Diagnostic accuracy of abdominal ultrasound to detect pathology that needs surgical exploration in children with umbilical discharge

Background: Umbilical discharge is common in children and mostly attributed to infection or granuloma. However, an underlying congenital abnormality warranting surgery might also be present. Ultrasound is the imaging modality of choice to diagnose the presence of a congenital abnormality. The aim of this study is to investigate diagnostic accuracy of the ultrasound to detect pathology requiring surgical excision. Methods: All patients ≤ 18 years with umbilical discharge from January 2008 to September 2019 were retrospectively included. Diagnostic accuracy, i.e., sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR +) and negative likelihood ratio (LR −), were calculated. Results: Eighty-one patients were included and 56 were operated. The ultrasound was false positive in 10 patients and false negative in 13 patients. The sensitivity of ultrasound was 71.1% (95% CI 55.7–83.6), specificity 72.2% (54.8–85.8), PPV 76.2% (64.7–84.8), NPV 66.7% (54.8–76.8), LR + 2.6 (1.5–4.5) and LR − 0.40 (0.2–0.7). Conclusions: This study shows that the diagnostic accuracy of ultrasound for detecting underlying congenital abnormalities warranting surgery for umbilical discharge in the pediatric population is low, even with experienced pediatric radiologists. Therefore, the role of the ultrasound in the diagnostic workup and value in clinical decision making is limited. Type of study: Study of diagnostic test. Level of evidence: III