--though sorry for having a condition or conditions that led you here,

Please do come over to the neuropathy forum, if you haven't already, and post some details:

http://neurotalk.psychcentral.com/fo...sprune=-1&f=20

A neuropathy that is limited to one area like an arm implies some sort of pressure/compression related etiology, or possibly a condition like thoracic outlet syndrome (we have a forum here for that, too):

http://neurotalk.psychcentral.com/forum24.html

What type of investigation into causes have you had?