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A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M.; 2013.

A.D.A.M. Medical Encyclopedia.

Pyloric stenosis

Congenital hypertrophic pyloric stenosis; Infantile hypertrophic pyloric stenosis; Gastric outlet obstruction

Last reviewed: August 22, 2013.

Pyloric stenosis is a narrowing of the pylorus, the opening from the stomach into the small intestine.

Causes

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.

Symptoms

Vomiting is the first symptom in most children:

  • Vomiting may occur after every feeding or only after some feedings
  • Vomiting usually starts around 3 weeks of age, but may start any time between 1 week and 5 months of age
  • Vomiting is forceful (projectile vomiting)
  • The infant is hungry after vomiting and wants to feed again

Other symptoms appear several weeks after birth and may include:

  • Abdominal pain
  • Burping
  • Constant hunger
  • Dehydration (gets worse as vomiting gets worse)
  • Failure to gain weight or weight loss
  • Wave-like motion of the abdomen shortly after feeding and just before vomiting occurs

Exams and Tests

The condition is usually diagnosed before the baby is 6 months old.

A physical exam may reveal:

  • Signs of dehydration, such as dry skin and mouth, less tearing when crying, and dry diapers
  • Swollen belly
  • Olive-shaped mass when feeling the upper belly, which is the abnormal pylorus

Ultrasound of the abdomen may be the first imaging test. Other tests that may be done include:

Treatment

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.

Outlook (Prognosis)

Surgery usually relieves all symptoms. As soon as several hours after surgery, the infant can start small, frequent feedings.

When to Contact a Medical Professional

Call your health care provider if your baby has symptoms of this condition.

References

  1. 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.
  2. Pandya S, Heiss K. Pyloric stenosis in pediatric surgery. Surg Clin N Am. 2012;92:527-553. [PubMed: 22595707]

Review Date: 8/22/2013.

Reviewed 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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Copyright © 2013, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only — they do not constitute endorsementscof those other sites. © 1997–2011 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

Copyright © 2013, A.D.A.M., Inc.

What works?

  • Erythromycin for the prevention of chronic lung disease in intubated preterm infants at risk for, or colonized or infected with Ureaplasma urealyticumErythromycin for the prevention of chronic lung disease in intubated preterm infants at risk for, or colonized or infected with Ureaplasma urealyticum
    More evidence needed on using antibiotics to try and prevent chronic lung disease in preterm babies testing positive for U urealyticum. Chronic lung disease (CLD) is a major health risk often faced by preterm babies on ventilation (machine‐assisted breathing). Ureaplasma urealyticum is a common type of infection that may be one of the causes of CLD, although this has not been proven. Erythromycin is an antibiotic used for other infections caused by U urealyticum. When a baby tests positive for U urealyticum, erythromycin has been tried as a preventive measure. The review found that there is not enough evidence from trials to show whether or not testing preterm babies for U urealyticum and using erythromycin can prevent CLD or mortality.
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