COLONIC TRANSIT-TIME IN CONSTIPATED CHILDREN - DOES PEDIATRIC SLOW-TRANSIT CONSTIPATION EXIST

In adults, slow-transit constipation is a well-established form of con stipation with abdominal pain and an empty rectum on examination. Mark er studies in these patients, mainly women, show a markedly slowed tra nsit time in all colonic segments. No studies in constipated children are available that assess the existence of slow-transit constipation. In a prospective study, a total of 94 referred constipated pediatric p atients, 63 boys and 31 girls (median age, 8.0 years), underwent colon ic-transit-time measurements using radioopaque markers to evaluate the pattern of transit. In addition, orocecal-transit-time measurements u sing the hydrogen breath (lactulose) test, anorectal manometry, and be havior studies using the Child Behavior Checklist were performed in al l children. Based on the upper limit (mean + 2 SD) of total colonic tr ansit time (CTT) in constipated children, we arbitrarily separated pat ients into two groups. Children with CTTs >100 h were said to have ped iatric slow-transit constipation (PSTC), while patients with CTTs <100 h were said to have normal- or delayed-transit constipation (NDTC). I n 94 constipated children, PSTC was found in 24 children; in 70 childr en, total CTT was <100 h (NDTC). Total and segmental CTTs were signifi cantly prolonged in PSTC (median, 189 h; range, 104.4-384) versus NDTC (median, 46.8 h; range, 3.6-99.4) hours. No significant differences w ere found in orocecal transit time. Significant clinical differences i n children with PSTC versus those with NDTC existed regarding nighttim e soiling (71 vs. 11%); daytime soiling episodes (14 vs. 7 each week, median), and nighttime soiling episodes (5 vs. 0 each week, median); a bsent urge to defecate (33 vs. 14%); and palpable abdominal (71 vs. 39 %) and/or rectal (71 vs. 13%) masses. All manometric parameters were c omparable in the two groups, except for a significantly lower maximal squeeze pressure with PSTC. Using the Child Behavior Checklist, both g roups differed significantly from controls (26 and 43%, respectively), with no significant differences in behavior problems found between th e NDTC and the PSTC groups. In conclusion, based on objective marker s tudies, our findings suggest the existence of pediatric slow-transit c onstipation. This entity can be recognized by clinical features, most importantly nighttime soiling and a palpable rectal mass. The probabil ity of PSTC with both of these symptoms was 0.82; in the absence of th ese two symptoms, it was 0.07. It is of interest that CTTs in PSTC are comparable with CTTs in adults with slow-transit constipation, althou gh the clinical presentation is clearly different. Further studies are needed to investigate whether the prolonged CTT characterizes a disti nct form of constipation in children or is an epiphenomenon of the und erlying constipation itself. The mechanisms responsible for the slow t ransit in these children and the appropriate therapeutic approach need to be studied.