--of diabetic neuropathy before, that is certainly a possibility; diabetic neuropathy does not HAVE to present as a distal symmetric set of symptoms. There are even some presentations that are acute or sub-acute in onset and involve particular nerve tracts:

http://neuromuscular.wustl.edu/nother/diabetes.htm

Often, these presentations are the result of the "double crush" effect. A nerve pathway that is already weakened through diabetic ischemic compromise is then compressed by some other force--such as a bulging disc in the spine pressing on a nerve root--and the combined effect symptomologically is more than the "sum of the parts".

Given the area, I think she needs some imaging of the cervical spine, and possibly the shoulder. Compressive neuropathies are very common in those areas anyway (as they are at the wrist and at the elbow, as you've mentioned), and people with impaired glucose tolerance tend to be more sensitive to them.