Selective use of ultrasonography for acute appendicitis in children

BACKGROUND: TO evaluate the role of ultrasonography in children with equivo cal signs of acute appendicitis, and correlate with initial clinical impres sion and pathological findings. METHODS: This is a prospective evaluation of all children presenting with a possible diagnosis of appendicitis during a 14-month study period. Patient s with unequivocal clinical signs of appendicitis underwent appendectomy wi thout ultrasonography. Patients with equivocal signs had documentation of t he clinical impression and subsequent abdominal ultrasound. Statistical ana lysis of results was performed using the chi-square test (P <0.05 significa nt). RESULTS: TWO hundred fifteen consecutive children were enrolled. Signs were unequivocal in 116 and equivocal in 99. Seven patients in the first group had a normal appendix at operation. Of the 99 patients with equivocal signs , there were 28 true positives, 3 false positives, 64 true negatives, and 4 false negatives. In equivocal cases, sensitivity of the initial clinical i mpression versus ultrasound was 50% and 88%, respectively (P <0.05). Specif icity was 85% and 96%, respectively. The positive and negative predictive v alues improved from 63% to 90% and 78% to 94%, respectively, with the use o f ultrasonography. CONCLUSIONS: The low false positive rate (6%) in clinically obvious cases o f appendicitis does not, in our opinion, warrant ultrasonography. In clinic ally equivocal cases, ultrasonography is a fast, sensitive, and specific di agnostic modality to diagnose or rule out appendicitis, avoiding the need f or prolonged observation and/or hospitalization. (C) 1999 by Excerpta Medic a, Inc.