“Amr Sign”: A Case-Control Study Evaluating the Diagnostic Value of a New Clinical Sign in the Diagnosis of Acute Appendicitis

Abstract

Introduction Acute appendicitis, a prevalent cause of acute abdominal pain and a common indication for emergency surgery, presents a diagnostic challenge due to its diverse clinical presentation and variability in appendix location and symptoms. Traditional diagnostic approaches, including physical examination, clinical scoring systems, and imaging techniques, have limitations. This study introduces the "Amr sign," a new diagnostic indicator characterized by sudden reflex hyperextension of the neck upon palpation of the right iliac fossa, which is hypothesized to reflect local peritoneal irritation from an inflamed appendix. Methods We conducted a prospective observational study at Alwakra Hospital from November 2016 to January 2019 that included 195 patients aged 15 years and older with right iliac fossa pain and an Alvarado score of four or more. The "Amr sign" was evaluated alongside standard clinical examination and imaging results. Diagnostic accuracy was assessed via histopathological confirmation, which is the gold standard. Results The "Amr sign" had a sensitivity of 68.6% and a specificity of 67.3%. The positive predictive value (PPV) was 89%, whereas the negative predictive value (NPV) was 45%. Receiver operating characteristic (ROC) analysis revealed an area under the curve (AUC) of 0.679 for the "Amr sign" compared with 0.622 for the other imaging modalities, suggesting comparable diagnostic performance. The "Amr sign" demonstrated a higher likelihood ratio of a positive test (2.3) and a lower likelihood ratio of a negative test (0.46). Conclusion The "Amr sign" is a promising diagnostic tool for acute appendicitis, offering a simple, reliable, and quick test that can be performed by less experienced physicians. While its sensitivity and specificity are moderate, its high PPV suggests that it is particularly useful in confirming appendicitis. Further research and validation are needed to fully establish its role in clinical practice.