Pyloric Stenosis

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.

Diagnosis

An examination of the abdomen may allow the doctor to feel the enlarged pyloric muscle, called an "olive." If the pylorus cannot be felt, pyloric stenosis can be diagnosed by an ultrasound study or by X-rays taken after the infant drinks a liquid called "contrast." This is a study that examines the stomach and small intestine and is called an "upper GI", which stands for upper gastrointestinal study.

Treatment

Pyloric stenosis does not improve by itself and must be corrected with an operation. The operation is called a "pyloromyotomy." Prior to the operation, your child will be admitted to the hospital for intravenous fluids. Feedings will be held temporarily and restarted after surgery. A blood sample will be taken to check for dehydration and electrolyte abnormalities. Electrolytes are a measure of the amount of sodium, potassium, carbon dioxide and chloride in the blood. Frequent vomiting can make the electrolytes abnormal. The surgeon will schedule the operation as soon as the infant's electrolyte levels are normal and dehydration is corrected. This may take a day of treatment with intravenous fluids.

A pyloromyotomy, which used to be done through a horizontal incision that left a scar across the abdomen, now is performed using a small telescope, two miniature instruments and several pencil-tip size incisions. The operation usually takes about an hour.

Most infants are discharged from the hospital one to two days after the operation.