Congenital Duodenal Obstruction

Epidemiology and Etiology

Epidemiology

• Overall incidence: 2.5–10 per 100,000 live births
• Duodenal atresia: 
  • Incidence: 1 in 10,000 live births
  • 50% of infants with duodenal atresia are premature.
  • Common concomitant anomalies:
    • Down’s syndrome (25%–40%)
    • Congenital heart disease (30%): associated with increased mortality
    • Annular pancreas (30%): associated with late pancreatitis, gastroesophageal reflux disease, peptic ulcer disease, and gastric cancer
    • Malrotation (20%–30%)
    • Renal anomalies (5%–15%)
    • Esophageal atresia (5%–10%)
    • Skeletal malformations (5%)
    • Anorectal anomalies (5%)
• Annular pancreas:
  • Incidence: 5–15 per 100,000 adults
  • Common concomitant abnormalities:
    • Maternal polyhydramnios 
    • Meckel’s diverticulum
    • Down’s syndrome
    • Imperforate anus
    • Duodenal atresia
    • Esophageal atresia
• Duplication cysts:
  • Incidence: 1 in 45,000 births
  • Duodenal duplication cysts make up only 5% of reported cases.
• Congenital bands: Incidence of duodenal obstruction due to Ladd’s bands is not reported. 

Etiology

• Intrinsic (most common):
  • Duodenal atresia (most common): failed recanalization of the duodenum during embryonal development
  • Duodenal stenosis: incomplete recanalization of the duodenum during embryonal development
• Extrinsic: 
  • Annular pancreas: band of pancreatic tissue surrounding the duodenum arising from incorrect rotation of the pancreatic bud during embryonal development 
  • Congenital bands (Ladd’s bands): fibrous bands of peritoneum that persist due to malrotation of the small intestines
  • Duplication cyst: cystic malformations of the small intestines that can deform the lumen of the duodenum
• Intrinsic and extrinsic causes may occur concomitantly.

Clinical Presentation

Signs and symptoms of intestinal obstruction:

• Polyhydramnios and bile-stained amniotic fluid may be present at birth.
• Bilious vomiting without abdominal distension on 1st day of life (hallmark)
• Delayed symptoms or prolonged vomiting and failure to thrive based on severity of occlusion
• Abdominal peristaltic waves may be present, especially early in the course.

Associated abnormalities:

• Biliary atresia
• Agenesis of gallbladder
• Renal, limb, and vertebral malformations

Diagnosis and Management

Diagnosis

History

• Prenatal: 
  • Duodenal obstruction in other pregnancy
  • Bowel dilatation or polyhydramnios on prenatal screening
  • Maternal diabetes mellitus
• Perinatal:
  • Gestational age
  • Hours from birth to onset of vomiting
  • Timing of meconium passing
• Family history:
  • Siblings with intestinal malformations
  • Cystic fibrosis

Physical exam

• General:
  • Signs pointing to dehydration
  • Dysmorphic features suggestive of associated abnormalities seen with atresia (e.g., Down’s syndrome)
• Skin: jaundice
• Abdomen: Distension suggests that obstruction is not duodenal but more distal.
• Rectal exam: anal atresia associated with duodenal atresia

Imaging

• Prenatal ultrasound: 
  • Shows “double bubble” sign (air-filled stomach and duodenum) 
  • May reveal polyhydramnios 
• Radiography:
  • Double bubble sign confirms diagnosis of duodenal obstruction. 
  • Contrast studies may occasionally be needed to rule out malrotation and volvulus.
• Computed tomography (CT) or magnetic resonance imaging (MRI) may be used for better visualization.

Management

Medical therapy

• Nasogastric decompression 
• Fluid resuscitation

Surgical management

• Duodenal atresia and/or annular pancreas are corrected with duodenoduodenostomy. 
• Long-term prognosis is excellent.