Identification of a prodromal period in Crohn's disease but not ulcerative colitis

Irritable bowel syndrome, a common gastrointestinal diagnosis, has not been clearly studied in inflammatory bowel disease. Some of the residual symptoms in subjects treated with Crohn's disease and ulcerative colitis are thought to be related to irritable bowel syndrome. The aims of this study were 1) to describe the duration and nature of complaints before the diagnosis of Crohn's disease and ulcerative colitis (prodromal period), and 2) to determine the role of IBS in this prodromal period.

A total of 66 patients with confirmed inflammatory bowel disease were enrolled in the study. The subjects received a questionnaire to ascertain the nature and duration of symptoms preceding the diagnosis of Crohn's disease or ulcerative colitis, including features described under the Rome criteria for irritable bowel syndrome.

Of the 66 subjects analyzed, 45 had Crohn's disease and 21 had ulcerative colitis. The prodromal period was 7.7 +/- 10.7 yr for Crohn's disease and 1.2 +/- 1.8 yr for ulcerative colitis (p < 0.05). Once patients meeting the Rome criteria for irritable bowel syndrome during the prodrome were excluded, the duration of the prodromal period (non-IBS) for ulcerative colitis dropped to 0.8 +/- 1.3 yr compared to 6.9 +/- 9.8 yr in the Crohn's disease group (p < 0.05). The symptoms of the non-IBS prodrome in subjects with Crohn's disease were bloating, diarrhea, stomach pain, heartburn, fever, weight loss, and fatigue. Further analysis demonstrated that subjects whose Crohn's disease initially began as colonic disease had a longer prodrome than with small bowel. In the non-IBS Crohn's group, there was also a correlation between the age at the time of diagnosis and the duration of prodrome (r = 0.67, p < 0.0001).

There is a significant prodromal period before the time of diagnosis of Crohn's disease that is not found in ulcerative colitis even after exclusion of subjects with IBS.