I think cost is big thing with IVIG. It runs upwards of $3K depending on much is needed. If the PN is autoimmune then certainly IVIG would make a difference. For that matter, IMHO if it's early autoimmune-y, say a body's hyper reaction to something that maybe isn't a full autoimmune disease (think drug or viral reaction) then steroids knocking the immune system down a notch could be helpful before all the damage is done. I wouldn't be afraid of a short course of oral steroids. You're not talking long term. I think you'd know pretty soon if you had something that would respond.