Diagnostic Accuracy of Ultrasound in Determining the Cause of Bilious Vomiting in Neonates

Background: Plain radiography and contrast radiologic studies are traditionally the main options in evaluating neonates presenting with bilious vomiting. While ultrasonography (US) is more available, its diagnostic accuracy is in question.Objectives: The purpose of this study is to determine the diagnostic accuracy of US in evaluating these patients with bilious vomiting.Patients and Methods: All neonates with bilious vomiting or bilious nasogastric tube drainage presented to a children’s hospital in a 1.5-year period were included. US were performed in all patients. The results were compared with clinical and radiological data and the final diagnosis. We used chi-square and Fisher’s exact tests for analysis.Results: The cause of bilious vomiting for 18 of the 23 included patients was surgical. All patients labeled as surgical candidates by US ended in surgery [positive predictive value (PPV) = 100%], while only 50% of the patients with inconclusive US were operated [negative predictive value (NPV) = 50%, Confidence Interval (CI) 95%: 29%-71%]. The sensitivity and specificity of US in diagnosing intestinal atresia (n = 9) was 89% [CI 95%: (68% - 100%)] and 100%. In cases with malrotation (n = 4) and midgut volvulus (n = 2), sonographic diagnosis was in concordance with final surgical diagnosis.Conclusion: This study suggested that in cases in which US makes a certain diagnosis, its accuracy eliminates the need for further diagnostic tests, but if it is inconclusive, further radiological contrast studies should be tried to make the final diagnosis.