Is preoperative distinction between complicated and uncomplicated acute appendicitis feasible without imaging?

Background. One of the main aims of appendicitis research is the differential diagnostics between complicated and uncomplicated acute appendicitis that enable provision of the optimal treatment for each patient. Methods. Data in the present study were collected prospectively in our randomized antibiotic treatment for uncomplicated acute appendicitis trial (APPAC) comparing surgery and antibiotic treatment for uncomplicated acute appendicitis (NCT01022567). We evaluated 705 patients who had acute appendicitis on computed tomography. Patients with uncomplicated acute appendicitis (n = 368) were compared with all complicated acute appendicitis patients (n = 337), and subgroup analyses were performed between uncomplicated acute appendicitis and an appendicolith appendicitis (CA1; n = 256) and uncomplicated acute appendicitis and perforation and/or abscess (CA2; n = 78). Age, sex, body temperature (degrees C), duration of symptoms, white blood cell count (E9/L), and C-reactive protein (mg/L) were recorded on admission. Receiver operating characteristic curves were calculated for white blood cell count, C-reactive protein, and temperature. Results. CA2 patients had significantly greater C-reactive protein levels (mean 122 and 47, respectively, P < .001) and longer duration of symptoms than uncomplicated acute appendicitis patients; 81 % of CA2 patients and 38% of uncomplicated acute appendicitis patients had symptoms >24 hours before admission (P < .001). In receiver operating characteristic analysis, C-reactive protein and temperature had clinically significant results only in comparison with uncomplicated acute appendicitis and CA2 (area under the curve >0.7), but no optimum cutoff points could be identified. Conclusion. In clinical decision making, neither clinical findings nor laboratory markers are reliable enough to estimate the severity of the acute appendicitis accurately or to determine the presence of an appendicolith. The current results emphasize the role of computed tomography in the differential diagnosis of complicated and uncomplicated acute appendicitis.