Constipation Is Related to Small Bowel Disturbance Rather Than Colonic Enlargement in Acquired Chagasic Megacolon

Background: Constipation is the main symptom of acquired chagasic megacolon. However, a number of patients with Chagas disease without colon involvement also have the same complain. This study evaluated the role of small bowel in constipated patients with Chagas disease with and without megacolon. Methods: Orocecal transit time (OCTT) and oral glucose tolerance test (OGTT) in constipated non-chagasic and chagasic patients with and without megacolon were performed. One hundred fifteen patients were included in this study and were divided into two groups based on the presence or absence of constipation, which is defined as at least 7 days without bowel movements for more than 1 year. These two groups were further divided into three subgroups based on the serology test results for Trypanosoma cruzi and the presence and absence of megacolon on barium enema. All patients were subjected to OCTT and OGTT. Results: Among 70 constipated patients, 64.3% had OCTT longer than 120 min, higher than the non-constipated patients (31.1%, P < 0.000). The proportion of patients within the three subgroups in the non-constipated group was not different from each other (P = 0.345). Among the constipated subgroup, 94.44% of the chagasic megacolon subgroup had OCTT longer than 120 min, higher than the other two subgroups (P = 0.005). Chagas patients with constipation, without or without megacolon, showed higher blood glucose levels at 30, 60, and 90 min after oral ingestion of 70 g glucose than normal subjects with or without constipation. Conclusions: Constipated, either non-chagasic or chagasic, patients have a prolonged OCTT. This result suggests that slow small bowel transit may be a significant factor for constipation.