26.7  Duodenal Atresia

Traditionally it is reported that a third of infants born with duodenal atresia have Down syndrome.6 With a decrease in the number of Down children being born, this figure may be as low as 1 in 10. Conversely, 1 in 20 Down infants are born with duodenal atresia.7 Approximately half of cases are diagnosed antenatally with the appearance of a fluid-filled dou- ble-bubble on ultrasound.Over half have associated congenital abnormalities including Down’s syndrome, cardiac anomalies, VACTERL, malrotation and other bowel atresias.8 Vomiting may or may not be green depending on the site and configuration of the abnormality. The typical appearance on plain abdominal film is a double-bubble which represents a dilated, air-filled stomach and duodenum. If there is stenosis causing the obstruction, there may be distal air also present on the plain film. However, in this case it is important to consider that malrotation may be the diagnosis. Surgical treatment involves creating an anastomosis between the proximal and distal duodenum without disturbing the atresic or stenotic segment as the common bile duct commonly enters the bowel here (duodenoduodenostomy) (Fig. 26.4).

26.8  Small Bowel Atresia

Atresias may occur more distally in the jejunum, ileum or rarely in the colon. There may be a single atresia, a large atresic segment like an apple-peel or multiple atresias. The level of the most proximal atresia determines the degree of abdominal distension, the timing of onset of vomiting, and the number of distended bowel loops that will be evident on plain abdominal film. Associated abnormalities include gastroschisis, cystic fibrosis and cardiac anomalies as well as atresias in other parts of the GI tract. Surgical management involves resection of the atresic segment and either primary anastomosis or temporary stoma formation. Extensive

248 R.T. Peters and S.S. Marven

FIGURE 26.4.  Plain abdominal film demonstrating typical doublebubble appearance in duodenal atresia with no distal gas.

atresia(s) may leave a child with short gut syndrome (Fig. 26.5).

26.9  Meconium Ileus

Meconium ileus is the presenting feature in up to 1 in 5 children with cystic fibrosis.9 However, 1 in 5 of neonates presenting with meconium ileus will not have cystic fibrosis.10 This condition occurs when abnormally thick meconium impacts in and obstructs the distal ileum. Abdominal distension is a key feature and plain abdominal film may show a soap bubble appearance of the meconium. Diagnosis and treatment is with (high osmolar) water-soluble contrast medium.Should this fail then surgical intervention is required.

FIGURE 26.5.  Plain abdominal film of distal atresia (colonic atresia).

Interestingly, the long term pulmonary outcome of cystic fibrosis children does not differ between those who present with meconium ileus and those who do not.11

26.10  Hirschsprung’s Disease

Agangliosis of a continuous segment of the large bowel extending for a variable distance proximally from the rectum leads to a functional bowel obstruction. The aganglionic bowel maintains a tonic contraction with dilated normal bowel proximal to this. Delayed passage of meconium or constipation in the first 4 weeks of life should raise the

250 R.T. Peters and S.S. Marven

suspicion of Hirschsprung’s disease.12 Contrast enema may be suggestive but diagnosis is confirmed by rectal suction biopsy demonstrating an absence of ganglion cells and presence of acetyl cholinesterase (AChE)-positive hypertrophic nerve fibers. Initial management involves rectal washouts (proximal to the contracted bowel) to decompress the bowel or stoma formation until definitive procedure(s).

26.11  Anorectal Malformations

Babies with early discharge after birth may go home with an unrecognized anorectal malformation and it is vital that a proper inspection of the perineum and anus occurs before discharge. The passage of meconium does not exclude abnormal anatomy as there may be a fistulous tract with the rectum communicating with the urinary tract in boys, the vestibule or vagina (as a cloaca) in girls or the perineum in either. The finding of an anorectal malformation should trigger a search for associated abnormalities, particularly belonging to the VACTERL association (V-vertebral, A-anorectal, C-cardiac, TE-tracheo-esophageal, R-renal, L-limb). After a thorough pre-operative work-up, initial surgical management involves either a procedure to restore correct anatomy or a defunctioning colostomy.

26.12  Conclusion

Bile-stained vomiting in the neonate may herald intestinal obstruction. Delay in referral or in diagnosis may result in perforation, ischemia or death. Happily, all the anomalies may be corrected with little or no long term effects.

References

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