Hirschsprung Disease

**Definition:** Congenital MEGACOLON resulting from the absence of ganglion cells (aganglionosis) in a distal segment of the LARGE INTESTINE. The aganglionic segment is permanently contracted thus causing dilatation proximal to it. In most cases, the aganglionic segment is within the RECTUM and SIGMOID COLON.

**Tree numbers:** - C06.198.439 - C06.405.469.158.701.439 - C16.131.314.439

**Synonyms:** - Aganglionic Megacolon - Congenital Megacolon - Hirschsprung's Disease - Megacolon, Aganglionic - Megacolon, Congenital