A Clinical Decision Rule to Establish the Diagnosis of Acute Diverticulitis at the Emergency Department

Abstract

The aim of this study was to identify patients in whom the clinical diagnosis of diverticulitis can be made with a high certainty, distinguishing them from patients requiring imaging. We prospectively recorded clinical features in patients with acute abdominal pain presenting at the emergency department, before they underwent imaging. We identified features significantly associated with a final diagnosis of acute diverticulitis using multivariate logistic regression analysis and developed a decision rule based on these features. We evaluated the performance of the rule in identifying patients with a high probability of having diverticulitis. In total, 112 of the 1021 patients (11%) had a final diagnosis of diverticulitis. Of the 126 patients with clinically suspected diverticulitis, 80 had a final diagnosis of diverticulitis. In 32 patients with diverticulitis as their final diagnosis, another clinical diagnosis was made. A decision rule was based on the 3 strongest clinical features: direct tenderness only in the left lower quadrant, the absence of vomiting, and a C-reactive protein >50 mg/L. Of the 126 clinically suspected patients, 30 patients had all 3 features (24%), of whom 29 had a final diagnosis of acute diverticulitis (97%; 95% CI: 83%-99%). Of the 96 patients without all 3 features, 45 (47%) did not have diverticulitis. In a quarter of patients with suspected diverticulitis, the diagnosis can be made clinically based on a combination of direct tenderness only in the left lower quadrant, the absence of vomiting, and an elevated C-reactive protein. In patients without these features, imaging is required to reach adequate diagnostic accuracy.