Written by Vivian Lei
When faced with an equivocal appendix on ultrasound (US), use of secondary findings such as appendix diameter ≥ 7mm, presence of appendicolith, associated inflammatory changes, and WBC count greater than 10,000/mL can increase diagnostic certainty.
Why does this matter?
Even when the appendix is visualized on ultrasound, the diagnosis of appendicitis can still be uncertain. This study assessed secondary sonographic findings and lab results predictive of appendicitis in children.
Clinical correlation is recommended
This was a prospective study of children who underwent abdominal ultrasound during the workup of suspected appendicitis. Of the 1,252 initial enrolled patients, 762 (60.8%) had a visualized appendix on US. Researchers found the following sonographic findings to significantly increase the likelihood of acute appendicitis as confirmed by surgical pathology:
Appendix diameter of ≥ 7 mm (OR 12.4, 95% CI 4.7–32.7)
Presence of appendicolith (OR 3.9, 95% CI 1.5–10.1)
Presence of inflammatory changes (OR 10.2, 95% CI 3.9–26.1)
Additionally, a WBC count ≥10,000/μL had an odds ratio of 4.8 (95% CI 2.4–9.7), while a duration of abdominal pain of 3 days or more was significantly less likely to be associated with appendicitis in this model (OR 0.3, 95%CI 0.08–0.99).
Predictors for Acute Appendicitis in Children. Pediatr Emerg Care. 2019 May 24. doi: 10.1097/PEC.0000000000001840. [Epub ahead of print]
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Reviewed by Thomas Davis