia, which developed acute neurological worsening presenting as cauda equina syndrome. Lumbosacral magnetic resonance imaging revealed enlarged nerve roots with diffuse heterogeneous gadolinium enhancement. Treatment with steroids resulted in substantial clinical improvement. Increased recognition of atypical presentations may lead to improved characterization of anti-MAG neuropathy as a more widespread disease.
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Abstract
PURPOSE OF REVIEW Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and its variants comprise a group of immune-mediated neuropathies with distinctive clinical presentations and electrodiagnostic features. Prompt recognition of these treatable disorders is mandatory as delays result in significant disability and morbidity. This article highlights the clinical presentation, pathophysiology, diagnostic evaluation, and treatment approach of these polyneuropathies. RECENT FINDINGS The spectrum of CIDP is expanding with the recent characterization of neuropathies associated with nodal and paranodal antibodies. These neuropathies are distinguished by their unique presentations and are often refractory to IV immunoglobulin (IVIg) therapy. Subcutaneous immunoglobulins have recently been approved as a treatment option for CIDP and join corticosteroids, IVIg, and plasma exchange as first-line treatment. SUMMARY CIDP is characterized by progressive symmetric proximal and distal weakness, large fiber sensory loss, and areflexia, with clinical nadir reached more than 8 weeks after symptom onset. Autoimmune demyelinating neuropathies fall on a continuum, with differences in the type of nerve fibers affected and pattern of deficits. Distinguishing between typical CIDP and its variants allows for selection of the most appropriate treatment.
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Polyneuropathie im Alter. Internist (Berl) 2020; 61:254-260. [DOI: 10.1007/s00108-020-00748-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
ZusammenfassungDas periphere Nervensystem ist im Laufe des Alternsprozesses Veränderungen unterworfen. So kommt es unter anderem zu einer Abschwächung von Muskeleigenreflexen und Propriozeption. Davon abzugrenzen sind Polyneuropathien als krankhafte Veränderungen des peripheren Nervensystems. Die jährliche Inzidenz von Polyneuropathien wird auf 118/100.000 geschätzt, die Prävalenz liegt bei etwa 1 %, für ältere Populationen werden 7 % angegeben. Die Ursachen sind vielfältig und ähnlich den Ursachen von Neuropathien des jüngeren Alters: Neben metabolischen, immunvermittelten, hereditären, toxischen und infektiösen Ätiologien können Polyneuropathien Ausdruck von Systemerkrankungen sein. Entsprechend der Altersverteilung der verschiedenen Ursachen sind Neuropathien im Zusammenhang mit Diabetes, monoklonalen Gammopathien und Malignomen im Alter häufiger. Allerdings nimmt der Anteil der kryptogenen Neuropathien, also ohne eindeutige Ursache, mit dem Alter zu. Bei alten Menschen führen Polyneuropathien zu einer zusätzlichen Beeinträchtigung der Mobilität und einem erhöhten Sturzrisiko, was auch die Abklärung funktioneller Fähigkeiten erforderlich macht.
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Different distribution of demyelination in chronic inflammatory demyelinating polyneuropathy subtypes. J Neuroimmunol 2020; 341:577170. [PMID: 32006783 DOI: 10.1016/j.jneuroim.2020.577170] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 01/19/2020] [Accepted: 01/23/2020] [Indexed: 12/11/2022]
Abstract
In demyelinating polyneuropathies, distribution patterns of demyelination reflect underlying pathogenesis. Median and ulnar nerve conduction studies were reviewed in 85 typical chronic inflammatory demyelinating polyneuropathy (CIDP) patients and 29 multifocal acquired demyelinating sensory and motor neuropathy (MADSAM). Distal latencies were prolonged in typical CIDP and near normal in MADSAM. Abnormal amplitude reductions in the nerve trunks were more frequent in MADSAM than typical CIDP. Presumably because the blood-nerve barrier is anatomically deficient at the distal nerve terminals, antibody-mediated demyelination is a major pathophysiology in typical CIDP. In contrast, blood-nerve barrier breakdown is likely to be predominant in MADSAM.
