Health Encyclopedia

Pyloric stenosis

Definition

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

Alternative Names

Congenital hypertrophic pyloric stenosis; Hypertrophic pyloric stenosis; Gastric outlet obstruction

Causes, incidence, and risk factors

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

Symptoms generally appear several weeks after birth:

Abdominal fullness prematurely after meals
Abdominal pain
Belching
Constant hunger
Dehydration (gets worse with the severity of the vomiting and diarrhea)
Diarrhea (loose, watery stools)
Failure to gain weight or weight loss
Wave-like motion of the abdomen shortly after feeding and just before vomiting occurs
Vomiting
- Persistant vomiting after every feeding
- Projectile vomiting

Signs and tests

The condition is usually diagnosed before the baby is 6 months old.

A physical exam may reveal signs of dehydration. The infant may have a swollen belly area. The doctor may detect the abnormal pylorus, which feels like an olive-shaped mass, when touching the stomach area.

An ultrasound of the abdomen may be the first imaging test performed. Other tests that may be done include:

Blood chemistry panel -- often reveals an electrolyte imbalance
Barium x-ray -- reveals a swollen stomach and narrowed pylorus

Treatment

Treatment for pyloric stenosis involves surgery (called a pyloromyotomy) to split the overdeveloped muscles.

Balloon dilation does not work as well as surgery, but may be considered for infants when the risk of general anesthesia is high.

The patient will be given fluids through a vein, usually before surgery.

Expectations (prognosis)

Surgery usually provides complete relief of symptoms. The infant can usually tolerate small, frequent feedings several hours after surgery.

Complications

Vomiting after surgery -- this is very common and generally improves with time
Failure to gain weight in the newborn period
Risks associated with any surgery, which include:
- Bleeding
- Infection

Calling your health care provider

Call your health care provider if your baby has symptoms of this condition.

Review Date:9/28/2007
Reviewed By:Deirdre O’Reilly, MD, MPH, Neonatologist, Division of Newborn Medicine, Children’s Hospital Boston and Instructor in Pediatrics, Harvard Medical School, Boston, Massachusetts. Review Provided by VeriMed Healthcare Network.

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