Background: Constipation is a frequent symptom in pediatric clinical practice, although the underlying pathogenesis is not fully understood. Estimating the colonic transit time may help identify subgroups of patients with different physiopathologic mechanisms.
Methods: Thirty children with normal bowel habits and 38 children with chronic idiopathic constipation, aged 2 to 14 years, were studied. The total and segmental colonic transit times were estimated by administering multiple radiopaque markers for 6 days and performing a single abdominal radiograph on day 7. Anorectal function was evaluated using manometry with an Arhan probe.
Results: The observed upper reference values were 19.02 hours for the right colon, 19 hours for the left colon, 32 hours for the rectosigmoid colon, and 45.7 hours for the total colon. Fifty percent of the children with chronic idiopathic constipation had colonic transit times within reference values, whereas 37% had left colonic and rectosigmoid delays and 13% had global delay in all colonic segments (colonic inertia). Paradoxic anal contraction was observed in 64% of the constipated children with distal delay but in none of the subjects with colonic inertia.
Conclusions: Estimating colonic transit time is a simple and noninvasive technique for classifying patients with constipation. Colonic inertia may be a manifestation of global motility dysfunction. Children with delayed distal colonic transits are more likely to have abnormal defecation dynamics.