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Anti-MAG IgM: differences in antibody tests and correlation with clinical findings. Neurol Sci 2019; 41:365-372. [DOI: 10.1007/s10072-019-04089-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/24/2019] [Indexed: 12/28/2022]
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Diagnosis and management of neuropathies associated with plasma cell dyscrasias. Hematol Oncol 2017; 36:3-14. [PMID: 28397326 DOI: 10.1002/hon.2417] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 02/14/2017] [Accepted: 03/06/2017] [Indexed: 12/16/2022]
Abstract
Neuropathies associated with plasma cell dyscrasias are a major cause of morbidity for patients managed by medical oncologists. Because of similarities in clinical presentation and on nerve conduction studies, identifying the underlying disease leading to a paraproteinemic neuropathy can often be difficult. In addition, the degree of neurologic deficit does not strictly correlate with the extent of abnormalities on common clinical laboratory testing. Fortunately, with increasing understanding into the biologic mechanisms of underlying hematologic diseases, additional biomarkers have recently been developed, thus improving our diagnostic capacity. Neuropathies associated with plasma cells dyscrasias are seen with Monoclonal gammopathy of undetermined significance (MGUS) particularly IgM subtype, followed by IgG and IgA MGUS, multiple myeloma, Waldenström's macroglobulinemia, amyloid, Castleman's disease, and POEMS syndrome. The mechanisms of neuronal injury associated with plasma cell dyscrasia vary based on underlying diagnosis and include malignant infiltration, immune-mediated antibody deposition, or local compression of nerve roots. The polyneuropathies are frequently demyelinating, although axonal and mixed neuropathies can also be seen. As demonstrated by the cases included in this review, patients frequently present with symmetric sensory disturbance, followed by progressive motor weakness. Unfortunately, because of the complexity of diagnostic testing, patients are frequently examined late, often after receiving several ineffective therapies. The aim of this case-based review is to provide clinicians with insight on how to properly recognize these atypical neuropathies and send the appropriate diagnostic work, increasing the likelihood of accurately classify the patient's underlying hematologic disorder.
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Is distal motor and/or sensory demyelination a distinctive feature of anti-MAG neuropathy? J Neurol 2016; 263:1761-70. [DOI: 10.1007/s00415-016-8187-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/25/2016] [Accepted: 05/29/2016] [Indexed: 12/27/2022]
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Ultrasound in the diagnosis of peripheral neuropathy: structure meets function in the neuromuscular clinic. J Neurol Neurosurg Psychiatry 2015; 86:1066-74. [PMID: 25653385 DOI: 10.1136/jnnp-2014-309599] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 01/08/2015] [Indexed: 02/06/2023]
Abstract
Peripheral nerve ultrasound (US) has emerged as a promising technique for the diagnosis of peripheral nerve disorders. While most experience with US has been reported in the context of nerve entrapment syndromes, the role of US in the diagnosis of peripheral neuropathy (PN) has recently been explored. Distinctive US findings have been reported in patients with hereditary, immune-mediated, infectious and axonal PN; US may add complementary information to neurophysiological studies in the diagnostic work-up of PN. This review describes the characteristic US findings in PN reported to date and a classification of abnormal nerve US patterns in PN is proposed. Closer scrutiny of nerve abnormalities beyond assessment of nerve calibre may allow for more accurate diagnostic classification of PN, as well as contribute to the understanding of the intersection of structure and function in PN.
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Neuropatie sensitive. Neurologia 2015. [DOI: 10.1016/s1634-7072(15)70522-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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IgM MGUS associated with anti-MAG neuropathy: a single institution experience. Ann Hematol 2015; 94:1011-6. [DOI: 10.1007/s00277-014-2294-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 12/23/2014] [Indexed: 11/24/2022]
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Abstract
Background:Neuropathy is common in Waldenström's macroglobulinemia (WM, an IgM-associated lymphoplasmacytic lymphoma) and in IgM-monoclonal gammopathy of undetermined significance (IgM-MGUS). Paraneoplastic or paraimmune mechanisms are thought to be involved in the pathogenesis of these neuropathies. Attempts at distinguishing WM and IgM-MGUS neuropathies are lacking especially among bone marrow (BM) confirmed patients.Methods:Retrospective analyses were performed on BM confirmed WM (N=30) and IgM-MGUS (N=73) neuropathy patients with neurologic assessments and hematologic features.Results:The presence of anemia and quantity of IgM monoclonal protein were significantly greater in WM. Based on multiple neurologic assessments differences were not found for: 1) length of time from neurologic symptom onset to evaluation; 2) chief complaint of painless loss of feeling in the feet, Romberg's sign and tremor; and 3) clinical motor, sensory and reflex abnormalities. Autonomic testing was normal in both diseases. Using nerve conduction (NCS) criteria for demyelination, 62% of IgM-MGUS and 27% of WM met this criteria (p=0.013). IgM MGUS patients had greater terminal conduction slowing by ulnar residual latency calculation (<0.01). The degree of axonal loss as measured by summated compound muscle action potentials and available nerve biopsy was not significantly different between diseases.Conclusion:Although WM and IgM-MGUS must be distinguished for hematologic prognosis and treatment, clinical neuropathy presentations of WM and IgM-MGUS are similar and likely related to comparable axonal loss in both conditions. Despite these similarities, evidence of demyelination was found by electrophysiologic studies much more commonly in IgM-MGUS. This difference may reflect varied immune mechanism(s) in the two disorders.
