Plasma Sodium and Laboratory Parameters in Determining Complicated Appendicitis in Children

Dear Editor,

We have attentively read the article entitled “The Predictive Value of Plasma Sodium and Other Laboratory Parameters in Determining Complicating Appendicitis in Children” by Zvizdic et al. [1]. The authors contribute to our knowledge on diagnostics using preoperative reduced plasma sodium in addition to elevated C-reactive protein (CRP) and white blood cell (WBC) count tests that might reliably predict complicated acute appendicitis (CAA) in pediatric patients. But, sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were not calculated for sodium, CRP, and WBC tests in this study. In addition, continuous variables to determine optimal cut-off points for distinguishing uncomplicated acute appendicitis (UAA) and CAA are incomplete, and ROC curve analysis is confused about the diagnostic accuracy of three tests in distinguishing between UAA and CAA, as depicted in Figure 3.

Hyponatremia at admission may be linked to gangrenous cholecystitis and soft tissue infections, and colonic perforation, preoperative hyponatremia (serum sodium level <131.8 mmol/L) could be distinguished from perforated/gangrenous appendicitis versus UAA, and pediatric patients aged less than 5 years [2]. An interdisciplinary diagnostic approach for UAA and CAA is based on medical history, acute abdominal pain/experiencing symptoms for more than 24 h, clinic examination, imaging scans, diagnostic laparoscopy, scoring systems, histopathological report of the appendicitis specimen, and laboratory tests such as having a WBC count greater than 12 × 10⁹ and a CRP level greater than 10 mg/L [2, 3]. A recent study has reported that CRP displayed the highest sensitivity, specificity, and positive and negative predictive values for predicting CAA versus UAA [4]. In spite of such diagnostic advances, establishing an early and accurate diagnosis of acute appendicitis and effectively differentiating CAA from UAA becomes a diagnostic trouble in the emergency department, and the initial misdiagnosis is approximately 28–57% in children below 12 years of age [5]. Blood tests can help emergency physicians as potential markers upon admission for discriminating between UAA and CAA in children, thus current findings and novel biomarkers need to be confirmed in larger prospective studies.