frequency of colonic extension by colonoscopy in ulcerative colitis patients in kermanshah province in the years 2002-2005

introduction: ulcerative colitis (uc) is a chronic colonic mucosal disease with unknown etiology. its frequency is rising in our country in recent years. with application of newer topical preparation in treatment of uc a true recognition of its colonic extension pattern is needed.  reports from iran are scarce. reports from the world are contradictory. this study, therefore, was done to determine frequency of colonic extension in patients with uc in western part of iran.  materials and methods: to this prospective sectional descriptive study which was prospected between the years (2002-2005) in taleghani hospital affiliated of kermanshah university of medical sciences, all patients with lower gastrointestinal bleeding and chronic diarrhea were referred to this hospital were enrolled and then were highly evaluated. those patients who had three criteria of copenhagen in favor of uc and had not received any treatment were enrolled to the study. segments of colon that had criteria of colonic involvement in any colonoscopy grading between (0-4) were considered as diseased segments and classified as:1. proctitis, 2. proctosigmoiditis, 3. sigmoiditis, 4.left-sided uc, 5. pan colitis.  copenhagen criteria is included: 1. the history of diarrhea, bleeding, infection evacuation at least for a week; 2. colonoscopy criteria including circulated ulcer, vulnerable & granular membrane; 3. histopathology findings according to uc. analysis was done by spss using windows version 13. data is expressed in numerical and percentage system. results: 85 patients met criteria of ulcerative colitis. mean age at the time of diagnosis was 34.09 years old. male to female ratio was 1/0.8.  the most frequent sites of colonic involvement in colonoscopy view were as follow: proctosigmoiditis 30 patients (35.3%), proctitis 20 patients (23.5%), left-sided uc 18 patients (21.17%), sigmoiditis 10 patients (11.77%), and pan colitis 7 patients (8.23%). rectal sparing according to colonoscopy view was seen in 18 patients (21.17%). conclusion: this study showed that proctosigmoiditis in colonoscopy view is the most frequent site of involvement in uc in western part of iran and frequency of rectal sparing in colonoscopy view from the beginning of disease is 21.17%. the reports are the same in western countries, but different from in middle east & south-west of asia accordingly.