Pyloric Stenosis, Infant

Outline of a baby's body that shows the pylorus, stomach, and small intestine.

Pyloric stenosis refers to a condition in which the muscular opening between the stomach and the small intestine (pylorus) becomes unusually narrow. Normally, food moves easily from the stomach into the small intestine through the pylorus. If the muscles of the pylorus are thicker than normal (hypertrophy), the opening narrows and prevents food from passing easily out of the stomach. Pyloric stenosis can almost completely block this opening.

Pyloric stenosis usually develops in the first few weeks after birth. The most common sign is very forceful (projectile) vomiting immediately after a feeding.

What are the causes?

The cause of this condition is not known.

What increases the risk?

The risk of pyloric stenosis may be greater if:

Your child is between 3–6 weeks old.
Your child is male.
There is a family history of pyloric stenosis.
The mother used tobacco during pregnancy.
Your child was put on a certain type of antibiotic (macrolides) shortly after birth.

What are the signs or symptoms?

The main symptom of pyloric stenosis is projectile vomiting in the first weeks of life without any other signs of illness. Other signs and symptoms include:

Constant hunger, even after vomiting.
Rippling of belly muscles.
An olive-sized lump that can be felt in the middle of the belly.
Lack of weight gain.

Signs that your child is dehydrated:

Dry skin, dry mouth, or dry diapers.
Little or no tears.
Sleeping more than usual or difficult to wake up.

How is this diagnosed?

This condition is diagnosed based on:

Your child's symptoms.
A physical exam and medical history.

Your child may also have other tests, including:

Blood tests.
Ultrasound of the abdomen.
X-rays taken after a special dye is swallowed (upper GI series).

How is this treated?

Initial treatment for this condition involves rehydration. This would:

Require placement of an IV to administer the right balance of fluids and electrolytes.
Possibly include the placement of a tube that goes into the stomach.

After your infant is rehydrated, this condition is treated with surgery. You will not be expected to take your infant home until after surgery. Surgery will happen after diagnosis and once blood tests show that it is safe for your child to have surgery. In this procedure, the pyloric muscle is split to open the passage from the stomach to the small intestine (pyloromyotomy).

Summary

Pyloric stenosis is when the muscular opening between your child's stomach and the small intestine (pylorus) becomes unusually narrow.
If the muscles of the pylorus are thicker than normal (hypertrophy), this makes the opening narrow and prevents food from passing easily out of the stomach.
The main symptom of pyloric stenosis is projectile vomiting in the first weeks of life without any other signs of illness.
This condition is treated with rehydration and surgery (pyloromyotomy).

This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.