CIRCADIAN ACIDITY PATTERN IN GASTRIC-ULCERS AT DIFFERENT SITES

Objective: Continuous intragastric pH monitoring was used in a large g roup of gastric ulcer patients to assess whether the 24-h acidity patt ern varies in relation to the ulcer location within the stomach and to assess whether there is a circadian rhythm of pH fluctuations in this disease. Methods: One hundred and thirty-three consecutive patients ( 79 male and 54 female, mean age 53 yr) with endoscopically and histolo gically proven benign gastric ulcer and 131 healthy subjects (70 male and 61 female, mean age 48 yr) were studied with a pH minielectrode po sitioned in the gastric corpus. Ulcer patients were divided into four subgroups in relation to the crater site: 1) above the angulus (n = 23 ); 2) angularis (n = 42); 3) antral (n = 26); and 4) prepyloric (n = 4 2). Results: Subgroups 1 and 2 are characterized by significantly lowe r acidity (p < 0.0001) than healthy subjects for every time segment ex amined (24-h, day and night). Antral ulcers are less acidic than norma l for both the total 24-h period (p < 0.01) and the night period (p < 0.0001), whereas prepyloric ulcers are less acidic for the night only (p < 0.01). In all subgroups of gastric ulcer, the acidity is higher d uring the evening than the night. Conclusions: The circadian acidity o f gastric ulcer patients is significantly lower than normal, and this is particularly true during the nocturnal period. There is a gradient of gastric acidity that increases progressively as the lesion approxim ates to the pylorus. The well known circadian rhythm of gastric acidit y with relatively higher acid levels during the evening than the night was maintained in all of the gastric ulcer subgroups we created.