Stomach

Pyloric Stenosis

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Pyloric Stenosis, Hypertrophic Pyloric Stenosis, Pyloric Stenosis Ultrasound

  • Epidemiology
  1. Ages 4-12 weeks old (mean 3 weeks)
  • Pathophysiology
  1. Hypertrophy of pylorus of Stomach causing a gastric outlet obstruction
  • Risk factors
  1. Bottle Feeding
  2. Family History of Pyloric Stenosis (especially northern european)
  3. Male gender (4 times more common than in girls)
  1. Non-Bilious Vomiting
  2. Starts intermittently
  3. Progressively increases in frequency and severity
  4. Projectile Vomiting in up to 70% of cases
  • Signs
  1. Typically, otherwise well appearing infant with benign Abdomen
  2. Palpable swelling ("olive") present in >60% of cases in past when delayed presentation was common
    1. In 2016 olive is rare due to early presentations
    2. Inferior to xiphoid process and inferior or deep to left liver edge
  • Labs
  1. Basic metabolic panel
    1. Hypochloremic hypokalemic Metabolic Alkalosis
      1. Rarely seen due to early presentations in U.S.
  1. Technique
    1. Linear probe in subxiphoid location, horizontal probe
    2. Look for gastric rugae, smooth outer serosal surface, slightly thicker wall
    3. Trace the outer surface of the Stomach down to the pylorus and duodenum
      1. Duodenal wall is much thinner than pylorus
  2. Diagnosis
    1. Thickened and elongated pylorus
      1. Pylorus wall thickness >3 mm
      2. Pylorus length >15 mm (variable)
    2. No relaxation
    3. No fluid passage within channel
      1. May see very minimal flow (string sign)
  • Complications
  1. Pediatric Dehydration
  2. Hypochloremic hypokalemic Metabolic Alkalosis
    1. Rarely seen due to early presentations in U.S.
  • Management
  1. Correct fluid and electrolyte abnormalities
  2. Surgery (pyloromyotomy)
  • Resources
  1. Pyloric Stenosis Ultrasound
    1. https://vimeo.com/156797541
  • References
  1. Bukata (2013) Pediatric Emergencies, EM Bootcamp, CEME
  2. Nazer (2013) Pediatric Hypertrophic Pyloric Stenosis, EMedicine
    1. http://emedicine.medscape.com/article/929829-overview#showall