Pyloric stenosis: Difference between revisions
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*Hypertrophy of the pyloric muscle causing gastric outlet obstruction | *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> | *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: | *Typical presentation: 2-6 week old infant (range 1-5 months) | ||
*Incidence: ~2-4 per 1,000 live births | *Incidence: ~2-4 per 1,000 live births | ||
*Male:female ratio = 4:1 | *Male:female ratio = 4:1 | ||
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*'''Non-bilious, projectile vomiting''' — immediately after feeds | *'''Non-bilious, projectile vomiting''' — immediately after feeds | ||
**Progressively worsening over days to weeks | **Progressively worsening over days to weeks | ||
**Infant is | **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) | *Visible gastric peristaltic waves (left to right across upper abdomen) | ||
*Signs of dehydration: poor skin turgor, depressed fontanelle, decreased urine output, lethargy | *Signs of dehydration: poor skin turgor, depressed fontanelle, decreased urine output, lethargy | ||
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==Evaluation== | ==Evaluation== | ||
* | *Abdominal ultrasound — diagnostic study of choice | ||
**Pyloric muscle thickness | **Pyloric muscle thickness >=3 mm | ||
**Pyloric channel length | **Pyloric channel length >=15 mm | ||
**Sensitivity and specificity >95% | **Sensitivity and specificity >95% | ||
* | *Labs (critical to check before surgery): | ||
**BMP: | **BMP: hypochloremic, hypokalemic metabolic alkalosis (classic finding) | ||
**Loss of HCl from vomiting → paradoxical aciduria | **Loss of HCl from vomiting → paradoxical aciduria | ||
**May also have hyponatremia and hypoglycemia | **May also have hyponatremia and hypoglycemia | ||
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==Management== | ==Management== | ||
*'''This is NOT a surgical emergency''' — correct electrolytes and dehydration FIRST | *'''This is NOT a surgical emergency''' — correct electrolytes and dehydration FIRST | ||
* | *IV fluid resuscitation | ||
**Initial: NS 20 mL/kg bolus, repeat as needed | **Initial: NS 20 mL/kg bolus, repeat as needed | ||
**Maintenance: D5 0.45% NS + 20 mEq/L KCl (after urine output established) | **Maintenance: D5 0.45% NS + 20 mEq/L KCl (after urine output established) | ||
**Goal: correct chloride, potassium, and alkalosis before surgery | **Goal: correct chloride, potassium, and alkalosis before surgery | ||
* | *NPO, NGT for decompression if significant distension | ||
*Surgical consultation for | *Surgical consultation for pyloromyotomy (Ramstedt procedure) — definitive treatment | ||
**Laparoscopic approach is standard; very high success rate | **Laparoscopic approach is standard; very high success rate | ||
*Surgery should be delayed until electrolytes are corrected (target: Cl >100, HCO3 <30, K >3.5) | *Surgery should be delayed until electrolytes are corrected (target: Cl >100, HCO3 <30, K >3.5) | ||
==Disposition== | ==Disposition== | ||
* | *Admit for IV fluid resuscitation and surgical repair | ||
*Pediatric surgery consultation | *Pediatric surgery consultation | ||
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
- ↑ Sreedharan R, Liacouras CA. Major symptoms and signs of digestive tract disorders. In: Kliegman RM, ed. Nelson Textbook of Pediatrics. 21st ed. Elsevier; 2020.