Question
A 2-week-old infant is brought to the emergency room because of 4 episodes of bilious vomiting and inconsolable crying for the past 3 hours. Abdominal examination shows no abnormalities. An upper GI contrast series shows the duodenojejunal junction to the right of the vertebral midline; an air-filled cecum is noted in the right upper quadrant. Which of the following is the most likely cause of this patient’s condition?
| A. |
Defective neural crest migration
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| B. |
Failure of duodenal recanalization
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| C. |
Nonrotation of the intestines
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| D. |
Incomplete intestinal rotation
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Show Answer
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Correct Answer � D
Explanation
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Answer D) Incomplete intestinal rotation
The duodenojejunal junction normally lies to the left of the midline, adjacent to the vertebral bodies.
Incomplete intestinal rotation
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Incomplete intestinal rotation, indicated by a malpositioned duodenojejunal junction (usually located to the left of the midline) and cecum (normally located in the right lower quadrant), can manifest as duodenal obstruction, causing bilious vomiting without abdominal distension, as seen in this infant.
Obstruction is due to an extrinsic duodenal compression by peritoneal bands (Ladd bands) that cross over the duodenum to fix the abnormal cecum to the liver or peritoneum.
Defective neural crest migration
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Defective neural crest migration to the distal colon results in Hirschsprung disease. The aganglionic segment of the colon fails to relax, which causes functional intestinal obstruction.
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Although Hirschsprung disease would manifest with bilious vomiting, it also causes significant abdominal distension.
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Moreover, it typically manifests right after birth with failure to pass meconium within 48 hours or later in childhood with constipation and abdominal distention.
Failure of duodenal recanalization
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Failure of duodenal recanalization results in duodenal atresia, which would manifest with complete intestinal obstruction at birth.
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Hallmark imaging findings are the double bubble sign as well as a completely gasless distal small bowel, neither of which are seen in this patient.
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Moreover, duodenal atresia is associated with maternal polyhydramnios.
Nonrotation of the intestines
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With complete nonrotation of the intestine, the cecum usually remains in the left lower quadrant.
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However, this patient’s GI series shows a cecum located in the right upper quadrant. Patients with nonrotation may be asymptomatic or present with varying degrees of small bowel obstruction.
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Radiologically, the small bowel is seen to occupy the right side of the abdomen, with the colon predominantly on the left.
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