The use of the clinical scoring system by Alvarado in the decision to perform computed tomography for acute appendicitis in the ED

Study Objective: Appendicitis is part of the differential of an acute abdomen and can be a difficult diagnosis to make. Strategies to suggest which patients presenting to the emergency department (ED) should undergo computed tomography (CT) scan to confirm appendicitis have not been addressed. We develop guidelines for CT scanning based on Alvarado clinical scores for patients with suspected and confirmed cases of appendicitis. Methods: A retrospective review of 150 charts of patients aged 7 and older who presented with abdominal pain to the ED of a 392-bed acute care facility over a 6-month period were evaluated by ED physicians and underwent CT to rule out appendicitis. Patient demographics, presenting signs, and symptoms were documented. Using the scoring system for appendicitis, developed by Alvarado, each chart was retrospectively scored. The Alvarado scores were correlated with positive pathology findings, as well as Alvarado scores with a negative CT scan. Equivocal scores, having neither high sensitivity nor specificity for appendicitis were calculated. Results: Computed tomography scans with Alvarado scores of 3 or lower were performed in 37% (55/150) of patients to rule out appendicitis. The sensitivity of Alvarado scores 3 or lower for not having appendicitis was 96.2% (53/55), and the specificity 67% (2/3). Patients with Alvarado scores 7 or higher had an incidence of acute appendicitis of 77.7% (28/36). The sensitivity of Alvarado scores 7 or higher for appendicitis was 77% (28/36), and the specificity 100% (8/8). The sensitivity of equivocal Alvarado scores, defined as scores of 4 to 6, for acute appendicitis was 35.6% (21/59), and the specificity 94% (36/38). The sensitivity and specificity of CT scans in patients with equivocal Alvarado scores remained high, at 90.4% and 95%, respectively. Conclusions: In the equivocal clinical presentation of appendicitis as defined by Alvarado scores of 4 to 6, adjunctive CT is recommended to confirm the diagnosis in the ED setting. If clinical presentation suggests acute appendicitis by an Alvarado score of 7 or higher, surgical consultation is recommended. Computed tomography is not indicated in patients with Alvarado scores of 3 or lower to diagnose acute appendicitis. (c) 2007 Elsevier Inc. All rights reserved.