Snapshot A newborn infant has not passed meconium in 2 days. Distended abdomen is appreciated on exam. During digital rectal examination, gas and stool is explused. Distended loops of bowel and an absence of gas in the rectum is seen on abdominal radiography. Introduction Congenital megacolon functional (vs mechanical) intestinal obstruction Epidemiology Boys > girls (4:1) ETIOLOGY Pathogenesis absence of ganglion cells/enteric nervous plexus in intestine Auerbach’s myenteric plexus Meissner’s submucosal plexus lack of nerves causes constant contraction failure of neural crest cell migration 99% localized in rectum Genetics associated with mutations in RET gene Associated conditions risk ↑ with Down syndrome risk ↑ with Chagas disease acquired disease as a result of amastigote destruction of ganglion cells MEN2 Waardenburg’s syndrome Presentation Symptoms bilious vomiting failure to pass meconium in first 48 hours of life chronic constipation large bowel obstruction Physical exam abdominal distention extremely tight anal sphincter no stool in rectal vault Imaging Abdominal radiography distended bowel loops lack of air in rectum Contrast enema – best initial test retention of barium for > 24 hours funnel-shaped transition zone STUDIES Manometry ↑ pressure in anal sphincter Differential Imperforate anus Functional constipation Intussusception Duodenal atresia Meconium ileus DIAGNOSIS Gold standard diagnosis rectal suction biopsy lack of ganglionic cells in submucosa Treatment Supportive care Surgical resection removal of affected bowel section if entire colon is involved, diverting ileostomy with appendectomy Complications ↑ risk of enterocolitis most common cause of death Rupture Prognosis Very good Overall mortality < 1% Normal quality of life in most patients