Pyloric stenosis is a narrowing of the pylorus, the opening of the stomach into the small intestine.

Pyloric stenosis is caused by a thickening of the muscles of the pylorus. This thickening prevents the stomach from emptying into the small intestine.

The cause of the thickening is unknown, although genetic factors may play a role. Pyloric stenosis occurs more commonly in boys than in girls, and is rare in patients older than 6 months. The condition is usually diagnosed by the time a child is 6 months old.

Symptoms generally appear several weeks after birth:

• Vomiting
  • Usually mild at first
  • Becomes more forceful within 30 minutes of feeding
  • Projectile vomiting
• Infant appears constantly hungry
• Diarrhea (loose green stools)
• Wave-like motion of the abdomen shortly after feeding and just before vomiting occurs
• Dehydration (becoming more profound with the severity of the vomiting)
• Failure to gain weight or weight loss
• Abdominal fullness prematurely after meals
• Belching
• Abdominal pain

Physical examination may show signs of dehydration. The infant may have a distended abdomen. Palpation of the abdomen may reveal the abnormal pylorus, which feels like an olive-shaped mass.

• Chemistry panel often reveals electrolyte imbalances.
• Ultrasound of abdomen may be the first imaging test performed.
• Barium x-ray reveals a distended stomach and narrowed pylorus.

Treatment for pyloric stenosis involves surgery (Ramstedt pyloromyotomy) to split the overdeveloped muscles of the pylorus.

Balloon dilation is less effective, but may be considered for infants when the risk of general anesthesia is high.

The patient will be given intravenous fluids, usually prior to surgery.

Surgical repair usually provides complete relief of symptoms.

Small, frequent feedings are usually well tolerated several hours after the surgery.

• Postoperative vomiting (This is very common and generally improves with time.)
• Failure to gain weight in the newborn period
• Risks associated with any surgery

Call your health care provider if symptoms suggestive of pyloric stenosis develop in your infant.