To Scan or Not To Scan: What Is the Best Imaging Technique for Diagnosis of Appendicitis in Children?

When a child presents to the ER with abdominal pain, I am always faced with a decision.  Could this be an appendicitis?  Should I order an abdominal CT scan?  With recent research indicating that radiation from CT scans in pediatric patients triples the risk of developing leukemia and brain tumors, this is a weighty decision.  Appendicitis can also be diagnosed with ultrasound imaging.  Given the risk of radiation exposure with CT, which test is better for the diagnosis of appendicitis in pediatric patients?

Dr. Gerald Brennan discusses the diagnosis of appendicitis in children.  He notes that this can be a particularly difficult condition to diagnose in children as 30 to 50% of pediatric patients present atypically.  A delay in diagnosis and treatment of appendicitis of greater than 48 hours is 80% more likely to lead to perforation of the appendix and 60% more likely to lead to complications.  Given the need for timely diagnosis, providers must decide quickly if imaging is warranted and if so, what kind.

Use of Ultrasound for Diagnosis of Appendicitis

Ultrasound of the appendix must be done by a specially trained ultrasound technician.  It is most useful in patients without excess abdominal fat.  The drawback of using ultrasound to diagnose appendicitis include that it's efficacy can be affected by the skill of the ultrasound technician and that it is insensitive in cases where the appendix is perforated or only the distal tip is involved.  The overall accuracy of ultrasound in diagnosis ranges from 59 to 98% overall but narrows to 89 to 98% in pediatric patients.  The benefit of ultrasound for diagnosis of appendicitis is that unlike CT scans, it does not expose the patient to radiation.

Use of CT for Diagnosis of Appendicitis

CT is the most accurate method for diagnosis of appendicitis with an accuracy of 91 to 97%.  CT does not depend on operator accuracy and therefore any qualified CT technician can preform the study.  The only drawback of CT, then is exposure to radiation.  Because children have a higher number of dividing cells than adults and less protective tissue, their risk of suffering from malignancy due to radiation is much higher than that of an adult.  Dr. Brennan draws out the numbers of possible pediatric deaths resulting from radiation induced malignancy.  If 70,000 children each year suffer from appendicitis, we can assume that at least and additional 70,000 more received CT scans to rule-out the diagnosis.  Based on these numbers, we can expect that between 150 and 250 of these children will die as a result of radiation induced malignancy.

What Does This Mean for Healthcare Providers?

Based on these numbers, ultrasound should be our primary method of diagnosing appendicitis in children.  Although accuracy of diagnosis is better with CT, ultrasound is still quite effective and should be used as a first-line diagnostic tool.  If your pediatric patient has a negative ultrasound but you remain highly suspicious of appendicitis, only then should CT be used for diagnosis.