It is important to recognize vitamin B12 deficiency because this disorder can cause neuropathy as well as myelopathy. Selected drugs that can cause neuropathy are listed in Table 7. Monoclonal gammopathy affects approximately 10 percent of patients with idiopathic polyneuropathy. Underlying hematologic disorders, such as myeloma, amyloidosis, Waldenstrom's disease, lymphoma or 1ymphoproliferative disease, are sometimes found. Most polyneuropathies associated with MGUS are insidious sensorimotor distal neuropathies with onset usually during the sixth decade.
Some cases have features of a chronic inflammatory demyelihating polyneuropathy.
In 50 percent of patients, IgM antibodies are directed against myelin-associated glycoprotein. Treatment may include intravenous immunoglobulin, plasmapheresis, corticosteroids and cyclophosphamide. All patients with Malignancies. Patients with cancer commonly have a nonspecific, mild, sensorimotor, distal polyneuropathy. However, because serious neurologic complications, such as spinal cord compression and leptomeningeal disease, are Immune-Mediated Polyneuropathies.