Pyloric Stenosis, Infant

Pyloric stenosis refers to a condition in which the opening between the stomach and the small intestine (pylorus) is 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 soon 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.
Excess burping.
Rippling of belly muscles.
An olive-sized lump that can be felt in the middle of the belly.
Dry skin, dry mouth, or dry diapers. These are signs that your child is dehydrated.
Lack of weight gain.

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?

This condition is treated with surgery. In this procedure, the pyloric muscle is split to open the passage from the stomach to the small intestine (pyloromyotomy). Surgery will likely happen soon after pyloric stenosis has been diagnosed and blood tests show that it is safe for your child to have surgery.

Follow these instructions at home:

Feed your child according to the schedule given to you by your child's health care provider. Your child's health care provider may recommend feeding your child formula or breast milk, as well as a fluid that contains salts and minerals (electrolytes).
Give over-the-counter and prescription medicines only as told by your child's health care provider.
Do not give your child aspirin because of the association with Reye syndrome.
Keep track of how much stool and urine your child passes. This may involve weighing your child's diapers and recording the weight. If you notice any significant changes to the output, contact your health care provider.
Keep all follow-up visits as told by your child's health care provider. This is important.

Contact a health care provider if:

Your child loses weight or does not gain weight while waiting for surgery.

Get help right away if your child:

Shows signs of dehydration, such as:
- Little or no urine.
- Dry mouth or lips.
- Little or no tears.
- Irritability.
- Fatigue.
Has blood in his or her vomit.
Is younger than 3 months and has a temperature of 100°F (38°C) or higher.
Has skin or the whites of the eyes that turn yellow (jaundice).

Summary

Pyloric stenosis is when the opening between your child's stomach and the small intestine (pylorus) is 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 surgery (pyloromyotomy).