Leukocytes, C-Reactive Protein and Interleukin-6 in Acute Appendicitis in Children: Diagnostic Value and Association with Histological Findings

Background: Many efforts have been made to find diagnostic tools that would help select children with clinical signs of acute appendicitis that would need immediate appendectomy and to find tools that would reduce the numbers of negative appendectomies. Aim: We aimed to show the association between leukocyte count, level of C-reactive protein and interleukin-6 in peripheral blood on the one side and the degree of histological findings on appendix after appendectomy on the other side in children with high clinical probability for appendicitis (Alvarado score>7). Methods: We analyzed 80 patients of both genders, younger than 15 years, with Alvarado score>7, which underwent open appendectomy with subsequent histological analysis of removed appendices. We sampled 20 consecutive cases without signs of inflammation (group I), 20 cases with pathological signs of incipient inflammation (group II), 20 cases with signs of phlegmonous inflammation (group III) and 20 cases with signs of perforated appendix (group IV). Prior to appendectomy, a peripheral blood was sampled and sent for analysis of leukocyte count and C-reactive protein and interleukine-6 level. We compared values of all 3 measured parameters according to histological findings; we also used Receiver Operating Characteristics (ROC) analysis in order to evaluate diagnostic thresholds for detecting the histological signs of appendicitis. Results: The lowest values of all observed parameters were found in group of negative appendicitis while highest were observed in the group of perforated appendicitis. We have observed a significant between group differences in values of all three parameters according to the degree of histological inflammation (p<0.001). ROC analysis demonstrated that interleukine-6 had the best diagnostic performance in detecting patients with histological signs of appendicitis (AUROC=0.99; 95% CI=0.99-1.00) when compared to CRP and leukocyte count (p<0.05). There was no significant difference in diagnostic performance between CRP and leukocytes counts (p=0.35). Conclusion: Leukocyte count, CRP and interleukine-6 are very useful markers which may help in diagnostics and differentiation of phlegmonous and perforated appendicitis. In patients with high probability of appendicitis, measurement of interleukine-6 may help in better patient selection.