Predictive ability of CT findings in the differentiation of complicated and uncomplicated appendicitis: a retrospective investigation of 201 patients undergone appendectomy at initial admission

Background Paradigm shift toward nonoperative management (NOM) of adult appendicitis has made computed tomography (CT) more important than ever, particularly in differentiating complicated from uncomplicated disease. Complete surgical and pathological data of appendicitis in a place where appendectomy at initial admission is a standard of care would allow retrospective review of preoperative CT for performance and predictive ability in identifying those that may benefit from NOM in the future. Results The study included 201 CT scans of consecutive adult patients who presented for appendectomy at initial admission with pathologically confirmed acute appendicitis. Complicated appendicitis referred to gangrene or perforation on pathological or operative findings. The overall CT sensitivity, specificity and accuracy for differentiation of complicated from uncomplicated appendicitis were 87.2%, 75.7% and 81.1%, respectively. The most sensitive CT findings of complicated appendicitis were mucosal enhancement defect (83.2%; 95% CI 74.1–90.0) and moderate-to-severe periappendiceal fat stranding (96.8%; 95% CI 91.1–99.3), both independently predictive of complicated appendicitis with adjusted odds ratios (ORs) of 4.62 (95% CI 1.86–11.51) and 4.41 (95% CI 1.06–18.29), respectively. Phlegmon, fluid collection, extraluminal appendicolith, periappendiceal air and small bowel dilatation had specificity of 98.1–100%. Intraluminal appendicoliths were found more frequently in complicated appendicitis (52.6% vs. 22.6%) but not predictive for this diagnosis. Independent clinical predictors of complicated appendicitis were lack of pain migration (OR 2.06), neutrophilia ≥ 82% (OR (2.87) and symptoms ≥ 24 h (OR 5.84). Conclusions CT findings were highly accurate in differentiating complicated from uncomplicated appendicitis among patients undergone appendectomy at initial admission.

Does Serum Bilirubin Add Value in the Diagnosis of Appendicitis? A Multi-Institution Analysis of 2024 Patients

BACKGROUNDEven with modern diagnostics, appendicitis can be difficult to diagnose accurately. Negative appendicectomies (NA) and delayed diagnosis of complicated appendicitis (CA, i.e. perforation or abscess) remain common. Serum bilirubin has been proposed as an additional biomarker to assist with the diagnosis of appendicitis. In this large series, we assessed the value of bilirubin in the diagnosis of appendicitis.METHODS A retrospective review of patients with suspected appendicitis at three hospitals over a three year period was performed. All consecutive patients with appendicectomy were included. In addition, a “discharged” sub-group of consecutive patients who were admitted with suspected appendicitis but discharged without an operation was also identified.Demographic data, presence of fever, tachycardia, total white cell count (WCC), neutrophil count, total serum bilirubin, operative findings and final histology were recorded. Multivariate logistic regression was performed to determine independent predictors of appendicitis and CA. Receiver-operator analysis was performed to compare bilirubin to WCC and neutrophil count.RESULTS There were 2024 patients: 1167 had uncomplicated appendicitis, 355 had CA and 303 underwent NA. 200 non-surgical "discharged" patients were included for comparison. Compared to those without appendicitis (NA and discharged groups), increased serum bilirubin was associated with an increased likelihood of appendicitis (OR 1.030 (1.013, 1.048), p<0.0001) and increased likelihood of CA (OR 1.035, 95% CI (1.021, 1.050), p<0.001). These results remained significant when the discharged group, NA group and uncomplicated appendicitis groups were analyzed separately.The sensitivity and specificity of bilirubin was inferior to neutrophil count for the diagnosis of appendicitis (AUC 0.657 versus 0.725, p<0.0001). Bilirubin, WCC and neutrophils each were all relatively insensitive and non-specific over a variety of cut-off values and combinations did not improve their accuracy.CONCLUSION Hyperbilirubinaemia was independently associated with an increased likelihood of both uncomplicated and complicated appendicitis, however had similar sensitivity and specificity when compared to WCC or neutrophils. Bilirubin, neutrophil count and WCC alone are not discriminatory enough to be used in isolation but may be incrementally useful adjuncts in pre-operative assessment of patients with suspected appendicitis.