Whenever, I see a patient with neuropathy the first step is to attempt to affirm the etiology-as you have learned part of this is to determine if the neuropathy may be associated a paraproteinemia- plasma cell disorder (e.g. MGUS, Smoldering Myeloma, Multiple Myeloma or Primary Amyloidosis, POEMS) or lymphoma (e.g. Waldentrsoms Macroglobulinemia, cryoglobuliemia). About 10% of neuropathic syndromes may be associated with paraproteinemias. So, we frequently see referrals from neurologists. You have to make sure that these are not two unrelated, but parallel issues. Jsut because you have MGUS and have neuropathy- they are not strickly speaking cause and effect. You need to rule out other causes of neuropathy. So, ensure that you are following with an excellent neurologist as well.
In the setting of neuropathy and a plasma cell disorder (or like disease), you want to find out the appropriate diagnosis of the underlying disorder- CBC, CMP, LDH,ESR, CRP, beta 2 microglobulin, SPEP, UPEP, qIg, SFLCs, Bone marrow biopsy, bone survey, consider PET/CT or MRI, CT NTAP (because you are also concerned about lymphoma). You also want to try to identify what maybe causing the neuropathy as it can be associated with auto-antibodies such as anti-MAG or anti-GM1 or amyloid deposition in the nerves (and other organs) among other things. Therefore, generally you want specialized testing. You want to determine if this is associated with Amyloidosis – check for Congo red staining of a bone marrow biopsy, fat pad aspirate(s) and potentially a nerve biopsy. I also screen for autoantibodies (MAG, GM1, GQ1b, GD1b, SGPG, and anti-Hu antibodies). Anti-MAG antibodies are frequently associated with IgM MGUS patient’s (50%) and constitute a MAG-neuropathy subgroup.
MGUS with neuropathy occurs with some frequency-although remains rare. For treatment the risks and benefits need to be carefully discussed- specifically the toxicities vs neuropathic symptoms. Anti-myeloma therapy or anti-lymphoma therapy is sometimes necessary. However, at times therapy to remove or decrease the expression of the antibodies is all that is necessary. For instance, Rituximab has been shown to be reasonable for the treatment of IgM-MGUS associated peripheral neuropathy. Other forms may respond to IVIG or plasmaphoresis (IgG and IgA associated neurophathies). Amyloidosis is treated systemically and in transplant eligible patient with HDM-ASCT [high-dose melphalan followed by an autologous stem cell transplant] in the upfront setting.
Regardless of the therapy (or observation- I have a number of patients with minimal neuropathy where the potential side effects of treatment outweigh their current symptoms) monitoring for progression to myeloma must continue (every 3-6 months).
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Re: Bone Marrow Biopsy
I had a BMB 10-3-10 upon MGUS diagnosis in Little Rock and have had 4 since. Although they say it is like "drilling for oil", you sometimes miss the concentration of plasma cells, it is one of the regularly prescribed tests at UAMS-MIRT. I am not a doctor and the type 2 diabetes is a concern.
I would strongly suggest you query your oncologist at length.
Hope this helps
Keith
I would strongly suggest you query your oncologist at length.
Hope this helps
Keith
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keithvirgin
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