Minimally Invasive Surgery

Pyloric Stenosis

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

Pyloric stenosis, also called infantile hypertrophic pyloric stenosis, is caused by an enlarged pylorus, a muscle that opens and closes to allow food to pass through the stomach into the intestine. When this muscle becomes enlarged, digested food is blocked from emptying out of the stomach. The retained food causes the infant to vomit. There is no known reason for this condition.

Pyloric stenosis is one of the most common conditions requiring surgery in infants. It is more common in boys than girls and usually affects children who are born at full term. It rarely occurs in premature infants. Although not thought to be hereditary, pyloric stenosis occurs more commonly in children of parents who had pyloric stenosis themselves as infants.

The main symptom is vomiting undigested breast milk or formula soon after a feeding. Vomiting usually begins at four weeks of age but can happen as early as two weeks after birth. Once vomiting begins, it becomes more frequent and severe, and is often described as "forceful" or "projectile." Infants with pyloric stenosis may become fussy. Since they can't keep down food, they are hungry between feedings and don't gain weight normally. If vomiting continues, infants may become ill from dehydration.

Reviewed by health care specialists at UCSF Children's Hospital.
Last updated January 15, 2008