Chapter 60

1. Problem. No stool has been passed in over 48 h. Ninety-nine percent of term infants and 76% of premature infants pass a stool in the first 24 h of life. Ninety-nine percent of premature infants pass a stool by 48 h.

2. Immediate questions

1. Has a stool been passed since birth? If a stool has been passed since birth but not in the last 48 h, constipation may be the cause. If a stool has never been passed, imperforate anus or some degree of intestinal obstruction may be present. Table 60–1 shows the time after birth at which the first stool is typically passed.

1. What is the gestational age? Prematurity is associated with a delayed passage of stool because of immaturity of the colon and lack of triggering effect of enteral feeds on gut hormones when the patient is maintained on NPO.

1. Were maternal drugs used that could cause a paralytic ileus with delayed passage of stool?Magnesium sulfate, which is used to slow the premature onset of labor, may cause paralytic ileus. Narcotics for pain control or use of heroin by the mother may also cause delayed passage of stool in the neonate.

3. Differential diagnosis

1. Constipation.

1. Anorectal abnormalities such as imperforate anus. Imperforate anus may pass meconium if a fistula exists.

1. Bowel obstruction

1. Meconium plug is an obstruction in the lower colon and rectum caused by meconium. It is more common in infants of diabetic mothers (as seen in neonatal small left colon syndrome, in which the plug extends to the splenic flexure) and in premature infants. (Note: A rectal biopsy should be considered in all these patients because they have an increased incidence [10–15%] of Hirschsprung disease.)

1. Meconium ileus occurs when meconium becomes obstructed in the terminal ileum. Ninety percent of patients with meconium ileum have cystic fibrosis (CF) and thus should be tested for CF. It is the most common presentation of CF in the neonatal period.

1. Hirschsprung disease accounts for ~15% of infants who have delayed passage of stool. A functional obstruction is caused by aganglionosis of cells in Meissner and Auerbach plexus in the rectum and variable amounts of the distal colon. The affected segment of colon and rectum are aperistaltic.

1. Jejunal/Ileal atresia can occur secondary to meconium ileus, Hirschsprung disease, incarcerated hernia, or intussusception. Signs include abdominal distention, bilious vomiting, and failure to pass meconium.

1. Adhesions. Postoperatively, such as after surgery for necrotizing enterocolitis (NEC), there is a 30% chance of having adhesions.

1. Incarcerated hernia when hernia contents cannot be reduced and the bowel is obstructed. Signs include irritability, cramps, bilious vomiting, and abdominal distention. The risk of incarceration for an inguinal hernia in infancy is 20–30%; the risk of bowel obstruction secondary to an inguinal hernia is 9%.

1. Malrotation is the failure of the gastrointestinal tract to properly rotate and adhere. Volvulus is a specific malrotation of the gut and is a surgical emergency because it can cause ischemia of the gut, with resulting shock, bowel necrosis, and possibly ...

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