The role of ultrasound in diagnosing acute appendicictis

Most patients with acute appendicitis present with typical clinical features, and diagnosis was traditionally based on clinical data. But the clinical diagnosis is not always straightforward, since 30-45% of patients have atypical clinical presentation. Recent reports indicate ultrasound is accurate test for diagnosis of appendicitis. Thus, the objective of this study was to assess the sensitivity, specificity and accuracy of graded compression ultrasound in the diagnosis of appendicitis in our setup. A total of 194 patients with suspected appendicitis, who have visited the Tikur Anbessa Hospital from July 2002-November 2003, were prospectively evaluated with graded compression ultrasound The outcome of 147 patients was known, of which 58 were operated and 89 were clinically followed. The sensitivity of US in diagnosing acute appendicitis was found to be 87.9% with specificity of 86.5%. The positive and negative predictive values were 80.9% and 91.7%, respectively, with accuracy of 87.1%. The criteria for diagnosing appendicitis by US were consistent. US also help to give an alternative diagnosis, which can mimic appendicitis. Twenty-nine (27.4%) alternative diagnoses were made at US. Based on our findings, we recommend that US can be used as imaging modality of choice in investigating appendicitis, especially in patients with atypical presentation.