Aphthous found in terminal ileum and pseudopolyps

I was diagnosed with ulcerative colitis in 1991.   I was diagnosed with gastroparesis in 2001.   My question is this.   There are times that I get horrible abdominal pain that radiates down the right side and across my lower abdomen.  Sometimes it will be on the left side.  I get so nauseated and at times I will pass out.   I find that if I am put on IV fluids and antinausea medication for a few days I seem to be okay.  But then they send me home and sometimes it starts all over again.  They will do CAT scans, upper endoscopy etc. and the only thing they find are aphthous ulcers in my stomach and scarring into the small bowel.  No one can come up with a etiology or even a diagnosis for this.  I was hoping that someone out their might be able to point in the right direct.