Pyloric stenosis: Difference between revisions

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==Background==
==Background==
*Hypertrophy of the pyloric muscle causing gastric outlet obstruction
*Most common surgical cause of vomiting in infants<ref name="sreedharan">Sreedharan R, Liacouras CA. Major symptoms and signs of digestive tract disorders. In: Kliegman RM, ed. ''Nelson Textbook of Pediatrics''. 21st ed. Elsevier; 2020.</ref>
*Typical presentation: 2-6 week old infant (range 1-5 months)
*Incidence: ~2-4 per 1,000 live births
*Male:female ratio = 4:1
*Risk factors: firstborn, male sex, family history, macrolide antibiotics (erythromycin) in first 2 weeks of life


==Clinical Features==
*'''Non-bilious, projectile vomiting''' — immediately after feeds
**Progressively worsening over days to weeks
**Infant is hungry after vomiting ("hungry vomiter")
*Olive-shaped mass in right upper quadrant/epigastrium (palpable in ~70% with experienced examiner)
*Visible gastric peristaltic waves (left to right across upper abdomen)
*Signs of dehydration: poor skin turgor, depressed fontanelle, decreased urine output, lethargy
*Weight loss or poor weight gain
*Jaundice (in ~2% due to decreased hepatic glucuronyl transferase activity)


* more common in males & 1st born children. d/t pyloric hypertrophy in 1st mos of life (usu 3-6 wks, w/ a range of 1-10 wks)
==Differential Diagnosis==
* rare in 1st days of life
*[[Gastroesophageal reflux]] (GER)
*[[Malrotation]] with [[Midgut volvulus|volvulus]] ('''bilious''' vomiting = surgical emergency)
*Formula intolerance / milk protein allergy
*[[Intussusception]] (typically older age 6-36 months)
*Adrenal crisis ([[Congenital adrenal hyperplasia|CAH]]) — can mimic metabolic findings
*Gastroenteritis
*Increased intracranial pressure
*Inborn errors of metabolism


==Diagnosis==
==Evaluation==
*Abdominal ultrasound — diagnostic study of choice
**Pyloric muscle thickness >=3 mm
**Pyloric channel length >=15 mm
**Sensitivity and specificity >95%
*Labs (critical to check before surgery):
**BMP: hypochloremic, hypokalemic metabolic alkalosis (classic finding)
**Loss of HCl from vomiting → paradoxical aciduria
**May also have hyponatremia and hypoglycemia
*Upper GI series (if US inconclusive): "string sign," "shoulder sign," "beak sign"


==Management==
*'''This is NOT a surgical emergency''' — correct electrolytes and dehydration FIRST
*IV fluid resuscitation
**Initial: NS 20 mL/kg bolus, repeat as needed
**Maintenance: D5 0.45% NS + 20 mEq/L KCl (after urine output established)
**Goal: correct chloride, potassium, and alkalosis before surgery
*NPO, NGT for decompression if significant distension
*Surgical consultation for pyloromyotomy (Ramstedt procedure) — definitive treatment
**Laparoscopic approach is standard; very high success rate
*Surgery should be delayed until electrolytes are corrected (target: Cl >100, HCO3 <30, K >3.5)


* S/S: vomiting (often projectile), ask if blurp up milk or clears the clothes. infant hungry but vomits soon after eating w/ NEVER any bile, maybe some blood. constipation, olive in RUQ to mid quadrant, occ see peristaltic waves
==Disposition==
* Labs might show a low K, Low Cl, & hypo-Cl alkolosis
*Admit for IV fluid resuscitation and surgical repair
* AXR w/ lg stomach bubble may suggest gastric obstruction but usu nl
*Pediatric surgery consultation
* U/S used to look at dm of pylorus, UGI shows "string sign" from narrow pylorus


==Treatment==
==See Also==
*[[Vomiting (peds)]]
*[[Malrotation]]
*[[Intussusception]]
*[[Pediatric abdominal pain]]


==References==
<references/>


* NGT, IVF (do NOT give LR b/c more alkalotic & infant already vomiting up all its HCl, alkalosis can= apnea in infants!), after initial NS can give D5NS w/ KCl, surgery needed (pyloromyotomy) but can be delayed 24-36 hr to reydrate infant
[[Category:Pediatrics]]
 
[[Category:Gastroenterology]]
 
 
[[Category:Peds]]

Latest revision as of 10:25, 22 March 2026

Background

  • Hypertrophy of the pyloric muscle causing gastric outlet obstruction
  • Most common surgical cause of vomiting in infants[1]
  • Typical presentation: 2-6 week old infant (range 1-5 months)
  • Incidence: ~2-4 per 1,000 live births
  • Male:female ratio = 4:1
  • Risk factors: firstborn, male sex, family history, macrolide antibiotics (erythromycin) in first 2 weeks of life

Clinical Features

  • Non-bilious, projectile vomiting — immediately after feeds
    • Progressively worsening over days to weeks
    • Infant is hungry after vomiting ("hungry vomiter")
  • Olive-shaped mass in right upper quadrant/epigastrium (palpable in ~70% with experienced examiner)
  • Visible gastric peristaltic waves (left to right across upper abdomen)
  • Signs of dehydration: poor skin turgor, depressed fontanelle, decreased urine output, lethargy
  • Weight loss or poor weight gain
  • Jaundice (in ~2% due to decreased hepatic glucuronyl transferase activity)

Differential Diagnosis

  • Gastroesophageal reflux (GER)
  • Malrotation with volvulus (bilious vomiting = surgical emergency)
  • Formula intolerance / milk protein allergy
  • Intussusception (typically older age 6-36 months)
  • Adrenal crisis (CAH) — can mimic metabolic findings
  • Gastroenteritis
  • Increased intracranial pressure
  • Inborn errors of metabolism

Evaluation

  • Abdominal ultrasound — diagnostic study of choice
    • Pyloric muscle thickness >=3 mm
    • Pyloric channel length >=15 mm
    • Sensitivity and specificity >95%
  • Labs (critical to check before surgery):
    • BMP: hypochloremic, hypokalemic metabolic alkalosis (classic finding)
    • Loss of HCl from vomiting → paradoxical aciduria
    • May also have hyponatremia and hypoglycemia
  • Upper GI series (if US inconclusive): "string sign," "shoulder sign," "beak sign"

Management

  • This is NOT a surgical emergency — correct electrolytes and dehydration FIRST
  • IV fluid resuscitation
    • Initial: NS 20 mL/kg bolus, repeat as needed
    • Maintenance: D5 0.45% NS + 20 mEq/L KCl (after urine output established)
    • Goal: correct chloride, potassium, and alkalosis before surgery
  • NPO, NGT for decompression if significant distension
  • Surgical consultation for pyloromyotomy (Ramstedt procedure) — definitive treatment
    • Laparoscopic approach is standard; very high success rate
  • Surgery should be delayed until electrolytes are corrected (target: Cl >100, HCO3 <30, K >3.5)

Disposition

  • Admit for IV fluid resuscitation and surgical repair
  • Pediatric surgery consultation

See Also

References

  1. ↑ Sreedharan R, Liacouras CA. Major symptoms and signs of digestive tract disorders. In: Kliegman RM, ed. Nelson Textbook of Pediatrics. 21st ed. Elsevier; 2020.
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