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Reply to “The significance of significance: Overstating in the setting of many comparisons”. Clin Neurophysiol 2014; 125:1073-4. [DOI: 10.1016/j.clinph.2013.09.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 09/27/2013] [Indexed: 10/26/2022]
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Pathophysiology of immune-mediated demyelinating neuropathies--Part II: Neurology. Muscle Nerve 2013; 49:4-20. [PMID: 24037667 DOI: 10.1002/mus.24068] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2013] [Indexed: 12/13/2022]
Abstract
In the second part of this review we deal with the clinical aspects of immune-mediated demyelinating neuropathies. We describe the relationship between pathophysiology and symptoms and discuss the pathophysiology of specific disease entities, including Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy, anti-myelin-associated glycoprotein neuropathy, and POEMS syndrome.
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Clinical–neurophysiological correlations in a series of patients with IgM-related neuropathy. Clin Neurophysiol 2013; 124:1899-903. [DOI: 10.1016/j.clinph.2013.02.116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Revised: 02/03/2013] [Accepted: 02/18/2013] [Indexed: 01/06/2023]
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Rituximab Improves Subclinical Temporal Dispersion of Distal Compound Muscle Action Potential in Anti-MAG/SGPG Neuropathy Associated with Waldenström Macroglobulinemia: A Case Report. Case Rep Neurol 2013; 5:34-9. [PMID: 23525653 PMCID: PMC3604870 DOI: 10.1159/000348395] [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: 12/14/2022] Open
Abstract
Patients with anti-myelin-associated glycoprotein (MAG)/sulfated glucuronyl paragloboside (SGPG) neuropathy associated with Waldenström macroglobulinemia show demyelinating neuropathy, but the temporal dispersion of distal compound muscle action potential (CMAP) in motor nerve conduction studies (NCS), which represents heterogeneous demyelination at the motor nerve terminal, is rare. We report on a 70-year-old man with anti-MAG/SGPG neuropathy associated with Waldenström macroglobulinemia; he had a 2-year history of mild dysesthesia of the foot sole without any motor symptoms. He showed marked temporal dispersion of distal CMAP in the tibial nerve with other demyelinating findings in the NCS. The temporal dispersion of distal CMAP in the tibial nerve improved significantly, and motor function was again normal 1 year after rituximab monotherapy. The temporal dispersion of distal CMAP in anti-MAG/SGPG neuropathy is rare, but it could occur from an early stage when the patients show mild or no motor symptoms. Rituximab therapy before secondary axonal degeneration has great potential to reverse the effects of the demyelination including the temporal dispersion of distal CMAP, and to prevent the deterioration of neuropathy in anti-MAG/SGPG neuropathy.
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Abstract
The association of neuropathy with monoclonal gammopathy has been known for several years, even if the clinical and pathogenetic relevance of this association is not completely defined. This is not a marginal problem since monoclonal gammopathy is present in 1-3% of the population above 50 years in whom it is often asymptomatic, and in at least 8% of patients is associated with a symptomatic neuropathy, representing one of the leading causes of neuropathy in aged people. Monoclonal gammopathy may result from malignant lymphoproliferative diseases including multiple myeloma or solitary plasmocytoma, Waldenström's macroglobulinemia (WM), other IgM-secreting lymphoma or chronic lymphocytic leukemia, and primary systemic amyloidosis (AL). In most instances it is not associated with any of these disorders and is defined monoclonal gammopathy of undetermined significance (MGUS) for its possible, though infrequent, evolution into malignant forms. Several data support the pathogenetic role of the monoclonal gammopathy in the neuropathy particularly when of IgM isotype where IgM reactivity to several neural antigens has been reported. Increased levels of VEGF have been implicated in POEMS syndrome. However, there are as yet no defined therapies for these neuropathies, as their efficacy has not been confirmed in randomized trials.
