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== | ==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== | ==Differential Diagnosis== | ||
*[[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 | |||
== | ==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 | ||
* Surgery | *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== | ==See Also== | ||
*[[ | *[[Vomiting (peds)]] | ||
*[[Malrotation]] | |||
*[[Intussusception]] | |||
*[[Pediatric abdominal pain]] | |||
==References== | ==References== | ||
<references/> | |||
[[Category: | [[Category:Pediatrics]] | ||
[[Category: | [[Category:Gastroenterology]] | ||
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.