Congenital hyperophic pyloric stenosis is characterized by progressive gastric outlet obstruction. Incidence of congenital hyperophic pyloric stenosis is highest in:

Hyperophic pyloric stenosis (HPS) is postnatal muscular hyperophy of the pylorus. HPS occurs in approximately 1-8 per 1000 bihs and originally was believed to occur in first-born males between 3 and 6 weeks of age. Infants with HPS present with nonbilious vomiting that becomes increasingly projectile over the course of several days to weeks. Eventually, the infant develops almost complete gastric outlet obstruction. Infants with HPS develop a hypochloremic, hypokalemic metabolic alkalosis. Ramstedt pyloromyotomy is the treatment of choice and consists of incision down to the mucosa along the pyloric length. Ref: Sundaram S.S., Hoffenberg E.J., Kramer R.E., Sondheimer J.M., Furuta G.T. (2012). Chapter 21. Gastrointestinal Tract. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e.