Rapid distal small bowel transit associated with sympathetic denervation in type I diabetes mellitus.

BACKGROUND The pattern of progression of a meal from the stomach to the caecum in diabetes mellitus is controversial and the differential roles of transit through the jejunum and the ileum have not been investigated in diabetes. AIMS To determine gastric emptying and transit rates through proximal and distal regions of the small bowel in type I diabetic patients. SUBJECTS The study included six diabetic patients with evidence of autonomic neuropathy (DM-AN group), 11 diabetics without autonomic dysfunction (DM group), and 15 control volunteers. METHODS Gastric emptying and small bowel transit of a liquid meal were evaluated scintigraphically in these subjects. Transit through regions of interest corresponding to the proximal and distal small intestine up to the caecum was determined and correlated with gastric emptying rates, cardiovascular measurements of autonomic function, and the occurrence of diarrhoea. RESULTS Gastric emptying and transit through the proximal small bowel were similar in the three groups. The meal arrived to the caecum significantly earlier in DM-AN patients (median; range: 55 min; 22-->180 min) than in the DM group (100 min; 44-->180 min, p < 0.05) or in controls (120 min; 80-->180 min, p < 0.02). Accumulation of chyme in the distal small bowel was decreased in DM-AN patients, who showed values for peak activity (30%; 10-55%) significantly lower than in the DM group (49%; 25-77%, p = 0.02) and controls (50%; 30-81%, p = 0.02). In DM patients (n = 17), the time of meal arrival to the caecum was significantly correlated with both orthostatic hypotension (coefficient of contingency, C = 0.53, p < 0.01) and diarrhoea (C = 0.47, p < 0.05), but not with gastric emptying rates. CONCLUSIONS Patients with type I diabetes mellitus and sympathetic denervation have abnormally rapid transit of a liquid meal through the distal small bowel, which may play a part in diarrhoea production.