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What are the differences in distribution between ulcerative colitis and Crohns disease?
Ulcerative colitis is left-sided colonic disease, beginning at the anorectal junction and extending continuously and retrogradely a variable distance (proctosigmoiditis, left-sided colitis, pancolitis). Ulcerative colitis symmetrically involves a bowel segment.
Crohn’s disease involves the colon and terminal ileum in 55% of patients.
Terminal ileal involvement alone is seen in 14% of patients. Terminal ileal and distal small bowel involvement alone is seen in 13% of patients. Pure colonic involvement is seen in about 15% of patients.
Crohn’s disease is discontinuous, having patchy involvement locally and between loops, called skip areas. Crohn’s disease is asymmetric, first involving the mesenteric side of bowel.
Comparison of Crohns Disease and Ulcerative Colitis
CROHN’S DISEASE | ULCERATIVE COLITIS |
---|---|
Right-sided | Extends proximally from rectum |
Discontinuous | Continuous |
Asymmetric | Symmetric |
Terminal ileal changes in 85% | Backwash ileitis in 10% |
Aphthoid ulcers | Mucosal granularity |
Ulcers on background of normal mucosa | Ulcers on background of mucosal granularity |
Severe perianal disease | Colon cancer in larger percentage of patients |
Sinus tracks and fistulas | Sclerosing cholangitis in larger percentage of patients |
Abscess formation |