Pyloric stenosis

Background

• More common in males (5:1) & firstborn children (30%)
• Symptoms usually begin between 3-6 weeks of age, rarely after 12 weeks

Clinical Features

• Immediate post-prandial, non-bilious, often projectile vomiting, but desires to feed ("hungry vomiter")
• Palpable mass in in RUQ to epigastric region, occassionally may see peristaltic waves

Differential Diagnosis

Pediatric Abdominal Pain

0–3 Months Old

• Emergent
  • Necrotizing Enterocolitis
  • Volvulus
  • Testicular torsion
  • Inguinal hernia
    • Incarcerated hernia
  • Trauma
  • Pyloric stenosis
  • Toxic megacolon
  • Hirschsprung's Disease
• Nonemergent
  • Constipation
  • Acute Gastroenteritis
  • Colic

3 mo–3 y old

• Emergent
  • Intussusception
  • Testicular Torsion
  • Trauma
  • Volvulus
  • Appendicitis
  • Toxic megacolon
  • Vaso-occlusive crisis
• Nonemergent
  • Acute Gastroenteritis
  • Constipation
  • Urinary tract infection
  • Henoch-Schonlein purpura

3 y old–adolescence

• Emergent
  • Appendicitis
  • DKA
  • Vaso-occlusive crisis
  • Toxic ingestion
  • Testicular Torsion
  • Ovarian Torsion
  • Ectopic Pregnancy
  • Trauma
  • Toxic megacolon
  • Inflammatory bowel disease
  • Gastric ulcer disease
  • Ovarian cyst
  • Pregnancy
  • Pancreatitis
  • Cholecystitis
  • Intussusception (to age 6)
• Nonemergent
  • Constipation
  • Acute Gastroenteritis
  • Nonspecific viral syndrome
  • Streptococcus pharyngitis
  • Urinary tract infection
  • Pneumonia
  • Renal Stone
  • Henoch-Schonlein purpura
  • Inflammatory bowel disease
  • Vulvovaginitis

Diagnosis

• Labs may show hypokalemia, hypochloremia alkalosis
• Imaging
  • Abdominal xray: May show large stomach bubble
  • U/S: ~ 95% Sn/Sp
    • normal measurements- canal length <12mm; wall width < 3mm

Treatment

• IVF
  • Normal electrolytes and no e/o dehydration
    • 5% dextrose w/ 0.25% NaCl and 2 meq KCl per 100 mL
  • Moderate or severe dehydration
    • Higher NaCl concentrations (0.5% to normal saline) and higher rates of administration (1.5 to 2 times maintenance)
• NGT
• Surgery
  • Can be delayed 24-36 hr to rehydrate infant and correct electrolytes
  • Ensure correction of bicarbonate level, as it may be a hypoventilation risk

Precautions

• Ensure that kidneys are functional prior to giving potassium
• Do not give LR
  • May lead to worsening alkalosis > apnea in infants

See Also

• Abdominal Pain (Peds)