Evaluation of the modified alvarado score as a diagnostic tool for appendicitis

Abstract

Background: Decision making in cases of acute appendicitis may be difficult especially for junior surgeons. This was reflected in the high negative appendicectomy rate in Mulago hospital. Modified Alvarado Scoring System (MASS) was helpful in minimizing unnecessary appendicectomies. The aim of this study was to evaluate the validity of MASS as a diagnostic tool for appendicitis. Patients and methods: All patients aged 13 years and above who were admitted with a provisional diagnosis of appendicitis into Mulago Hospital, Kampala Uganda, over the period of October 2004 to April 2004 were prospectively entered into the study. The study included 204 patients between the ages 13 and 84 years. They were prospectively evaluated on admission using the Modified Alvarado Score System (MASS) to determine whether or not they had acute appendicitis. The MASS was correlated with the operative and histopathological findings. Results: 151 patients (74.0%) had appendicectomies of which 24 patients (15.9%) had normal appendices on histopathology examination. Overall the MASS showed a sensitivity of 71.3% and a specificity of 62.55%. For males the sensitivity was 72.4% and the specificity was 50.0%. For females the sensitivity and specificity were 69.0% and 68.8% respectively. Conclusion: From the results, the MASS is not sufficiently valid to be adopted as a sole method of diagnosing acute appendicitis in adults in out environment. Rather it can be used for screening cases that may require further radiological evaluation. Further requirements may be needed to improve its sensitivity and specificity.