The Alvarado scoring system in acute appendicitis: A 6-month cross-sectional study to evaluate its reliability in reducing the rate of negative appendicectomy at Queen’s Hospital, Burton

Abstract

Introduction

Globally, acute appendicitis is the most common paediatric intra-abdominal surgical emergency. The variations at presentation and the lack of a single reliable test to aid diagnosis may pose challenges to experienced surgeons. There are many scoring systems employed by surgeons to reduce the percentage of negative appendicectomies. One such example is the Alvarado system. The aim of our study was to evaluate the usefulness of the Alvarado scoring system in reducing the percentage of negative appendicectomies at Queen’s Hospital, a small district general hospital in England.

Case description

A 6-month cross-sectional study was carried out. Patients who were 16 years old or younger with a preliminary diagnosis of acute appendicitis were included in the study and their Alvarado score calculated. On the basis of their individual Alvarado score, they were placed in one of two groups: Group A (Alvarado score <6) and Group B (Alvarado score ≥6). The signs, symptoms, laboratory values, surgical interventions and histopathological reports, the gold standard for diagnosis of acute appendicitis, were then evaluated. The reliability of Alvarado scoring system was assessed by calculating the rate of negative appendicectomies which we defined as patients showing no signs of appendiceal inflammation on histopathology of the surgically removed appendix.

Results and Conclusions

26 patients (21 males, 5 females) were included in the study. They comprised 9 patients in Group A (34.6%) and 17 patients in Group B (65.4%). The largest age group was represented by 10-15 year olds (n=16, 61.5%). The symptoms at presentation included right iliac fossa pain (92.3%), nausea or vomiting (76.9%) and anorexia (73.1%). Clinical examination revealed tenderness in the right iliac fossa in all patients (100%), rebound tenderness in 16 cases (61.5%) and elevated temperature in 3 cases (11.5%). Laboratory analysis showed raised total leukocyte count in 12 cases (46.2%) with neutrophilia in 10 cases (38.5%). Of the 26 cases, 84.6% (n=22) were confirmed to have inflamed appendix by the surgeon performing the appendicectomy at the time of surgery. However, final diagnosis of inflamed appendix based on histopathology reports were confirmed in 19 cases (73.1%). The overall negative appendicectomy rate was therefore 26.9% (7 cases). The rate of negative appendicectomies in males and females were 15.4% and 11.5% respectively. The negative appendicectomy rate in Group A and B were 33.3% and 17.6% respectively. Sensitivity and specificity of Alvarado score in our study were 82% and 100% respectively.

Take home message

Regarding, the reliability of the Alvarado scoring system, our recommendations are:

(1) false negatives are few especially in high Alvarado scores (9 or greater);

(2) further investigations may be employed in low scores (<6) where the number of false negatives are greater;

(3) the Alvarado scoring system should be used to supplement the diagnostic accuracy of acute appendicitis. It does not however replace the experience and expertise of the surgeon.

Surgery were performed in all the cases, along with conservative treatment pre-and post-surgery. Final diagnosis using histopathology reports was confirmed in 19 cases (73.1%) The overall rate of negative appendicectomy was therefore 26.9%. Sensitivity and positive predicted value of the Alvarado score were 82% and 100% respectively.