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Abstract
Disorders of the peripheral nerve system (PNS) are heterogeneous and may involve motor fibers, sensory fibers, small myelinated and unmyelinated fibers and autonomic nerve fibers, with variable anatomical distribution (single nerves, several different nerves, symmetrical affection of all nerves, plexus, or root lesions). Furthermore pathological processes may result in either demyelination, axonal degeneration or both. In order to reach an exact diagnosis of any neuropathy electrophysiological studies are crucial to obtain information about these variables. Conventional electrophysiological methods including nerve conduction studies and electromyography used in the study of patients suspected of having a neuropathy and the significance of the findings are discussed in detail and more novel and experimental methods are mentioned. Diagnostic considerations are based on a flow chart classifying neuropathies into eight categories based on mode of onset, distribution, and electrophysiological findings, and the electrophysiological characteristics in each type of neuropathy are discussed.
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Neuropathies associées à une IgM monoclonale anti-MAG. Rev Med Interne 2012; 33:686-92. [DOI: 10.1016/j.revmed.2012.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 05/14/2012] [Indexed: 12/23/2022]
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Neurophysiological and clinical responses to rituximab in patients with anti-MAG polyneuropathy. Clin Neurophysiol 2011; 122:2518-22. [DOI: 10.1016/j.clinph.2011.05.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Revised: 05/19/2011] [Accepted: 05/21/2011] [Indexed: 12/29/2022]
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Non-anti-MAG DADS neuropathy as a variant of CIDP: clinical, electrophysiological, laboratory features and response to treatment in 10 cases. Eur J Neurol 2010; 18:899-905. [PMID: 21199182 DOI: 10.1111/j.1468-1331.2010.03312.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND PURPOSE Some patients within the spectrum of chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) have distal acquired demyelinating symmetric (DADS) neuropathy, usually associated with anti-myelin-associated-glycoprotein (MAG) IgM monoclonal gammopathy. The aim of this retrospective study was to investigate patients with DADS neuropathy without anti-MAG antibodies, and study their response to immunotherapy. METHODS Patients were selected on the basis of (i) 'Definite CIDP' according to the EFNS/PNS Guideline criteria, (ii) The presence of disproportionately prolonged motor latencies resulting in a terminal latency index (TLI) ≤ 0.25 in at least two motor nerves and (iii) The absence of anti-MAG antibodies on ELISA. Response to immunotherapy was defined as persistent improvement by at least one point on the INCAT disability score. RESULTS Data from 146 CIDP patients were analysed, and 10 patients were included. Six had clinically pure sensory neuropathy, and four had sensorimotor neuropathy. Ataxia was present in nine patients, generalized areflexia in seven and postural tremor in two. Five of the 10 patients had abnormal sensory potentials only in the upper limbs. An associated condition was found in nine patients: two chronic lymphocytic leukaemias, four IgG monoclonal gammopathies (one associated with non-Hodgkin's lymphoma) and two IgM monoclonal gammopathies of unknown significance. Patients were mostly improved with intravenous immunoglobulin (IVIg), corticosteroids, plasma exchanges, or a combination thereof. CONCLUSION DADS neuropathy without anti-MAG antibodies is more likely to be considered a variant of CIDP. In addition, such patients should be systematically investigated for an associated haematological or immunological condition.
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Pupil-involving third nerve palsy as a manifestation of anti-myelin-associated glycoprotein neuropathy. J Neuroophthalmol 2010; 31:29-33. [PMID: 21164358 DOI: 10.1097/wno.0b013e3181f2e27a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A 56-year-old man developed a pupil-involving left third nerve palsy. Imaging studies of the brain and intracranial vessels were normal. Neurological examination demonstrated a sensory polyneuropathy and mild distal weakness. Nerve conduction studies showed prolonged distal motor latencies. An enzyme-linked immunosorbent assay test detected high titers of anti-myelin-associated glycoprotein (MAG) antibodies. The patient improved with prednisone and rituximab treatment. Anti-MAG neuropathy should be considered when evaluating a patient with an undiagnosed cranial neuropathy, especially in the setting of a sensory neuropathy.
