X-ray Guidelines for Fecal Incontinence in Children
Abdominal radiographs have limited diagnostic value in children with fecal incontinence and should not be routinely performed for initial diagnosis, but may be useful for monitoring bowel management therapy in select cases.
Initial Diagnostic Approach
The diagnosis of fecal incontinence in children is primarily clinical and does not require routine imaging 1, 2. The evidence shows:
- Conflicting evidence exists for an association between clinical symptoms of constipation/fecal incontinence and fecal loading on abdominal radiographs 1
- A systematic review found the likelihood ratio for clinical versus radiological diagnosis of constipation was close to 1.0 (LR 1.2; 95% CI 1.0-1.4), indicating minimal diagnostic utility 1
- No clinical variable, either alone or in combination, accurately identifies patients with radiographically proven constipation (sensitivity 77%, specificity only 35%) 3
When X-rays May Be Considered
Plain abdominal radiographs should be reserved for specific clinical scenarios rather than routine evaluation 2:
Emergency Situations
- Suspected bowel perforation or obstruction - A left lateral decubitus or upright radiograph should be performed in addition to supine views to assess for pneumoperitoneum 4, 5
- Severely ill children with acute abdominal symptoms - Radiographs may identify complications requiring emergent intervention 4
Monitoring Bowel Management Programs
- Daily abdominal radiographs during a 1-week period can monitor the effectiveness of enema therapy by showing the amount of stool remaining in the colon 6
- This approach allows modification of enema type based on clinical results and radiographic findings, achieving up to 95% success rates in fecal incontinence management 6
Radiographic Scoring Systems
If radiographs are obtained, the Barr score is the preferred method for assessing fecal impaction 7:
- The Barr score showed good interobserver agreement (kappa 0.56-0.69) and demonstrated statistically significant reduction after fecal disimpaction (p < 0.001) 7
- The Leech score also showed good agreement (kappa 0.53-0.61) 7
- The Blethyn score had poor interobserver reliability (kappa 0.26-0.36) and should be avoided 7
Important Caveats
- No relationship exists between radiographic fecal loading scores and colonic transit time, limiting the physiologic interpretation of plain films 7
- Distinguish true fecal incontinence from pseudoincontinence (overflow incontinence from constipation) before determining imaging needs 6
- Contrast enema may be more useful than plain radiographs for determining colon characteristics (dilated versus non-dilated) to guide treatment strategy 6
Alternative Imaging When Cross-Sectional Imaging Is Needed
If complications are suspected requiring advanced imaging 4, 8:
- Ultrasound is the initial imaging modality of choice for suspected intra-abdominal pathology in children 4, 8
- MRI is a reasonable alternative if ultrasound is non-diagnostic and available 4
- CT should be reserved for cases where ultrasound/MRI are inconclusive and clinical suspicion remains high, given radiation exposure concerns 4, 8