Evaluation of Factors Predicting Successful Outcome in Patients Undergoing Expectant Management of Uncomplicated Acute Appendicitis

Background: Expectant management, or non-operative management (NOM), with standalone intravenous antibiotic therapy, has emerged as an effective alternative to appendectomy for the treatment of uncomplicated acute appendicitis. Various clinical, biochemical, and radiological factors have been implicated in predicting the success or failure of outcomes. Therefore, it is important to identify patients at the onset who are likely to have successful outcomes for conservative management of uncomplicated acute appendicitis.

Methods: We prospectively enrolled 85 surgical patients diagnosed with uncomplicated acute appendicitis in our study. On admission, clinical features such as duration of symptoms, pulse rate (PR), history of fever within 24 hours of admission, modified Alvarado score and adult appendicitis score, biochemical parameters such as C-reactive protein (CRP), and hematological parameters such as total leukocyte count (TLC) were recorded. Radiological imaging of patients, namely ultrasonography and contrast-enhanced CT abdomen to evaluate appendix diameter and mural enhancement, was also undertaken. The outcome of expectant management for these patients (success or failure) was recorded, and the above-mentioned factors were evaluated to find a possible correlation with successful expectant management.

Results: We found that among 85 patients, 77.6% had a successful NOM of appendicitis, whereas 22.4% had a failed NOM of appendicitis. The duration of symptoms, pulse rate, fever within 24 hours of admission, TLC, percentage of neutrophils, CRP level, appendix diameter, modified Alvarado score, and adult appendicitis score were found to be statistically significant predictors of successful NOM of appendicitis according to univariate analysis. According to multivariable analysis, pulse rate and appendix diameter value were found to be statistically significant predictors of successful NOM of appendicitis. With each beat per minute (bpm) increase in pulse rate, there was a 0.30% decrease in the probability of a successful NOM of appendicitis. With each mm increase in appendix diameter, there was an 82% decrease in the probability of a successful NOM of appendicitis.

Conclusion: From our study, it can be concluded that patients who met the following criteria, i.e., duration of symptoms before presenting to surgical emergency less than two days, presence of fever within 24 hours of presenting to surgical emergency, pulse rate >90 bpm, TLC >12000 cells/dL, CRP >20 mg/L, appendix diameter >10 mm, modified Alvarado score ≥ 9, and adult appendicitis score ≥ 18, have a higher probability of failure of NOM and hence should be excluded from expectant management.