A newborn child is brought to the attention of the pediatrician since he has still failed to pass meconium in the first 72 hours and that there is no stool in the diaper. On examination, the infant has a notably distended abdomen, and there is good anal tone. A pilocarpine sweat test is within normal limits. An ultrasound of abdomen is within normal limits. A barium enema shows a large dilated segment of transverse colon.What is most likely cause for this infant’s constipation?
Defective CFTR transporter
Duodenal atresia
Lack of ganglion cells in distal colon
Telescoping of bowel segment
Hypertrophic pylorus
Correct answer
Lack of ganglion cells in distal colon
Feedback
correct answer: C
This infant is suffering from Hirschsprung’s disease, which is congenital megacolon caused by a lack of Auerbach’s and Meissner’s plexuses of the distal colon (option C). Infants with Hirschsprung’s often will not pass meconium in the first couple of days in the hospital and will continue to have constipation. A barium enema showing a dilated colon followed by a biopsy showing a lack of ganglion cells is diagnostic of the disease. The only treatment is surgical removal of the affected colon.
Although the child did not pass meconium (possible meconium ileus), he is not suffering from cystic fibrosis (defective CFTR transporter, option A) since his sweat test is within normal limits.
Duodenal atresia (option B) and hypertrophic pylorus (pyloric stenosis, option E) would present with vomiting with feeding rather than constipation.
Telescoping of bowel segment (option D) is the cause of intussusception. Intussusception would cause a bowel obstruction and therefore constipation. Any passed stool is likely to be bloody, classically described as “current jelly.” However, this condition would not appear with failure to pass meconium (most commonly presenting between five months and three years) and a barium enema would show the overlapping segment of bowel and is the usually the first line treatment (along with air-contrast enema).