Pyloric stenosis
(Redirected from Pyloric Stenosis)
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.