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 a nd whether roentgenographic evidence of fecal retention is associated with clinical findings on presentation in encopretic children. Design: Retrospective case studies. Setting: Two pediatric incontinence clini cs. Participants: Sixty children (72% male), aged 4 to 18 years (mean, 8 years), who met Diagnostic and Statistical Manual of Mental Disorde rs, Revised Third Edition criteria for the diagnosis of encopresis. Al l had a plain abdominal roentgenogram obtained on presentation. Interv entions: None. Results: Using a systematic assessment tool with good i nterrater 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 hi story of difficult toilet training (P=.018) than nonretentive encopret ic children. There was no association between fecal retention and seve ral clinical factors, including historical features commonly attribute d to fecal retention. Retentive encopretic children were no more likel y to have a palpable abdominal mass than nonretentive encopretic child ren, but they were more likely to have excessive stool on rectal exami nation (P=.015). Using the plain abdominal roentgenogram as the gold s tandard, the rectal examination showed a positive predictive value of 84.8% and a negative predictive value of 50% in assessing fecal retent ion. Conclusions: Fecal retention in encopretic children can be assess ed 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 rec tal examination may not rule out fecal retention, in which case an abd ominal roentgenogram may be useful to make that diagnosis.