What is pyloric stenosis?

Pyloric stenosis

Pyloric stenosis is a condition in which a baby's pylorus (the connection between the stomach and the first part of the small intestine) gradually swells and thickens, which interferes with food entering the intestine. This causes the baby to vomit most or all of his or her feedings.

Vomiting caused by pyloric stenosis usually starts gradually and gets worse over time. As the pylorus becomes tighter, the baby vomits more frequently and more forcefully (projectile vomiting). As vomiting continues, the baby will lose weight and become dehydrated.

Pyloric stenosis can occur any time between birth and 5 months of age, but it most commonly develops about 3 weeks after birth. The start of symptoms may be delayed if the baby was premature.

Pyloric stenosis is corrected with surgery (pyloromyotomy). After a baby has the surgery, pyloric stenosis usually does not occur again.

What are the symptoms of pyloric stenosis?

A baby with pyloric stenosis may:

  • Vomit soon after a feeding.
  • Have a full, swollen upper belly after a feeding.
  • Act fussy and hungry a lot of the time.
  • Have fewer and harder stools than normal.
  • Pass less urine than normal.

Vomiting usually starts gradually. As the pylorus becomes tighter, the vomiting may become more frequent and more forceful.

As the vomiting continues, your baby may:

  • Lose weight.
  • Become dehydrated.
  • Be sleepier than normal and very fussy when awake.

How is pyloric stenosis treated?

Pyloric stenosis is treated with surgery to widen the opening through the pylorus between the stomach and the small intestine. Surgery rarely causes problems.

Your baby likely will be ready to go home within 2 days after surgery. Being involved in your baby's care at the hospital may help you feel more comfortable when you take your baby home. Talk with the doctor about how to feed your baby and what to expect. It's normal to feel nervous, but don't be afraid to hold and handle your baby.

How is pyloric stenosis diagnosed?

Your doctor will do a physical exam and ask about your baby's symptoms. If your baby has pyloric stenosis, the doctor may be able to feel a small lump in the upper part of the belly.

In some cases your baby may need imaging tests, such as an upper GI (gastrointestinal) series or an abdominal ultrasound. Your baby also may need blood tests to see if he or she is dehydrated.

How can you care for your child who has pyloric stenosis?

Your baby's care team will make sure that you have the information you need to take care of your baby at home. Follow your doctor's instructions for feeding your baby. Give any medicines as instructed. And go to any follow-up visits.

Pyloric stenosis

Location of pylorus in baby's abdomen, with detail of narrowed pylorus (stenosis) before and after surgery

The pylorus is the connection between the stomach and the first part of the small intestine. Pyloric stenosis is a condition in which a baby's pylorus gradually swells and thickens. This interferes with food entering the intestine and causes the baby to vomit most or all of his or her feedings.

To treat pyloric stenosis, a surgeon widens the channel between the stomach and the intestine. Pyloric stenosis does not usually occur again after a baby has been treated.

What causes pyloric stenosis?

Experts don't know what causes pyloric stenosis. It may be passed down through families.

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