Appendiceal outer diameter as an indicator for differentiating appendiceal mucocele from appendicitis

Lien, Wan-Ching; Huang, Shih-Pei; Chi, Chun-Lin; Liu, Kao-Lang; Lin, Ming-Tsan; Lai, Ting-I; Liu, Yueh-Ping; Wang, Hsiu-Po

doi:10.1016/j.ajem.2006.04.003

« Previous Next »American Journal of Emergency Medicine
Volume 24, Issue 7 , Pages 801-805, November 2006

Appendiceal outer diameter as an indicator for differentiating appendiceal mucocele from appendicitis

Wan-Ching Lien, MD
- Department of Emergency Medicine, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei 100, Taiwan
Shih-Pei Huang, MD
- Department of Internal Medicine, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei 100, Taiwan
Chun-Lin Chi, MD
- Department of Emergency Medicine, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei 100, Taiwan
Kao-Lang Liu, MD
- Department of Radiology, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei 100, Taiwan
Ming-Tsan Lin, MD, PhD
- Department of Surgery, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei 100, Taiwan
Ting-I Lai, MD
- Department of Emergency Medicine, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei 100, Taiwan
Yueh-Ping Liu, MD
- Department of Emergency Medicine, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei 100, Taiwan
Hsiu-Po Wang, MD
- Department of Emergency Medicine, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei 100, Taiwan
- Corresponding author. Tel.: +886 2 23123456x2831; fax: +886 2 23223150.

Received 24 November 2005; received in revised form 2 April 2006; accepted 27 April 2006.

Abstract

Background

Patients with appendiceal mucocele (AM) commonly present with features indicative of acute appendicitis. In emergency departments, accurate preoperative diagnosis is crucial to prompt appropriate treatment. This study investigates the clinical and sonographic characteristics of AM, which may prove useful in preoperatively differentiating AM from appendicitis.

Methods

This case-control study compares the clinical and sonographic findings of 16 histologically confirmed AM with sex- and age-matched control subjects (n = 64) with appendicitis by a 1:4 ratio. Conditional logistic regression was applied to estimate the odds ratio (OR) and 95% confidence intervals (CI) of clinical and sonographic parameters associated with AM.

Results

Univariate analysis demonstrated that the larger appendiceal outer diameter by sonography was positively correlated with diagnosis of AM (OR, 2.31; 95% CI, 1.42-3.72) and right lower quadrant abdominal pain was negatively correlated (OR, 0.38; 95% CI, 0.17-0.82). However, multiple regression analysis suggested that only outer diameter remained significant (OR, 2.21; 95% CI, 1.36-3.59) after adjusting for age, sex, and right lower quadrant pain. An outer diameter of 15 mm or more was predictive of AM diagnosis, with a sensitivity of 83% and specificity of 92%.

Conclusion

When the threshold is set at 15 mm, appendiceal outer diameter by sonography is a useful preoperative measurement for differentiating between AM and acute appendicitis.