Contributor: Neil Cella, MD Educational Pearls: Pylorus becomes hypertrophied and does not allow food or liquid to pass through to the duodenum tOccurs between the ages of 3 weeks to 3 months Classic presentation includes projectile nonbilious vomiting and palpable abdominal mass Ultrasound can visualize/diagnose pyloric stenosis and the treatment is surgical correction Be aware that electrolyte abnormalities and acid/base disturbances may occur References Garfield K, Sergent SR. Pyloric Stenosis. [Updated 2021 Feb 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK555931/ Summarized by John Spartz, MS4 | Edited by Erik Verzemnieks, MD