J. M. Held1, C. McEvoy1, S. Foster1, R. Ricca1 1Naval Medical Center Portsmouth,Pediatric Surgery,Portsmouth, VA, USA
Introduction: Appendicitis is a common cause of abdominal pain in children. Ultrasound is the primary imaging tool used for evaluation of appendicitis in children. Visualization of the appendix is the gold standard for diagnosis; however, the quality of the study is dependent upon the ultrasonographer and radiologist’s expertise. Recent studies performed at tertiary care hospitals, presumably interpreted by fellowship-trained pediatric radiologists, suggest that presence of secondary signs of appendicitis can be used diagnostically in ultrasounds that do not visualize the appendix. There have been no similar studies conducted in the community hospital setting.
Methods: Right lower quadrant ultrasounds, performed in children aged 2-17 due to clinical suspicion for appendicitis in a one-year time period, were studied. Those which identified the appendix were excluded. Secondary signs of inflammation, free fluid, ileus, fat stranding, abscess and lymphadenopathy were documented. Patients were followed for one year for the primary outcome of appendectomy. Data was analyzed using Mann-Whitney, Pearson’s Chi Squared, Fisher’s Exact Tests as well as logistic regression to determine whether the presence or absence of these signs can be used to make or exclude the diagnosis of appendicitis.
Results: 138 right lower quadrant ultrasounds were performed; 91 did not identify the appendix. Of these, 11 (12.1%) identified at least 1 secondary sign of inflammation. Of the 91 patients, 33 (36.3%) were admitted for observation, 20 had additional imaging (17 CT, 2 MRI, 1 CT and MRI) and 12 (13.2%) were ultimately taken for appendectomy. There was no statistically significant relationship between presence of secondary signs on ultrasound and diagnosis of appendicitis. A subset analysis compared patients admitted for serial abdominal exams without further imaging to those who had a CT or MRI; there was no difference in diagnosis of appendicitis between these groups. The appendix was unable to be found in 87% (79/91) of the patients without appendicitis making this the most predictive factor.
Conclusion: Prior studies at tertiary care hospitals have shown utility in using secondary signs of inflammation present on ultrasound with a non-visualized appendix. Our data suggest that this may not be applicable in the community setting although non-visualization of the appendix alone may be diagnostic. The secondary sign that was most strongly associated with a diagnosis of appendicitis was presence of free fluid; however, the association was not statistically significant. Observation alone after a non-diagnostic ultrasound may be as useful as further imaging. Expansion of the time period analyzed to include more patients and increase the power of this study will be conducted to further delineate utility of secondary signs, as well as whether children can be safely observed to avoid the cost and radiation risk associated with potentially unnecessary imaging.