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European Federation of Neurological Societies/Peripheral Nerve Society Guideline* on management of paraproteinemic demyelinating neuropathies. Report of a Joint Task Force of the European Federation of Neurological Societies and the Peripheral Nerve Socie. J Peripher Nerv Syst 2010; 15:185-95. [DOI: 10.1111/j.1529-8027.2010.00278.x] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Polyneuropathy associated with IgM vs IgG monoclonal gammopathy: comparison between clinical and electrophysiological findings. Acta Neurol Scand 2010; 122:52-7. [PMID: 20003083 DOI: 10.1111/j.1600-0404.2009.01259.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The neuropathy associated with IgM monoclonal gammopathy (IgM-MG) is regarded as a sensorimotor, mainly demyelinating neuropathy. It is not fully known whether the neuropathy in IgG-MG is caused by the same mechanisms and shows the same electrophysiological characteristics. We aimed at making a comparison between clinical and neurophysiological findings in these two conditions. PATIENTS AND METHODS Twenty-seven patients with IgM-associated neuropathy [18 with anti-myelin-associated glycoprotein (anti-MAG) antibodies] were compared with 15 age-matched patients with IgG-associated neuropathy. RESULTS Patients with IgM-associated neuropathy (especially those with anti-MAG antibodies) had significantly clinically more severe disabilities with involvement of both motor and sensory functions compared with patients with IgG-associated neuropathy in whom clinical sensory disturbances were more prominent than motor dysfunction. Motor and sensory conduction velocities were significantly lower and distal latencies significantly longer in the IgM group than in the IgG group concerning the median, ulnar and peroneal nerves. Fifty-four per cent of the patients in the IgM group did not present a sensory response of the median nerve vs 13% in the IgG group. There was also a significant difference concerning absent responses from the peroneal and sural nerves in the IgM vs IgG group (peroneal: 48% vs 13%, sural: 88% vs 27%). CONCLUSION Polyneuropathy associated with IgM-MG, especially when associated with anti-MAG antibodies, appears to have more of a demyelinating involvement that meets the criteria for demyelination. This was not as clear in those associated with IgG. The IgG neuropathy showed less and milder deficit in the electrophysiological studies.
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Les polyneuropathies avec IgM monoclonale anti-MAG : étude descriptive clinique, biologique, électrophysiologique et anatomopathologique d’une cohorte de 13 patients. Rev Neurol (Paris) 2009; 165:1071-9. [DOI: 10.1016/j.neurol.2009.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 03/17/2009] [Accepted: 04/24/2009] [Indexed: 11/17/2022]
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Management of extreme carpal tunnel syndrome: Evidence from a long-term follow-up study. Muscle Nerve 2009; 40:86-93. [DOI: 10.1002/mus.21265] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Entrapment in anti myelin-associated glycoprotein neuropathy. J Neurol 2009; 256:620-4. [PMID: 19306083 DOI: 10.1007/s00415-009-0132-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 09/23/2008] [Accepted: 10/23/2008] [Indexed: 11/25/2022]
Abstract
Anti-myelin associated glycoprotein (MAG) neuropathy is a chronic disorder in which IgM antibodies react with Schwann cell glycoproteins, including MAG and peripheral myelin protein 22 (PMP22). Nerve conduction studies show features of axon loss and predominantly distal slowing consistent with demyelination. Because a genetic loss of PMP22 function yields hereditary neuropathy with liability to pressure palsies (HNPP), loss of PMP22 function due to anti- MAG antibodies may result in increased sensitivity to entrapment. We investigated this by performing standardized electrophysiological studies in 16 patients with anti-MAG neuropathy and 16 disease controls with genetically confirmed HNPP. Disproportionate slowing relative to adjacent segments occurred in similar proportions of patients with anti-MAG neuropathy and HNPP, and was of the same magnitude in each group. Affected were the elbow, carpal tunnel and the wrist-hand segments of the median and ulnar nerves. However, in anti-MAG neuropathy as compared to HNPP, absolute values of distal motor latencies and conduction velocities outside entrapment sites were slower and amplitudes were lower. In conclusion, increased sensitivity for entrapment may occur in anti-MAG neuropathy and contribute to part of the nerve damage.
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Intérêt de l’électroneuromyogramme dans le diagnostic des neuropathies dysimmunes. Rev Neurol (Paris) 2007. [DOI: 10.1016/s0035-3787(07)92158-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Terminal latency index in neuropathy with antibodies against myelin-associated glycoproteins. Muscle Nerve 2007; 35:196-202. [PMID: 17068765 DOI: 10.1002/mus.20678] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Neuropathy with antibodies against myelin-associated glycoproteins (MAG/SGPG-N) and hereditary sensorimotor neuropathy type 1 (HMSN1) are characterized by chronic demyelination with little conduction block. Electrodiagnostic studies suggest that in HMSN1 conduction slowing occurs uniformly along the nerve, whereas in MAG/SGPG-N it is predominantly distal. Some but not all previous reports have shown that the terminal latency index (TLI) was useful to distinguish MAG/SGPG-N from chronic idiopathic demyelinating polyneuropathy. We compared median TLI from 21 patients with MAG/SGPG-N with those obtained from 26 patients with HMSN1, 20 with HMSN2, and 12 healthy volunteers. All patients with TLI <0.26 had MAG/SGPG-N, and all patients with TLI > or =0.32 had HMSN1. In the remaining patients with intermediate TLI values, ulnar distal motor latency (DML) aided in differentiation between MAG/SGPG-N and HMSN1 with an overall sensitivity of 100% and specificity of 98%. In conclusion, median TLI in combination with ulnar DML can further guide the demyelinating neuropathy evaluation toward hereditary or autoimmune causes.
