What is pyloric stenosis?

Pyloric stenosis is an abnormal thickening and/or narrowing of the pylorus muscle. Normally, food and other stomach contents pass into the small intestine through the pylorus, which is the exit of the stomach. The thickened pyloric muscle causes a narrowing of the pyloric channel. As a result, liquid and/or food cannot pass out of the stomach into the small intestine.

What are the symptoms of pyloric stenosis?

Because infants with pyloric stenosis are unable to tolerate their feedings, they may have the following symptoms:

  • Frequent episodes of projectile vomiting (forceful vomiting) within 30 to 60 minutes after feedings (could be after every feeding, or occasionally)
  • Small stools
  • Dehydration
  • Weight loss
  • Irritability
  • Hunger after feedings
  • Abdominal pain
  • Wave-like motion of the abdomen shortly after feeding and just before vomiting occurs

How common is pyloric stenosis?

Pyloric stenosis affects 3 out of every 1,000 babies born. It is more likely to affect full-term, first-born male infants, and less likely to affect female infants. Pyloric stenosis is more common in Caucasian infants, especially those of European descent.

About 15% of infants born with pyloric stenosis have a family history of the condition. An infant is three times more likely to develop pyloric stenosis if the mother had the disease as an infant, as compared to the father

When does pyloric stenosis occur?

The symptoms of pyloric stenosis usually occur starting around the third week of life, but it could be up to age five months.

How is pyloric stenosis diagnosed?

Your health care provider will ask you several questions about your child's feeding habits and will then examine your child. During the physical exam, the health care provider may be able to feel an olive-sized lump (the thickened pyloric muscle) in your child's abdomen. If the thickened pylorus is felt, no further studies are needed.

If the thickened pylorus cannot be felt, an abdominal ultrasound may be done. During this examination, a probe is gently applied against the abdomen. The probe transmits sound waves through the body tissues, receives the echoes, and transforms them into diagnostic images. Often, the enlarged pyloric muscle can be seen on the ultrasound images.

In some cases, an upper gastrointestinal series must be done if the physical exam and abdominal ultrasound do not reveal any abnormalities. This test requires that your child drink a special liquid. This liquid can be seen on an X-ray as it travels through the stomach and small intestine. The pediatric radiologist will be viewing the X-ray while your child drinks the liquid to determine whether or not the liquid is able to move out of the stomach through the pylorus.

How is pyloric stenosis treated?

If pyloric stenosis is seen and diagnosed from the physical exam, ultrasound or gastrointestinal studies, surgery must be done to correct the condition. Because infants with HPS are often dehydrated from extended vomiting, proper replacement of fluids is necessary before surgery can be performed. Blood tests can help detect dehydration. Sometimes, delivering fluids intravenously (through a vein in the arm) is necessary.

Before the surgery

Your child will not be allowed to have any milk or formula for 6 hours before surgery to reduce the risk of vomiting and aspiration while under anesthesia.

During the surgery

The following events will take place in the event of a surgery:

  • A pediatric anesthesiologist (a physician who specializes in sedation and pain relief in children) gives your child general anesthesia, which induces sleep.
  • A small incision is made on the left side of the abdomen, higher than the umbilicus (belly button).
  • The surgeon then performs a "pyloromyotomy," which involves making an incision in the thickened pylorus to allow food to move out of the stomach into the intestines properly. This procedure generally takes less than an hour to complete.

After the surgery

The usual length of stay after surgery is 24 to 36 hours. Several hours after surgery, your child will be able to eat again. Oral (by mouth) feedings are started very slowly, in very small amounts. The volume and concentration of the formula will be increased as your child is able to tolerate the feeding. If you breastfeed your child, breast milk must be given to your child through a bottle for the first few feedings so that it can be accurately measured.

Sometimes, babies will still vomit after surgery, but this does not mean that they have pyloric stenosis again. Your child might vomit after surgery because of the anesthesia. Your child also might vomit if feedings advance too quickly or if your child is not adequately burped after feedings. If your child continues to vomit for a prolonged periods, he or she may need more tests. Problems with vomiting should be corrected before your child is discharged from the hospital.

How do I care for my child after surgery?

Your child will be eating normally by the time you go home. Usually, non-narcotic pain medication (such as Tylenol) is all that is needed to control minimal post-operative pain. You may give your child a sponge bath the day after surgery. You may bathe your child in the tub 3 days after surgery.

The small piece of tape covering the incision (called a Steri-Strip™) will gradually fall off on its own. Do not pull this tape off yourself. If the Steri-Strip has not fallen off by the time of your follow-up appointment, your healthcare provider will remove it for you.

When to call your child's healthcare provider

You may notice some minor swelling around the incision. This is normal. However, call your healthcare provider if your child has a fever, excessive swelling, redness or drainage from incision, distended or enlarged stomach, bleeding, or increasing pain.

Follow-up appointment

A follow-up outpatient visit will be scheduled 7 to 10 days after your child�s surgery. Your child's health care provider will examine the wound site and evaluate your child's recovery.


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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 12/22/2016...#4524