Lower esophageal sphincter function in children with and without gastroesophageal reflux.

Resting lower esophageal sphincter (LES) pressure was assessed in infants and children 2 weeks to 12 years of age. There were 62 control subjects and 35 patients with reproducible gastroesophageal reflux (GER) determined radiologically. In control subjects without GER: (1) LES pressure was well developed by 2 weeks of age; (2) in children less than 1 year of age, mean LES pressure (43.3 +/- 2.4 mm Hg) was significantly greater than mean LES pressure (30.6 +/- 2.3 mm Hg) children older than 1 year of age; (3) LES sphincter length increased with age; and (4) bethanechol 0.1 mg per kg subcutaneously caused a rise in LES pressure that increased in magnitude as LES resting pressures increased. In patients with GER: (1) only 16 or 35 children had LES pressures below the normal range for their appropriate age group; (2) LES length was shorter than control values in children beyond 6 months of age; (3) GER usually occurred in the absence of hiatus hernia; (4) clinical improvement was common and in patients with low LES pressure was associated with a rise in LES pressures to normal, even in the presenece of hiatus hernia; and (5) bethanechol caused a change and an absolute rise in LES pressure that were not significantly different from those observed in controls. These results indicate that in infants and children low LES pressure is not the sole determinant of GER, and that pharmacological stimulation of the Les could prove to be a useful adjunct to the medical management of GER.