Intestinal methanogen overgrowth and its impact on gastrointestinal disorders in children: a retrospective study

Intestinal methanogen overgrowth (IMO) is increasingly recognized as a contributor to gastrointestinal symptoms in children. This study aimed to investigate the clinical characteristics and endoscopic features of pediatric patients with IMO.

A retrospective analysis was conducted on children with gastrointestinal symptoms hospitalized in the Department of Gastroenterology, Shanghai Children's Hospital, from September 2021 to November 2022. Patients were stratified into IMO positive and IMO negative groups based on lactulose methane breath test (LBT) results, followed by a comparative analysis of clinical characteristics between the groups. Among them, 102 patients who underwent gastroscopy and/or colonoscopy were included for analysis of endoscopic and histopathological features. Clinical information was obtained from electronic medical records.

Among 124 children with gastrointestinal symptoms, 79 (63.7%) were IMO positive. Compared to the IMO negative group (n = 45), the IMO positive group had a lower proportion of diarrhea, with a statistically significant difference (P < 0.05). Villous blunting in the terminal ileal mucosa was more prevalent in the IMO positive group (P < 0.05). No significant differences were observed in nutritional status between groups. Of 70 children ultimately diagnosed with functional gastrointestinal disorders (FGID), 48 (68.6%) were IMO positive. Among FGID patients, age distribution differed significantly between IMO positive and IMO negative groups (P < 0.05), with school-aged children predominating in the IMO positive group compared to preschool-aged and adolescent children.

IMO positivity is prevalent in children with gastrointestinal symptoms, particularly prominent among those with FGID. The IMO positive group exhibited a lower incidence of diarrhea and more frequently demonstrated terminal ileal villous blunting. In FGID patients, IMO positivity correlates with age, showing higher rates in school-aged children.