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.

Antibiotics as first-line therapy for acute appendicitis: evidence for a change in clinical practice.

BACKGROUND: Randomized studies have indicated that acute appendicitis may be treated by antibiotics without the need of surgery. However, concerns have been raised about selection bias of patients in such studies. Therefore, the present study was aimed to validate previous findings in randomized studies by a full-scale population-based application. METHODS: All patients with acute appendicitis at Sahlgrenska University Hospital (May 2009 and February 2010) were offered intravenous piperacillin plus tazobactam according to our previous experience, followed by 9 days out-hospital oral ciprofloxacin plus metronidazole. Endpoints were treatment efficacy and complications. Efficient antibiotic treatment was defined as recovery without the need of surgery beyond 1 year of follow-up. RESULTS: A total of 558 consecutive patients were hospitalized and treated due to acute appendicitis. Seventy-nine percent (n = 442) received antibiotics as first-line therapy and 20 % (n = 111) had primary surgery as the second-line therapy. Seventy-seven percent of patients on primary antibiotics recovered while 23 % (n = 100) had subsequent appendectomy due to failed initial treatment on antibiotics. Thirty-eight patients (11 %) of the 342 had experienced recurrent appendicitis at 1-year follow-up. Primary antibiotic treatment had fewer complications compared to primary surgery. CONCLUSIONS: This population-based study confirms previous results of randomized studies. Antibiotic treatment can be offered as the first-line therapy to a majority of unselected patients with acute appendicitis without medical drawbacks other than the unknown risk for long-term relapse, which must be weighed against the unpredicted but well-known risk for serious major complications following surgical intervention.