[Current views concerning the etiopathogenesis of reflux esophagitis in children].

Esophagitis is caused by a gastro-esophageal reflux sometimes reflecting anatomical inadequacy of structures that secure the relationships between the cardia and the diaphragm, fundus of the stomach, and other surrounding viscera, but more often due to functional deficiency of lower esophageal sphincter (LES), this representing the main factor for maintenance of the mechanism of cardial continence. Manometric studies of intraluminal pressures in the esophagus have revealed the presence of a high-pressure segment in the distal esophagus, where a mean pressure of 12-13 mm Hg obtains over a length of 3 or 4 cm. In the first two weeks of extrauterine life the LES is between 0.5 and 1 cm long, with a pressure of 3 mm Hg; pressure values in the LES equal adult values at about one month of age, showing that neuromuscular control of the sphincter has been achieved. Gastro-esophageal reflux, however, is very common in the newborn and not enough by itself to cause peptic disease of the esophagus; this requires the concomitance of morphological defects of the esophageal mucosa and/or dynamic-functional disturbances. This, according to the authors, is why esophagitis actually occurs in only about 60% of patients with radiologically and pHmetrically demonstrated gastro-esophageal reflux.