| Subject | Contents |
| Definition | Pyloric stenosis is a narrowing of the outlet from the stomach to the small intestine (called the pylorus) that occurs in infants. |
| Alternative Names | Congenital hypertrophic pyloric stenosis; Hypertrophic pyloric stenosis; Gastric outlet obstruction |
| Causes, incidence, and risk factors | In infants, this condition is caused by a thickening of the muscles of the pylorus, which stops the stomach from emptying into the small intestine. The cause of the thickening is unknown, although genetic factors may play a role. It occurs more commonly in males than in females. Approximately 1 out of 4,000 infants is affected. Symptoms appear several weeks after birth. |
| Symptoms | Vomiting (usually mild at first becoming progressively more forceful within one half hour of feeding) projectile vomiting Infant appears constantly hungry Diarrhea (loose green stools) Wave-like motion of the abdomen shortly after feeding and just before vomiting occurs Dehydration (becoming more profound with the severity of the vomiting) Failure to gain weight or weight loss Additional symptoms that may be associated with this disease:Abdominal fullness prematurely after mealsBelching Apparent abdominal pain |
| Signs and tests | Physical examination may show signs of dehydration . The infant may have a distended abdomen . Palpation of the abdomen reveals an olive-shaped mass (the pylorus). A chemistry panel often reveals electrolyte imbalances . A barium X-ray reveals a distended stomach and narrowed pylorus. An ultrasound of abdomen may also be performed. |
| Treatment | A surgical procedure to split the over-developed muscles of the pylorus is the treatment for this disorder. Rehydration with intravenous fluids usually takes place prior to surgery. Small, frequent feedings are usually well tolerated several hours after the surgery. |
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| Expectations (prognosis) | The complete relief of symptoms occurs after adequate surgical repair. |
| Complications | Failure to gain weight in the newborn period Risks associated with surgery |
| Calling your health care provider | Call your health care provider if symptoms of pyloric stenosis develop in your infant. |
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