What is the differential diagnosis for a newborn with bilious vomiting?

Differential Diagnosis for Newborn with Bilious Vomiting

Bilious vomiting in a newborn is a surgical emergency until proven otherwise, with midgut volvulus being the most critical time-sensitive diagnosis that must be excluded immediately. 1

Life-Threatening Diagnoses (Require Urgent Surgical Evaluation)

Midgut Volvulus with Malrotation

• This is the most critical diagnosis to exclude as it represents a time-critical surgical condition where delayed treatment compromises gut viability 1, 2
• Accounts for 20% of bilious vomiting cases in the first 72 hours of life 1
• Can present with or without abdominal distension 3

Intestinal Atresias

• Duodenal atresia: Most common proximal obstruction, presents with "double bubble" sign on radiograph 1
• Jejunoileal atresia: Presents with "triple bubble" sign and absent distal gas 1
• Vomiting typically begins within first 2 days of birth and is bilious 1
• About 15% may present with nonbilious vomiting despite proximal obstruction 1

Other Surgical Conditions

Meconium Ileus

• Associated with failure to pass meconium and distal bowel obstruction pattern 4, 3
• May require therapeutic enema rather than immediate surgery 1

Hirschsprung Disease

• Presents with distal bowel obstruction and failure to pass meconium 4, 3
• Requires rectal biopsy for definitive diagnosis 1

Small Bowel Obstruction

• Accounts for surgical cases in newborns with bilious vomiting 4
• Can be due to internal hernia, duodenal web, or obstructing duplication cyst 1, 5

Lower GI Causes (11% of cases)

Meconium Plug Syndrome

• Presents with distal obstruction pattern 1
• Often resolves with observation or therapeutic enema 1

Left-Sided Microcolon

• Part of the lower GI causes in newborns with bilious vomiting 1

Acquired Conditions

Necrotizing Enterocolitis (NEC)

• More common in premature infants 3, 6
• Can present with bilious vomiting and abdominal distension 3

Intussusception

• Less common in newborns but must be considered 7
• May present with crampy pain, bloody "currant jelly" stools, and progression to bilious vomiting 7

Critical Clinical Pearls

Physical examination findings that increase likelihood of surgical diagnosis:

• Abdominal distension (74% sensitivity for surgical diagnosis) 2
• Abdominal tenderness (62% sensitivity for surgical diagnosis) 2
• Abnormal abdominal X-ray (97% sensitivity for surgical diagnosis) 2

Important caveat: Normal clinical findings do NOT exclude time-critical surgical conditions—23 of 163 newborns (14.1%) had time-critical conditions requiring urgent surgery 2. Therefore, all term neonates with bilious vomiting should be prioritized as time-critical transfers 2.

Radiographic patterns guide differential:

• Double bubble with no distal gas = duodenal obstruction (most commonly atresia) 1
• Triple bubble with no distal gas = jejunal obstruction (usually atresia) 1
• Multiple dilated loops with decreased distal gas = distal obstruction (meconium ileus, Hirschsprung, meconium plug) 1
• Normal abdominal X-ray reduces probability of surgical diagnosis from 50% to 16%, but does not exclude it 2