The role of abdominal sonography compare to clinical Alvarado criteria in diagnosis of appendicitis

Background:  Acute appendicitis is the most common emergency operation in the world. Considering negative appendectomy, it is necessary to use accurate diagnostic methods to lower the rate. This study evaluated the sensitivity and specificity of abdominal sonography in comparison to clinical Alvarado criteria in patients with suspected appendicitis.

Methods:  370 patients with suspected appendicitis selected from Imam Reza Hospital in Kermanshah, Western Iran. Clinical Alvarado score was calculated for each patient and then all of them followed by abdominal sonography and abdominal operation. Necessary data such as age, sex, weight and duration of symptoms were recorded. Diagnostic accuracy of sonography and Alvarado criteria was calculated in compare to pathology as a gold standard. Reducible rate of negative appendectomies with sonography was also calculated.

Results: Sensitivity and specificity of sonography was 98.3% and 76.4% respectively. Positive Predictive Value and Negative Predictive Value of sonography was 95.7% and 89.4% respectively. Negative appendectomy rate was 14.9% (55 patients), which 42 patients (76%) had negative sonography. 11.4% of all operated patients could avoided according to sonography resulta. 10.9% of patients with Alvarado score of 9-10, 14% with score of 7-8 and 19.4% with score of 5-6 had negative appendectomy respectively.

Conclusion: Abdominal sonography prior to operation can avoid unnecessary operation in patients with suspected appendicitis. Clinical Alvarado criteria can still be a good tool for screening of patients with abdominal pain.