CIRCADIAN ACIDITY PATTERN IN PREPYLORIC ULCERS - A COMPARISON WITH NORMAL SUBJECTS AND DUODENAL-ULCER PATIENTS

We used continuous 24-h pH monitoring to compare the circadian intraga stric acidity of 36 patients with prepyloric ulcers (PPU) with that of 101 normal subjects (NS) and that of 206 patients with duodenal ulcer (DU). The ulcer crater was endoscopically ascertained in all cases, a nd PPU were located within an area up to 2 cm proximal to the pylorus. The pH curve pertaining to DU patients ran below that of NS during mo st of the circadian period, whereas the pH profile of PPU patients was higher than that of NS, and this was particularly true during the eve ning and the night. The acidity of PPU patients was significantly lowe r (p < 0.01) than that of NS during the night only, whereas it was low er (p < 0.05-0.001) than that of DU patients during each time interval analysed (24 h, nighttime, and daytime). Our findings show that the g astric acidity of PPU patients differs greatly from that of DU patient s, since it is lower throughout the whole 24-h period, and particularl y during the night. Thus these two entities are pathophysiologically d ifferent with regard to the acidity pattern and should be considered t wo distinct subgroups of peptic ulcer disease instead of being incorpo rated, as usually happens, in the clinical group 'duodenal ulcer disea se'.