Most congenital gastrointestinal (GI) anomalies present as intestinal obstruction and frequently manifest as feeding difficulties, distention, emesis, and an inability to pass gas and stool at birth or within 1 or 2 days of age. Some congenital GI malformations, such as malrotation, have a very good outcome, whereas others, such as congenital diaphragmatic hernia, have a poor outcome (including having a mortality rate of 10 to 30% or even higher depending on the study) (1).
A common type of anomaly is atresia, in which a segment of the GI tract fails to form or develop normally or it forms and then is destroyed by an intrauterine event, such as a vascular disruption. The most common type is esophageal atresia, followed by atresia in the jejunoileal region and in the duodenum.
Because approximately one third of infants with a GI malformation may have another congenital anomaly (eg, up to 50% in those with congenital diaphragmatic hernia and up to 70% in those with omphalocele), they should be evaluated for malformations of other organ systems, especially of the central nervous system, heart, and kidneys.
Esophageal, Gastric, and Duodenal Obstruction
Esophageal, gastric, duodenal, and sometimes jejunal obstruction should be considered when excess amniotic fluid (polyhydramnios) is seen on a prenatal ultrasound, because such obstructions prevent the fetus from swallowing and absorbing amniotic fluid.
Once cardiovascular stability has been attained after delivery, a nasogastric tube should be passed into the neonate’s stomach. Finding large amounts of fluid in the stomach, especially if bile-stained, supports the diagnosis of upper GI obstruction. Inability to pass the tube into the stomach suggests esophageal atresia. Once the neonate is stable, radiographic studies are performed for further evaluation.
Jejunoileal and Large-Bowel Obstruction
(See also Meconium Ileus and Meconium Plug Syndrome.)
Obstruction of the jejunum and ileum can occur as the result of jejunoileal atresia, malrotation, or meconium ileus. Large-bowel obstruction is typically caused by meconium plug syndrome, colonic atresia, or anal atresia.
In many cases, there is no history of maternal polyhydramnios because much of the swallowed amniotic fluid can be absorbed from the intestine proximal to the obstruction. Disorders that result in bowel obstruction, other than malrotation, intestinal duplication, and Hirschsprung disease, typically manifest in the first few days of life with feeding problems, abdominal distention, and emesis that may be bilious or fecaloid. The neonate may pass a small amount of meconium initially but thereafter does not pass stools. Malrotation, intestinal duplication, and Hirschsprung disease can manifest in the first several days of life or, in some cases, even years later. Hirschsprung disease may present as a neonatal colonic perforation (2).
General diagnostic approach and preoperative management include the following:
No oral food or liquid intake
Nasogastric tube to prevent further bowel distention or possible aspiration of vomitus
Correction of fluid and electrolyte disturbances
Abdominal x-ray series
In addition, a contrast enema may be helpful to delineate the anatomy and may also relieve the obstruction in neonates with meconium plug syndrome or meconium ileus. If Hirschsprung disease is suspected from the contrast enema, a confirmatory rectal biopsy is required. A biopsy is positive if it is devoid of intestinal ganglion cells (enteric neurons).
Defects in Abdominal Wall Closure
Several congenital defects involve the abdominal wall (eg, omphalocele, gastroschisis), allowing protrusion of the viscera through the defect.
References
1. Guner YS, Delaplain PT, Zhang L, et al: Trends in Mortality and Risk Characteristics of Congenital Diaphragmatic Hernia Treated With Extracorporeal Membrane Oxygenation. ASAIO J 65(5):509-515, 2019. doi:10.1097/MAT.0000000000000834
2. Komuro H, Urita Y, Hori T, et al: Perforation of the colon in neonates. J Pediatr Surg 40(12):1916-1919, 2005. doi:10.1016/j.jpedsurg.2005.08.006
