Predictors and outcomes of nondiagnostic ultrasound for acute appendicitis in children

Abstract

Ultrasound assessments of children with possible acute appendicitis (AA) are often nondiagnostic. We aimed to identify the predictors of nondiagnostic ultrasound and to investigate the outcomes. A retrospective review was conducted on children aged 4 to 17 years evaluated in 2013 for AAwith ultrasound at a tertiary hospital pediatric emergency department. Demographics, clinical data, and outcomes were analyzed. Of 528 children, 194 (36.7%) had diagnostic ultrasounds and 334 (63.3%) had nondiagnostic ultrasounds. Nondiagnostic ultrasounds were more common after-hours (7 PM-7 AM weekdays and on weekends, 70.7%) than during business hours (7 AM-7 PM weekdays; 29.3%). After-hours timing and female sex were identified as independent predictors of nondiagnostic ultrasounds (P < 0.05 for both). AA was diagnosed in 35 children with a nondiagnostic ultrasound (10.5%; P < 0.05). No child who underwent a nondiagnostic ultrasound was found to have AA with laboratory values of white blood cell < 11 × 103/μL and c-reactive protein (CRP) < 5 mg/dL. Children with nondiagnostic ultrasounds have a low likelihood of AA if white blood cell < 11 and CRP < 5. We propose a management algorithm that we hope will help reduce admissions and decrease the use of computed tomography scans.