THE FATIGUE RATE INDEX IS HIGHER IN CHILDREN WITH FUNCTIONAL CONSTIPATION AND RETENTIVE FECAL INCONTINENCE.

Area of Science:

• Pediatric Gastroenterology
• Physiology
• Diagnostic Tools

Background:

• The Fatigue Rate Index (FRI) assesses external anal sphincter function during sustained voluntary contraction in anorectal manometry (ARM).
• FRI aids in detecting fecal incontinence in adults, even with normal squeeze pressures.
• In adults, FRI is similar between functional constipation patients and controls.

Purpose of the Study:

• To evaluate the feasibility and values of FRI in children.
• To compare pediatric FRI values to established adult norms.
• To differentiate FRI between children with functional constipation and retentive fecal incontinence versus those without.

Main Methods:

• Retrospective analysis of 105 ARM procedures; 42 selected patients with functional constipation.
• 14 patients sustained voluntary contraction for 40 seconds for FRI calculation.
• Comparison between a retentive fecal incontinence group (n=7) and a reference group (n=7) without incontinence.

Main Results:

• FRI evaluation was feasible in 14 of 42 selected pediatric patients.
• The fecal incontinence group exhibited a significantly higher mean FRI in the first 20 seconds (2.48±1.39 min) compared to the reference group (1.13±0.72 min).
• Higher anal resting pressure was noted in the fecal incontinence group, though not statistically significant.

Conclusions:

• The Fatigue Rate Index (FRI) is a feasible parameter for assessing pediatric anorectal function.
• Pediatric FRI values in this study were lower than those reported for constipated adults.
• Children with functional constipation and retentive fecal incontinence demonstrated higher mean FRI compared to constipated children without incontinence.