Review Question - QID 106307

In a newborn with dilated loops of bowel and megacolon on contrast enema suspect Hirschsprung disease. Treatment is surgical and if the disease affects the entire colon, it requires diverting ileostomy.

Recall that enteric neurons arise from neural crest cells that must travel from the caudal hindbrain throughout the gut. In Hirschsprung disease, these ganglion cells fail to migrate to the bowel, especially the colon. Clinically, newborns may present with failure to pass meconium. On physical examination, there is an absence of stool in the rectal vault. Risk factors for the disease include Down syndrome, Chagas disease, Waardenburg's syndrome, and MEN 2. Enterocolitis is the most common and feared side effect. Treatment is purely surgical and involves resection of the affected bowel segments. There is no medical management for the disease.

Figure A depicts the classic appearance of a transition point found in short segment Hirschsprung's disease.
Figure B is a rectal biopsy characteristic of Hirschsprung's disease representing nonmyelinated nerve in the mesenteric plexus and an absence of ganglion cells.

Incorrect Answers:
Answer 1: The disease more commonly affects males than females
Answer 2: Trisomy 21, not Trisomy 18, is a risk factor for the disease.
Answer 3: The vast majority of cases just affect the rectum, not the entire bowel.
Answer 4: MEN II is a risk factor for the disease.