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THE FATIGUE RATE INDEX IS HIGHER IN CHILDREN WITH FUNCTIONAL CONSTIPATION AND RETENTIVE FECAL INCONTINENCE
Bruno Paganotti1, Marcio Miasato1, Mauro Batista de Morais1
1Universidade Federal de São Paulo, Departamento de Pediatria, Disciplina de Gastroenterologia Pediátrica, São Paulo, SP, Brasil.
Insights
The Fatigue Rate Index (FRI) is feasible in children, showing higher values in those with fecal incontinence. This anorectal manometry parameter aids in diagnosing constipation-related incontinence in pediatric patients.
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.
Background:
The Fatigue Rate Index (FRI) is a parameter in anorectal manometry (ARM) to assess sustained voluntary contraction, considering the squeeze pressure and fatigability of the external anal sphincter. It is used in adults to detect fecal incontinence even in patients who present normal squeeze pressures. The FRI in adult patients with functional constipation is similar to controls.
Objective:
The aim of this study was to evaluate the feasibility and values of FRI in children in relation to the values previously established in adults and comparing children with functional constipation and retentive fecal incontinence to children without retentive fecal incontinence.
Methods:
This retrospective study evaluated 105 ARM performed from Jan 2014 to Apr 2015. 42 patients were selected (were able to perform a voluntary contraction and had no co-morbidities other than functional constipation). 14 (33.3%) of those collaborated in sustaining contraction for 40 seconds (s), allowing the evaluation of the FRI. Patients with retentive fecal incontinence secondary to functional constipation (n=7, aged 6 to 13 years, six boys) were our interest group. Patients with functional constipation without fecal incontinence (n=7, aged 6 to 13 years, four boys) were considered a reference group. The ARM were performed with a radial eight-channel perfusion catheter (DynamedTM, São Paulo, Brazil) and the FRI was calculated (Proctomaster 6.4) in the first 20 s and overall 40 s of sustained voluntary contraction.
Results:
14 of the selected 42 collaborated in sustaining contraction for 40 s, allowing the evaluation of the FRI. In the first 20 s of contraction, the fecal incontinence group showed a significantly higher mean FRI (2.48±1.39 min) compared to the reference group (1.13±0.72 min, P=0.042), which was not observed in the 40 s interval due to less uniform contraction. The anal resting pressure was higher in the fecal incontinence group (76.83 mmHg) than in the reference group (54.13 mmHg), but the statistical study did not reach significance (P=0.051).
Conclusion:
The FRI is feasible in children. The mean FRI obtained in this study is lower than the reported in constipated adults. The mean FRI among children with functional constipation and retentive fecal incontinence is higher than among constipated children without retentive fecal incontinence.
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