Duodenal Atresia
Intrinsic causes (within the duodenum)
These are the most common after duodenal atresia.
1. Duodenal Stenosis
- Partial obstruction rather than complete
- Mild Polyhydramnios may be milder
- May present later
2. Duodenal Web
- Thin mucosal membrane obstructing lumen
- Can produce a “windsock deformity” postnatally
3. Annular Pancreas
- Pancreatic tissue encircles the duodenum
- Often associated with Duodenal Atresia
4. Malrotation with Midgut Volvulus
- May show double bubble plus:
- Dilated proximal bowel
- Abnormal SMA/SMV relationship
5. Ladd Bands
- Fibrous bands compressing the duodenum
6. Preduodenal Portal Vein
- Often associated with Heterotaxy Syndrome
7. Enteric Duplication Cyst (duodenal duplication)
- Can appear as cyst near second part of duodenum
Functional or transient causes
8. Megaduodenum
- Functional dilatation
9. Transient duodenal dilatation
- Seen occasionally in early gestation
- May resolve on follow-up
Mimics of double bubble
10. Choledochal Cyst
- Usually separate from stomach
11. Cystic Biliary Atresia
12. Pancreatic Cyst
Associations
- Trisomy 21 (25–40%)
- Congenital Heart Defects (especially AV canal)
- Malrotation
- Esophageal Atresia
- VACTERL Association
- Heterotaxy Syndrome
Classic features of Duodenal Atresia
- Double bubble sign
- Dilated stomach
- Dilated proximal duodenum
- No distal bowel dilatation
- Progressive polyhydramnios
- Usually detected after 24 weeks
| Feature | Suggests |
|---|---|
| Persistent double bubble | True obstruction |
| Distal bowel seen | Stenosis/web rather than atresia |
| Separate cystic structure | Duplication cyst / biliary cyst |
| Changing bowel pattern | Malrotation/volvulus |
Genetic association
- Trisomy 21 - ~25–40% risk