[The Alvarado score validation in diagnosing acute appendicitis in children at Braga Hospital].

Introduction: Acute appendicitis (AA) is the leading cause of emergency abdominal surgery in children. The diagnosis is essentially clinical, but some methodologies, such as Alvarado score (AS), have been developed in order to avoid non-therapeutic laparotomy (15-30%). AS ≥ 5 or 6 is compatible with AA and is an indication for the patient to remain on observations, if AS ≥ 7 a laparotomy procedure may be indicated.

Objective: To validate the AS for the AA diagnosis of children admitted at Braga Hospital.

Methods: A validation study of diagnostic method (AS) using the histological examination as a gold standard. The study population consisted of 192 children (4-17 years) with abdominal pain that underwent appendectomy in the last 20 months (December 2008 to July 2010). It was determined the values of sensitivity (S), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR) and the ROC curve for three different cut-off points (SA =5, 6 and 7).

Results: We found that as the cut-off point of AS decreases progressively the sensitivity and specificity increases and reduces the VPN and VPP. Assuming a cut-off value of 5, only 18 children would be false negatives, instead of the 67 children if the cut-off point was 7 points. The analysis of ROC curves demonstrated a greater area under the curve for a cut-off equal to or greater than 5 (AUC = 70%).

Discussion: We recommend using a cut-off value of 5 points, since only 18 children with AA were initially classified as appendicitis unlikely, this value would increase to 67 patients for the SA value of ≥ 7. The AS is a valuable tool in screening children with abdominal pain for the diagnosis of AA. Nonetheless the diagnosis and final decision must be based on clinical and systematic reassessment of patients.