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Pyloric stenosis in infants

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

Pyloric stenosis is a narrowing of the opening from the stomach into the small intestine. This is called the pylorus. This article describes the condition in infants.

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Digestive system
Pyloric stenosis

Presentation

Infantile pyloric stenosis - series

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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 exact 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. Other risk factors include:

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:

Other symptoms appear several weeks after birth and may include:

Exams and Tests

The condition is often 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 may include:

Treatment

Treatment for pyloric stenosis involves surgery to widen the pylorus. The surgery is called pyloromyotomy.

If it is not safe to put the infant to sleep for surgery, an endoscope is used. This is a long, flexible tube with a camera and a tiny balloon at the end. 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.

Possible Complications

If pyloric stenosis isn't treated, a baby won't get enough nutrition and fluid. The child can become underweight and dehydrated.

When to Contact a Medical Professional

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

References

Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Pyloric stenosis and other congenital anomalies of the stomach. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 355.

Seifarth FG, Soldes OS. Congenital anomalies and surgical disorders of the stomach. In: Wyllie R, Hyams JS, Kay M, eds. Pediatric Gastrointestinal and Liver Disease. 6th ed. Philadelphia, PA: Elsevier; 2021:chap 25.

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Review Date: 8/10/2021  

Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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