So frustrating! I guess on the EMG he just means any number of causes? Abnormal is still abnormal and does mean something.
Neuritis can be neuroinflammatory, auto-immune or mechanical/compressive. I had saphenous neuritis clearly caused by repetitive aggravation at Hunter's Canal caused by the recumbent bike. It was a bear figuring that out...
I found this info about Parsonage Turner Syndrome today while getting a link for nerve injury. I only clicked on it because I'd never heard of it but I immediately thought of you. Interesting about the viral thing.
http://nerve.wustl.edu/nd_parsonage.php
I hope third time is a charm! Maybe ask about the Parsonage Turner business...