Accuracy of Alvarado Scoring System and Selective Computed Tomography in Diagnosis of Suspected Cases of Acute Appendicitis

Objective: To evaluate the diagnostic accuracy of combined Alvarado scoring system and selective computed tomography (CT) in the diagnosis of suspected cases of acute appendicitis. Material and methods: This study was conducted during the period March 2018 to January 2020 at Prince Mohammed bin Abdul-Aziz hospital (NGHA) in Al Madinah, KSA. It is a prospective study involving 100 consecutive patients attending the emergency department with right iliac fossa pain, excluding children below the age of 14 years and pregnant women. All patients were initially assessed by the Alvarado scoring system, and the result of each patient was recorded in a separate predesigned data sheath. Based on the patient's calculated Alvarado scores, patients were stratified into three groups: Group A (score ≤ 4), Group B (score 5-6), and group C (score ≥ 7). All patients in group A were discharged from the emergency department with instruction to return if their symptoms persist or get worse while all patients in group B had an abdominal multidetector CT scan (MDCT) with IV contrast and no oral contrast to help the diagnosis. Group C patients had surgery without further investigation. Alvarado scores were compared to intraoperative findings and histopathological examination of the removed appendix in those who were operated. The sensitivity, specificity, positive and negative predictive values of the scoring system in each group were calculated with special reference to the role of CT scan in improving the diagnostic accuracy of the scoring system in the middle group (group B). Result: 58 patients were male and 42 were female. Age range between 14 and 43 years with median age 24 years. Out of the 100 patients, 14 (8 males, 6 females) belonged to Group A, 23 (11 males, 12 females) to Group B and 63 (39 males, 24 females) to group C. Two patients from group A (one male and one female) were returned with worsening symptoms and subsequently operated for acute appendicitis. CT scan established the diagnosis of acute appendicitis in 16 out of the patients of group B with subsequent histological confirmation of acute appendicitis in 15 of them. Histopathology confirmed the diagnosis of acute appendicitis in 32 out of 63 patients of group C. Conclusion: Alvarado score has a high accuracy of ruling in and out acute appendicitis at the extremes of the score (≤7 and ≥4), however, the accuracy of the score to confirm or rule out acute appendicitis in the middle group (5 -6) is significantly low. Selective utilization of CT scan in patients in the middle of the score improves the diagnostic accuracy of the score and limits overutilization of CT scan in the other patients at the extremes of the score saving patients unnecessary exposure to radiation and health authorities’ time and cost without increasing the rate of negative appendectomy.