What does bilous (bile-containing) vomitus indicate in a patient?

What Bilious Vomitus Indicates

Bilious vomiting indicates intestinal obstruction distal to the ampulla of Vater and must be treated as a surgical emergency until proven otherwise, requiring immediate evaluation regardless of patient age. 1, 2

Critical Pathophysiology

The presence of bile in vomitus definitively localizes the obstruction point to somewhere beyond the ampulla of Vater, where bile enters the duodenum. 1 This anatomic fact is crucial because it immediately narrows the differential diagnosis to conditions affecting the mid-to-distal small bowel or colon.

Life-Threatening Considerations

In neonates presenting within the first 72 hours of life, 20% of bilious vomiting cases represent midgut volvulus, a time-critical surgical emergency. 1 The pathophysiology is devastating: the mesentery twists around the superior mesenteric artery, causing venous congestion, arterial compromise, transmural intestinal ischemia, and potentially complete bowel necrosis within hours. 1 This can result in massive bowel resection, short gut syndrome, or death. 1

Age-Specific Differential Diagnosis

Neonates (First Days of Life)

• Midgut malrotation with volvulus (most urgent to exclude) 1
• Intestinal atresia (duodenal, jejunal, or ileal) 1
• Hirschsprung disease 1
• Meconium ileus 3

Older Infants and Children

• Intussusception 1, 4
• Internal hernia (particularly post-gastric bypass surgery) 1
• Jejunal stricture from non-specific jejunoileitis (in developing countries) 5

Associated Clinical Findings

When bilious vomiting occurs with gastric distension, this strongly suggests proximal bowel obstruction. 1 In infants with intussusception, progression from non-bilious to bilious emesis indicates worsening obstruction. 4 Additional concerning features include crampy intermittent abdominal pain (manifested as inconsolable crying or leg drawing in infants) and "currant jelly" stools indicating mucosal damage. 4

Physical examination findings that increase likelihood of surgical pathology include abdominal distension (74% sensitivity), abdominal tenderness (62% sensitivity), though these findings do not reliably differentiate time-critical conditions from less urgent surgical problems. 6

Immediate Diagnostic Approach

The American College of Radiology mandates that normal abdominal radiographs do NOT exclude malrotation or volvulus—clinical suspicion based on bilious vomiting alone requires proceeding to upper GI contrast study regardless of radiograph findings. 1

Step 1: Abdominal Radiograph (Immediate)

• Obtain immediately to look for "double bubble" sign (duodenal obstruction), multiple dilated bowel loops with absent/decreased distal gas, or distended loops. 1
• Sensitivity of 96% for detecting malrotation, but 10-15% false-positive and up to 7% false-negative rates. 1
• Abnormal X-ray findings correlate with surgical diagnosis, but normal X-ray only reduces posterior probability of surgical diagnosis from 50% to 16%—still unacceptably high. 6

Step 2: Upper GI Contrast Series (Urgent)

• This is the definitive study for bilious vomiting and should be performed urgently. 1
• Identifies abnormal position of the duodenojejunal junction (ligament of Treitz), indicating malrotation. 1, 4
• Demonstrates presence of midgut volvulus requiring immediate surgery. 1
• Sensitivity of 96% for detecting malrotation with 85.7% positive predictive value for surgical findings. 1, 3
• Meticulous technique is essential to avoid false results from redundant duodenum or bowel distension. 1

Inferior or Inappropriate Studies

• Contrast enema: 20% false-negative rate for malrotation, reserved only for suspected distal bowel obstruction. 1, 4
• Ultrasound: 21% false-positive and 2-3% false-negative rates for malrotation; should not delay upper GI series. 1
• Endoscopy: No role in acute evaluation of intestinal obstruction. 4

Management Algorithm

1. Any patient with bilious vomiting → Immediate surgical consultation 4
2. Obtain abdominal radiograph immediately 1, 4
3. Proceed directly to upper GI contrast series (do not wait for radiograph results if high clinical suspicion) 1
4. If upper GI confirms malrotation/volvulus → Immediate surgery 1
5. Term neonates with bilious vomiting should be prioritized as time-critical for transfer, as 14.1% have conditions where delay compromises gut viability 6

Critical Pitfall to Avoid

Do not be falsely reassured by a normal abdominal radiograph or soft, non-distended abdomen. 1, 6 In a retrieved cohort study, 46% of term neonates with bilious vomiting had surgical diagnoses, and clinical findings at referral could not reliably differentiate between those with or without time-critical conditions. 6 The only safe approach is urgent upper GI contrast study for all patients with bilious vomiting. 1

Important Distinction

Bilious vomiting must be differentiated from non-bilious regurgitation or reflux. 1 Pyloric stenosis presents with non-bilious projectile vomiting in infants 2 weeks to 3 months old and warrants ultrasound, not upper GI series. 4