Before I outline the possible causes of peripheral neuropathy, I think it's important to list an email from a regular acor mm listserv contributor regarding the likelihood of developing neuropathy while undergoing conventional therapy for multiple myeloma:
Date: Tue, 3 Oct 2006 19:54:26 -0400
From: brad rothkopf <72277.3263@COMPUSERVE.COM>
Subject: neuropathy
Was listening to a presention by Dr Richardson (DFCI) re neuropathy. While at one time it was felt mm patients had little neuropathy at onset, this is not true. Electrophysiologic studies show a 75% incidence of subclinical neuropathy, and examination, about 30% incidence of subclincal neuropathy.
This apparently involves the small sensory fibers more than
the motor fibers, and may be caused by an antiangiogenic mechanism, which is partly how Imids like thal work in mm. (it's possible it interferes
with the blood supply of the nerves, which is by the vasa nervorum)
regards
brad
What causes peripheral neuropathy in myeloma?
There are a number of potential causes of peripheral neuropathy in myeloma. These include:
The presence of the paraprotein itself can cause peripheral neuropathy as it can be deposited on nerve tissue
Treatments - such as vincristine, thalidomide and bortezomib (VELCADE) - can damage nerve cells, particularly in higher doses. Previous treatment with any of these drugs may increase the risk of peripheral neuropathy occurring.
High levels of paraprotein can lead to thickening of the blood, called hyperviscosity. This may decrease circulation and lead to symptoms of peripheral neuropathy
Shingles (a viral infection) can cause neuropathic pain and altered sensation in the affected area.
In addition, diabetes and a history of high alcohol consumption in patients may contribute to peripheral neuropathy
My neurologist, Dr. David Preston’s initial evaluation of my condition, before my first emg study contained the following: “The patient’s neurologic examination is abnormal and his case is complex. He clearly has a peripheral neuropathy, which may be multifactorial in nature. He has had a plasmacytoma in the past and myeloma, and has undergone chemotherapy, which included Vincristine. Thus, he has more than adequate reasons to have a peripheral neuropathy on the examination.”
I have a peripheral neuropathy - perhaps several causes
Myeloma itself, can cause peripheral neuropathy
Toxic chemotherapies such as vincristine, can cause peripheral neuropathy
Dr. Preston’s evaluation from our last examination of 9/27/05 said this: “He (David Emerson) underwent EMG and nerve conduction studies today. Compared to the prior study, there has been clear improvement.
First, in regards to distal motor and sensory potentials below the ankle, these are unchanged from his prior examination. However, the peroneal motor response is markedly improved. Looking at all three EMGs from November of 2004, March of 2005, and today, the left peroneal motor amplitude has gone from 0.3 mV to 4 mV to 4.9 mV today. The right peroneal motor amplitude is gone from 0.6 mV to 2.9 mV to 5.5 mV today.”
From this exam, I understand that my plexopathy is healing but the jury is still out regarding the peripheral neuropathy in my feet. Dr. Preston holds out the possibility of a complete recovery. My nerve conduction studies continue to show improvement. I will use this site and information packets to communicate with members as to my progress.
If any of you have experience with either peripheral neuropathy or plexopathy and possible therapies, please go to the side effects discussion and post your experiences.