Evaluation of proadrenomedullin as a diagnostic or prognostic biomarker of acute appendicitis in children

Abstract

IntroductionA delay in the diagnosis of acute appendicitis (AA), with the added complication of symptoms that mimic other self-limited causes of abdominal pain, can lead to an increase in ruptured appendices and morbimortality. None of the serum biomarkers evaluated to date have shown a predictive value for early diagnosis. ObjectiveThe objective of this study was to evaluate the usefulness of proadrenomedullin (MR-proADM) in the diagnosis of AA in children presenting with acute abdominal pain. MethodsA single-center prospective observational study was conducted in 136 children who presented to the emergency department with suspected AA. ResultsForty-four (32.5%) children had AA, and 9 (20.5%) had perforated appendicitis. The mean concentration of MR-proADM was significantly higher in children with AA than in children with nonspecific abdominal pain (NAP) (0.54 nmol/L; 95% confidence interval, 0.46-0.55 and 0.37 nmol/L; 95% confidence interval, 0.35-0.40, respectively). Performance characteristics of MR-proADM alone were not optimal. However, after combining best cutoff points, the combination of a C-reactive protein level of <0.3 mg/dL and a MR-proADM level of <0.34 nmol/L showed 100% sensitivity and negative predictive value, with 61% specificity. ConclusionsAlthough MR-proADM values are higher in children with AA than in children with nonspecific abdominal pain, these values do not help in the early diagnosis of AA. The combination of low C-reactive protein and low MR-proADM levels is useful for the identification of children with a low risk of AA.