Most patients with active symptomatic duodenal ulcers fail to develop ulcer-type pain in response to gastroduodenal acidification.

The most frequent symptom of duodenal ulcer is epigastric pain. However, the pathogenesis of duodenal ulcer pain is not established, although it is often attributed to duodenal acidification. The purpose of this study was to determine whether or not gastroduodenal acidification with either 400 ml of pH 1 citric acid or pH 0.85 hydrochloric acid resulted in ulcer-type pain in patients with endoscopically documented active symptomatic duodenal ulcer under doubled-blind randomized conditions. Thirteen consecutive male duodenal ulcer patients with daytime and nocturnal epigastric pain were studied before beginning medical therapy; five with citric acid or sodium citrate at pH's 1, 3, and 7, and eight with hydrochloric acid at pH 0.85 and pH 7 sodium citrate. Ten normal subjects served as controls. Four of the five symptomatic duodenal ulcer patients failed to have pain with the pH 1 citric acid, while one developed pain. Five of the eight patients tested with 0.15 mM hydrochloric acid had no pain. Of the three who developed pain with hydrochloric acid, two had endoscopic evidence of esophagitis (one developed retrosternal pain and one both retrosternal and epigastric pain), and one had the sensation of epigastric "fullness" with both the pH 0.85 and pH 7 solutions. There were no significant differences (p greater than 0.1) between the responses of the duodenal ulcer and normal subjects nor within the duodenal ulcer group in response to the pH 0.85 or 1.0 solutions versus the pH 7 solution. In summary, gastric acidification equivalent to 80 mmol/hour failed to induce pain in most patients with active symptomatic duodenal ulcer. These observations suggest that duodenal ulcer pain is largely unrelated to duodenal acidification.