Gastro Intestinal System
Aganglionic segment is encountered in which part of colon in case of Hirschsprung's disease - (AIIMS Nov 2013)
|A||Distal to dilated segment|
|B||In whole colon|
|C||Proximal to dilated segment|
|D||In the dilated segment|
Distal to dilated segment
Congenital aganglionic megacolon (Hirschsorung disease)
a. Hirschsprung disease is a congenital disorder characterby aganglionosis of a portion of the intestinaltract.
b. An intestinal segment lacks both Meissner submucosal andAuerbach myenteric plexuses. This loss of enteric neural coordination leads to functional obstruction and intestinal dilation proximal to the affected segment.
c. Histological findings are -
i. Absence of ganglion cells and ganglia in the muscle wall and submucosa of the affected segment.
ii. Thickening and hypertrophy of nerve trunk.
d. Rectum is always affected with involvement of more proximal colon to variable extent - most cases involve the rectum and sigmoid only.
e. Proximal to the aganglionic segment, the colon undergoes progressive dilation and hypertrophy.
f. With tthe proximal innervated colon may become massively distended -- megacolon'