Ultrasound for Diagnosis of Appendicitis in a Community Hospital Emergency Department has a High Rate of Nondiagnostic Studies.

BACKGROUND

Radiation concerns are changing the way emergency physicians evaluate patients. This is especially prevalent in pediatrics, and exemplified by abdominal pain management. Large academic center-based studies suggest appendix ultrasound (U/S) is sensitive and specific for appendicitis, with low nondiagnostic rates.

OBJECTIVES

We sought to determine the diagnostic rate of appendix U/S and incidence of follow-up computed tomography (CT) imaging for pediatric patients at a community hospital.

METHODS

Design

Retrospective cohort.

SETTING

Emergency department with 85,000 annual visits.

POPULATION: Patients younger than 21 years old that had an appendix U/S over a 12-month period. U/S were performed by technicians and interpreted by radiologists. Investigators classified readings as "diagnostic" ("positive" and "negative") or "non-diagnostic" ("borderline" and "appendix not visualized") and identified follow-up CT studies and interpretations.

RESULTS

There were 441 pediatric appendix U/S performed; 26% were diagnostic (14% positive for appendicitis, 12% negative) and 74% nondiagnostic (5% borderline, 69% appendix not visualized). Follow-up CT scans were obtained in 19% of all patients, including 8% with positive U/S, 4% negative, 32% borderline, and 22% not visualized. Follow-up CT was nearly four times more likely in the nondiagnostic group than the diagnostic group (23% vs. 6%, p < 0.0001).

CONCLUSION

The utility of U/S to diagnose appendicitis at a community hospital is limited by a high rate of nondiagnostic studies. Some patients with diagnostic U/S even had follow-up CT imaging. To minimize radiation exposure in children, improvements should be made in the performance and acceptance of U/S as the primary modality of abdominal pain imaging at community hospitals.