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
QUESTIONS 1 of 4 1 2 3 4 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M2.PD.15.45) A 2-week-old boy presents to general pediatrics clinic with constipation. His mother reports that he has not had a bowel movement for over 5 days and is quite concerned. On further examination, you discover that the boy is in the 5th percentile for weight. Physical examination shows a distended abdomen. Rectal examination shows an absence of stool in the rectal vault. A contrast enema reveals the following seen in Figure A. A rectal biopsy is performed (Figure B). Which of the following is true regarding this illness? QID: 106307 FIGURES: A B Type & Select Correct Answer 1 The disease more commonly affects females than males 4% (1/25) 2 Trisomy 18 is a risk factor for this disease 4% (1/25) 3 The vast majority of the cases of this illness affect the entire length of the bowel 0% (0/25) 4 MEN I is a risk factor for this disease 0% (0/25) 5 The mainstay of treatment is surgical 88% (22/25) M 6 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic