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Mucosal function and breath hydrogen excretion: comparative studies in the clinical evaluation of children with
Insights
The lactose breath hydrogen test accurately detects lactose malabsorption in children. It reliably identifies isolated lactase deficiency but may miss cases secondary to mucosal injury.
Area of Science:
- Pediatric Gastroenterology
- Diagnostic Testing
- Gastrointestinal Disorders
Background:
- Chronic abdominal complaints are common in children.
- Lactose malabsorption is a potential cause.
- Accurate diagnostic methods are crucial for effective management.
Purpose of the Study:
- To assess the efficacy of the lactose breath hydrogen test (LBHT) in diagnosing lactose malabsorption.
- To compare LBHT results with lactose tolerance tests, symptom reporting, and small bowel biopsy findings.
- To evaluate LBHT's role in children with chronic nonspecific abdominal complaints.
Main Methods:
- 131 children with abdominal pain or diarrhea underwent LBHT after a lactose load.
- Results were compared with lactose tolerance tests, symptom data, and small bowel biopsies (n=31).
- Breath hydrogen levels were analyzed for early and late increases post-lactose ingestion.
Main Results:
- An early increase in breath hydrogen (>10 ppm by 120 min) accurately identified isolated lactase deficiency.
- Late increases were consistent with normal function or secondary lactase insufficiency.
- LBHT predicted lactase activity in isolated deficiency but showed false negatives in secondary cases.
- Lactose malabsorbers reported more symptoms, but symptoms and tolerance tests were unreliable discriminators.
Conclusions:
- The lactose breath hydrogen test is a valuable tool for objectively diagnosing lactose malabsorption in children.
- It is highly effective for detecting isolated lactase insufficiency.
- Caution is advised for cases where lactase deficiency may be secondary to mucosal injury.
Abstract:
To evaluate the role of the lactose breath hydrogen test for the detection of lactose malabsorption in children with chronic nonspecific abdominal complaints, breath hydrogen excretion was measured in 131 children with recurrent abdominal pain (n = 75) or chronic nonspecific diarrhea (n = 56) following a lactose load (2 gm/kg; maximum 50 gm). The data were compared to those obtained from lactose tolerance tests (n = 113) and symptom response following a lactose load (n = 109) performed simultaneously with the lactose breath hydrogen test, and with results from small bowel biopsies obtained in 31 children to determine dissacharidase activity and mucosal histology. The results indicate that an increase in breath hydrogen of greater than 10 ppm above base line values (delta ppm) by 120 minutes ("early increase" response) completely discriminates between biopsy-proven isolated lactase-insufficient and lactase-sufficient children. A similar increase after 120 minutes ("late increase" response) is consistent both with normal mucosal function and partial lactase insufficiency due to mucosal injury. Breath hydrogen responses predicted assayed lactase activity in all patients with isolated lactase insufficiency, but were "falsely negative" in four of ten children whose lactase insufficiency was secondary to mucosal injury. In both clinical groups, lactose malabsorbers report significantly more symptoms than absorbers (P less than .001), but neither symptom reports nor tolerance tests are accurate methods for distinguishing lactose malabsorbers from absorbers. Although the lactose breath hydrogen test provides objective documentation of lactose malabsorption, it is equally predictive of assayed lactase activity in all clinical groups.