title: Are neurological complications of monoclonal gammopathy of undetermined significance underestimated?
abstract: OBJECTIVE
  Monoclonal gammopathy of undetermined significance (MGUS) is a premalignancy preceding multiple myeloma (MM) or related disorders. Neurological symptoms caused by the monoclonal immunoglobulins or free light-chains are often associated with a high morbidity. We analyzed the prevalence of neuropathy, clinical features and the long-term outcome in 223 patients (pts.) with MGUS.
  
  
  METHODS
  Between 1/2005 and 3/2015, 223 adult pts. with MGUS were identified in our database.
  
  
  RESULTS
  In36/223 pts. (16%) a neuropathy was diagnosed (MGUS associated neuropathy, MGUS-N). 20 pts. (55%) had a distal symmetric axonal neuropathy, 10 pts. (28%) had a chronic inflammatory demyelinating polyneuropathy and 6 pts (17%) a distal acquired demyelinating symmetric polyneuropathy. In MGUS-NN (without neuropathy) and in MGUS-N, progression to smoldering MM, MM or Waldenstrom's macroglobulinemia (WM) occurred in 17% of the pts. The Immunoglobulin subtype was predominantly IgG in MGUS-NN and IgM in MGUS-N and ≥5.5% plasma cells in the bone-marrow predicted progression to MM and AL-amyloidosis in MGUS-NN and to WM in MGUS-N (p<0.05).
  
  
  CONCLUSIONS
  Due to the substantial prevalence of neuropathies, MGUS pts. should be monitored carefully and referred to a specialized center if neurological symptoms occur.
authors.affiliation: Department of Internal Medicine V (Hematology and Medical Oncology), Medical University of Innsbruck, A-6020 Innsbruck, Austria.
authors.forename: Normann
authors.initials: N
authors.lastname: Steiner
authors.affiliation: Department of Internal Medicine V (Hematology and Medical Oncology), Medical University of Innsbruck, A-6020 Innsbruck, Austria.
authors.forename: Angelika
authors.initials: A
authors.lastname: Schwärzler
authors.affiliation: Department of Medical Statistics, Informatics and Health Economics, Medical University of Innsbruck, A-6020 Innsbruck, Austria.
authors.forename: Georg
authors.initials: G
authors.lastname: Göbel
authors.affiliation: Department of Neurology, Medical University of Innsbruck, A-6020 Innsbruck, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Löscher
authors.affiliation: Department of Neurology, Medical University of Innsbruck, A-6020 Innsbruck, Austria.
authors.forename: Julia
authors.initials: J
authors.lastname: Wanschitz
authors.affiliation: Department of Internal Medicine V (Hematology and Medical Oncology), Medical University of Innsbruck, A-6020 Innsbruck, Austria.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Gunsilius
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000150:complications* / Q000276:immunology; D009422:Nervous System Diseases / Q000145:classification* / Q000453:epidemiology* / Q000276:immunology; D015995:Prevalence; D012189:Retrospective Studies; D016019:Survival Analysis
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M
keywords: MGUS; MGUS associated neuropathy; monoclonal gammopathy of undetermined significance; multiple myeloma