![]() ![]() The clinical presentation, treatment, and prognosis of PPN differs based on the subtype and associated disorders. PPN may be caused by interaction of antibodies with specific antigenic targets on peripheral nerves or by deposition of immunoglobulins or amyloid. Several disorders of the peripheral nervous system are closely associated with the presence of excessive amounts of abnormal immunoglobulins in the blood. Multiple myeloma is part of the spectrum of diseases ranging from MGUS to plasma cell leukemia, and similar to MGUS, is characterized by proliferation of a plasma cell clone and subsequent overabundance of monoclonal paraprotein (M protein). In the case of IgG monoclonal gammopathy, studies have shown improvement on impairment measures following treatment with rituximab, cyclophosphamide/prednisone, or fludarabine. CIDP-MGUS (non-IgM) has the same clinical and electrodiagnostic characteristics as pure CIDP and has the same treatment choice and algorithms (please note however that many neurologists still try standard CIDP treatments first before considering immunosuppression, even though they are not as effective as in idiopathic CIDP). MGUS-associated neuropathies are generally not treated, except in the case of a disabling IgM monoclonal gammopathy or when associated with chronic inflammatory demyelinating neuropathy (CIDP), as in certain cases of IgG or IgA monoclonal gammopathy. Three criteria define MGUS: A monoclonal paraprotein band less than 30 g/L (3 g/dL) plasma cells less than 10 % on bone marrow examination and no evidence of bone lesions, anemia, hypercalcemia, or renal insufficiency related to the paraprotein. MGUS is a common, age-related medical condition characterized by an accumulation of bone marrow plasma cells derived from a single abnormal clone without proliferation of malignant cells. ĭespite the range of associated hematologic disorders, paraproteins most commonly occur as a monoclonal gammopathy of undetermined significance (MGUS). Commonly associated disorders include multiple myeloma, cryoglobulinemia, lymphoma, amyloidosis, Waldenstrom macroglobulinemia, and POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein spike, and skin manifestations) syndrome. Clonal proliferation may occur in the context of a hematologic malignancy or a premalignancy. These monoclonal proteins exist as heavy chain subtypes (IgG, IgA, IgG, and less commonly IgD or IgE) and light chain subtypes (kappa or lambda). Paraproteins are immunoglobulins that are produced in excess by an abnormal clonal proliferation of B-lymphocytes or plasma cells. Therapies depend on the particular PPN subtype and the pathophysiology involved, and range from intravenous immunoglobulin (IVIG), plasma exchange, and corticosteroids to rituximab and various chemotherapies. Peripheral neuropathy symptoms may precede by years other clinical symptoms or diagnosis of the antibody-producing condition, whether it be hematologic malignancy or monoclonal gammopathy of undetermined significance. Sometimes there is multiorgan involvement. Typically manifested neurologically as a length-dependent axonal loss sensorimotor polyneuropathy, PPN affects some or all sensory modalities causing allodynia, hyperpathia, cramps, or mild distal weakness (rarely it can be associated with more profound motor symptoms). As neuropathy is relatively common with M-protein and vice-versa, PPN may therefore be defined further as a heterogeneous group of neuropathies, which share the common feature of a homogeneous immunoglobulin in the serum. Several monoclonal antibody-producing conditions are associated with peripheral neuropathy, and in these circumstances, the constellation of neurological symptoms are often referred to as paraproteinemic neuropathy (PPN). The condition appears clinically as muscle weakness and atrophy, pain, and numbness. April 26, 2019.Peripheral neuropathy is defined as a disease or degenerative state of the peripheral nerves in which motor, sensory, or vasomotor nerve fibers are affected. Rochester, Minn.: Mayo Foundation for Medical Education and Research 2019. Monoclonal gammopathy of undetermined significance (MGUS) (adult). Clinical course and management of monoclonal gammopathy of undetermined significance. Diagnosis of monoclonal gammopathy of undetermined significance. Monoclonal gammopathy of undetermined significance (MGUS).Monoclonal gammopathy of undetermined significance (MGUS). Philadelphia, Pa.: Saunders Elsevier 2016. ![]()
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