Emma, it sounds as if…

your doc isn’t one of the stingy ones! Count your blessings thru all that happens!
Rate is soo related to how well you can tolerate the infusions. After all, you are having something ‘foreign’ being put into yourself. All said and done? Just be super cautious in keeping trak of what is all being put into you and at what rates. Sometimes, just taking an extra ten minutes to do the infusion can make all the difference for YOU!
I myself, find I can tolerate a fast acceleration of the rate but to a medium high one, and not as high as the max recommended…So I go up sooner in the rate, but stay at a less high rate for longer with out side effects. This is where each and every one of us is very DIFFERENT. AND, to be aware that there can and will be differences is crucial to your own infusion success or not. Further, some home services tend to ‘try’ and rush some infusions, BE VERY SURE that your doctor orders specific rates based on your past infusions in his orders. IF a nurse skips steps, that nurse could be on a carpet, should some bad effects occur. Usually, doc’s orders come with the delivery package of supplies and IVIG… READ them! Honestly, only you can protect yourself in this respect.
I can attest that different brands have effect or not with me. It’s a doctor preference or availability… and at times, I suspect an insurance thing.
I truly wish there were easy answers to all this, but what we have is complex, how it’s treated is even more complex and how we cope with it all is mind-boggling at times.
I hope that you start to MUCH feel better with it all and soon! At least, that ‘things’ don’t spread? That is a valid and reasonable fear. Hope always