Causes of Duodenal Obstruction
Neonatal Causes (Most Common)
Duodenal atresia is the leading cause of congenital duodenal obstruction in neonates, accounting for 46.9% of cases and presenting with the classic "double bubble" sign on radiography. 1, 2
Intrinsic Causes
- Duodenal atresia represents 91% of cases presenting with the classic "double bubble" sign and no distal gas, making it the most common intrinsic cause 1, 3
- Duodenal stenosis is a less severe variant that may present similarly but allows some distal gas passage 1, 2
- Duodenal web creates a membranous obstruction within the duodenal lumen and is a rare intrinsic cause 1, 3, 4
- Duplication cysts can cause obstructing lesions within the duodenal wall 1, 3
Extrinsic Causes
- Malrotation with midgut volvulus is a surgical emergency that must be excluded urgently, occurring in 20% of infants with bilious vomiting in the first 72 hours of life and 40.7% of duodenal obstruction cases 1, 3, 2
- Annular pancreas accounts for approximately 30-37% of neonatal duodenal obstruction cases and represents the second most common cause after atresia 2, 4
- Internal hernia can cause duodenal obstruction, particularly in specific anatomical contexts 1, 3
Pediatric and Adult Causes
In adults, duodenal webs are the most common congenital anomaly (69% of cases), while annular pancreas accounts for 24%, with peptic ulceration occurring in 65% of web patients. 5
Congenital Anomalies Presenting Later
- Duodenal webs may remain asymptomatic until adulthood, presenting with nausea, vomiting, abdominal pain, and weight loss 5
- Annular pancreas can present in adults without prior symptoms, though less commonly than webs 5
- Combined anomalies (both web and annular pancreas) occur in approximately 7% of adult cases 5
Acquired Causes in Adults
- Peptic ulcer disease with duodenal stenosis occurs frequently in patients with underlying congenital webs (65% of cases) 5
- Malignancies including pancreatic cancer, duodenal tumors, or periampullary neoplasms can cause extrinsic compression 6
- Carcinomatosis peritoneal can cause extrinsic compression of the duodenum 3, 7
- Superior mesenteric artery syndrome from external vascular compression (though not explicitly mentioned in guidelines, this is a recognized clinical entity)
Critical Diagnostic Pitfall
Never assume a "double bubble" sign represents benign duodenal atresia—malrotation with volvulus can present identically and requires immediate surgical intervention to prevent bowel necrosis and death. 3 In one study, of 35 neonates with classic "double bubble" sign, 32 had duodenal atresia but 2 had malrotation with volvulus requiring emergency surgery 1
Key Distinguishing Features
- Classic "double bubble" with NO distal gas suggests duodenal atresia (91% of cases), but volvulus must still be excluded 1, 3
- "Double bubble" with SOME distal gas or non-classic appearance mandates urgent upper GI series to exclude malrotation, which has 96% sensitivity for diagnosis 1, 3
- Bilious vomiting in first 72 hours carries 20% risk of midgut volvulus and requires immediate evaluation 1, 3
Associated Anomalies
Associated congenital anomalies occur in 67.5% of duodenal obstruction cases and are the primary determinant of postoperative morbidity and mortality, not the duodenal obstruction itself. 4
- Down syndrome is present in 30-38% of duodenal atresia cases 4
- Cardiac anomalies are the most common associated defect and primary cause of postoperative complications 4
- Gastrointestinal anomalies including esophageal atresia and anorectal malformations occur frequently 4
- Renal anomalies are commonly associated 4
- Multiple atresias occur in approximately 15% of cases 1