It seems to be mainly up to the doctor's discretion and the specifics of what symptoms you have, how long you've been having symptoms, etc. I have only been hospitalized once, and it was just a few months ago. I started flaring in July, and in August I had lost 17 lbs and couldn't seem to digest any food, not even Ensure. I was having watery BMs 20 times per day and felt horrendous with a lot of pain - basically I couldn't eat, couldn't sleep, couldn't function as a human being. I had gone to the ER a few times for IV fluids, and the 3rd time I went to the ER, which was in late August, they decided to admit me because they could see I was getting worse, losing more weight, etc. So they did some tests and got me on IV steroids and started me on EEN, and that finally turned the flare around. I ended up being in the hospital for 5 days total.