Hello Ruth,
Hard decisions! I can only offer an approach, not an answer.
First, are you able to predict an oncoming episode? If you get enough warning, then perhaps you can get a dose of IVIG only when needed. I tried to get some idea by daily weight, bp, haematocrit etc but it didn't work for me. May work for you. Do your Drs have any thoughts?
Secondly, while IVIG has kept me out of trouble for 15 weeks, it is at max dose. Higher doses can cause SERIOUS side effects. This may well be an area for discussion with your Drs.
Third, and this is not for me, it is possible to get IVIG subcutaneously at home with the District Nurse, once dose etc is established.
Sorry I can't offer more. Good luck.
John