Post-operative antibiotics after appendectomy and post-operative abscess development: a retrospective analysis.

Background: Appendectomy is one of the most common emergency operations. Prophylaxis against infective complications involves post-operative antibiotics. There is no consensus as to the optimum antibiotic regimen. This study aimed to assess the relation between the duration of the post-operative antibiotic administration and intra-abdominal infections (IAIs).

Methods: All patients who underwent appendectomy between September 1, 2009, and August 31, 2010, were identified. The appearance of the appendix at operation, post-operative antibiotics, white blood cell count, and temperature at the time of conversion of intravenous (IV) to oral antibiotics were compiled. IAIs were assessed as the final outcome.

Results: Two hundred sixty six patients underwent appendectomy-188 for simple appendicitis and 78 for complicated appendicitis. There were 18 IAIs (6.8%) overall, 10 (12.8%) after complicated appendicitis and eight (4.2%) after simple appendicitis. Prolonging antibiotics beyond the operation in the simple appendicitis group did not alter the incidence of IAI. Similarly, in the complicated appendicitis group, prolonging antibiotics beyond five days did not alter the incidence of IAI. Furthermore, in patients with complicated appendicitis, the presence of leukocytosis, fever, or both when IV antibiotics were converted to oral drugs was associated with the development of IAI (p=0.013).

Conclusions: In simple appendicitis, post-operative antibiotics may not be beneficial at all. In complicated appendicitis, prolonging the course of antibiotics was not associated with a reduced IAI rate. However, cessation of IV antibiotics when fever or leukocytosis was present was associated with IAI development.