JEJUNOILEAL ATRESIA IN THE NEWBORN

jejunoileal atresia in the newborn :
Atresia of the jejunum or ileum is more common than duodenal atresia, occurring in 1 in 1500 births. Small-bowel obstruction from jejunoileal atresia may also lead to polyhydramnios. Premature delivery is observed in one third of patients with intestinal atresia. In contrast to duodenal atresia, jejunoileal atresia is widely considered to be a condition acquired during development, rather than a preprogrammed anomaly. In classic work on fetal dogs in 1955, Louw and Barnard demonstrated the pathophysiology by which intrauterine mesenteric vascular accidents produce atresia in the segment of intestine that is devascularized.

The extent of atresia and the appearance of the atretic intestinal segment vary according to the timing and degree of the disruption of the mesenteric blood supply. Atresias may be focal or multiple throughout the small bowel. Interruption of the main superior mesenteric blood supply can result in atresia of most of the jejunum and ileum. Other abdominal conditions, such as gastroschisis or intrauterine intussusception, may be associated with intestinal atresia, presumably from kinking, stretching, or otherwise disrupting the blood supply to the fetal bowel.

Chromosomal anomalies are rare (<1%) in children with jejunoileal atresia. Infants with jejunoileal atresia may present with distention and vomiting. Thumb-sized loops of bowel with air-fluid levels can be observed on plain radiography. As many as 12% of newborns with jejunoileal atresia may have intra-abdominal calcifications observed on plain radiography. These calcifications are consistent with meconium peritonitis, resulting from necrosis and perforation of a devascularized loop of bowel. Blood flow to the segments immediately proximal and distal to the atresia may be compromised. For this reason, preoperative nasogastric decompression is vital to limit distention of the intestine proximal to the atresia. A delay in diagnosis or operation may distend and compromise the poorly vascularized, dilated, often bulbous bowel.

Some surgeons insist on a contrast enema to exclude colonic atresia, while others examine the colon intraoperatively to ensure patency of the distal bowel. Surgery for jejunoileal atresia involves resection and primary anastomosis of the atretic segments. Diverting ostomies are avoided if possible. As with surgery for duodenal atresia, tapering of the proximal dilated segment occasionally is necessary to limit the motility problems observed with dilated proximal bowel. If at all possible, the ileocecal valve is preserved. Long-term outcomes are generally excellent if sufficient bowel is present for absorption and growth.