High incidence of upper gastrointestinal tract involvement in Crohn's disease.

A better definition of gastric mucosal histology in Crohn's disease permits a more accurate estimation of the frequency of upper gastrointestinal tract involvement in Crohn's disease. In a retrospective study of 792 patients with known Crohn's disease the incidence of lesions associated with the disease was determined in the duodenum, duodenal bulb, and gastric antrum and body mucosa. Crohn's disease was identified histologically in the antrum in 41.5%, in the body in 37.1%, in the duodenum in 12.1%, and in the duodenal bulb in 13%. In a further 15% and 17.4% of cases, Crohn's disease of the duodenum and duodenal bulb, respectively, was suspected. The positive predictive value of focal gastritis in patients undergoing upper endoscopy and not yet known to have Crohn's disease is as high as 94%. Thus, a high proportion of Crohn's disease patients show upper gastrointestinal tract involvement, with the major involvement in the antrum. Focal gastritis suggesting Crohn's disease turned out to have a high positive predictive value in patients not known to have Crohn's disease at the time of gastroscopy.