Bowel dysfunction in cystic fibrosis: importance of breath testing

Abstract

<h4>Objective</h4>To investigate the prevalence of carbohydrate malabsorption and bacterial overgrowth in children with cystic fibrosis (CF) and abnormal stool pattern referred for breath hydrogen testing.<h4>Methods</h4>Results from 89 tests using lactose, sucrose and lactulose in 54 children with CF were compared with 5430 tests on children with non-CF-related stool abnormalities.<h4>Results</h4>Children with CF were more frequently unable to ferment lactulose to hydrogen (39% vs. 20%, P<0.03); they had significantly longer oro-caecal transit times (mean 99 vs. 68 min, P<0.0003); they had a higher incidence of bacterial overgrowth (32% vs. 7%, P<0.003) and sucrose malabsorption (47% vs. 14.5%, P<0.004); but they had no increase in lactose malabsorption (40% vs. 31%). Children with bacterial overgrowth in both groups had longer transit times (CF 123 min, non-CF 108 min) compared to the non-CF children without overgrowth (68 min) and reference normal children (69 min).<h4>Conclusions</h4>Bacterial overgrowth and carbohydrate malabsorption, particularly of sucrose, should be considered when assessing children with CF and abnormal stool patterns.