Pyloric Stenosis

What is pyloric stenosis?

Pyloric stenosis is a condition in which a baby's pylorus gradually swells and thickens, which interferes with food entering the intestine. The pylorus is the connection between the stomach and the first part of the small intestine (duodenum).

Pyloric stenosis can occur any time between birth and 5 months of age. But it most commonly develops about 3 weeks after birth. If your baby was premature, symptoms may be delayed.

See a picture of pyloric stenosis.

What causes pyloric stenosis?

The exact cause of pyloric stenosis is not known. The condition likely develops for more than one reason. In some cases, pyloric stenosis may be passed down through families (inherited), or a baby may have the problem as part of another genetic condition. Antibiotics, such as erythromycin, given to a baby within the first 2 weeks of life may slightly increase his or her chances for developing pyloric stenosis. But it is very unlikely that taking antibiotics would by itself cause pyloric stenosis.

In the past, pyloric stenosis was considered a birth defect. Now there is some evidence that it develops after birth.

What are the symptoms?

Vomiting all or most of feedings is the main symptom of pyloric stenosis. Vomiting usually starts gradually, but as the pylorus becomes tighter over time, your baby's vomiting becomes more forceful (projectile vomiting). If your baby's vomit is yellow or green, it may suggest a more serious problem than pyloric stenosis.

A baby with pyloric stenosis acts irritable and hungry, even immediately after being fed. You also may notice that your baby has fewer wet diapers and fewer, harder stools. If the vomiting continues, your baby can become dehydrated.

How is pyloric stenosis diagnosed?

Your baby's doctor can diagnose pyloric stenosis by a physical examination and by reviewing your baby's symptoms. An upper gastrointestinal (UGI) series or an abdominal ultrasound can be used to diagnose the condition. Blood tests also may be done to see whether your baby is dehydrated.

How is it treated?

Pyloric stenosis is corrected by surgery. Almost all babies recover completely.

Frequently Asked Questions

Vomiting all or most of feedings on a repeated basis is the main symptom of pyloric stenosis. Vomiting usually begins between a few days after birth and 5 months of age. But if your baby was premature, the start of symptoms may be delayed.

Vomiting caused by pyloric stenosis usually starts gradually and gets worse over time. As the pylorus, the connection between your baby's stomach and intestine, becomes tighter, the vomiting becomes more frequent and more forceful (projectile vomiting). Your baby likely has a problem different from pyloric stenosis if his or her vomit is yellow or green.

A baby with pyloric stenosis:

• Vomits formula or breast milk shortly after a feeding.
• Has a full (distended) upper abdomen after a feeding.
• Acts irritable and hungry.
• Has fewer and harder stools (constipation) than normal.
• Passes smaller amounts of urine than normal.

As the vomiting continues, your baby will:

• Lose weight.
• Develop symptoms of not getting enough fluids (dehydration).
• Be sleepier than normal and very fussy when awake.

When to call a doctor

Call your doctor if your baby:

• Has vomited most or all of his or her feeding for two feedings in a row.
• Is vomiting yellow or green liquid (bile). This could indicate a problem more serious than pyloric stenosis.
• Has symptoms of dehydration.
• Is 5 months of age or younger and has symptoms of pyloric stenosis, such as repeated forceful vomiting shortly after feedings, irritability, hunger, and less urine.

Pyloric stenosis is diagnosed by a physical exam and your baby's medical history and symptoms. An upper gastrointestinal (UGI) series or an abdominal ultrasound can be used to diagnose pyloric stenosis.

During the physical examination, the doctor will check your baby's abdomen for:

• A wavelike motion shortly after feeding and before vomiting.
• An olive-sized lump between the stomach and the intestine. Your doctor feels for this lump in the upper part of your baby's belly.

The doctor will also examine your baby for signs of dehydration. Blood tests may be done to check for dehydration.

Pyloric stenosis is always treated with surgery (pyloromyotomy). After your baby has the surgery, pyloric stenosis usually will not develop again.

Types of surgery

Two methods of surgery are used to correct pyloric stenosis—open surgery and laparoscopic surgery. Your doctor will choose which one is best for your baby.

• During open surgery, a small incision is made in the baby's abdominal wall. The ring of muscle (pyloric sphincter) is then cut to widen the channel between the stomach and the intestine.
• During laparoscopic surgery, an instrument called a laparoscope is inserted through a small incision made in the baby's belly button. The laparoscope provides access to the pyloric muscle so the muscle can be cut. Several other small incisions are usually necessary.

Before surgery

Your baby may not go to surgery immediately after being diagnosed with pyloric stenosis. If your baby is dehydrated, he or she may need to receive fluids through a vein (intravenous, or IV) for 24 to 48 hours. Another tube may be put through your baby's nose to drain fluids from the stomach (nasogastric tube).

After surgery

After surgery, your baby may be fed special fluids for one or two feedings and then formula or breast milk within 24 hours. Your baby likely will go home within 2 days after surgery.

It is normal for a baby to vomit a small amount during the first day or two after surgery. But if your baby continues to vomit after you return home, call your doctor. In some cases, persistent vomiting indicates an incomplete cutting of the pyloric muscle.

Complications from surgery (which may include infection at the incision site) are rare. A red or raised incision, with or without drainage, may indicate an infection.

It is normal for babies to spit up small amounts from their feedings. But vomiting most or all of feedings is not normal. If your baby 5 months of age or younger has repetitive forceful vomiting shortly after feedings, is irritable and acts hungry, and has fewer wet diapers than usual, he or she may need to be evaluated for pyloric stenosis. Talk to a doctor about your baby's symptoms.

After surgery for pyloric stenosis

While your baby is in the hospital for pyloric stenosis, be actively involved in his or her care so that you will feel more comfortable doing it on your own after you take your baby home. Don't be afraid of holding or handling your baby. After one or two feedings of a clear liquid (glucose water), you may be allowed to give your baby breast milk or formula.

When your baby comes home from the hospital, give small, frequent feedings, according to your doctor's instructions. Your baby may vomit occasionally for the first few days after surgery. If vomiting is frequent or persistent (lasts beyond 2 to 3 days after surgery), call your doctor.

Complications from surgery to correct pyloric stenosis are rare. But call your doctor if you are concerned about the wound healing properly. A red or raised incision, with or without drainage, may indicate an infection.

Online Resource

Organization

• Dehydration
• Vomiting, Age 3 and Younger

Other Works Consulted

• Middlesworth W, Kadenhe-Chiweshe A (2006). Neonatal intestinal obstruction. In FD Burg et al., eds., Current Pediatric Therapy, 18th ed., pp. 289–293. Philadelphia: Saunders Elsevier.

• Russo MA, Redel CA (2006). Anatomy, histology, embryology, and developmental anomalies of the stomach and duodenum. In M Feldman et al., eds., Sleisenger and Fordtran's Gastrointestinal and Liver Disease, 8th ed., vol. 1, pp. 981–998. Philadelphia: Saunders Elsevier.

• Safford SD, et al. (2005). A study of 11,003 patients with hypertrophic pyloric stenosis and the association between surgeon and hospital volume and outcomes. Journal of Pediatric Surgery, 40(6): 967–973.

• Wegner KJ (2006). Pyloric stenosis. In MR Dambro, ed., Griffith's 5-Minute Clinical Consult, pp. 940–941. Philadelphia: Lippincott Williams and Wilkins.