title: Sonographic Differentiation of Complicated From Uncomplicated Appendicitis: Implications for Antibiotics-First Therapy.
abstract: OBJECTIVE
  To evaluate sonographic findings as indicators of complicated versus uncomplicated appendicitis in the setting of known appendicitis, a necessary distinction in deciding whether to proceed with antibiotic therapy or with appendectomy.
  
  
  METHODS
  With Institutional Review Board approval and Health Insurance Portability and Accountability Act compliance, appendiceal sonograms of 119 patients with histopathologically proven appendicitis were retrospectively blindly reviewed to determine the presence or absence of the normally echogenic submucosal layer, the presence of mural hyperemia, periappendiceal fluid, appendicoliths, and hyperechoic periappendiceal fat and to determine the maximum outside diameter. Results were compared with the presence of complicated versus uncomplicated appendicitis on histopathologic examination and assessed by both univariate and mulitvariate logistic regression; confidence intervals (CIs) of proportions were assessed by the exact binomial test.
  
  
  RESULTS
  Thirty-two (26.9%) of the 119 patients had complicated appendicitis, including 11 with gangrenous appendicitis without perforation and 21 with gangrenous appendicitis and perforation. Loss of the submucosal layer was the only independent significant indicator of complicated appendicitis in multivariate regression (P < .001) and provided sensitivity and specificity values of 100.0% (95% CI, 89.1%-100.0%) and 92.0% (95% CI, 84.1%-96.7%), respectively.
  
  
  CONCLUSIONS
  Loss of the normally echogenic submucosal layer was the most useful sonographic finding for discriminating complicated from uncomplicated appendicitis, being the only finding independently and significantly associated with complicated appendicitis and, additionally, providing both high sensitivity and high specificity. This information may help a physician decide whether to proceed with antibiotic therapy or with appendectomy when treating a patient with appendicitis.
authors.affiliation: Department of Radiology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Yingding
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Radiology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: R Brooke
authors.initials: RB
authors.lastname: Jeffrey
authors.affiliation: Department of Radiology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Stephanie T
authors.initials: ST
authors.lastname: Chang
authors.affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, California, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: DiMaio
authors.affiliation: Department of Radiology, Stanford University School of Medicine, Stanford, California, USA.|Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA.
authors.forename: Eric W
authors.initials: EW
authors.lastname: Olcott
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001062:Appendectomy; D001064:Appendicitis / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000601:surgery; D001065:Appendix / Q000000981:diagnostic imaging / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents
keywords: appendectomy; appendicitis; appendix; diagnostic imaging; gastrointestinal ultrasound; sonography