Rectum sizes: Assessment by ultrasonography in children with functional constipation

AIM: This study aimed to compare the transverse diameter and thickness of the anterior wall of the rectum in children with normal bowel movement and children with functional constipation in different age groups. Another objective was to find correlations of rectum sizes with faecal incontinence and constipation duration. METHODS: In the study, we included children with normal bowel movement and functional constipation diagnosed based on the Rome III and Rome IV criteria. We collected clinical data from the parents. We measured the rectum transverse diameter and the thickness of the anterior wall by abdominal ultrasound. RESULTS: The study included 65 children, 31 with normal bowel movement and 34 with functional constipation. The rectum transverse diameter and the thickness of the anterior wall had statistically significant higher values in patients with constipation (P < 0.05). There was a moderate and significant correlation between the duration of the disease (mean ± standard deviation = 31.7 ± 33.1 months) and rectum transverse diameter (r = 0.54; P = 0.0009). The rectum transverse diameter correlated moderately with the presence of faecal incontinence (r = 0.62; P = 0.003), but the thickness of the anterior wall did not correlate with this symptom (r = 0.02; P = 0.39). CONCLUSIONS: We found statistically significant differences between the transverse rectal diameter and thickness of the rectum anterior wall, measured by abdominal ultrasound, in children with functional constipation compared with normal defaecation patterns. Faecal incontinence and long-term constipation were correlated with the increased rectum diameter.