Evaluation of the relationship between c-reactive protein, leukocyte, neutrophil count, and ultrasonography in the differential diagnosis of acute appendicitis and ovarian cyst in female patients with lower right abdominal pain in emergency department

Introduction and Objective: Patients presenting to the emergency department with right lower quadrant abdominal pain hold particular importance for emergency physicians due to the differential diagnoses including acute appendicitis and ovarian pathologies. The similar clinical and physical examination findings encountered in these cases pose challenges for emergency physicians. Our study aims to provide statistical data to assist the emergency physician in making accurate decisions by comparing laboratory values and ultrasonography findings in the differential diagnosis of acute appendicitis and ovarian cyst rupture. Materials and Methods: The data of 148 female patients who presented to the Emergency Department with abdominal pain and were diagnosed with either Acute Appendicitis (78 patients) or Hemorrhagic Ovarian Cyst Rupture (70 patients) through CT or USG were retrospectively examined. Laboratory and ultrasonography results were analyzed and recorded in terms of hemoglobin (HGB), white blood cell (WBC), neutrophil count (NEU#), neutrophil percentage (NEU%), and C-reactive protein (CRP), along with the amount of free fluid in ovarian cyst rupture patients, and appendix diameter in acute appendicitis patients. Patients diagnosed with acute appendicitis and ovarian cyst rupture were divided into two groups, and their hemoglobin (HGB), white blood cell (WBC), neutrophil count (NEU#), neutrophil percentage (NEU%), and C-reactive protein (CRP) values were compared. The correlations between these laboratory values and the amount of free fluid measured in ultrasonography in ovarian cyst rupture patients, and the appendix diameter measured in acute appendicitis patients, were examined within each patient group. Results: In patients with acute appendicitis, leukocyte, neutrophil#, neutrophil%, and CRP levels were significantly higher compared to patients with ovarian cyst rupture (respectively; 13.07±4.74 vs 9.37±3.57 p<0.001; 10.18±4.75 vs 6.17±3.26 p<0.001; 74.89±11.59 vs 64.07±10.94 p<0.001; 33.26±54.73 vs 5.83±16.46 p<0.001), while no significant difference was observed in hemoglobin values (respectively 13.17±1.78 vs 13,19±1,44 p=0.949). The sensitivities and specificities for the same parameters according to ROC analysis and Youden Index were as follows: neutrophil count (AUC=0.779; vii Sensitivity=73.08; Specificity=75.71), leukocyte count (AUC=0.757; Sensitivity=51.28; Specificity=91.43), Neutrophil percentage (AUC=0.756; Sensitivity=73.08; Specificity=70.00), CRP (AUC=0.731; Sensitivity=64.10; Specificity=78.57). Within the acute appendicitis patient group, a comparison was made between Leukocyte, Hemoglobin, Neutrophil#, Neutrophil%, CRP values and the ultrasonographically measured appendiceal diameter. This comparison revealed a positive correlation between CRP value and the measured appendiceal diameter (p=0.004, Pearson correlation score=0.323). Conclusions: Our study suggests that neutrophil count can be a critical determinant in cases where differentiation between acute appendicitis and ovarian cyst rupture is required. Particularly in young female patients with inconclusive diagnoses of acute appendicitis, reevaluating patients whose laboratory values are inconsistent with the diagnosis and repeating ultrasonography in patients with increasing CRP levels can clarify the diagnosis. In cases of diagnostic inconsistency with blood parameters, the use of advanced imaging methods such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) could become routine. This approach is believed to contribute to the prevention of misdiagnoses and unnecessary surgical interventions.