Hirschsprung's Disease

IntroductionHirschsprung's disease (HD) is a form of functional intestinal obstruction that results from the absence of ganglion cells in the myenteric plexus of the intestine. The precursors of the ganglion cells are neural crest cells that migrate into the intestine from cephalad to caudad. The process is completed by the twelfth week of embryonic life, but the migration from midtransverse colon to anus takes 4 weeks. This increases the time period of vulnerability for failure of migration and accounts for the fact that most cases of aganglionosis involve the rectum and rectosigmoid. Longer segments of absent ganglion cells also may occur, and total colonic aganglionosis, although rare, is also seen.