The non-visualized appendix and secondary signs on ultrasound for pediatric appendicitis in the community hospital setting

Background: Secondary signs of appendicitis on ultrasound may aid with diagnosis in the setting of a non-visualized appendix (NVA). This role has not been shown in the community hospital setting. Materials and methods: All right lower quadrant ultrasounds performed in children for clinical suspicion of appendicitis over a 5-year period in a single community hospital were evaluated. Secondary signs of inflammation including free fluid, ileus, fat stranding, abscess, and lymphadenopathy were documented. Patients were followed for 1 year for the primary outcome of appendicitis. These data were analyzed to determine the utility of secondary signs in the diagnosis of acute appendicitis when an NVA is reported. Results: Six hundred and seventeen ultrasounds were reviewed; 470 of these had an NVA. Of NVAs, 47 (10%) of patients were diagnosed with appendicitis. Sensitivity and specificity of having at least one secondary were 38.3% and 80%, respectively. The positive and negative predictive values of having at least one secondary sign were 17.3% and 92%, respectively. Conclusion: These data suggest that the absence of secondary signs has a strong negative predictive value for appendicitis in the community hospital setting; however, the full utility of secondary signs may be limited in this setting.