Evaluation of the usefulness of modified alvarado scoring system regarding early diagnosis of acute appendicitis and in reduction of negative appendicectomies at Kenyatta National hospital: a prospective study

Abstract

AIM The aim of the study was to evaluate the impact of the modified Alvarado score on the negative appendicectomy rate in acute appendicitis.

SETTING KNH emergency department, general and paediatric surgical units, Nairobi, Kenya . MATERIALS AND METHODS A prospective study was undertaken between June 30th, and December 30th, 2004 that It included 116 patients who presented with a suspicion of acute appendicitis and underwent apendicectomy. All the patients were examined and a sample for haemogram taken at the emergency department to facilitate the scoring. The patients were then followed up to the ward a decision to operate on them was made independent of the score, but based on the operator's clinical judgment. At surgery, all the 116 patients had their gross intra-operative findings noted, specimen taken for histopathological reporting. The histopathological finding~ were used to verify the true diagnosis of acute appendicitis. RESULTS A total of 116 patients aged between seven and fifty-five years with an average age of twenty-seven point zero one (27.03 (9.87) years had appendicectomy and specimens taken for histopathological analysis. Seventy-nine patients were males whereas thirty seven patients were females giving a ration of2.l :1. All the 116 specimens were processed, 87 (75%) were reported as positive for acute appendicitis and the rest 29 (25%) as normal vermiform appendix. The patients who had a score 0-4 points were 20 out of which 16 (13.7)% patients had normal appendicectomy and 4 (3.4%) had acute 1 appendicitis. Those who scored 5-6 points were 35 patients, and 27 (23.3%) had acute appendicitis whereas 8 (6.8%) had normal appendicectomy. Those who scored 7-10 points were 61 patients, and 56 (48.3%) had acute appendicitis whereas 5 (4.3%) had unnecessary appendicectomy. The overall negative appendicectomy rate (NA) was 25%, of which 21.5% of the males and 32.5% ofthe females had normal appendix removed. The modified Alvarado score adjusted NA rate was calculated to be 11.2%(P value of 0.000) CONCLUSIONS The study showed a male preponderance ratio of2.1 :1, with a peak age incidence between 10-30 years. Twenty five percent of the appendicectomies were normal based on clinical judgment of the senior house officers. When Modified Alvarado score was applied in retrospect the negative appendicectomy rate reduced to 11.2% (p value of 0.000).