Hypertrophic pyloric stenosis

Last updated: June 30, 2022

Summarytoggle arrow icon

Hypertrophic pyloric stenosis, the most common cause of gastric outlet obstruction in infants, is characterized by hypertrophy and hyperplasia of the pyloric sphincter in the first months of life. Clinical manifestations usually appear between three and five weeks of age. The primary symptom is regurgitation progressing to nonbilious, projectile vomiting, which occurs intermittently or after feeding. The infant is irritable and demonstrates a strong rooting and sucking reflex because of hunger. Constant vomiting leads to hypokalemic and hypochloremic metabolic alkalosis. The diagnosis is usually clinical and involves the detection of a palpable, olive-shaped structure in the epigastrium (a sign of marked hypertrophy of the pylorus) and visible gastric peristalsis proximal to the site of obstruction. The condition may also be diagnosed on ultrasound in the absence of a palpable, olive-shaped structure. Initial management involves adequate rehydration and correction of electrolyte imbalances. The definitive treatment is Ramstedt pyloromyotomy.

Epidemiologytoggle arrow icon

Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

Clinical featurestoggle arrow icon

  • Symptoms usually develop between the 2nd and 7th week of age (rarely after the 12th week).
  • Frequent regurgitation progressing to projectile, nonbilious vomiting immediately after feeding
  • An enlarged, thickened, olive-shaped, nontender pylorus (diameter of 1–2 cm) should be palpable in the epigastrium
  • A peristaltic wave, moving from left to right, may be evident in the epigastrium
  • "Hungry vomiter": demands re-feeding after vomiting, demonstrates a strong rooting and sucking reflex, irritable
  • If left untreated: dehydration, weight loss, failure to thrive

Diagnosticstoggle arrow icon

Nowadays, hypertrophic pyloric stenosis is diagnosed early, and infants generally do not present with significant electrolyte imbalances.

Differential diagnosestoggle arrow icon

Differential diagnosis of newborn vomiting
Condition Findings
Hypertrophic pyloric stenosis
Midgut volvulus and intestinal malrotation
Gastroesophageal reflux in infants
  • Regurgitation and/or vomiting of food shortly after feeding
  • Healthy children with normal development
Gastroesophageal reflux disease in infants
Congenital adrenal hyperplasia with salt loss
Cyclical vomiting syndrome [4]

Gastroesophageal reflux in infants [5][6]

  • Definition: the movement of stomach contents into the esophagus with or without spitting up and regurgitation due to transient lower esophageal sphincter relaxation
  • Epidemiology: physiologic process in infants, typically occurs shortly after feeding
  • Etiology
    • Esophageal sphincter: transient lower relaxation due to frequent, large volume feedings
    • Esophagus: short length and/or supine position
  • Clinical features
    • Spitting up or regurgitation shortly after feeding
    • Normal physical examination and development (normal weight gain, no difficulty feeding)
  • Diagnostics: clinical findings
  • Management
  • Prognosis: : the frequency of episodes decreases with age, usually resolves spontaneously by 12–18 months of age

Gastroesophageal reflux disease (GERD) [5]

See “Gastroesophageal reflux disease in infants.”

Cyclical vomiting syndrome [4][8]

Sandifer syndrome [9]

The differential diagnoses listed here are not exhaustive.

Treatmenttoggle arrow icon

Prognosistoggle arrow icon

Referencestoggle arrow icon

  1. Rosenthal YS et al.. The incidence of infantile hypertrophic pyloric stenosis and its association with folic acid supplementation during pregnancy: A nested case–control study. J Pediatr Surg. 2019; 54 (4): p.701-706.doi: 10.1016/j.jpedsurg.2018.05.005 . | Open in Read by QxMD
  2. Krogh C, Gørtz S, Wohlfahrt J et al.. Pre- and perinatal risk factors for pyloric stenosis and their influence on the male predominance. American Journal of Epidemiology. 2012; 176 (1): p.24-31.doi: 10.1093/aje/kwr493 . | Open in Read by QxMD
  3. Krogh C, Biggar RJ, Fischer TK et al.. Bottle-feeding and the Risk of Pyloric Stenosis. Pediatrics. 2012; 130 (4).doi: 10.1542/peds.2011-2785 . | Open in Read by QxMD
  4. Aziz I, Palsson OS, Whitehead WE, Sperber AD, Simrén M, Törnblom H. Epidemiology, Clinical Characteristics, and Associations for Rome IV Functional Nausea and Vomiting Disorders in Adults. Clin. Gastroenterol. Hepatol.. 2019; 17 (5): p.878-886.doi: 10.1016/j.cgh.2018.05.020 . | Open in Read by QxMD
  5. Smith CH, Israel DM, Schreiber R, Goldman RD. Proton pump inhibitors for irritable infants.. Can Fam Physician. 2013; 59 (2): p.153-6.
  6. Baird DC, Harker DJ, Karmes AS. Diagnosis and Treatment of Gastroesophageal Reflux in Infants and Children.. Am Fam Physician. 2015; 92 (8): p.705-14.
  7. Edmond D. Shenassa, Mary-Jean Brown. Maternal Smoking and Infantile Gastrointestinal Dysregulation: The Case of Colic. Pediatrics. 2004; 114 (4): p.e497-e505.doi: 10.1542/peds.2004-1036 . | Open in Read by QxMD
  8. Hayes W, VanGilder D, Berendse J, Lemon M, Kappes J. Cyclic vomiting syndrome: diagnostic approach and current management strategies. Clinical and Experimental Gastroenterology. 2018; Volume 11: p.77-84.doi: 10.2147/ceg.s136420 . | Open in Read by QxMD
  9. Sandifer syndrome. Updated: March 1, 2007. Accessed: May 12, 2020.
  10. Hernanz-schulman M. Infantile hypertrophic pyloric stenosis. Radiology. 2003; 227 (2): p.319-31.doi: 10.1148/radiol.2272011329 . | Open in Read by QxMD

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