Prospective evaluation of a clinical pathway for suspected appendicitis.

Objective: To evaluate the diagnostic accuracy of a clinical pathway for suspected appendicitis combining the Samuel's pediatric appendicitis score (PAS) and selective use of ultrasonography (US) as the primary imaging modality.

Methods: Prospective, observational cohort study conducted at an urban, academic pediatric emergency department. After initial evaluation, patients were determined to be at low (PAS 1-3), intermediate (PAS 4-7), or high (PAS 8-10) risk for appendicitis. Low-risk patients were discharged with telephone follow-up. High-risk patients received immediate surgical consultation. Patients at intermediate risk for appendicitis underwent US.

Results: Of the 196 patients enrolled, 65 (33.2%) had appendicitis. An initial PAS of 1-3 was noted in 44 (22.4%), 4-7 in 119 (60.7%), and 8-10 in 33 (16.9%) patients. Ultrasonography was performed in 128 (65.3%) patients, and 48 (37.5%) were positive. An abdominal computed tomography scan was requested by the surgical consultants in 13 (6.6%) patients. The negative appendectomy rate was 3 of 68 (4.4%). Follow-up was established on 190 of 196 (96.9%) patients. Overall diagnostic accuracy of the pathway was 94% (95% confidence interval [CI] 91%-97%) with a sensitivity of 92.3% (95% CI 83.0%-97.5%), specificity of 94.7% (95% CI 89.3%-97.8%), likelihood ratio (+) 17.3 (95% CI 8.4-35.6) and likelihood ratio (-) 0.08 (95% CI 0.04-0.19).

Conclusions: Our protocol demonstrates high sensitivity and specificity for diagnosis of appendicitis in children. Institutions should consider investing in resources that increase the availability of expertise in pediatric US. Standardization of care may decrease radiation exposure associated with use of computed tomography scans.