Diagnosis of hypertrophic pyloric stenosis: Value of sonography when used in conjunction with clinical findings and laboratory data

OBJECTIVE. This study aimed to determine the value of sonography in the diagnosis of hypertrophic pyloric stenosis in patients with no palpable olive-shaped mass. MATERIALS AND METHODS. One hundred and five children with projectile vomiting but no palpable mass had sonography because of possible hypertrophic pyloric stenosis. The patients' history, signs and symptoms, and results of laboratory tests were incorporated into the statistical analysis. Using medical history, signs and symptoms, and laboratory results in one case and history, signs and symptoms, laboratory results, and pyloric measurements based on sonographic findings in another case, we composed the best predicting logistic regression models. RESULTS. The ability to predict hypertrophic pyloric stenosis is greatly increased by adding information obtained from sonography. At 91% specificity of the final model, only 5% of the patients with no evidence of the abnormality actually had hypertrophic pyloric stenosis. The positive predictive value is thus 94%, and the negative predictive value is 95%. CONCLUSION. The results justify the use of sonography as the diagnostic procedure of choice for infants suspected of having hypertrophic pyloric stenosis.