Clinical predictors of gangrenous appendicitis: elevated total bilirubin level and computed tomography scan findings

Patients with gangrenous appendicitis usually require emergency surgery. Preoperative diagnosis of gangrenous appendicitis is clinically important but not always straightforward. We undertook this study to identify preoperative predictors of gangrenous appendicitis.

This was a single-center case-control study. We identified 162 patients who underwent appendectomy between September 2011 and August 2014 after the diagnosis of acute appendicitis was established. We identified laboratory parameters and computed tomography (CT) scan findings predictive of histologically or surgically diagnosed gangrenous appendicitis by univariable and multivariable analyses.

Of 146 study patients, gangrenous appendicitis was confirmed in 102. Univariable analysis showed that two laboratory factors (C-reactive protein []and total bilirubin [T-Bil]) and three CT scan findings were significant predictors for gangrenous appendicitis. Multivariable analysis showed that T-Bil and two CT scan findings (appendicolith and fat stranding around the appendix) were independent predictors. The combination of "T-Bil ≥ 1.0 mg/dL or appendicolith" was able to predict gangrenous appendicitis with a sensitivity of 90.5%, positive predictive value of 80.4%, and accuracy of 77.8%. The combination of "T-Bil ≥ 1.0 mg/dL or fat stranding around the appendix" was able to predict gangrenous appendicitis with a sensitivity of 98.9%, positive predictive value of 76.4%, and accuracy of 71.9%.

These combinations of laboratory and CT scan findings could be valuable as predictors of gangrenous appendicitis.