Accuracy of ultrasonography in the diagnosis of peritonitis compared with the clinical impression of the surgeon.

HYPOTHESIS Peritonitis is a well-known indication for surgery, but its preoperative cause usually is not established. We hypothesize that abdominal ultrasonography is superior to the clinical impression of the surgeon in detecting the cause of peritonitis. DESIGN A prospective case series. SETTING A major university hospital in Taiwan, Republic of China. PATIENTS AND METHODS One hundred two patients with a diagnosis of peritonitis admitted to the Department of Emergency Medicine, National Taiwan University Hospital, Taipei, were included in this study. All 102 patients underwent an abdominal ultrasonographic examination; and the ultrasonographic findings of these patients were classified into 2 categories: positive findings and normal screening results. The accuracy of clinical impression in detecting the cause of peritonitis was compared with the accuracy of abdominal ultrasonography. RESULTS Ultrasonography and clinical impression accurately diagnosed the peritonitis in 85 (83.3%) and 52 (51.0%) of the patients, respectively. The difference between ultrasonography and clinical impression in the diagnosis of peritonitis was significant (P<.001). Among 45 patients without a preoperative clinical diagnosis, a diagnosis was made by ultrasonography for 32 (71%) of them. There were a total of 98 patients with positive ultrasonographic findings, and 4 patients had normal screening results. Of the 98 patients with positive ultrasonographic findings undergoing surgery, all had abdominal pathological characteristics. The 4 patients with normal screening results received nonoperative treatment. CONCLUSIONS Ultrasonography is a more sensitive technique than clinical judgment in diagnosing peritonitis. Ultrasonography may be a useful diagnosing modality in patients with peritonitis in whom the clinical cause is unclear.