KidsMD Health Topics

Pyloric Stenosis

  • Overview

    Pyloric stenosis is a common problem that occurs in babies during early infancy. Babies with this condition have vomiting as their primary symptom.

    • The vomiting usually happens in infants when they are 2 to 3 weeks old, but can happen as late as 6 weeks old.
    • The vomiting is usually forceful and projectile—it can be so forceful that it can be ejected from one to four feet from your child.
    • The vomit consists of clear fluid or curdled milk.
    • The infants are healthy and vigorous, but develop episodes of spitting up and vomiting that progressively worsen.
    • The vomiting tends to occur within 30 to 60 minutes of feeding. Commonly, after your infant vomits, he is then very eager to eat again.

    pyloric stenosis, stomach, duodenum, pyloric stenosis diagram, slow weight gain infant baby

    How Children's approaches pyloric stenosis

    Boston Children's Hospital is a world leader in the field of pediatric gastroenterology and child nutrition. Our specialty programs provide innovative care not available at other hospitals for children with gastrointestinal problems and nutritional problems.

    We offer a full range of diagnostic and therapeutic procedures and have a new state-of-the-art endoscopy and motility unit. Our innovative Rapid Response Program is designed to aid pediatricians requesting urgent referrals for their patients.

    Boston Children's Hospital 
    300 Longwood Avenue
    Boston MA 02115


  • In-Depth

    How does a child get pyloric stenosis?

    • Pyloric stenosis occurs when the muscle surrounding the pyloric sphincter at the outlet to the stomach becomes thickened. This thickening can block the pyloric channel preventing the passage of feedings from the stomach into the small intestine. Vigorous contractions of the stomach wall attempt to force the feedings through the obstruction, but as it becomes tighter, these contractions result instead in the projectile vomiting.
    • Pyloric stenosis is more common in boys than girls, and it occurs in up to 1 percent of otherwise healthy infants.
  • Tests

    How do I know if my child has pyloric stenosis?

    • Many infants appear well with pyloric stenosis. The classic symptom is vomiting. However, with persistent vomiting the infants loose weight and may appear yellow or jaundiced and become dehydrated and lethargic.
    • Your infant's pediatrician and/or surgeon may be able to diagnose pyloric stenosis based on the history and physical exam. The abnormality in the pyloris may be felt by your pediatrician or surgeon.
    • Often, doctors conduct a radiology study, which is helpful in determining if your infant has pyloric stenosis. These radiology studies can include an ultrasound or an upper gastrointestinal series (UGI).
  • Pyloric stenosis is a serious condition that can cause severe dehydration, weakness and weight loss if not diagnosed and treated effectively. Once the diagnosis has been made, the recommended treatment for pyloric stenosis is surgery.

    At Boston Children's Hospital, skilled pediatric surgeons and other professionals will manage your infant's care. Prior to surgery, your baby will be nourished intravenously. He'll also have blood work done to make sure that the dehydration is corrected and that it is safe to proceed with anesthesia and surgery.

    What does surgery entail?

    A small tube may be placed through your baby's nose into the stomach to help prevent persistent vomiting. Your child may receive antibiotics during the hospital course to prevent the possibility of any infection. You will meet with a pediatric surgeon and anesthesiologist to discuss the surgery and anesthesia prior to the operation.

    What happens after the surgery?

    After surgery, your infant will be monitored closely. About six hours after the surgery, your child will be able to resume feedings.

    This may include taking small amount of formula from a bottle or breast-feeding with mom.

    Our nurses and surgeons will monitor the exact amounts of fluid that your baby has taken. It is common after the surgery that your infant may still have some intermittent episodes of vomiting, but this should stop within a few days.

    Your nurses will monitor your baby for normal urine and bowel movements. Once your infant is tolerating a normal diet and appears well, preparations for discharge will be made. Your infant should be weighed prior to leaving the hospital.

    What do I need to do or look for once I am at home?

    • Make a follow-up appointment with the pediatric surgeon for about two weeks after discharge, as well as with your pediatrician within one week.
    • Remember that a small amount of intermittent vomiting with feedings is expected after surgery. However, it should not occur with every feed, and it should get better each day. If your baby is still having persistent vomiting with every feed, call your pediatrician, pediatric surgeon or the pediatric nurse practitioner.
    • Keep the incision clean and dry, no tub bathing until you follow up with the pediatric surgeon or nurse practitioners.

    Symptoms that you should call your pediatrician or pediatric surgeon for include:

    • any questions or concerns
    • if your baby is lethargic or feeding poorly
    • persistent vomiting with every feed
    • fever greater than 100
    • infected wound with pus, odor or redness at the incision site
    • decreased numbers of wet diapers with urine
    • decreased numbers of diapers with stool
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