How do the Blethyn Score and the Starreveld Score differ in evaluating fecal loading in children?

Comparison of Blethyn Score and Starreveld Score for Evaluating Fecal Loading in Children

Critical Finding: Starreveld Score Does Not Exist in the Medical Literature

The "Starreveld Score" is not a validated or published scoring system for evaluating fecal loading in children. The available evidence discusses only three established radiological scoring systems for assessing childhood constipation on plain abdominal radiographs: the Barr score, the Leech score, and the Blethyn score 1, 2, 3.

The Blethyn Score: Characteristics and Performance

Methodology

• The Blethyn score is one of three scoring systems developed to quantify fecal loading on plain abdominal radiographs in children with constipation 1, 2.
• The system evaluates stool burden across different colonic segments, with scores ranging from 0 (no stool) to 5 (gross fecal loading with bowel dilatation) in three areas of the colon, yielding a total score of 0-15 3.

Reproducibility and Reliability

• The Blethyn score demonstrates poor interobserver reproducibility compared to other scoring systems. In a systematic assessment, the Blethyn score showed a kappa coefficient of only 0.670 between two observers, which was the lowest among the three validated systems 1.
• A separate study confirmed moderate interobserver reproducibility with a best kappa value of only 0.48, indicating substantial variability between different observers 4.
• The Blethyn score shows significant observer experience-dependency, with consultant radiologists producing higher scores than junior doctors or students (P<0.01) 4.

Diagnostic Accuracy

• The Blethyn score demonstrates only moderate diagnostic accuracy when compared to colonic transit time (CTT) as the gold standard, with the largest area under the ROC curve of 0.84 4.
• The correlation between Blethyn scores and CTT is modest at best, with a maximum correlation coefficient of 0.51 4.
• More than 20% of children with functional constipation have normal Blethyn scores, while more than 50% of children with nonretentive fecal incontinence have abnormal scores, demonstrating poor discriminative value 5.

The Superior Alternative: Leech Score

Why the Leech Score Outperforms the Blethyn Score

The Leech score demonstrates significantly superior reproducibility and clinical utility compared to the Blethyn score and should be the preferred radiological scoring system when plain abdominal radiography is indicated. 1, 2

• The Leech score shows the highest interobserver reproducibility with kappa coefficients of 0.91 in the first assessment and 0.84 in the second assessment, compared to the Blethyn score's 0.670 2.
• Intraobserver agreement for the Leech score is excellent, with kappa values of 0.88 and 1.00 for two different observers (P<0.05) 2.
• The Leech score demonstrates the strongest correlation with colonic transit time (r = 0.861, P < 0.001) and Bristol stool form scale (r = -0.818, P < 0.001) in constipated children 1.
• The Leech score shows statistically significant associations with clinically relevant parameters including defecation frequency per week (r = -0.569 and -0.625) and abdominal pain (r = 0.574 and 0.567) 1.

Critical Clinical Recommendations

When to Use Radiological Scoring

• Plain abdominal radiography should be reserved for investigation of intractable constipation only, not routine evaluation. 3
• To limit exposure to ionizing radiation, radiography accuracy is improved if all radiographs are scored by the same observer to minimize interobserver variability 3.
• Assessment of fecal loading is inherently subjective and varies between observers, though one observer will consistently score the same radiograph on successive occasions 3.

Limitations of All Radiological Scoring Systems

• All three validated scoring systems (Barr, Leech, and Blethyn) show poor interobserver reproducibility despite good intraobserver correlation 5.
• The discriminative value between functional constipation and nonretentive fecal incontinence is low for all radiological scores 5.
• Current evidence confirms the limited value of plain abdominal x-rays in the evaluation of children with constipation, regardless of which scoring system is used. 5

Recommended Clinical Approach

• The Leech score combined with the Bristol stool form scale provides the most practical diagnostic approach for pediatricians assessing childhood fecal loading in outpatient clinics, supplemented by thorough clinical history 1.
• Clinical assessment should focus on defecation characteristics, abdominal pain, anorexia, nausea, and bowel habit patterns rather than relying primarily on radiological scoring 1.
• Observation of rectal impaction by ultrasound may assist diagnosis and response to treatment in the clinical setting as an alternative to radiography 6.