Pyloric stenosis is a narrowing of the pylorus, the opening from the stomach into the small intestine.
Normally, food passes easily from the stomach into the first part of the small intestine through a valve called the pylorus. With pyloric stenosis, the muscles of the pylorus are thickened. This prevents the stomach from emptying into the small intestine.
The cause of the thickening is unknown. Genes may play a role, since children of parents who had pyloric stenosis are more likely to have this condition.
Pyloric stenosis occurs most often in infants younger than 6 months. It is more common in boys than in girls.
Vomiting is the first symptom in most children:
Other symptoms appear several weeks after birth and may include:
The condition is usually diagnosed before the baby is 6 months old.
A physical exam may reveal:
Ultrasound of the abdomen may be the first imaging test. Other tests that may be done include:
Treatment for pyloric stenosis involves surgery to widen the pylorus. The surgery is called pyloromyotomy.
If putting the infant to sleep for surgery is not safe, a device called an endoscope with a tiny balloon at the end is used. The balloon is inflated to widen the pylorus.
In infants who cannot have surgery, tube feeding or medicine to relax the pylorus is tried.
Surgery usually relieves all symptoms. As soon as several hours after surgery, the infant can start small, frequent feedings.
Call your health care provider if your baby has symptoms of this condition.
Congenital hypertrophic pyloric stenosis; Infantile hypertrophic pyloric stenosis; Gastric outlet obstruction
Hunter AK, Liacouras CA. Pyloric stenosis and congenital anomalies of the stomach. In: Kliegman RM, Stanton BF, St. Geme JW III, et al., eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Elsevier Saunders; 2011: chap 321.
Pandya S, Heiss K. Pyloric stenosis in pediatric surgery. Surg Clin N Am. 2012;92:527-553.
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.
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