Effects of Provocative Testing on Phase III Migrating Motor Complex in Children

Antroduodenal manometry (ADM) is used to evaluate antral and small intestinal motility, with the presence of phase III migrating motor complexes (MMCs) indicating an intact enteric neuromuscular system. The lack of evidence-based or consensus-driven established norms for MMC in fasting phase and after provocative testing marks a major limitation in the interpretation of ADM studies. We aimed to determine the characteristics of MMC in fasting and post-provocative phase in children.

Data from subjects ages <20 years with ADM results evaluated at neuro-gastroenterology and Motility Disorders Center, Cincinnati Children's Hospital Medical Center from January 2018 to March 2019 were analyzed.

Forty-eight ADM tracings that did not demonstrate abnormal patterns were included; the mean age was 10.00 ± 5.72 years and 50% were male. Indications for ADM included: vomiting (27.1%), feeding intolerance (27.1%), abdominal pain (16.6%), nausea (14.6%), and abdominal distension (14.6%). Thirty-seven percent of subjects had enteral access for feeds. During fasting, one-third of all MMC originated in the antrum. Azithromycin-induced MMC occurred in 28% of subjects and two-thirds of these originated in the antrum with antral contractions of significantly higher frequency and amplitude compared to fasting. Octreotide significantly increased frequency, amplitude, and duration of MMC compared to fasting, with 76% originating in the antrum. Both azithromycin and octreotide induced more than one MMC in a third of subjects.

We describe the characteristics of antral and small intestinal motility during fasting and after provocative testing in children. These values will help standardize our interpretation of pediatric ADM studies.