Clinical and Imaging Correlates of Pediatric Mucosal Appendicitis.

BACKGROUND: Mucosal appendicitis is a controversial entity that is histologically distinct from transmural appendicitis. There is mixed opinion regarding mucosal inflammation as a spectrum of appendicitis versus a negative appendectomy. The ability to distinguish these diagnoses preoperatively is of importance to prevent unnecessary surgery. We hypothesize that patients with mucosal appendicitis can be discriminated from those with transmural disease based on specific preoperative clinical and imaging findings. MATERIALS AND METHODS: After IRB approval, all patients who underwent laparoscopic appendectomy at our institution during 2015 were reviewed in the electronic medical record. 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 history, examination, laboratory, and imaging findings. Preoperative factors associated with mucosal appendicitis were modeled using binomial logistic regression analysis. RESULTS: Of 1153 appendectomies performed during 2015, 103 patients had pathologic diagnosis of mucosal appendicitis. When compared with patients with mucosal infection, leukocytosis >10,000 per microliter led to 5.9 times higher likelihood of transmural pathology (P = 0.000). Noncompressibility on ultrasound was associated with 7.3 times higher likelihood of transmural disease (P = 0.015). Echogenic changes were predictive of transmural appendicitis, conferring 3.9 times the risk (P = 0.007). Presence of free fluid led to 2.3 times the rate of transmural pathology (P = 0.007). Finally, for every millimeter decrease in appendiceal diameter, patients were half as likely to exhibit transmural disease (P = 0.000). Together, these variables can successfully predict presence of mucosal appendicitis on final pathology report at a rate of 82.1%, and explain 60% of the variance in diagnosis of mucosal versus transmural appendicitis (P = 0.000). CONCLUSIONS: Mucosal appendicitis remains a controversial pathologic entity, but is not associated with greater complications compared with transmural appendicitis when treated with laparoscopic appendectomy. Transmural disease can be predicted by leukocytosis, noncompressible appendix, presence of free fluid, larger appendiceal diameter and echogenicity.

Diagnostic Utilization and Accuracy of Pediatric Appendicitis Imaging at Adult and Pediatric Centers.

BACKGROUND: Diagnostic imaging in pediatric appendicitis may decrease rates of negative appendectomy and identify alternate pathologies. We compared imaging practices for children transferred from nonpediatric facilities versus directly admitted to our tertiary children's hospital for laparoscopic appendectomy, and assessed the diagnostic accuracy in each population based on final pathologic diagnosis. MATERIALS AND METHODS: After institutional review board approval, all cases of laparoscopic appendectomy at our children's hospital during 2015 were reviewed. Demographic and clinical data were collected, including age, transfer status, imaging studies, and pathologic diagnosis. Imaging practices in patients transferred from adult centers were compared with those directly admitted. RESULTS: There were 1153 included patients who underwent laparoscopic appendectomy for acute appendicitis during the study period, with 242 (20.9%) presenting as transfers from nonpediatric facilities. Of these, 73.5% underwent preoperative computed tomography (CT), compared with 26.4% of nontransfer patients (P < 0.000). All remaining patients received ultrasound (US). Despite variation in imaging strategies, rates of negative appendectomy were similar in transfer and nontransfer groups (1.7% versus 2.0%, respectively, P = 0.744). There were marginal differences in sensitivity of US and CT to detect appendix features between the transferring and referral centers. CONCLUSIONS: Our results show that nonpediatric facilities use CT more frequently to diagnose pediatric appendicitis. Rates of nontherapeutic surgery were equivalent between transferred and directly admitted patients, which is likely related to high performance of both imaging strategies. Transferring centers should strive to rely more heavily on US, which may require education and development of improved pediatric US capacity.