CLINICAL RELEVANCE OF THE NON-VISUALISED APPENDIX ON ULTRASONOGRAPHY OF THE ABDOMEN IN CHILDREN WITH ABDOMINAL PAIN

Purpose:

To evaluate the clinical relevance of the non-visualised appendix on ultrasound where acute appendicitis is a possible cause of the pain.

Method(s):

With ethical approval, we retrospectively reviewed all children admitted into the paediatric surgical unit for abdominal pain between January to December 2013 who had abdominal ultrasound for evaluation of right-sided and lower abdominal pain. Those imaged for suspected intussusception or genitourinary symptoms were excluded. Demographic data, ultrasound  findings, final diagnosis and histological reports were captured. As part of institutional protocol, all patients were contacted 3 days after discharge for review.

 Result(s):

Of 1359 admissions, 810 had ultrasound abdomen and/or pelvis. We excluded 131 with suspected intussusception. Another 38 did not evaluate the appendix, leaving 641 reports for analysis.

Appendix was not visualised in 160 but 14 had ultrasound findings suggesting intra-abdominal inflammation (with 13 proven appendicitis and 1 histologically normal appendix).  In 3 of the 160 with normal ultrasound reports (1.9%), appendicitis was histologically proven.   

Appendix was partially visualized in 51, the segment of appendix that could be seen clearly normal in 34, obviously inflamed in 13 and equivocal in 4 with the obviously inflamed and equivocal cases positive for appendicitis on histology.  

 Overall, 232 children underwent appendicectomy, of whom 58 had no ultrasound done and the appendix was histologically normal in 5, giving overall negative appendicectomy rate of 2.2%.

 Conclusion(s):

When appendix is not visualized with no evidence of intra-abdominal inflammation on ultrasound, the likelihood of appendicitis is less than 2%. When appendix is partially visualized, those abnormal or equivocal on ultrasound are positive for appendicitis.

Clinicians may safely use these reports to supplement their clinical assessment even when the appendix is not completely visualised.