Duodenal Obstruction

Eva Ilse Rubio, MD

DIFFERENTIAL DIAGNOSIS

Common

Malrotation/Midgut Volvulus
Duodenal Atresia
Duodenal Stenosis/Web

Less Common

Jejunal Atresia
Superior Mesenteric Artery (SMA) Syndrome
Duodenal Hematoma
Gastrointestinal Duplication Cyst

Rare but Important

Bezoar
Lymphoma
Annular Pancreas

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Differentiate between proximal (high) or distal (low) obstruction in neonates
- High (proximal) obstruction
  - Malrotation/midgut volvulus
  - Duodenal atresia or stenosis
  - Duodenal web
  - Duodenal hematoma
  - Annular pancreas
  - Jejunal atresia (proximal portion)
  - Extrinsic compression from mass or cyst
- Mid-level obstruction
  - Jejunal atresia
  - Extrinsic compression from mass or cyst
- Low (distal) obstruction
  - Anorectal malformation/anal atresia
  - Hirschsprung disease
  - Meconium plug syndrome (small left colon syndrome)
  - Ileal atresia
  - Meconium ileus
  - Extrinsic compression from mass or cyst
Duodenal obstruction falls into proximal (high) obstruction differential
Conventional radiograph may show distention of stomach, duodenum, or a few proximal small bowel loops
Midgut volvulus must be urgently excluded in patients presenting with bilious emesis
UGI is initial radiographic exam for evaluation of proximal (high) obstruction

Helpful Clues for Common Diagnoses

Malrotation/Midgut Volvulus
- Malrotation: Abnormal fixation of duodenum to retroperitoneum; prone to twisting upon itself
- Midgut volvulus: Twisting of malrotated bowel that may result in obstruction, ischemia, and bowel necrosis
  - Malrotation with midgut volvulus must be excluded in patients who present with bilious emesis
- Radiographic findings range from normal abdominal x-ray to distended stomach and proximal duodenum
- UGI is next step in work-up
  - Entire duodenal sweep must course through retroperitoneum on UGI lateral view
  - Duodenojejunal junction must be situated to left of spinal pedicle and at same level as duodenal bulb
- Note: Volvulus may occur in normally rotated patients who have other bowel pathology, such as mass or cyst, adhesions, inspissated meconium, etc.
Duodenal Atresia/Stenosis/Web
- Accepted etiology is failure of canalization of lumen in utero rather than vascular insult (as with other atresias)
- Distended, air-filled stomach and duodenum appear as “double bubble” sign
- Distal bowel gas
  - Usually absent in duodenal atresia
  - Present in varying amounts in duodenal stenosis or web
- Normal caliber colon on contrast enema (unless ileal atresia is present)
- Associated with other anomalies
  - Down syndrome (25%)
  - Other GI anomalies, such as malrotation, pancreatic and biliary anomalies, Meckel diverticulum, other atresias, gastrointestinal duplications (25%)
  - Vertebral or rib anomalies (> 33%)
  - Congenital heart disease
  - Assess for VACTERL sequence anomalies

Helpful Clues for Less Common Diagnoses

Jejunal Atresia
- Few distended loops of bowel may appear as “triple bubble” sign
- Intrauterine vascular insult is commonly accepted cause
- Associated with other abnormalities
  - Malrotation/volvulus
  - Anterior abdominal wall defects
- Other, more distal atresias may be present; contrast enema should be performed
  - If colon caliber is normal, ileal atresia very unlikely
  - If there is microcolon, other distal (ileal) atresias are present
Superior Mesenteric Artery (SMA) Syndrome
- Often in older children with recent history of weight loss
- 3rd portion of duodenum compressed by overlying superior mesenteric artery
- Best diagnosed with upper GI
  - Proximal half of duodenum often mildly distended
  - Contrast material has difficulty passing beyond middle of 3rd portion of duodenum, sloshes back and forth
  - Contrast column halts at vertical linear extrinsic compression caused by SMA
  - Expect difficulty passing feeding tube beyond this point
Duodenal Hematoma
- Typically traumatic in nature
  - Handlebar injury, direct blow/punch
  - May result from endoscopy/biopsy
- Variable appearance
  - Focal intramural bulge into lumen
  - Circumferential wall thickening narrowing lumen
Gastrointestinal Duplication Cyst
- Typically round or tubular, highly variable size, commonly present with obstruction
  - US: Contents may be anechoic, hypoechoic, or complex with debris; may demonstrate bowel wall layers
  - CT: Low-attenuation contents
- Most do not communicate with true bowel lumen

Helpful Clues for Rare Diagnoses

Bezoar
- Foreign body bezoar
  - Appearance is commonly swirled or mottled; depends on what patient has eaten (hair, soil/sand, plant matter, household products)
Lymphoma
- Nonspecific soft tissue mass
  - CT: Homogeneous or mildly heterogeneous, low to intermediate attenuation
  - US: Homogeneous or mildly heterogeneous, hypoechoic
Annular Pancreas
- Usually seen in conjunction with other anomalies, such as duodenal web/stenosis

Image Gallery

Lateral upper GI shows the “corkscrew” sign associated with midgut volvulus. There is abrupt termination of contrast material at the point of the volvulus

Axial CECT shows the swirled appearance of twisted mesenteric vessels

in a teenager who presented with nonspecific abdominal pain. Note the dilated loop of contrast-filled obstructed bowel located proximally

(Left) Axial CECT shows abnormally reversed positions of the mesenteric artery and vein. In this patient with midgut malrotation and volvulus, the mesenteric artery is on the right