Pediatric Pyloric Stenosis Clinical Presentation

Updated: Nov 13, 2018
  • Author: Sathyaseelan Subramaniam, MD, FAAP; Chief Editor: Kirsten A Bechtel, MD  more...
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  • Classically, the infant with pyloric stenosis has nonbilious vomiting or regurgitation, which may become projectile (in as many as 70% of cases), after which the infant is still hungry. [12]
  • Emesis may be intermittent initially, or occur after each feeding.
  • Emesis should not be bilious as the obstruction is proximal to the common bile duct. The emesis may become brown or coffee color due to blood secondary to gastritis or a Mallory-Weiss tear at the gastroesophageal junction.
  • As the obstruction becomes more severe, the infant begins to show signs of dehydration and malnutrition, such as poor weight gain, weight loss, marasmus, decreased urinary output, lethargy, and shock.
  • The infant may develop jaundice, which is corrected upon correction of the disease.


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  • In as many as 60-80% of the infants with infantile hypertrophic pyloric stenosis (IHPS), a firm, nontender, and mobile hard pylorus that is 1-2 cm in diameter, described as an "olive," may be present in the right upper quadrant at the lateral edge of the rectus abdominis muscle. This is best palpated after the infant has vomited and when calm, or when the gastric contents have been removed via nasogastric tube. The palpation of an olive mass has a 99% positive predictive value for IHPS diagnosis. [13]
  • Clinicians may also observe gastric peristalsis just prior to emesis as the peristaltic waves try to overcome the obstruction.
  • Signs of dehydration include depressed fontanelles, dry mucous membranes, decreased tearing, poor skin turgor, and lethargy.
  • Due to the widespread early use of ultrasonography to aid in diagnosis, the classic signs of infantile hypertrophic pyloric stenosis are becoming less common. The mean age of presentation is getting significantly younger, and infants are not developing the physical signs or electrolyte abnormalities they were in the past.


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  • The etiology of infantile hypertrophic pyloric stenosis is unknown and is probably multifactorial (genetic and environmental factors).