RESUMEN
Infantile hypertrophic pyloric stenosis(IHPS) is one of the most common causes of nonbilious vomiting in early infancy, and is caused by hypertrophied pyloric muscle but its exact etiology and pathogenesis are still unknown. Fredet-Ramstedt pyloromyotomy has been accepted as the treatment of choice for IHPS. Atropine is a cholinergic blocking agent with potent antimuscarinic activity that decreases peristaltic contractions by relaxing smooth muscles. We treated a case of IHPS in a 33-day-old male infant by administering atropine sulfate intravenously. One day after atropine sulfate administration, he did not vomit any more. Ultrasonograms of the pyloric canal which were done on eight days and three weeks after atropine treatment revealed no limitation in the passage of gastric content, and no changes in the muscle thickness and length of the pyloric canal. Thereafter, he did not show up at follow ups, we received his mother's answer through phone that he did not suffer from vomiting and he was growing well at 5 months of age.