Anorectal manometric examination in encopretic-constipated children

We have investigated the use of anorectal manometry to distinguish encopretic-constipated children (n = 88) from sibling controls (n = 16) and nonsibling controls (n = 11).

Study variables included manometrically determined resting and maximum voluntary anal sphincter pressure, depth and speed of rectoanal inhibitory reflex, minimum rectal volume sensation, critical distending volume for fecal urgency, rectal and anal pressure responses during attempted defecation, and ability to defecate a water-filled balloon.

Change in anal sphincter pressure during attempted defecation (P = 0.03), gradient between rectal and sphincter pressure during attempted defecation (P = 0.02), critical distending volume for fecal urgency (P = 0.02), and ability to defecate a water-filled balloon (P = 0.05) distinguished encopretic-constipated from control children. The change in rectal pressure associated with the rectoanal inhibitory reflex just escaped significance at P = 0.07.

Anal sphincter spasm and megacolon are pathophysiologic abnormalities associated with pediatric constipation-encopresis.