A Comparative Study of Appendicitis Inflammatory Response Score and Abdominal Ultrasound in Evaluation of Patients with Acute Appendicitis at University Teaching Hospital of Kigali

BACKGROUND: The presentation of acute appendicitis is sometimes atypical, creating a diagnostic problem. The appendicitis inflammatory response (AIR) score may help overcome this challenge. This study aimed to compare AIR score and abdominal ultrasound (US) for the evaluation of patients with acute appendicitis. METHODS: This prospective, descriptive, observational study included 42 patients who underwent appendectomy. Patients were classified as having either a high or intermediate probability of acute appendicitis. Statistical analyses compared the diagnostic performance of AIR score versus US. RESULTS: Patients included 26 males and 16 females with a mean age of 31 years. Their mean duration of symptoms was 2.4 days. The AIR score had a sensitivity and specificity of 43% and 100%, respectively, while US had a sensitivity and specificity of 92% and 20%, respectively. The AIR score demonstrated a higher specificity (100%) in the high probability group while US showed better sensitivity (94%) and specificity (100%) in the indeterminate probability group. The positive predictive value was greater for US (100%) than for AIR score (86%), but the negative predictive value was greater for AIR score (67%) than for US (19%). The area under the receiver operating characteristic curve was 0.74 for AIR score and 0.56 for US (p = 0.09). CONCLUSION: The AIR score is more specific and accurate in patients with a high probability of acute appendicitis and convincingly selects patients who need abdominal US for definitive diagnosis. Abdominal US is better at confirming the diagnosis or ruling out the possibility of appendicitis in equivocal cases.