Ulcerative Colitis: Classification

Montreal classification in terms of extent in ulcerative colitis (CU).

E1: Ulcerative proctitis (rectal inflammation). Involvement is limited to the rectum (rectum)
E 2: Left-sided ulcerative colitis (inflammation of the colon; distal CU). Involvement of the rectum and left colon (large intestine; extending to the left colonic flexure).
E3: Extensive ulcerative colitis (pancolitis). Involvement beyond left colonic flexure, involvement of entire colon possible