--"co-morbid"; that is, have symptoms that are contributed to by more than one condition.

It is often very hard to tease out the symptoms of spinal/nerve root problems from those of problems of peripheral nerves farther down the line--the symptoms can be exactly the same. All people with chronic neurological symptoms definitely need imaging--usually MRI with and without contrast--of suspected spinal problem areas to see if nerve or spinal cord compression is frankly evident.

Moreover, rheumatoid arthritis is definitely one of those autoimmune conditions that can result in neuropathy:

http://neuromuscular.wustl.edu/antib...max.html#rheum

There is something called the "double crush hypothesis" in which it is theorized that nerves already compromised by one condition that then become compressed in some manner produce symptoms greater than the sum of the parts would lead one to expect. This is often mentioned for diabetics with nerve damage who then get spinal or nerve root compression on top of it, and have very bad symptoms, but I suspect it happens fairly commonly in other situations as well (such as when chemotherapy patients--many chemo agents are notoriously neurotoxic--experience nerve compression).