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Pyloric Stenosis

What is pyloric stenosis?

Pyloric stenosis is a problem that affects babies between 2 and 8 weeks of age and causes forceful vomiting that can lead to dehydration. It is the second most common problem requiring surgery in newborns.

The lower portion of the stomach that connects to the small intestine is known as the pylorus. In pyloric stenosis, the muscles in this part of the stomach enlarge, narrowing the opening of the pylorus and eventually preventing food from moving from the stomach to the intestine.

Illustration demonstrating pyloric stenosis
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What causes pyloric stenosis?

Pyloric stenosis (PS) is considered a "multifactorial trait." Multifactorial inheritance means that "many factors" (multifactorial) are involved in causing a birth defect. The factors are usually both genetic and environmental. Often one gender (either males or females) is affected more frequently than the other in multifactorial traits. There appears to be a different "threshold of expression," which means that one gender is more likely to show the problem, over the other gender. For example, pyloric stenosis is four times more common in males than females. Once a child has been born with pyloric stenosis, the chance for it to happen again depends upon the gender of the child already born with the condition, as well as the gender of the next child.

If a child with PS is female:

  • the likelihood of having a future son with PS is one in five.
  • the likelihood of having a future daughter with PS is one in 14.

If a child with PS is male:

  • the likelihood of having a future son with PS is one in 20.
  • the likelihood of having a future daughter with PS is one in 40.

Which babies are at higher risk for pyloric stenosis?

  • Two to three out of 1,000 infants are affected by pyloric stenosis (PS).
  • Babies 2 to 8 weeks old are at the highest risk.
  • Caucasians seem to develop pyloric stenosis more frequently than babies of other races.
  • Boys develop pyloric stenosis four to five times more often than girls.
  • Pyloric stenosis may be inherited; several members of a family may have had this problem in infancy.

Why is pyloric stenosis of concern?

Because the stomach opening becomes blocked and babies start vomiting, several problems can happen. The most serious problem is dehydration. When a baby vomits regularly, he/she will not get enough fluids to meet his/her nutritional needs. Babies have smaller bodies than adults and cannot tolerate losing fluid as easily as adults can. Minerals that the body needs to stay healthy, such as potassium and sodium, are also lost as the baby vomits. Babies who lack the right amount of water and minerals in their bodies can become very sick very quickly.

Another problem that occurs is weight loss. A baby who vomits most of (or all of) his/her feedings will not have adequate nutrition to gain weight and stay healthy.

What are the symptoms of pyloric stenosis?

The most common symptoms noted in a baby with pyloric stenosis is forceful, projectile vomiting. This kind of vomiting is different from a "wet burp" that a baby may have at the end of a feeding. Large amounts of breast milk or formula are vomited, and may go several feet across a room. The baby is usually quite hungry and eats or nurses eagerly. The milk is sometimes curdled in appearance, because as the milk remains in the stomach and does not move forward to the small intestine, the stomach acid "curdles" it.

Other symptoms may include:

  • weight loss
  • lack of energy
  • fewer bowel movements
  • constipation
  • frequent, mucous stools

The symptoms of pyloric stenosis may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.

How is pyloric stenosis diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for pyloric stenosis may include:

  • blood tests - to evaluate dehydration and mineral imbalances.
  • abdominal x-rays - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
  • abdominal ultrasound - a diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels.
  • barium swallow / upper GI series - a diagnostic test that examines the organs of the upper part of the digestive system: the esophagus, stomach, and duodenum (the first section of the small intestine). A fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an x-ray) is swallowed. X-rays are then taken to evaluate the digestive organs.

Treatment for pyloric stenosis:

Specific treatment for pyloric stenosis will be determined by your baby's physician based on:

  • your baby's gestational age, overall health, and medical history
  • the extent of the problem
  • your baby's tolerance for specific medications, procedures, or therapies
  • expectation for the course of the problem
  • your opinion and preference

Pyloric stenosis must be repaired with an operation. However, physicians may need to treat your baby's dehydration and mineral imbalances first. Water and minerals can be replaced through intravenous (IV) fluid.

Once your baby is no longer dehydrated, surgery can be performed. Under anesthesia, a small incision is made above the navel and the tight pyloric muscle is repaired.

What is the recovery time for pyloric stenosis surgery?

Babies can often begin drinking small amounts of clear liquids in the first 24 hours. Generally, clear liquids such as an electrolyte drink will be given to your baby first. However, babies may still vomit for several days after surgery due to swelling of the surgical site of the pyloric muscle. The swelling goes away within a few days.

Most babies will be taking their normal feedings by the time they go home. Babies are usually able to go home within two to three days after the operation.

What is the long-term prognosis for pyloric stenosis?

This problem is unlikely to reoccur. Babies who have undergone the surgery should have no long-term effects from it.

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