Clinical approach to a child with abdominal pain who might have appendicitis.

Appendicitis can usually be diagnosed on completion of a history and physical examination (abdominal pain, vomiting, right lower quadrant tenderness and guarding), although laboratory evaluation with a urinalysis and white blood cell count can be of assistance. In the few cases where doubt remains, plain films of the chest and abdomen can be helpful. Whether and when further imaging is indicated remains controversial. We reviewed reports of studies published since 2003 in which the sensitivity and specificity of CT and sonography for diagnosing appendicitis were determined. Sonography had an average sensitivity of 87.1% and an average specificity of 89.2% in the nine studies reported during that period. The average sensitivity of CT was 90.8% in 11 studies during that period, and there was an average specificity of 94.2% in 10 studies. We also looked at data from 299 patients who underwent appendectomies at our hospital. Of the appendices removed, only 10.7% did not have appendicitis. In many cases, CT or US imaging data were available in the form of reports or images or both from outside institutions. CT and US images were also available from our institution when the diagnosis was in question. This is how patients present in the real world-with studies that might not be the best, might not have been indicated, and might not have images available for another interpretation. Among patients operated on with neither CT nor US images, 10.9% did not have appendicitis. Among those in whom US imaging had been performed, 11.1% were negative for appendicitis, and among those in whom CT had been performed, 9.7% were negative. Although these studies were necessary because they were performed in patients whose diagnosis was the most difficult, it is in every patient's best interest to have a thorough examination by a surgeon prior to having a CT scan.