Estudo do tempo de trânsito colônico em crianças e adolescentes com constipação intestinal crônica e disfunção do trato urinário inferior

Abstract

Constipation and lower urinary tract dysfunction are associated and quite prevalent conditions in childhood and adolescence. There are multiple theories to explain this association, such as the mechanical effect of the full rectum against the wall and the bladder neck; stimulation of sacral reflexes from the distended rectum and, most recently, the association between the bladder and the rectum in the central nervous system. Refractory constipation is a commonly encountered symptom in many of these children and adolescents. This fact points to the possibility of a common neuromuscular disorder involving the colon and the lower urinary tract. The aim of this study was to evaluate the colon transit time in children and adolescents with refractory chronic constipation and lower urinary tract symptoms. This was an observational study with cross-sectional analysis of 16 subjects with refractory constipation and lower urinary tract symptoms; aged 7 to 14 years (mean age 9.67 years). Participants were assessed from their clinical history, physical exam, voiding and evacuation diaries, Bristol scale, Dysfunctional Voiding Scoring System valid for the Portuguese version, renal ultrasound scan of urinary tract and measurement of rectal diameter, urodynamics, colonic transit study with radiopaque markers and anorectal manometry. The colonic transit study was normal in three (18.75%) children. Ten (62.5%) children had slow transit constipation and three (18.75%) outlet obstruction. The urodynamic evaluation was abnormal in 14 of the 16 children studied: ten (76.9%) had detrusor overactivity associated with voiding dysfunction, three (23.1%) isolated overactive bladder, and one (6.25%) voiding dysfunction without overactive bladder. When comparing slow transit constipation and lower urinary tract dysfunction, ten (100%) subjects with slow transit constipation and three (50%) without slow transit constipation had bladder hyperactivity (p=0.036). Seven (70%) subjects with slow transit constipation and four (66.7%) without slow transit constipation showed voiding dysfunction (p=0.65). When comparing slow transit constipation and the presence of urinary incontinence, it was present in nine (90%) subjects with slow transit constipation and one (16.7%) with no slow transit constipation (p=0.008). As for urinary urgency, it was present in 10 (100%) and three (50%), respectively (p = 0.036). The Dysfunctional Voiding Scoring System score ranged from 6 to 21. The subgroup with slow transit constipation showed a Dysfunctional Voiding Scoring System score significantly higher than that of the subgroup without slow transit constipation. This study demonstrated a high prevalence of slow transit constipation in children and adolescents with refractory constipation and symptoms of lower urinary tract. This was a pioneering study in demonstrating the association between bladder hyperactivity and slow transit constipation and highlights the possibility of a common neuromuscular disorder responsible for bladder and colonic dysmotility. Future studies involving intestinal and bladder motility are needed for a better understanding of the subject-matter and further development of new therapeutic modalities.