Diagnostic value of abdominal radiography in constipated children: a systematic review.

BACKGROUND: Constipation is a common problem in children. Diagnosis is based on clinical features. In case of doubt about the presence of constipation, the existence of fecal retention can be evaluated on plain abdominal radiography.
OBJECTIVES: To describe and to assess the evidence from observational, controlled studies concerning the association between abdominal radiography and symptoms and signs related to constipation in children.
METHODS: MEDLINE was searched from inception to April 2004 using a specified search strategy. Studies that fulfilled predefined criteria were assessed for methodological quality. Study characteristics and associations were extracted and the results were summarized according to a best-evidence synthesis.
RESULTS: Of the 392 publications identified, 6 studies met the inclusion criteria. Only 2 studies were of high methodological quality. The best-evidence synthesis yielded conflicting evidence for an association between a clinical and a radiological diagnosis of constipation. The likelihood ratio (LR) in 2 high-quality studies was close to 1 (LR, 1.2; 95% confidence interval [CI], 1.0-1.4; and LR, 1.0; 95% CI, 0.5-1.6). Conflicting evidence was found for an association between digital rectal examination and fecal impaction on radiography. Limited evidence was found for an association between a history of hard stool and a finding of rebound tenderness and radiography (LR, 1.2; 95% CI, 1.0-1.4; and LR, 1.1; 95% CI, 1.0-1.2, respectively).
CONCLUSIONS: The limited amount of data available shows conflicting evidence for an association between clinical symptoms of constipation and fecal loading on abdominal radiographs in children. The recommendation to perform a plain abdominal radiograph in case of doubt of the presence of constipation in a child cannot be supported. Further research of good methodological quality is needed.