Pyloric Stenosis

What is pyloric stenosis?

Pyloric stenosis is a condition where there is narrowing of the pylorus. The pylorus is the area at the lower end of the stomach that connects to the small intestines. The pylorus acts as an outlet for food to pass out of the stomach. Pyloric stenosis occurs when the pylorus muscle of the stomach grows too large and too thick. Food is prevented by the narrowed pylorus from emptying into the intestine. This causes frequent vomiting that may lead to serious nutrition and growth problems in newborn babies. Surgery is often needed to correct pyloric stenosis.

What causes pyloric stenosis?

Caregivers do not exactly know what causes pyloric stenosis. It is thought that an absent or poor nerve supply to the pyloric muscles causes pyloric stenosis. Problems in the body's chemicals or enzymes may also cause pyloric stenosis. Having family members with pyloric stenosis may increase the chances of getting this disease.

What are the signs and symptoms of pyloric stenosis?

Symptoms are usually seen in babies from two weeks of age. Vomiting of newly fed milk is the most common symptom of pyloric stenosis. Vomiting then worsens over the next few days until nearly every feeding is forcefully vomited. The baby may seem to be more hungry right after every vomit. Frequent vomiting then leads to dehydration. This means that your baby has lost a lot of his body fluids and electrolytes (salts).

Signs and symptoms of dehydration include sunken eyes, dry mouth and tongue, and cracked lips. The fontanels (soft spots on top of your baby's head) may also be sunken. Skin may be sagging and doughy to touch. There may be a decreased amount of urine. The vomiting and dehydration may then lead to severe weight loss or failure to gain weight. An olive-sized lump may be also seen or felt in his abdomen (belly) if pyloric stenosis is present.

How is pyloric stenosis diagnosed?

Your baby's caregiver may feel your baby's abdomen and look for the lump. You may be asked about the times when your baby vomits and the appearance of the vomit. Your baby may have one or more of the following tests:

  • Blood tests: Your baby may need blood taken for tests. The blood may be taken from your baby's arm, hand, finger or heel. Caregivers will especially want to know about your baby's electrolytes. Electrolytes are blood salts. Some examples of electrolytes are sodium, potassium, and chloride. Electrolytes keep your baby's body working normally.

  • Ultrasound: This test uses sound waves to show pictures of the inside of your baby's abdomen. During the ultrasound, caregivers will look at your baby's stomach and small intestine on a TV-like screen. They will look for a pyloric muscle that is longer or thicker than it should be.

  • Upper GI x-rays: An x-ray machine is used to take pictures of your baby's upper gastrointestinal tract or upper GI tract. Your baby's upper GI tract includes the esophagus, stomach, and small intestines. Your baby may drink barium (chalky liquid) to help his organs show up better on the x-ray. Caregivers will look at the x-ray pictures on a TV-like screen to see how the barium fills his stomach. If he has pyloric stenosis, x-rays may show the stomach having problems passing barium to the small intestine.

How is pyloric stenosis treated?

Your baby may need any of the following:

  • Intravenous rehydration: When babies vomit often, they lose too much body fluid and electrolytes. Caregivers may insert an IV into your baby's vein (blood vessel). This is used to put fluids and salts back into your baby's body.

  • Surgery: Your baby may need surgery to treat pyloric stenosis. An incision (cut) through the thick pylorus may be made. This loosens up the muscles of the pylorus allowing food to easily pass through to your baby's intestines. Ask your caregiver for more information about this surgery called pyloromyotomy.

Where do I find more information?

Accepting that your baby has pyloric stenosis may be hard. You and those close to you may feel sad and frightened. These feelings are normal. Talk to your caregivers, family, or friends about your feelings. Contact the following for more information:

  • American Academy of Pediatrics
    141 Northwest Point Boulevard
    Elk Grove Village , IL 60007-1098
    Phone: 1- 847 - 434-4000
    Web Address:

Care Agreement

You have the right to help plan your baby's care. Learn about your baby's health condition and how it may be treated. Discuss treatment options with your baby's caregivers to decide what care you want for your baby. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

© 2013 Truven Health Analytics Inc. Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotes® are the copyrighted property of A.D.A.M., Inc. or Truven Health Analytics.

Learn more about Pyloric Stenosis