Diagnosis of acute appendicitis in children using a clinical practice guideline

Purpose: In October 2000, our institution implemented a clinical practice guideline (CPG) utilizing selective computed tomography (CT) and ultrasound scan (US) for the evaluation of children with suspected appendicitis. The authors sought to determine surgical outcomes and diagnostic accuracy in the CPG period. Methods: The authors retrospectively analyzed the medical records of patients evaluated under the CPG at their institution between January 1 and December 31, 2001. Depending on a patient's clinical presentation, the CPG recommends immediate surgery or further evaluation with CT or US. CPG patients were identified if they received an appendectomy or a CT or US for suspected appendicitis. Negative appendectomy and perforation rates, as well as admissions for inpatient observation were compared with control patients treated for suspected appendicitis at our hospital in 1997, before frequent utilization of imaging studies. Results: In the CPG period, 571 patients were evaluated for acute appendicitis, with 272 undergoing an appendectomy. Whereas 513 patients (90%) received a CT or US, only 34 patients (6%) were admitted to the surgical service for serial examinations. Patients with a histologically normal appendix decreased from 27 of 255 (10.6%) in 1997 to 15 of 272 (5.5%) in 2001 (P = .03). Fifty-seven patients (22.2%) in 2001 had a perforated appendix compared with 65 (28.5%) in 1997 (P = .11). The CPG, incorporating clinical judgment and selected imaging, had a sensitivity of 98.8%, a specificity of 95.2%, and positive and negative predictive values of 94.4% and 99.0%, respectively. Conclusions: A clinical practice guideline selectively utilizing CT and US is highly accurate in the diagnosis of acute appendicitis, minimizing the need for inpatient admission for serial examinations.