Polyeuropathy Associated with Paraproteinemia

Diagnosis:

  • This is a category of different neuropathies.
  • Neuropathy due to a gammopathy includes anti-MAG syndrome, POEMS, cryoglobulinemia, IgM MGUS polyneuropathy, Anti-GALOP (IgM against central myelin antigen): Gait Disorder, Autoantibody Late-age Onset Polyneuropathy
  • Evidence of paraproteinemia e.g. SPEP: paraproteinemia

Pathology, nerve biopsy:

Light microscopy:

  • Nonspecific, loss of myelin and/or axons
  • No inflammation except in cryoglobulinemia
  • For cryoglobulinemia: features of vasculitic neuropathy

Immunohistochemsitry:

  • Immunofluorescence with Anti-immunoglobulin for anti-MAG syndrome

Electron microscopy EM:

  • Widened myelin lamellae IgM
  • Uncompacted myelin lamellae (POEMS)
  • Capillary deposits (cryoglobulinemia)

Treatment:

Options:

  • Plasma exchange
  • Prednisone
  • Intravenous immunoglobulin IVIG
  • Azathioprine
  • Cyclophosphamide

For IgM MGUS polyneuropathy:

  • Cyclophosphamide 500 mg P.O. once DAILY X4 days +prednisone 60 mg P.O. once DAILY X5 days, every 28 days for 6 treatments.

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