Cortisone is not a good med for long term use. IVIG is given two ways, either intravenously by an infsion nurse once every 4weeks. It can also be self adminstered weekly with a hand held pump and prefilled syringes with replacement gamma globulin, mainly IgG. I have used the 2nd method, which is far safer, for the past 8 1/2 years with no problems. My immunolologist prescribed Hizentra, which I think is a superior product, The weekly schedule for subcu self administering means you are only taking 1/4 of the monthly dose with each infusion. Your body never has to cope with the huge monthly dose. Another advantage of subcu weekly infusions is the serum goes into your flesh (not your blood stream) and is more slowly absorbed by your body versus the IV route, which is directly into your vein and organs. There is the risk of kidney damage and other problems with IVIG. I'm sure that risk is greatly reduced with subcu infusion. I infuse my thighs with a 4 needle set, there are two 1/3 inch needles into each leg, and numbing cream makes the neele punctures very easy. I have never had a reaction or problem, and I am 90 yo. with 4 autoimmune diseases and a pig arterial valve and a bunch of other comorbidities. The Hizentra saved my life, because it prevented the destruction of the replacement heart valve by the same pneumonia bug that destroyed my biological valve. Your alternatives are not very good - disease progression and increasing weakness. I needed a friend to sit with me for a month of infusions until I built the courage to do it on my own. Now its seems simple.
all the best to you with making a good decision. I think the sucu route is a bother, but your best health option.