The plain abdominal roentgenogram in the management of encopresis.

OBJECTIVE To determine whether fecal retention in encopretic children can be assessed objectively using the plain abdominal roentgenogram and whether roentgenographic evidence of fecal retention is associated with clinical findings on presentation in encopretic children. DESIGN Retrospective case studies. SETTING Two pediatric incontinence clinics. PARTICIPANTS Sixty children (72% male), aged 4 to 18 years (mean, 8 years), who met Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition criteria for the diagnosis of encopresis. All had a plain abdominal roentgenogram obtained on presentation. INTERVENTIONS None. RESULTS Using a systematic assessment tool with good interrater reliability (kappa = 0.65), 78% (47) of the children had fecal retention by roentgenographic criteria on presentation, while 22% (13) did not. Retentive encopretic children were less likely to have a history of difficult toilet training (P = .018) than nonretentive encopretic children. There was no association between fecal retention and several clinical factors, including historical features commonly attributed to fecal retention. Retentive encopretic children were no more likely to have a palpable abdominal mass than nonretentive encopretic children, but they were more likely to have excessive stool on rectal examination (P = .015). Using the plain abdominal roentgenogram as the gold standard, the rectal examination showed a positive predictive value of 84.8% and a negative predictive value of 50% in assessing fecal retention. CONCLUSIONS Fecal retention in encopretic children can be assessed objectively from a plain abdominal roentgenogram. Most, but not all, encopretic children present with fecal retention. A positive rectal examination is strongly predictive of fecal retention, in which case a roentgenogram is not necessary to make that diagnosis. A negative rectal examination may not rule out fecal retention, in which case an abdominal roentgenogram may be useful to make that diagnosis.