Clinically distinguishing between appendicitis and right-sided colonic diverticulitis at initial presentation

PURPOSE: Most patients diagnosed with right-sided colonic diverticulitis complain of right lower quadrant pain, which is frequently confused for appendicitis and therefore may result in unnecessary emergency surgery. In this paper we intend to differentiate between right-sided colonic diverticulitis and appendicitis by initial presentation in the emergency department. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 450 patients between January 1997 and July 2003. Among these patients, 92 with right-sided colonic diverticulitis were classified as group I; 268 patients with simple appendicitis were classified as group II; and 90 patients with perforated appendicitis were classified as group III. RESULTS: Prodromal symptoms were less common in group I (p < 0.05) than in the other groups. In comparing the location of maximal tenderness among groups, 19.6% of group I patients complained of maximal tenderness at a point lateral to McBurney's point, a greater percentage than those in groups II and III (p=0.002). Group I experienced less leukocytosis (10,913.8/mm(3)) than did groups II (13,238.3/mm(3)) and III (15,589.3/mm(3)). The percentage of segmented forms in the differential counts was also smaller in group I (73.6%) than in groups II (79.1%) and III (81.8%). In addition, the proportion of lymphocytes was larger in group I (17.7%) than in groups II (13.9%) and III (9.3%). CONCLUSION: Among patients complaining of right lower quadrant pain in an emergency setting, right-sided colonic diverticulitis must be considered in the following conditions to avoid unnecessary emergency operations: lack of prodromal symptoms, tenderness at a point lateral to McBurney's point, and absent or mild leukocytosis with a low fraction of segmented forms and a high fraction of lymphocytes in the CBC.