Children with functional abdominal pain disorders demonstrate significantly delayed orocecal transit time compared to healthy controls, with functional dyspepsia showing the most pronounced delay. However, the absence of correlation between transit time and symptom severity indicates that small intestinal dysmotility alone is insufficient to explain FAPD pathophysiology, suggesting multifactorial mechanisms underlying these gut-brain interaction disorders.
Plain-Language Summary
This study measured how long it takes food to travel from the mouth to the beginning of the large intestine in children with functional abdominal pain disorders (chronic belly pain without a clear physical cause) compared to healthy children. Researchers used a breath test after giving children a sugar solution called lactulose to track this transit time. Children with abdominal pain disorders had slower transit times than healthy children, but surprisingly, the slowness didn't match how severe their pain was, suggesting that slow digestion alone doesn't fully explain their symptoms.
Abstract
Background: Functional abdominal pain disorders (FAPDs) are common gut-brain interaction disorders with unclear pathophysiology. While impaired gastrointestinal motility is thought to play a key role, small intestinal dysmotility remains largely unexplored. Orocecal transit time (OCTT), an indirect indicator of small intestinal transit, offers an insight into its potential contribution to FAPD's pathophysiology. Aim: To assess OCTT in children with FAPDs compared with healthy children using the lactulose breath hydrogen test. Methods: Thirty-four children (44.1% males, age 5-12 years, mean 7.2 ± 2.4 years) with FAPDs attending North Colombo Teaching Hospital, Ragama, Sri Lanka, were included in the analysis. FAPDs were diagnosed using the Rome IV criteria. None had clinical or laboratory evidence of organic diseases. They were compared with 19 healthy controls (47.1% males, age 5-12 years, mean 7.8 ± 2.7 years) from the same geographical area. OCTT was calculated after an 8-hour fast using a previously validated technique. Breath hydrogen levels were measured at baseline and 15-minute intervals for 180 minutes post-lactulose ingestion (10 g in 10% solution). At each time point, 3 breath samples were collected and analyzed. OCTT was quantified as the time taken to achieve a sustained breath hydrogen increase > 10 parts per million above baseline. Symptoms were recorded using the Rome IV questionnaire, and symptom severity was graded on a 0-4 Likert scale. Results: Patients with FAPDs had increased OCTT (median, 90 minutes; interquartile range, 75-120 minutes) compared to controls (median, 75 minutes; interquartile range, 60-75 minutes) (P = 0.0045, Mann-Whitney U-test). Children with functional dyspepsia had the longest mean OCTT (110.8 ± 26.7 minutes). There was no significant correlation between abdominal pain severity and OCTT (r = 0.18, P = 0.35, Spearman correlation coefficient). OCTT did not differ between those exposed to stressful events and those not exposed to such events (P > 0.05). Conclusion: Children with FAPDs have longer OCTT than healthy controls. However, the lack of a significant correlation between OCTT and symptom severity suggests that delayed small intestinal transit alone is not a substantial contributor to FAPD pathophysiology.