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Abstract
PURPOSE OF REVIEW The anti-myelin-associated glycoprotein (MAG) neuropathy is an antibody-mediated demyelinating neuropathy. The clinical picture is characterized by a distal and symmetric, mostly sensory neuropathy. Monoclonal immunoglobulin M anti-MAG antibodies are uniquely found in this condition and are believed to be pathogenic. This review focuses on recent progress in understanding the mechanisms of this neuropathy and discusses new therapeutic advances. RECENT FINDINGS Different electrophysiological parameters have been demonstrated to distinguish the anti-MAG-associated polyneuropathy from chronic inflammatory demyelinating polyneuropathy. The electrophysiological findings generally indicate a predominantly demyelinating neuropathy with a distal accentuation of conduction slowing. Analyses of pathology in nerve tissue from anti-MAG patients using classical nerve biopsy or skin biopsy tissue demonstrated immunoglobulin M deposits at the site of MAG localization, demyelination and axonal degeneration. MAG is a Schwann cell-based glycoprotein and has been implicated as a mediator of an outside-in signaling cascade influencing the cytoskeletal integrity of axons. SUMMARY Therapy in patients with anti-MAG neuropathy is directed at reducing the antibody concentration, blocking the effector mechanisms and depleting the monoclonal B cells. The recent availability of rituximab, a monoclonal antibody suppressing B-cell clones, which is not myelosuppressive and does not cause secondary malignancies, allows for early targeted intervention.
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European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of paraproteinaemic demyelinating neuropathies: report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society*. Eur J Neurol 2006; 13:809-18. [PMID: 16879290 DOI: 10.1111/j.1468-1331.2006.01467.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Paraprotein-associated neuropathies have heterogeneous clinical, neurophysiological, neuropathological and haematological features. Objectives. To prepare evidence-based and consensus guidelines on the clinical management of patients with both a demyelinating neuropathy and a paraprotein (paraproteinaemic demyelinating neuropathy, PDN). METHODS Search of MEDLINE and the Cochrane library, review of evidence and consensus agreement of an expert panel. RECOMMENDATIONS In the absence of adequate data, evidence based recommendations were not possible but the panel agreed the following good practice points: (1) Patients with PDN should be investigated for a malignant plasma cell dyscrasia. (2) The paraprotein is more likely to be causing the neuropathy if the paraprotein is immunoglobulin (Ig)M, antibodies are present in serum or on biopsy, or the clinical phenotype is chronic distal sensory neuropathy. (3) Patients with IgM PDN usually have predominantly distal and sensory impairment, with prolonged distal motor latencies, and often anti-myelin associated glycoprotein antibodies. (4) IgM PDN sometimes responds to immune therapies. Their potential benefit should be balanced against their possible side-effects and the usually slow disease progression. (5) IgG and IgA PDN may be indistinguishable from chronic inflammatory demyelinating polyradiculoneuropathy, clinically, electrophysiologically, and in response to treatment. (6) For POEMS syndrome, local irradiation or resection of an isolated plasmacytoma, or melphalan with or without corticosteroids, should be considered, with haemato-oncology advice.
