Does abdominal ultrasound is a useful tool in appendicitis diagnosis?

INTRODUCTION: Acute appendicitis is the most common acute abdominal illness. Despite diagnosis progress there is still 20% negative appendectomy rate. The aim of the study was to determine the usefulness of abdominal sonography in diagnosis of acute appendicitis.

MATERIALS AND METHODS: Data were collected retrospectively from 326 patients who were operated with suspected appendicitis and had abdominal ultrasound before surgery. Appendicitis was confirmed by pathologic reports. There were two variants of positive abdominal sonography. In the first variant, the positive ultrasound was visualized inflamed appendix. In the second variant, the sonographic diagnosis of appendicitis was based on visualized inflamed appendix or one of indirect signs of appendicitis - localized periappendiceal fluid collection, enlarged lymph nodes, thickening of intestinal wall in right iliac fossa. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were defined and compared.

RESULTS: 83,74% patients has appendicitis in pathologic report. In 39,53% cases appendix was visualized in abdominal ultrasound. In 65,95% cases of sonography indirect signs occurred. In the first variant sensitivity, specificity, PPV and NPV was 47,99%, 79,25%, 92,25% and 22,83%. In the second variant 67,77%, 43,40%, 86,05% and 20,72%. In the second variant sensitivity was significantly higher (p<0,001) but specificity was significantly lower (p<0,001).

CONCLUSION: Limited sensitivity and specificity cannot confirm appendicitis. Typical clinical course with negative ultrasound should not delay the correct diagnosis and early surgical treatment.