Acute appendicitis is among the most common conditions requiring emergency abdominal surgery in children. However, diagnosing it in children under the age of 5 presents significant challenges. Factors such as communication difficulties, non-specific symptoms, and the inability to perform a cooperative physical examination make the diagnostic process complex in this age group. These delays in diagnosis increase the risk of perforation and other complications. Research indicates that the perforation rates of appendicitis in younger children are higher compared to older children. Therefore, quickly and accurately diagnosing acute appendicitis in children under 5 is crucial to prevent complications. Various studies have been conducted over the years on scoring systems and biomarkers that can aid in prognosis prediction. Among these biomarkers, the Systemic Immune-Inflammation Index (SIII) stands out as a significant indicator for evaluating inflammatory responses. SIII is calculated by the ratio of platelet, neutrophil, and lymphocyte counts based on complete blood count results and is considered a systemic indicator of inflammation. In recent years, many studies have been conducted, especially regarding its use in predicting cancer prognosis. The Systemic Inflammatory Response Index (SIRI), which includes various inflammatory parameters (neutrophils, monocytes, and lymphocytes), has been proven to be a promising prognostic indicator in various cancer types [7, 8]. In this article, the prognostic power of new-generation biomarkers in patients with acute appendicitis was examined, and the diagnostic value of SII and SIRI, their role in predicting complications, and their potential clinical use were evaluated.
In our study, we found that the rate of complicated appendicitis was 54%. Literature review shows that complication rates in children under 5 range from 30–70% [9]. There was no difference in complication rates between genders in our cases. The general consensus in the literature is that gender is not a risk factor in the development of complications [10, 11]. However, one study reported that 70% of cases of perforated appendicitis were male [12].
One of our secondary endpoints was to compare the complaints of children with complicated appendicitis at admission with those of non-complicated children. As expected in complicated appendicitis, the proportion of all symptoms was higher in complicated cases compared to non-complicated ones. Due to the difficulty in describing and understanding symptoms in children under 5, we did not find a statistical difference in the evaluation of some symptoms. However, complaints and findings that could be reported by parents, such as anorexia and fever, were statistically higher compared to the non-complicated group. Given the challenges in symptoms and physical examination in young children, it is quite difficult to suspect complicated appendicitis based on symptoms and findings alone, making our finding an expected result [13].
Many studies use high WBC values to predict appendicitis patients. Feng and colleagues [2] examined the risk factors for complication development in children under 5 and found that leukocyte (WBC) levels were significantly higher in the complicated appendicitis group. Although many studies have reported higher WBC levels in complicated appendicitis, these data yield conflicting results depending on the cut-off value used. Our study results, however, contradict the literature on this point [2, 14, 15]. Although WBC levels were higher in the complicated group, this difference was not statistically significant.
The neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) are biomarkers that have gained popularity in recent years and have been studied in many diseases. Some studies evaluating the clinical use of these markers in predicting complications in acute appendicitis have reported that they can be used as prognostic markers [16–18]. In a meta-analysis including 17 studies with 8,914 patients, the NLO cut-off value for distinguishing complicated appendicitis was reported as 8.8 (with a sensitivity of 76.9% and a specificity of 100%). Accordingly, NLO > 8.8 was concluded to be a predictor of complicated appendicitis (OR:43, P < 0.0001). However, our analysis did not find a difference in NLR and PLR levels between the two groups.
In our study, laboratory values of platelets, monocytes, SIRI, CRP, and procalcitonin in the complicated appendicitis group were higher compared to those in the simple appendicitis group. Chung et al. [19] reported that CRP level is a good indicator of appendix perforation or abscess formation in children. Other studies have also indicated that high levels of CRP and procalcitonin can be good indicators of complicated appendicitis [20, 21]. Cesur et al. [22] found that CRP was the most significant marker for prognosis in children diagnosed with acute appendicitis. According to our study data, CRP level was the strongest marker in predicting complications (Cut-Off: >44.3; Sensitivity (%): 63.54; Specificity (%): 61.25; AUC: 0.643; 95%). The power of SIRI, one of the new biomarkers in inflammation, was found to be weaker in predicting prognosis. A recent study similar to ours compared SIRI and SII levels in children with complicated and non-complicated appendicitis and found that both had a higher predictive power for complications than in our study [23]. The larger number of patients in that study compared to ours may have created this difference. Another study examining SIII and SIRI in adult patients found that SIII had 88.9% sensitivity and 88.9% specificity with a cut-off value of 1,782.94 (×10^9 /L) in distinguishing complicated and non-complicated cases. In our study, there was no significant difference in SII levels between the groups.