K. Gee1, R. Jones1, S. Preston1, A. Beres1,2 1University Of Texas Southwestern Medical Center,Surgery,Dallas, TX, USA 2Children’s Medical Center,Surgery,Dallas, Tx, USA
Introduction: Mucosal appendicitis is a controversial entity that is histologically separate from transmural appendicitis. Therefore, the ability to distinguish mucosal appendicitis from transmural appendicitis preoperatively is of importance. We hypothesize that patients with mucosal appendicitis can be distinguished based upon specific preoperative imaging findings.
Methods: After IRB approval, charts were evaluated from all patients who underwent laparoscopic appendectomy at our institution during 2015. Patients with mucosal appendicitis were identified and matched 2:1 to a random cohort of nonperforated transmural appendicitis cases. Demographic and clinical data were collected, including imaging and pathology findings. Preoperative predictors of mucosal appendicitis were modeled using binomial logistic regression analysis. Predictive factors tested included sex, age, use of multiple imaging studies, and the following imaging features: whether the appendix was visualized, compressibility, hyperemia, thickened appendiceal wall, dilation of appendix, presence of abdominal free fluid, fluid collection, surrounding echogenicity, dilated bowel, lymphadenopathy, and appendicolith.
Results: Mucosal appendicitis was identified in 103 patients. Female patients were 1.8 more likely to have mucosal appendicitis (95% CI 1.1-3.3). Compressibility on ultrasound was associated with 2.9 times more likelihood of mucosal disease (95% CI 1.3-6.5). Non-dilated appendix correlated with 3.8 times more likelihood of mucosal infection (95% CI 1.4-9.8), and lack of free fluid led to 2.1 times more likelihood of mucosal disease (95% C I1.1-3.7). Most significantly, lack of echogenic changes in surrounding tissue was predictive of mucosal appendicitis, conferring 4.8 times the risk (95% CI 2.3-10.0). Finally, patients who underwent multiple imaging tests were 3.1 times more likely to have mucosal appendicitis (CI 1.2-8.0). Together, these variables can successfully predict presence of mucosal appendicitis on final pathology report at a rate of 74.5%, and explain 29% of the variance in diagnosis of mucosal versus transmural appendicitis (p <0.0001 ).
Conclusion: Mucosal appendicitis is a controversial entity. When compared to transmural appendicitis, US findings of mucosal appendicitis are more likely to include non-dilated, compressible appendix, lack of free fluid. Additional studies examining the presenting symptoms and post-operative complications of mucosal versus transmural appendicitis may further delineate the clinical significance of mucosal appendicitis.