Diagnosis of appendicitis by bedside ultrasound in the ED

Computed tomography (CT) has largely become standard of care for diagnosing appendicitis at the expense of increased patient radiation exposure, cost, and time to surgical intervention. To date, there are very limited data on the accuracy of bedside ultrasound (BUS) for the diagnosis of appendicitis in adults.

The objective of this study is to evaluate test characteristics of BUS for diagnosis of acute appendicitis in the emergency department.

Data were prospectively collected on 97 cases of suspected appendicitis, which had BUS performed by trained residents with attending supervision between August 2011 and November 2013. All BUS interpretation and additional diagnostic imaging were left to the discretion of the physician or surgical consultants. A blinded ultrasound fellowship-trained physician reviewed all images after clinical treatment. Bedside ultrasound findings and patient outcomes were reported.

A total of 97 adult cases underwent diagnostic ultrasound scans for suspected appendicitis. Of 97 cases, 34 had acute appendicitis by surgery/pathology report. Twenty-four BUS were positive for acute appendicitis and 11 were nondiagnostic. Of 24 positive ultrasounds, 23 had appendicitis on pathology report. There was 1 false-positive result, yielding a sensitivity of 67.65% (95% confidence limits, 49.5%-82.6%) and a specificity of 98.41% (95% confidence limits, 91.4%-99.7%). Of 23 positive BUS, 12 cases went to the Operating Room without an abdominal CT yielding a 12% reduction in CT utilization. If all positive BUS went to the OR without a CT scan, this would yield a 24% reduction in CT utilization.

Bedside ultrasound may be an appropriate initial test to evaluate patients with suspected acute appendicitis in the emergency department.