CLINICAL SPECTRUM OF FUNCTIONAL CONSTIPATION AND BOWEL-HABIT PATTERNS OF SCHOOLCHILDREN RECRUITED FROM TWO ELEMENTARY SCHOOLS AND A SPECIALIZED OUTPATIENT CLINIC

Assessing impaired gastric accommodation in children with functional constipation using the water load test

BACKGROUND

This study aimed to evaluate gastric accommodation in pediatric patients with functional constipation using the water load test.

METHOD

This was a cross-sectional case-control study. Herein, the water load test results of children aged >4 years with functional constipation referred to a Pediatric Gastroenterology Outpatient Clinic (functional constipation group) were compared with those of a control group (without functional constipation or chronic abdominal pain) recruited from two public schools. Clinical manifestations outlined in the Rome IV criteria were used to diagnose functional constipation. Water load tests were performed after 3 h of fasting. For the test, the participants were asked to drink as much water as possible in 3 min.

KEY RESULTS

A total of 36 patients and 77 students were included in the functional constipation and control groups, respectively. There was no significant difference in age between the groups (8.6 ± 2.3 years and 8.8 ± 1.8 years in the functional constipation and control groups, respectively). The water load test showed intake volumes of 390 ± 245 mL and 528 ± 219 mL in the functional constipation and control groups, respectively (p = 0.001). The maximum volume in the water load test correlated with the 24 h daily intake of energy (rS = +0.42, p = 0.012), protein (rS = +0.48, p = 0.004), and water (rS = +0.39, p = 0.020) only in the group with functional constipation.

CONCLUSIONS & INFERENCES

According to the water load test, gastric accommodation was impaired in children with severe functional constipation. The impairment of gastric accommodation in children with severe functional constipation is related to food intake.

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