How to avoid negative appendectomies: Can US achieve this?

Background: Clinical diagnosis of acute appendicitis is based primarily on symptoms and physical findings. However, diagnosis of appendicitis is not always straightforward. The aim of this study was to demonstrate the diagnostic effectiveness of ultrasonography (US) in these cases in combination with white blood cell count (WBC) and C-reactive protein (CRP) level.

Methods: Retrospective analysis of data collected on 470 consecutive patients who underwent appendectomy at the same institution between January 2014 and January 2016 was conducted. Data included demographic features, preoperative WBC and CRP levels, and US measurement of diameter of appendix. Patients were divided into 3 groups: lymphoid hyperplasia (LH), non-complicated acute appendicitis (NCAA), and complicated acute appendicitis (CAA), according to postoperative histopathological examination results.

Results: There were 331 male and 139 female patients with mean age of 32.29±11.44 years included in the study. Mean WBC level was 12.31103/µL (±4.47 103/µL), 13.3 103/µL (±3.87 103/µL) and 14.08 103/µL (±4.11 103/µL) in LH, NCAA, and CAA groups, respectively (p=0.016). Mean CRP level was 14.2±19 mg/L, 36.9±59 mg/L, and 40.8±66 mg/L in LH, NCAA, and CAA groups, respectively (p=0.008). Mean outer diameter of the vermiform appendix on US was 4.8 mm (±3.9 mm), 6.9 mm (±4.08 mm) and 7.6 mm (±3.92 mm) in LH, NCAA, and CAA groups, respectively (p<0.01). When all variables were compared with each other, there were statistically significant differences in US findings according to group.

Conclusion: WBC count and CRP level were higher in patients with acute appendicitis, but these findings alone were insufficient for definitive diagnosis. US findings were effectual both in diagnosis and demonstration of severe inflammation. US should be combined with laboratory tests and used as standard initial imaging in diagnostic pathway of patients with clinically suspected appendicitis. The authors of this study believe that this diagnostic pathway will reduce negative appendectomy rate.