Case 1: Bilious Vomiting in a Term Neonate.
A 2.34-kg male infant is born to a gravida 3 woman with 2 previous abortions at 37.1 weeks of gestation. A cesarean delivery is performed because of fetal distress with oligohydramnios and abnormal Doppler ultrasonography findings. The antenatal period is largely uneventful, with second-trimester antenatal anatomy ultrasound scan reported as normal. However, fetal growth is noted to be poor (lag of 2 weeks) on antenatal ultrasonography at 34 weeks and abnormal Doppler findings are reported at 37 weeks. The neonate does not require any active resuscitation at birth and is transferred to the NICU for low-birthweight care. Intravenous fluids are started initially in view of abnormal antenatal Doppler ultrasonography findings and feedings are introduced at around 21 hours after birth. First meconium is passed at 6 hours of age. The neonate, however, develops feeding intolerance in the form of bilious vomiting and abdominal distention on the second day. Sepsis screening result is negative (total white blood cell count: 7,500/μL [7.5×109/L]; absolute neutrophil count: 2,850/μL [2.85×109/L]; C-reactive protein: 0.1 mg/dL [9.5 nmol/L]; platelet count: 230×103/μL [230×109/L]; peripheral smear: no toxic granules).In view of the bilious vomiting, volvulus, malrotation, and intestinal obstruction are included in the differential diagnosis and abdominal radiography is ordered. Supine radiography (Fig 1) suggests the presence of a large cystic structure in the right iliac fossa, which persists on serial radiography. Pediatric surgery consultation is sought and a conservative approach is advised. The neonate is now kept nil per os (nothing by mouth) with the addition of a prokinetic agent (domperidone). Feedings are reintroduced after 24 hours (day 3 after birth) but it again leads to bilious vomiting; repeat radiography suggests persistence of the same cystic shadow in the right iliac fossa. Exploratory laparotomy is planned for the neonate on the 4th day after birth.Laparotomy reveals cystic dilation of the ileum with malrotation, along with an incidental finding of an asymptomatic annular pancreas. The dilated ileal segment is 5×4 cm in size with continuation of normal ileum on either side of the dilated segment (Fig 2). Because the primary pathology is cystic dilation of ileum, which is causing intestinal obstruction, resection of the dilated bowel along with end-to-end ileal anastomosis is performed. Malrotation can cause problems later on, so the Ladd procedure is performed, which includes surgical division of the Ladd band and widening of small intestine mesentery (Fig 2). An appendectomy is also performed at the same time, followed by reorientation of the small bowel on the right side and caecum and colon on the left side. Annular pancreas is left intact because it is not found to be causing any duodenal obstruction. Histopathology (Fig 3) shows all layers of intestine with normal intestinal mucosa and without any heterotopic tissue, consistent with the diagnosis of congenital segmental dilation (CSD) of the ileum.Also known as “segmental dilation of the ileum,” CSD is a dilated full-thickness segment of the ileum with normal‐caliber ileum on either side. It is a rare condition of unknown etiology with about half of the cases presenting in the neonatal period. (1) CSD is characterized by the Swenson and Rathauser criteria as: 1) limited bowel dilation with a 3‐ to 4-fold increase in caliber, 2) an abrupt transition between dilated and normal bowel, 3) no internal/external barrier distal to the dilation, 4) a clinical picture of intestinal obstruction (complete or partial) 5) a normal neuronal plexus, and 6) complete recovery after resection of affected segment. (2) The cause of CSD remains unknown. Postulated mechanisms include surrounding structures such as vitelline vessels and omphaloenteric bands compressing on the bowel loops at both ends, leading to focal segmental dilation without altering the bowel histology. (3)It can present as an isolated entity or can be associated with other congenital malformations as seen in the current case, where it was associated with malrotation. To our knowledge, this is the first case in the literature in which CSD coexisted with asymptomatic annular pancreas. The clinical presentation is generally nonspecific, with the affected neonate developing features of bowel obstruction in the form of abdominal distention and bilious vomiting. Differential diagnoses include malrotation, volvulus, and intestinal obstruction because of other causes. Constipation can sometimes be associated, in which case Hirschprung disease also becomes a possibility in the differential diagnosis.Antenatal ultrasonography can sometimes suggest a dilated bowel loop. Waters et al (4) and Paradiso et al (5) described the antenatal ultrasonographic features associated with CSD. In the current case though, antenatal ultrasonography findings were reported as normal. Postnatal diagnosis requires a high index of suspicion but the diagnosis is usually made only during exploratory laparotomy performed for clinical intestinal obstruction. Supine and erect radiography suggests a dilated loop of bowel in right iliac fossa (as seen in the current case) with or without air fluid levels but with an otherwise normal gas pattern in the rest of the bowel. (6) Rarely, barium enema studies are also ordered but usually reveal findings similar to those seen on plain radiography.Definitive treatment is resection of the dilated segment, followed by end-to-end anastomosis of the pre- (proximal) and post- (distal) ends. Prognosis is usually excellent after surgical resection. In the current case also, the surgery was well tolerated and the infant remained stable in the postoperative period. He continued to receive parenteral nutrition support for the next 3 days, after which feedings were initiated and gradually increased as tolerated. Full feedings were reached on the 10th postoperative day. The infant was discharged from the hospital on day 18 after birth, breastfeeding and doing well on follow-up and gaining adequate weight.
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