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Key Points

  • Most common cause of intestinal obstruction.

  • Proximal jejunum and distal ileum are the most common locations.

  • Vascular disruption is the etiology but this may be precipitated by intussusception or volvulus.

  • Cystic fibrosis may be an underlying factor in up to 10% of cases.

  • MRI may be helpful in excluding other diagnoses or defining associated intra-abdominal cysts in an evaluation of echogenic bowel.


Jejunoileal atresia and stenosis are among the most common causes of neonatal intestinal obstruction. Atresia is a complete obstruction of the lumen of the bowel. It is far more common than stenosis or partial luminal obstruction. These lesions can occur anywhere in the small bowel but are most common in the proximal jejunum or distal ileum, where they account for 31% and 36% of cases, respectively (Robertson et al., 1994). In addition, multiple atresias of the small bowel are found in 6% of cases (deLorimier et al., 1969). These conditions are thought to result from intrauterine vascular accidents such as volvulus, intussusception, internal hernia, or vascular constriction (Louw and Barnard, 1955). In utero vascular compromise as a cause of intestinal atresias was first suspected because of associated volvulus, intussusceptions, constriction at the abdominal wall defect in gastroschisis, and kinking of bowel that were often found in association with intestinal atresias. This was supported by experimental work by Louw and Barnard (1955), who were able to replicate the pathophysiology of small intestinal atresias in animals by in utero ligation of mesenteric vessels.

The bowel lumen distal to an atresia contains bile (bile is first seen at 11 weeks of gestation), planocellular epithelium (first seen at 12 weeks), and lanugo (first seen at 6–7 months), which suggests that a vascular accident occurred well after organogenesis was complete (Romero et al., 1988). In keeping with the theory of a mesenteric vascular accident, the incidence of associated chromosomal and extraintestinal anomalies associated with jejunoileal atresia is quite low. In addition to sporadic occurrence of jejunoileal atresias, they have also been reported as a complication of amniocentesis (Richwood, 1977; Swift et al., 1979; Therkelson and Rohder, 1981). Intussusception had been considered to be a rare cause of vascular disruption resulting in atresia (Nixon and Tawes, 1971; Dalla Vecchia et al., 1998). Komuro and colleagues suggest that antenatal intussusception with or without associated volvulus may be a more important etiology of small bowel atresia than has been previously recognized (Komuro et al., 2004). In a single institution's review of 48 newborns with small bowel atresia, this group found evidence of intussusception in 12 and volvulus in 13 cases at the time of surgery. They noted that neither intussusception nor volvulus was observed in cases of high jejunal atresia, apple peel deformity, or multiple atresias.

The most useful and commonly ...

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