Background & aims: There is limited information about the motor mechanisms responsible for gastroesophageal reflux (GER) in children. The aim of this study was to evaluate the relationship between esophageal body and lower esophageal sphincter (LES) motor events and the occurrence of GER.
Methods: Concurrent esophageal manometry and pH monitoring was conducted for 4 hours postprandially in 37 children referred for evaluation of suspected pathological GER. Presence of esophagitis and/or abnormal esophageal acid exposure was used to classify patients into two groups: those with pathological GER (group A; n = 24) and those in whom GER was not confirmed (group B; n = 13).
Results: GER occurred during LES relaxations unassociated with swallowing within 5 seconds before and 2 seconds after the onset of LES relaxation in 58% (group A) and 69% (group B) of the analyzable episodes. These swallow-independent sphincter relaxations satisfied criteria for classification as transient LES relaxations. An additional 23% (group A) and 19% (group B) of reflux episodes could have been a result of transient LES relaxation associated with swallowing by chance. Persistent absence of LES tone was an infrequent association of reflux and was confined to group A patients (8% of episodes).
Conclusions: Transient LES relaxation is the most important cause of GER in children. Absent basal LES pressure is a relatively infrequent cause of reflux and only in children with pathological GER.