Enterobius infection of the appendix: Is pre-operative distinction from true appendicitis possible?

Abstract Background: Enterobius vermicularis infection of the appendix can mimic appendicitis. Limited studies exist on preoperative evaluation of pinworm positive patients. We predict pediatric patients with post-operative appendiceal pathology showing Enterobius infection are distinguishable from typical acute appendicitis using clinical, laboratory, and imaging findings. Materials and Methods: Single center retrospective review of appendectomy patients was performed. Patients with surgical pathology positive for pinworms were matched with case controls, examining symptoms, pediatric appendicitis score, physical exam, laboratory values, imaging findings and post-operative pathology. Results: Of 1153 patients, 13 had pinworms on final pathology. Compared to controls, Enterobiasis patients were more likely to present with fever (p < .005) and less likely to have RLQ rebound tenderness (p < .005). These patients more often required multiple radiologic studies (p < 0.05) with smaller appendiceal diameter (8.1 vs 9.6 mm, p < 0.05). Pathologically, Enterobiasis patients more often had inflammation limited to the mucosa (p < .005). Conclusion: Our data aligns with other studies demonstrating limited appendiceal inflammation caused by pinworm infection. These patients presented with less impressive physical exam findings, a smaller appendix on US, and US that were equivocal for appendicitis when compared to controls. These patients could possibly avoid appendectomy via anti-helminth treatment.