Peds Appendix Ultrasound Often Non-diagnostic

Short Attention Span Summary

Has anyone ever gotten a positive appy ultrasound...ever?
In this study of over 400 pediatric ultrasound studies for appendicitis, 26% were diagnostic (positive or negative) and 74% were non-diagnostic.  Anecdotally, the non-diagnostic percentage seems even higher.  Improving sonographers' technical skill for this test could reduce the number of CT scans currently being done.

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Ultrasound is the right first imaging test to rule out appendicitis, but it's very important to set family expectations low and inform them that the study is often not diagnostic and that more imaging may be needed.  ALiEM has an outstanding post on "The non-visualized appendix quandary on ultrasound."


Abstract

J Emerg Med. 2017 Feb 28. pii: S0736-4679(17)30003-3. doi: 10.1016/j.jemermed.2017.01.003. [Epub ahead of print]

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

Alter SM1, Walsh B2, Lenehan PJ3, Shih RD1.

Author information:

1 Division of Emergency Medicine, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida.

2 Department of Emergency Medicine, Morristown Medical Center, Morristown, New Jersey.

3 Department of Emergency Medicine, California Hospital Medical Center, Los Angeles, California.

Abstract

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.

Copyright © 2017 Elsevier Inc. All rights reserved.

PMID: 28258881