Hi,
I'm sorry to hear about everything you have been through. When my B12 is low I get tingling in my hands. I also had this happen in my legs when I was on remicade. I saw a neurologist and he did a nerve conduction test which I passed (thank goddness). I would talk to your Dr. as I know this is fairly common in patients on remicade. Did any of your fistula's interfere with nerves? Just a thought! Please keep us posted.
I wish you well, and I hope you find an answer sooner than later.
Julia