David Gracey MBChB, Presenter: Nothing to Disclose

Mark Jonathan McClure MBBCh, Abstract Co-Author: Nothing to Disclose

To prospectively evaluate the impact of appendix ultrasound (US) on the clinical management of patients presenting with suspected acute appendicitis.

The referring surgeon completed a proforma for patients presenting with suspected acute appendicitis. Two visual analogue scales, graded 0-10, assessed clinical suspicion before and after knowledge of laboratory results. The surgeon also indicated if they intended to operate had US been unavailable. Graded compression US of the right iliac fossa was performed and the appendix considered inflamed if it was incompressible and measured ≥6mm. Findings were correlated with histopathology results.

During a 3-year period 327 patients (216 female, 111 male; age 3-89 yrs, mean 23.8) were examined. Clinical suspicion (mean 4.9, SE 0.1) was not significantly altered (mean 4.9, SE 0.1) by knowledge of laboratory results. The decision to operate if US had been unavailable, was "yes" in 70 cases (Group A), "no" in 231 (Group B) and incomplete in 26 (excluded). In Group A, 31 patients (44%) had a negative US. 6 of these proceeded to surgery demonstrating acute appendicitis (n=2), pinworm (n=2) and no abnormality (n=2). The remainder (n=25) avoided surgery. US confirmed 39 cases of appendicitis. 2 appendix abscesses were treated conservatively. 37 appendectomies were performed identifying appendicitis (n=34), fibrosis (n=1), appendicolith (n=1) and no abnormality (n=1). In Group B, 72 (31%) patients had a positive US. 5 appendix abscesses were treated conservatively. 61 appendectomies identified appendicitis (n=51), pinworm (n=3) and no abnormality (n=7). 10 patients with negative US progressed to surgery confirming appendicitis (n=4) and no abnormality (n=6). US sensitivity was 94.7% in Group A, 93.3% in Group B and 93.8% overall. Specificity was 90.6% in both Groups and overall. US findings were contrary to intended surgical management in 103 cases. Management was altered in 97 cases (32.2%), with a positive outcome in 85 (28.2%).

US of the appendix increases diagnostic accuracy, alters management and is more sensitive and specific than clinical impression, either alone, or in conjunction with laboratory results.

Gracey, D, McClure, M, The Impact of Ultrasound in Suspected Acute Appendicitis.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4416768.html