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[Polyneuropathy involving cranial nerves associated with monoclonal IgM antibodies with anti-MAG/SGPG/SGPLG/sulfatides activity]. Rev Neurol (Paris) 2006; 162:760-6. [PMID: 16840988 DOI: 10.1016/s0035-3787(06)75077-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
INTRODUCTION A typically distal and symmetrical, slowly progressive sensorimotor demyelinating neuropathy is caused by monoclonal IgM against myelin-associated glycoprotein (MAG) and SGPG, SGLPG glycolipids in the context of a benign IgM paraproteinemia. We studied a patient with a neuropathy that fulfilled the diagnostic criteria for CIDP in whom IgM kappa anti-MAG/SGPG/SGLPG were detected. OBSERVATION The patient was a 57-year-old man who had developed a slowly progressive distal sensorimotor neuropathy, involving the lower then upper limbs, with cranial nerves palsies (oro-pharyngo-laryngo territory). ENMG showed a demyelinating neuropathy with a disproportionate slowing of conduction in distal segments of motor and axonal features in the lower limbs. The first routine laboratory analysis revealed negative or normal findings. Several serum protein electrophoreses were normal. The third cerebrospinal fluid examination demonstrated a moderate and late rise in CSF protein level with no cells. Monoclonal IgM-kappa against MAG/SGPG/SGLPG, was detected; anti-MAG antibody titre in the serum was 20 059 BTU (N<1000). A small IgM-kappa paraprotein was identified by immunofixation. Electron microscopy failed to show nerve fibers with widening of outer lamellae of the myelin. There is no clinical improvement after different treatments, immunoglobulins IV, cortisteroids, plasma exchange, rituximab. CONCLUSION It is not known whether this neuropathy is an atypical form of PNMAG or an CIDP associated with anti-MAG. When ENMG show a disproportionate slowing of conduction in distal segments of motor nerves, one should screen the serum with immunofixation to identify small monoclonal components. If IgM-MGUS is present, search should be undertaken for anti-MAG/SGPG/SGLPG antibodies. Diagnosis enables optimal treatment using, in severe cases, expensive current strategies with immunoglobulins IV, plasma exchange, and corticosteroids, or, in the event of no response, rituximab before resorting to more toxic drugs like cyclophosphamide.
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[Electrophysiological manifestations of chronic inflammatory demyelinating polyradiculoneuropathy]. Rev Neurol (Paris) 2006; 162:522-6. [PMID: 16585915 DOI: 10.1016/s0035-3787(06)75045-7] [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: 11/19/2022]
Abstract
There are four basic electrophysiological parameters of demyelination: reduced motor conduction velocity, prolonged distal motor latency and F waves, and motor conduction blocks. These parameters are combined to determine an electrophysiological set of criteria for chronic inflammatory demyelinating polyneuropathy (CIDP). Whereas their specificity is good, their sensitivity level does not exceed 75 percent. However, these sets of criteria are not commonly used especially in benign forms, at the beginning of the disease, in associated forms or in case of secondary axonal degeneration. We can push the limits using others criteria such as the terminal latency index, sensory criteria, or by the contribution of others electrophysiological procedures such as the radicular stimulation or sensory evoked potentials. Due to the therapeutic implications, any axonal neuropathy without aetiologia, with at least one demyelinating electrophysiological criteria, could be considered as a putative CIDP.
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Les neuropathies périphériques : orientations et moyens diagnostiques. Rev Med Interne 2006; 27:302-12. [PMID: 16517027 DOI: 10.1016/j.revmed.2005.10.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2005] [Accepted: 10/24/2005] [Indexed: 01/11/2023]
Abstract
PURPOSES Neuropathies are defined as dysfunction of peripheral nerves, which may show motor, sensory and autonomic symptoms. Although most neuropathies are symmetric, it is important to distinguish a polyneuropathy from a mononeuropathy, a multiple mononeuropathy or a polyradiculoneuropathy. Electrophysiological procedures are helpful in determining the pathological process which may be either an axonopathy, a myelinopathy or a neuronopathy. MAIN POINTS Major progresses have been made in the ten past years in the management and diagnostic approaches of peripheral neuropathy. The history and the physical examination are the first steps to the evaluation of patients with peripheral neuropathy. Electrodiagnostic studies and then laboratory tests are the next step in the diagnostic procedures of peripheral neuropathies. These will lead to a proper identification of the cause of neuropathy, allowing to develop a specific treatment for the patient. However, even after a careful work-up of a patient with neuropathy, 25 to 40% of patients with polyneuropathies remain undiagnosed. PERSPECTIVES Further development are focused in better understanding the pathogenesis and molecular mechanisms of peripheral nerve diseases in order to provide a specific and adequate treatment for each neuropathy.
