Ultrasound vs. clinical diagnosis-which is better in diagnosing acute appendicitis?: a cohort study

Acute appendicitis is one of the most common causes of right iliac fossa pain which often warrants surgical management. In many cases, abdominal ultrasonography (USS) is done to confirm the diagnosis however negative appendicectomy is common due to atypical presentations and different visualisation rate. The unnecessary operative intervention can result in complications. The aim of this study was to compare the efficacy between clinical diagnosis and USS in diagnosing acute appendicitis to avoid negative appendicectomy and prevent further complications.

A retrospective cohort study was conducted in a district general hospital which 1046 cases of laparoscopic appendicectomy were included and examined for the use of USS or clinical diagnosis. The sensitivity, specificity, negative and positive predictive value in USS and data in clinical evaluation were analysed for their accuracy in the diagnosis of acute appendicitis based on the histology results post appendicectomy.

Clinical diagnosis without preoperative imaging was found to have a significantly lower negative appendicectomy rate of 27.20% compared with 42.67% in those who underwent ultrasound. 44.64% of the patients were misdiagnosed with a normal USS result who had a subsequent positive histology of appendicitis.

USS has been shown to be less sensitive for diagnosing acute appendicitis which results in high negative appendicectomy and misdiagnosis rate. With an increasing burden of health budget and resources, cautious and appropriate use of USS would avoid the misdiagnosis and prevent further complications. Thorough clinical evaluation remains an important first step and role in the diagnosis of acute appendicitis.