Defecation in SCI

1. How is the bowel affected in an UMN lesion?
2. How is the bowel affected in a LMN lesion?
3. How is the gastrocolic reflex utilized in SCI?
4. How is the anorectal reflex utilized in SCI?

Answer:
1. This creates a hyperreflexic bowel with decreased ability to sense urge to defecate. External anal sphincter cannot be voluntarily relaxed but the stool can be propelled by reflex activity.
2. This creates an areflexic bowel in which reflex defecation is absent and there is slow movement of stool, resulting in constipation.
3. Increased colonic activity occurs 30-60 min after a meal, so place patient on commode within one hour of a meal.
4. Suppositories and digital stim cause the bowel wall to stretch, resulting in relaxation of the internal anal sphincter.