A model to select patients who may benefit from antibiotic therapy as the first line treatment of acute appendicitis at high probability.

BACKGROUND

Randomized studies indicated that 88-95% of patients with acute appendicitis recover on antibiotics without surgery, although it is unclear which patient would benefit with high probability on antibiotics. We hypothesized that patients with phlegmonous appendicitis should be a group where antibiotics may be a sufficient treatment. Accordingly, our aim was to propose a model to support treatment application for unselected patients with acute appendicitis.

METHODS

Retrospective analyses of preoperative clinical and laboratory variables in 384 consecutive adult patients, who underwent appendectomy with histological examination of the appendix, were evaluated by logistic regressions. The proposed mathematical model was then evaluated on a prospectively collected population based material of 581 consecutive patients offered antibiotics as their first line treatment of acute appendicitis.

RESULTS

Patients with assumed appendicitis who fulfilled all criteria with CRP <60 g/L, WCC <12 × 10(9)/L, and age <60 years had 89% probability to have phlegmonous appendicitis. When these criteria were applied retrospectively on a prospective material, 88% of operated patients had phlegmonous inflammation and 89% had recovered on antibiotics without surgery.

CONCLUSION

Standard clinical and laboratory tests are individually weak predictors of phlegmonous appendicitis, but can be used in combinations as a bedside instrument to select patients suitable for antibiotic therapy.