Paraproteinemic neuropathies

Abstract

The paraproteinemias are a heterogeneous group of disorders in which monoclonal plasma cells cause the proliferation of monoclonal proteins. They are of importance to clinicians because they often occur in association with neuropathies. Neurologists play a particularly important role when the neuropathy is the presenting feature, in which case they may uncover clinical, laboratory, radiologic, electrodiagnostic, or biopsy findings that lead to identification of the underlying paraproteinemia. The frequency of neuropathies in these patients, and the extent to which such neuropathies dominate the clinical picture, varies significantly between the different paraproteinemias. Treatments may be aimed specifically at the neuropathy, or against the underlying hematologic disorder. In all patients with paraproteinemias, the neurologist can work collaboratively with the hematologist to formulate therapeutic plans and goals and can provide follow-up and monitoring to determine the response of the neuropathy to treatment.

Paraproteinemic neuropathy

“…38 Corticosteroid was not effective when used as a monotherapy, but it may be beneficial if applied in conjunction with other immunotherapeutic drugs such as cyclophosphamide. 8 Another RCT found no significant improvements in functional scales including the mRS. 36 IgM-MGUS-associated neuropathy may exhibit the typical pattern of CIDP. Patients with CIDP-like neuropathy associated with MGUS should receive the same treatment as patients with classical CIDP, but continuing treatment as in patients with CIDP is not always needed because a significant proportion of the former patients are stable without treatment.…”

“…5,8 Vascular endothelial growth factor (VEGF) levels should be checked in patients with suspected POEMS syndrome. A bone marrow examination or bone scan is usually performed in patients with an M-protein level of >15 g/L, although some hematologists will perform one of these investigations in all patients with paraproteinemia.…”

“…11 An initial paraprotein or M-protein concentration of >15 g/L, the detection of an IgM or IgA paraprotein, and an abnormal free-lightchain ratio (free kappa/lambda ratio; normal range = 0.26-1.65) are related to an increased risk of a malignant evolution. 8,12 In patients with MGUS presenting with peripheral neuropathy, progressive weight loss, progression of the neuropathy, and an M-protein level of >1 g/L also have been identified as independent predictors for a malignant transformation. 13,14 ".…”

“…The following conditions are suspected: (1) IgM paraproteinemic demyelinating neuropathy with negativity for anti-MAG antibodies, or IgG or IgA paraproteinemic demyelinating neuropathy with a chronic progressive course, and with the discovery of widely spaced myelin on electron microscopy or deposits of Ig and/or complement bound to myelin; (2) amyloidosis; and (3) malignant lymphoproliferative infiltration of nerves. General ideas were derived from "Raheja et al 8 " and "Rison et al 99 ".…”

“…51 The diagnosis of MM is usually based on the following clinical findings: (1) serum M-protein, (2) BenceJones proteinuria, (3) increased bone-marrow plasma cells (≥10%), and (4) evidence of end-organ damage, such as hypercalcemia (serum calcium ≥ 11.5 mg/dL), renal insufficiency (serum creatine >1.73 mmol/L), anemia (normochromic, normocytic with a hemoglobin level of >2 g/dL below the lower limit of normal, or a hemoglobin level of <10 g/dL), or osteolytic bone lesions. 8,11 About 50% of patients have an…”