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Newborns with intolerance of feeds and vomiting may have congenital blockage of the duodenum, a condition strongly associated with Trisomy 21. The characteristic diagnostic finding is a double bubble pattern of intestinal gas on abdominal x-ray.

  1. 1.

    Pathophysiology:

    1. (a)

      Normal embryology: development of the duodenum begins in the fourth week of gestation. The primitive digestive tube formed from the endoderm rotates to the right, with the distal portion being drawn to the left as the midgut rotates. During the fifth to seventh weeks of gestation, the duodenum is temporarily obstructed by epithelial proliferation, and it recanalizes by degeneration of epithelial cells during the eighth week.

    2. (b)

      The duodenum can be obstructed internally by atresia, a duodenal web, or a stenosis. Duodenal webs, or diaphragms, can vary in thickness, some are long and prolapse distally, like a wind sock, and some webs have an aperture that allows flow of succus, so they do not cause complete obstruction. These partially obstructing webs may not become apparent until later when solid foods are introduced. External obstruction can be caused by an annular pancreas, malrotation and volvulus, or presence of a duplication cyst.

    3. (c)

      Duodenal atresia usually occurs near the ampulla of Vater. In 80 % of children it is distal to the ampulla, resulting in bilious vomiting. In 5–10 % of cases it is proximal, with non-bilious vomiting. Some cases will have the atresia between the primary and secondary biliary ducts.

    4. (d)

      Classification of duodenal atresia

      Fig. 1
      figure 1

      Classification of duodenal atresia (Source: Christopher Coppola)

      Full size image
      1. (i)

        Type I: This type is most common, with a luminal web or membrane, consisting of mucosa and submucosa.

      2. (ii)

        Type II: Duodenum is reduced to a fibrous cord connecting the proximal and distal segments

      3. (iii)

        Type III: There is discontinuity of the duodenal segments with no intervening tissue.

  2. 2.

    Epidemiology: intrinsic duodenal obstruction occurs in 1:7,000 live births. It represents 49 % of small bowel atresia.

    1. (a)

      There is a strong association with trisomy 21; if duodenal atresia is detected, a karyotype should be performed.

    2. (b)

      Other associated conditions are Hirschsprung’s disease, Meckel’s diverticulum, esophageal atresia, imperforate anus, congenital heart disease, renal abnormalities and neurologic disorders.

  3. 3.

    Clinical features:

    1. (a)

      One third to one half of fetuses with duodenal atresia will have polyhydramnios from inability to pass amniotic fluid through the gastrointestinal tract.

    2. (b)

      After birth, newborns with duodenal atresia experience feeding intolerance, distention, discomfort, and vomiting, which is usually bilious.

    3. (c)

      Children may pass meconium and have a normal rectal exam.

    4. (d)

      Features of trisomy 21 will frequently be present.

  4. 4.

    Assessment:

    1. (a)

      Abdominal x-ray will reveal a double bubble sign formed by distention of the stomach proximal to the pylorus, and distention of the obstructed first and second portion of the duodenum, proximal to the duodenal atresia. Distal bowel gas will be present in cases of partial obstruction and rare cases of complete atresia when air can pass from proximal to distal via the papilla of Vater and the secondary papilla.

    2. (b)

      Upper gastrointestinal series fluoroscopic study can confirm the diagnosis and differentiate duodenal atresia from malrotation with midgut volvulus.

  5. 5.

    Initial resuscitation:

    1. (a)

      Admission to a NICU with IV placement and fluid resuscitation.

    2. (b)

      Electrolytes are checked and abnormalities from losses through vomiting are corrected.

    3. (c)

      Nasogastric tube is placed for decompression of stomach.

    4. (d)

      Evaluation for associated anomalies with echocardiography and renal sonography.

  6. 6.

    Treatment – operative repair:

    Fig. 2
    figure 2

    Diamond duodenoduodenostomy repair of duodenal atresia (Source: Christopher Coppola)

    Full size image
    1. (a)

      Repair is performed under general anesthesia after resuscitation. A transverse upper abdominal laparotomy is performed. Bowel is evaluated for malrotation, volvulus, and any other atresias or anomalies, including Meckel’s diverticulum. The proximal dilated duodenum is anastomosed to the distal decompressed duodenum. A diamond (Kimura) duodenoduodenostomy is created with a transverse incision on the most dependent portion of the proximal duodenum. This is anastomosed to a longitudinal incision on the distal duodenum with the two incisions oriented perpendicularly so that the aperture is held open to encourage flow of succus into the distal duodenum.

    2. (b)

      Care is taken to avoid injury of the papilla of Vater by using the portions of duodenum furthest from the interface with the pancreas.

    3. (c)

      When duodenal web is present, the duodenum is opened and the web is resected, taking care not to injure the ampulla of Vater which may form one portion of the web. If it is not clear that a web is present, the nasogastric tube can be advanced through the duodenum until it stops or causes dimpling of the walls of the duodenum as the web is pulled distally by the tip of the tube.

    4. (d)

      If annular pancreas is present, a duodenoduodenostomy is performed as a detour around the obstruction, without resection or division of the pancreas.

  7. 7.

    Recovery:

    1. (a)

      IV hydration is continued until the patient can tolerate enteral feeds.

    2. (b)

      A tube passed through the anastomosis at the time of surgery can be used to feed the gut distal to the duodenum. If a patient has post-operative vomiting, a nasogastric tube via the other nare can be used to decompress the stomach.

    3. (c)

      Prolonged postoperative ileus is present, and if the patient cannot tolerate oral feeds within 2 weeks after repair, an upper gastrointestinal series is performed to evaluate the anastomosis.

  8. 8.

    Outcome:

    1. (a)

      Some patients who fail to empty the stomach through the repair will require revision of anastomosis.

    2. (b)

      Patients may have long term delayed gastric emptying and gastroesophageal reflux.

    3. (c)

      In some cases, stasis of succus in a floppy redundant proximal duodenum with bacterial overgrowth will require reoperation for a tapering duodenoplasty. (Some surgeons will perform this at the time of initial operation.)

    4. (d)

      Mortality is <5 %.