Abdominal CT Does Not Improve Outcome for Children With Suspected Acute Appendicitis

Danielle I. Miano, BS; Renee M. Silvis, BS; Jill M. Popp, PhD; Marvin C. Culbertson, MD; Brendan Campbell, MD, MPH; Sharon R. Smith, MD

Disclosures

Western J Emerg Med. 2015;16(7):974-982. 

In This Article

Abstract and Introduction

Abstract

Introduction: Acute appendicitis in children is a clinical diagnosis, which often requires preoperative confirmation with either ultrasound (US) or computed tomography (CT) studies. CTs expose children to radiation, which may increase the lifetime risk of developing malignancy. US in the pediatric population with appropriate clinical follow up and serial exam may be an effective diagnostic modality for many children without incurring the risk of radiation. The objective of the study was to compare the rate of appendiceal rupture and negative appendectomies between children with and without abdominal CTs; and to evaluate the same outcomes for children with and without USs to determine if there were any associations between imaging modalities and outcomes.

Methods: We conducted a retrospective chart review including emergency department (ED) and inpatient records from 1/1/2009–2/31/2010 and included patients with suspected acute appendicitis.

Results: 1,493 children, aged less than one year to 20 years, were identified in the ED with suspected appendicitis. These patients presented with abdominal pain who had either a surgical consult or an abdominal imaging study to evaluate for appendicitis, or were transferred from an outside hospital or primary care physician office with the stated suspicion of acute appendicitis. Of these patients, 739 were sent home following evaluation in the ED and did not return within the subsequent two weeks and were therefore presumed not to have appendicitis. A total of 754 were admitted and form the study population, of which 20% received a CT, 53% US, and 8% received both. Of these 57%, 95% CI [53.5,60.5] had pathology-proven appendicitis. Appendicitis rates were similar for children with a CT (57%, 95% CI [49.6,64.4]) compared to those without (57%, 95% CI [52.9,61.0]). Children with perforation were similar between those with a CT (18%, 95% CI [12.3,23.7]) and those without (13%, 95% CI [10.3,15.7]). The proportion of children with a negative appendectomy was similar in both groups: CT (7%, 95% CI [2.1,11.9]), US (8%, 95% CI [4.7,11.3]) and neither (12%, 95% CI [5.9,18.1]).

Conclusion: In this uncontrolled study, the accuracy of preoperative diagnosis of appendicitis and the incidence of pathology-proven perforation appendix were similar for children with suspected acute appendicitis whether they had CT, US or neither imaging, in conjunction with surgical consult. The imaging modality of CT was not associated with better outcomes for children presenting to the ED with suspected appendicitis.

Introduction

Acute appendicitis in the pediatric population remains one of the most common surgical emergencies.[1] The risk of developing appendicitis over the course of a lifetime is 7% in females, and 9% in males.[2,3] In the United States, there are more than 70,000 appendectomies performed on pediatric patients 3–18 years old each year.[4] Despite its high incidence, appendicitis may be challenging to diagnose due to the overlap of symptoms with other acute abdominal conditions or atypical presenting symptoms.[5][8] Timely diagnosis and treatment of acute appendicitis is important to prevent complications such as a perforated appendix.[9] Radiographic imaging studies such as ultrasound (US) and computed tomography (CT) are frequently ordered to aid in the diagnosis of patients who present with symptoms consistent with acute appendicitis.

With the advent of the helical CT study, physicians can rapidly obtain a three-dimensional view of the appendix and abdominal region. Image capture is estimated to take less than one second, which diminishes the need to anesthetize the child before a CT.[10] The high image resolution, diagnostic accuracy, and convenience of a CT study have been contributing factors associated with its frequent use as a diagnostic tool.[11]

As the utilization of CT studies has increased over recent decades, the risks associated with varying doses of ionizing radiation have been estimated using data from atomic bomb survivors.[10–12] For children younger than 15 years, the estimated risk of dying from a radiation-induced malignancy ranges from 0.07%–0.10%, with children in the lower ages having a higher estimated risk.[13] In a recent retrospective cohort study the estimated risk for children younger than 15 developing leukemia and brain tumors tripled if a child had undergone more than two CTs.[14] Additionally, children are more susceptible to the effects of ionizing radiation because they have a higher rate of cell divisions in developing tissues. Their younger age also leaves more years of life in which a radiation-induced malignancy may develop.[15] Brenner and colleagues estimated that approximately one million children per year are unnecessarily exposed to harmful radiation from CTs.[10]

Despite the increased use of CTs, additional imaging studies may not improve the accuracy of the preoperative diagnosis of acute appendicitis.[16,17] Flum and colleagues found that the increased use of CT and US studies have not impacted the population-level rate of negative appendectomy.[18,19] In addition, a recent retrospective study found there was no increase in negative appendectomy or perforation rate following the implementation of a multi-disciplinary diagnostic protocol which used US as the initial diagnostic imaging study.[20]

The aim of this study was to determine if a correlation exists between children who received diagnostic imaging (CT and/or US) and two clinical outcomes: the rate of perforation and negative appendectomy. The hypothesis was that diagnostic imaging does not improve clinical outcomes for children with suspected acute appendicitis.

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