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European Federation of Neurological Societies/Peripheral Nerve Society Guideline* on management of paraproteinemic demyelinating neuropathies. Report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society. J Peripher Nerv Syst 2006; 11:9-19. [PMID: 16519778 DOI: 10.1111/j.1085-9489.2006.00059.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Paraprotein-associated neuropathies have heterogeneous clinical, neurophysiological, neuropathological, and hematological features. OBJECTIVES The aim of this guideline was to prepare evidence-based and consensus guidelines on the clinical management of patients with both a demyelinating neuropathy and a paraprotein [paraproteinemic demyelinating neuropathy (PDN)]. METHODS Disease experts and a representative of patients considered references retrieved from MEDLINE and the Cochrane Library and prepared statements that were agreed in an iterative fashion. RECOMMENDATIONS In the absence of adequate data, evidence-based recommendations were not possible, but the Task Force agreed on the following good practice points: (1) patients with PDN should be investigated for a malignant plasma cell dyscrasia; (2) the paraprotein is more likely to be causing the neuropathy if the paraprotein is immunoglobulin M (IgM), antibodies are present in serum or on biopsy, or the clinical phenotype is chronic distal sensory neuropathy; (3) patients with IgM PDN usually have predominantly distal and sensory impairment, with prolonged distal motor latencies, and often anti-myelin-associated glycoprotein antibodies; (4) IgM PDN sometimes responds to immunotherapies. Their potential benefit should be balanced against their possible side effects and the usually slow disease progression; (5) IgG and IgA PDN may be indistinguishable from chronic inflammatory demyelinating polyradiculoneuropathy clinically, electrophysiologically, and in response to treatment; and (6) for POEMS syndrome, local irradiation or resection of an isolated plasmacytoma, or melphalan with or without corticosteroids, should be considered, with hemato-oncology advice.
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Abstract
OBJECTIVE We sought to determine the prevalence, clinical features, and laboratory characteristics of polyneuropathies in Waldenström's macroglobulinaemia (WM), a malignant bone marrow disorder with lymphocytes that produce monoclonal IgM. METHODS We prospectively studied 119 patients with WM and 58 controls. Medical history was taken, and neurological examinations, electrodiagnostic tests, and serum studies were performed by different examiners who were blinded to results except the diagnosis of WM. RESULTS Polyneuropathy symptoms, including discomfort and sensory loss in the legs, occurred more frequently (p<0.001) in patients with WM (47%) than in controls (9%). Patients with WM had 35% lower quantitative vibration scores, and more frequent pin loss (3.4 times) and gait disorders (5.5 times) than controls (all p<0.001). Patients with IgM binding to sulphatide (5% of WM) had sensory axon loss; those with IgM binding to myelin associated glycoprotein (MAG) (4% of WM) had sensorimotor axon loss and demyelination. Patients with WM with IgM binding to sulphatide (p<0.005) or MAG (p<0.001) had more severe sensory axon loss than other patients with WM. Demyelination occurred in 4% of patients with WM with no IgM binding to MAG. Age related reductions in vibration sense and sural SNAP amplitudes were similar ( approximately 30%) in WM and controls. CONCLUSIONS Peripheral nerve symptoms and signs occur more frequently in patients with WM than controls, involve sensory modalities, and are often associated with gait disorders. IgM binding to MAG or sulphatide is associated with a further increase in the frequency and severity of peripheral nerve involvement. Age related changes, similar to those in controls, add to the degree of reduced nerve function in patients with WM.
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AIDP and CIDP having specific antibodies to the carbohydrate epitope (-NeuAcalpha2-8NeuAcalpha2-3Galbeta1-4Glc-) of gangliosides. J Neurol Sci 2005; 232:37-44. [PMID: 15850580 DOI: 10.1016/j.jns.2005.01.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Revised: 01/11/2005] [Accepted: 01/12/2005] [Indexed: 10/25/2022]
Abstract
Anti-ganglioside antibodies were investigated in plasma exchange solutions (PEs) from two patients with acute and chronic inflammatory demyelinating neuropathies (AIDP and CIDP). Both cases show markedly elevated antibody titers against the lacto-series gangliosides, GM3, GD3, and GT3. In the CIDP patient, the IgG antibody titer to GD3 was remarkably elevated (titer, 1:10,000), indicating maximal avidity to the tetrasaccharide epitope (-NeuAcalpha2-8NeuAcalpha2-3Galbeta1-4Glc-). There were also activities toward GM4 and GM2 with the affinity higher to GM4 than to GM2, indicating that the antibody activity was not highly specific. In contrast, the antibody activities in the AIDP patient showed similar avidity to GM3, GD3, and GT3. These two patients are very rare cases that have not previously encountered in GBS. The effects on co-cultured cells of rat spinal cord and muscle differed according to which PE was used. PE from the AIDP patient produced an inhibitory effect (reduction to 26.8%) on the spontaneous muscle action potential of the neuromuscular junction (NMJ), but the PE from the CIDP patient did not. Thus, in AIDP, the common epitope of GM3, GD3, or GT3 may be shared with certain antigens localized in the peripheral nervous system (PNS) and may participate in a component of conduction-related molecules in the NMJ. High titers of anti-GD3 antibody and the distortion of antibody recognition found in CIDP seem to have no immediate effect on electrophysiologic function in the PNS.
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