Ultrasound for Appendicitis: Performance and Integration with Clinical Parameters.

Fanny Löfvenberg,Martin Salö

doi:10.1155/2016/5697692

Abstract

Objective. To evaluate the performance of ultrasound in pediatric appendicitis and the integration of US with the pediatric appendicitis score (PAS) and C-reactive protein (CRP). Method. An institution-based, retrospective study of children who underwent abdominal US for suspected appendicitis between 2012 and 2015 at a tertiary pediatric surgery center. US results were dichotomized, with a nonvisualized appendix considered as a negative examination. Results. In total, 438 children were included (mean 8.5 years, 54% boys), with an appendicitis rate of 29%. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for US were 82%, 97%, 92%, and 93%, respectively, without significant age or gender differences. Pediatric radiologists had significantly higher sensitivity compared to general radiologists, 88% and 71%, respectively (p < 0.01), but no differences were seen for specificity, PPV, and NPV. The sensitivity, NPV, and negative likelihood ratio for the combination of negative US, PAS < 5, and CRP < 5 mg/L were 98%, 98%, and 0.05 (95% CI 0.03–0.15). Conclusion. US may be a useful tool for evaluating children with suspected appendicitis, regardless of age or gender, and should be the first choice of imaging modalities. Combining US with PAS and CRP may reduce several unnecessary admissions for in-hospital observation.

Highlights

Despite the high incidence of appendicitis during childhood, the diagnosis remains difficult with risk of diagnostic delay and perforation [1], as well as negative appendectomies [2]
When US is integrated with pediatric appendicitis score (PAS) and/or C-reactive protein (CRP), a high negative predictive value (NPV) can be reached for a substantial part of the patients
US for suspected appendicitis had a sensitivity of 82% for the entire cohort, which is similar to other studies [7, 10], though lower [12, 19, 22], and higher [11, 13, 14, 16], values have been reported

Summary

Introduction

Despite the high incidence of appendicitis during childhood, the diagnosis remains difficult with risk of diagnostic delay and perforation [1], as well as negative appendectomies [2]. Despite a higher negative appendectomy rate in girls [2,3,4,5], imaging is frequently more used in this group [6,7,8]. Perforated appendicitis and negative appendectomy have a reported frequency of 17–35% [4, 9,10,11] and 1–12%, respectively [4, 7, 8, 10]. When introducing preoperative imaging for suspected appendicitis in children, there were hopes for a reduction of perforations and negative appendectomies; the literature is showing inconsistent results [5, 7]. One study showed a lower sensitivity in girls [6] Another factor is the operator dependency of US. A higher identification rate of appendix would most likely increase the sensitivity and specificity of US for suspected appendicitis [19]

Methods

Results

Discussion

Conclusion