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  • • 0.1-0.4% incidence

    • 7% incidence among children of affected parent

    • 4:1 ratio male:female

    • Higher incidence in first born

Symptoms and Signs

  • • Nonbilious postprandial emesis 2-12 weeks of life becoming progressively projectile

    • Palpable pylorus in right upper quadrant or epigastric region ("olive")

    • Visible or palpable gastric peristaltic waves

Laboratory Findings

  • • Transient unconjugated hyperbilirubinemia in 1-2% of cases

    • Hypokalemic, hypochloremic, metabolic alkalosis

Imaging Findings

  • US: Shows hypertrophic pylorus, 95% sensitive

    Upper GI: Shows narrowed and elongated pylorus, 95% sensitive

  • • Repeated nonbilious vomiting in early infancy may be due to the following:

    • -Overfeeding

      -Intracranial lesions


      -Antral web

      -Gastroesophageal reflux

      -Pyloric duplication

      -Duodenal stenosis

      -Malrotation of the bowel

      -Adrenal insufficiency

  • • History and physical exam

    • Serum electrolytes

    • Abdominal x-ray

    • US of abdomen if diagnosis in doubt

    • Upper GI if diagnosis still in doubt


  • • Laparoscopic or open pyloromyotomy


  • • Normalization of serum electrolytes

    • Persistent vomiting


  • • Volume resuscitation and correction of chloride to at least 90 mEq/L and CO2 to less than 30 mEq/L

Treatment Monitoring

  • • Serum electrolytes before surgery


  • • Duodenal or gastric injury

    • Incomplete myotomy (recurrent gastric outlet obstruction)


  • • Excellent


Aspelund G. Langer JC. Current management of hypertrophic pyloric stenosis. Seminars in Pediatric Surgery 2007. 16(1):27-33.  [PubMed: 17210480]

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