Prevalence of abnormal lactose breath hydrogen tests in children with functional abdominal pain.

Objective: The study was undertaken to determine the prevalence of abnormal lactose breath hydrogen test in children with non-organic chronic abdominal pain.

Methods: Children with chronic abdominal pain were examined and investigated for organic causes. All children without a known organic cause underwent lactose and glucose breath hydrogen test. After a standard dose of 2 g/kg of lactose to a maximum of 50 g, hydrogen in breath was measured at 15 min intervals for 3 h. A rise of 20 ppm above baseline was considered suggestive of lactose malabsorption.

Results: Of 108 children screened, organic causes were found in 46 children. Sixty-two patients without any organic cause underwent hydrogen breath test. Lactose hydrogen breath test (HBT) was positive in 36 of 62 (58%), while 11 (17%) had positive HBT with glucose suggestive of small intestinal bacterial overgrowth (SIBO). Twenty out of 34 (59%) improved on lactose free diet while 8 out of 11 (72%) children of SIBO improved on antibiotics.

Conclusions: Lactose malabsorption was seen in 58% of children with non-organic chronic abdominal pain.