Intestinal plexuses in Crohn's disease and ulcerative colitis in children: pathologic and microdissection studies.

The relative fraction of neural tissue in the plane of the myenteric (Auerbach) plexus (MEP) of ileum and colon of patients with Crohn's disease and ulcerative colitis was analyzed by point-count morphometric analysis of microdissected flat-mount ("circuit diagram") preparations of the plexus. Increase in the relative fraction of neural tissue (myenteric plexus hyperplasia) was seen in the MEP of some patients in both ileum and colon in both diseases. The frequency of ulceration or inflammation extending into the bowel wall deep enough to injure the various levels of the intestinal plexus system (mucosal plexus of Cajal; upper submucosal plexus of Meissner; deeper submucosal plexus of Henle; intermuscular plexus of Auerbach; outer muscular/serosal plexus of Stöhr) was analyzed for small intestine, appendix, and colon for patients with both diseases. As expected, Crohn's disease tends to produce deeper intestinal wall damage in ileum versus colon, and ulcerative colitis the reverse. The effect of such injury on local and more distal motor control of the intestine and on integrative functions of the intestinal plexus system appears not to have been considered previously. Since injury deep enough to damage any given plexus necessarily damages all overlying plexus levels, analysis of such effects appears a fruitful field for study.