Liberal use of CT scanning helps to diagnose appendicitis in adults.

Appendicitis can be difficult to diagnose as patients get older and the incidence of other intra-abdominal processes increases. We hypothesize that with the use of helical computed tomography (CT), we will be better at diagnosing appendicitis in adults. We reviewed all the medical records of patients 18 years and older who were admitted to our service with the diagnosis of appendicitis (ICD-9: 540.0, 540.1, 540.9, and 541) from January 1999 through October 2002. In addition to demographics, we collected pathology results, if CTs were done, and CT results. This study was approved by the Institutional Review Board (IRB) of the University of Michigan. Three hundred thirty patients with the diagnosis of appendicitis were admitted to our service. We found the negative appendectomy rate in all patients to be 12.1 per cent. In all patients who had CT scans, the negative appendectomy rate was 7.3 per cent. In patients > or = 45 years, patients without CT had 5.6 per cent negative appendectomy rate versus 5 per cent (P = 0.02) with CT scanning. There were no mortalities. Our negative appendectomy rate in adult patients is lower than previously published reports. We believe our high rate of CT scanning helped in making the correct diagnosis. We recommend liberal use of CT scanning to help diagnose appendicitis in adults.