Pathophysiology The pathology of H

Pathophysiology
The pathology of HD relates to the absence of ganglion cells in affected areas of the intestine, resulting in a loss of the retosphincteric reflex and an abnormal microenvironment of the cell affected intestine ( Theocharato and Kenny, 2008) The term congenital aganglionic megacolon describes the primary defect, which is the absence of ganglion cells in the myenteric plexus of Auerbach and the submucosal plexus of Meissner
The absence of ganglion cells in the affected bowel results a lack of enteric nervous system stimulation, which decreasas the internal sphincter's ability to relax. Unopposed sympathetion stimulation of the intestine results in increased intestinal tone in addition to the contraction of the abnormal bowel and the resulting lack of peristalsis, there is a loss of the rectosphincteric reflex. Normally when a stool bolus enters the rectum, the internal sphincter relaxes and the stool is evacuated. In HD sphincter not relax. In most cases the aganglionic segment includes the rectum and some portion of the distal colon. However, the entire colon or part of the small intestine may be involved. Occasionally, skip segments or total intestinal aganglionosis may occur.