Abnormally rapid gastric emptying of an isosmotic liquid meal in patients with megaduodenum.

Duodenal resistance to gastric outflow is known to participate in the regulation of gastric emptying of liquids in animals, but the role of this mechanism in humans has not been extensively investigated. In this work we studied the gastric emptying of liquids in patients with megaduodenum, who putatively have increased duodenal receptivity to gastroduodenal transfer of liquids. Subjects included eight patients with megaduodenum and eight healthy volunteers. Since megaduodenum in all cases was associated with Chagas' disease, a further reference group consisting of 11 chagasic patients without megaduodenum was also studied. Fasted subjects ingested 200 ml of an isotonic dextrose solution labeled with 15 MBq of technetium-99m coupled to sulfur colloid, as an unabsorbable marker. Images of the anterior aspect of the stomach were taken immediately after test meal ingestion and thereafter up to 1 hr. Decay-corrected counts over the gastric region along time yield the calculation of early (5 min) and late (60 min) gastric retention as well as gastric emptying half-times (T1/2). Early gastric retention in patients with megaduodenum (median; range: 48%; 18-64%) was significantly lower (P < 0.05) than in both patients without megaduodenum (59%; 40-86%) and controls (82%; 68-99%). T1/2 values in patients with megaduodenum (5 min; 3-17 min) were also significantly lower (P < 0.01) than in patients without megaduodenum (23 min; 4 to >60 min) and controls (29 min; 13-60 min). There were no significant differences between the three groups concerning late gastric retention. We conclude that the early phase of gastric emptying of liquids is abnormally accelerated in patients with megaduodenum, which suggests that increased duodenal receptivity may have a significant effect on the gastroduodenal transfer of liquids in humans.