I was brought into hospital for a dose of IV steroids in October last year. I'd been really sick for a while but just struggling through it, made it to my Gastro appointment - my doc took one look at my bloods and told me I needed to come in for a few days. He arranged for me to come in that day.
How long you're in depends on how well you respond to the meds. I was lucky in that the IV steroids kicked in pretty quickly - my gastro doc originally wanted me on IV for 5 days, but I was back on tablets after 3. After the IV (which is a high dose - it's a different conversion from liquid to tablets so I can't remember what I was on) they started me back on 40mg Pred, and yeah, unfortunately you have to start tapering from there. I was in a couple more days for monitoring and tests but I was in and out in 5 or 6 days.
I'm from England so i can only speak from an NHS point of view on the treatment I got, but I imagine it's a similar process wherever you are.
I'm not sure about the side effects, as I've always been pretty lucky with steroids anyway - the only thing the IV infusion did was cause an explosion of spots on my back, but I didn't notice anything else. The IV steroids did, however, make me feel well again very quickly, and if your daughter's that sick, it's definitely worth considering.
Hope this helps, and hope Bratcat is better soon.