Neonatal bowel obstruction

Last revised by Joshua Yap on 4 Oct 2023

Neonatal bowel obstruction is the most common neonatal abdominal surgical emergency 1. It is generally divided into high and low obstruction according to the level of the transition point, since imaging appearances, underlying pathology, treatment, and prognosis differ.

It is divided into:

  • high bowel obstruction - proximal to the ileum

  • low bowel obstruction - involving the ileum or colon

It is estimated to occur in about 0.05% of all live births 2.

The clinical presentation is not specific and depends on the location of the obstruction. But usually, neonates will present with:

  • abdominal distension and tenderness

  • bilious vomiting

  • constipation

  • feed intolerance

  • bile-stained vomit/aspirates

  • respiratory distress with acidosis

  • sepsis, blood-stained stools, or diarrhea in case of necrotizing enterocolitis

  • failure to pass meconium in the first days

Small bowel obstruction

Large bowel obstruction

Abdominal radiographs are the first imaging modality in neonatal acute abdomens. The features vary widely depending on the level of the obstruction, and generally demonstrate:

  • dilated bowel loops: bowel diameter greater than the interpedicular width of L1 3

  • number of dilated loops

    • high obstruction <3 dilated loops

    • low obstruction >3 dilated loops

  • absence of rectal gas: can be confirmed only if the radiograph is performed >24 hours after birth

  • air-fluid levels: due to ineffective peristalsis

  • small bowel or colon involvement

    • if there is no gas in the rectum, AP abdominal radiographs are unreliable to differentiate the colon from small bowel, since haustra are hard to identify in neonates 4

    • to differentiate small and large bowel in neonates, a colon enema may be performed

  • intramural bowel gas: suggestive of necrotizing enterocolitis

    • granular feces should not be seen in the neonatal bowel (exclusive milk diet); if seen, it is indicative of pneumatosis intestinalis

  • neonatal pneumoperitoneum

  • portal venous gas

  • double bubble sign

  • triple bubble sign

Contrast enema is usually performed, to locate the level of obstruction. The features depend on the cause of the obstruction.

Ultrasound is the second line imaging modality for assessing acute abdomens in neonates. It may show:

  • dilated bowel loop

  • ineffective peristalsis

  • prominence of the valvulae conniventes

​Findings suggestive of bowel ischemia:

  • extraluminal free fluid

  • loss of peristalsis

  • bowel wall thickening with effacement of mural architecture

  • intramural bowel gas

The treatment depends on the etiology of the obstruction.

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