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Suspected Pediatric Appendicitis: When Should CT Scans Be Used?

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Suspected Pediatric Appendicitis: When Should CT Scans Be Used?

Apr 29, 2016

Have you ever treated a child with abdominal pain that you suspected might be caused by appendicitis? It’s tempting to go straight to a CT scan, but such scans expose children to ionizing radiation, which is potentially harmful. Eric Glissmeyer, MD, a pediatric emergency physician, discusses how doctors can know whether to employ advanced scanning in kids. He presented this information to his peers at the 2016 Pediatric Academic Societies meeting in Baltimore.

Episode Transcript

Announcer: Examining the latest research and telling you about the latest breakthroughs. The Science and Research Show is on The Scope.

Interviewer: All right. Here's a question. How can you reduce the use of imaging tests for patients that you are evaluating for appendicitis? That's what Dr. Eric Glissmeyer's research focused on. Thank you for coming to help answer that question. First of all, why did you want to answer that question?

Dr. Glissmeyer: Well, particularly when we're evaluating children that are being seen for abdominal pain and they may have appendicitis, we like to not do dangerous things or harmful things to children. It's not uncommon that a CT scan, a test with ionizing radiation that exposes the child to potential risk of harm, is done, especially in uncertain cases. So we wanted to try to set forth the protocol with the support of our surgeons and our radiologists that helps us one, standardize our approach and two, reduce CT use and that was our primary objective.

Interviewer: How have people tackled this problem before?

Dr. Glissmeyer: Well, there are a number of places around the country that have done great work in establishing protocols that many times have been just developed iteratively in a quality improvement kind of way, that have had the focus of reducing CT use.

I think that one unique approach that we took here is we didn't want to just know when is CT scan used in patients who are ultimately proven to have appendicitis, but when is it used in that larger demographic, that larger denominator of patients who are evaluated for suspected appendicitis? The doctor goes and feels their belly and says, "They may have appendicitis. I better rule them out for appendicitis."

What do you do next? We have a lot of tools at our disposal and there's a lot of variability in what people do. We wanted to standardize that with that objective of reducing advanced imaging tests like CT scans.

Determining Appendicitis in Children

Interviewer: All right. Here's the moment of truth. What do you do?

Dr. Glissmeyer: What we believe the best thing to do is to take a standardized approach driven by physical exam and utilizing a scoring scale. We use something called the Pediatric Appendicitis Score and there are a number of other scores being used. We don't really think it matters exactly what the score is. We don't think there's any magic in one particular lab value or one particular physical exam finding.

Appendicitis is sneaky and it likes to present many different ways. What we've found though is with the support of our surgeons and our radiologists all working together to determine an algorithm, that as we go down and we do a blood count and we do an exam and we see what some of those initial results come back as, we can either put the patient into a category of low risk and, "Gosh we're done." We really don't need to have much worry about appendicitis unless things get worse, intermediate risk, where perhaps an ultrasound test and certainly you have to have an organization that does ultrasound well.

Pediatric ultrasound for appendicitis is not an easy test. Our ultrasonographers have been doing this a long time at primaries and are very good at it. We actually know based on what they see on the ultrasound there are four different grades for the ultrasound result. We know what the likelihood of appendicitis is for those different grades.

So we've got some great data to drive our decision making out of the results we get. You know what? There are some patients who don't even need an imaging test to diagnose their appendicitis. If it's a classic case, straightforward, the labs support it, you're done, call the surgeon, take the appendix out. This was done 20 to 25 years ago with no imaging tests regularly because they didn't have any. So we kind of need to go back to that in some ways.

Appendicitis Screening Accuracy

Interviewer: And in your research, how accurate was this method?

Dr. Glissmeyer: For patients who come in and we see for having appendicitis, I want to first say how do we know when we were looking at this retrospectively that the patient was actually being evaluated for appendicitis? How did you crawl into that doctor's mind and determine, "Well, did they actually suspect appendicitis or were they just coming in for gastroenteritis?"

We developed a surrogate definition, whether they had an ultrasound done, whether they were coming in for a chief complaint or abdominal pain and the word appendicitis was used in the note and a CVC was obtained that 95% of those patients were evaluated for appendicitis.

It had a sensitivity and a specificity of 95%. We're confident that we could evaluate the patients or rather identify the patients that were being evaluated for appendicitis. So in that group, I think the real question people would want to know is what were you doing before you did this protocol and what did you achieve after in terms of the CT use?

Interviewer: Yeah, did it reduce it?

Dr. Glissmeyer: We were one of the lower utilizers in the country in CT. Our baseline data showed we were doing CT scan only 15% of the time in this cohort of patients being evaluated for appendicitis. If you look nationally, it's more around 30%. So we were already a low utilizer of CT.

But what I was so pleased to find was that as we instituted this protocol that has not just the standardization but this follow up option that we'll talk about too, we were able to drop that low rate in half again, from 13% to 6%, from 13% to 6%. So we were really pleased to see we were even able to cut that in half further.

Using the Rule of Thirds

Interviewer: Is there an ability to even cut that more, do you think?

Dr. Glissmeyer: I think potentially. But I think you achieve a certain baseline minimal rate where you get your unclear cases, you get your cases where your patient has been having pain for a week or so and you really suspect that this is a ruptured appendicitis and CT scan is really the optimal test to use. I think around 5% or so is probably about the minimum you want to achieve.

Interviewer: All right. Explain the follow up option you were talking about.

Dr. Glissmeyer: Probably somewhere around a third of patients who have abdominal pain are being evaluated for appendicitis. It's not totally clean, a third, a third, a third, but let's talk about it in those terms because it makes it easy.

If a third of patients come in and it's pretty obvious after your exam and some labs they don't have appendicitis, you're done. You don't need imaging tests. About maybe less than a third, somewhere around 15-20% and they come in and they have pretty clear evidence of appendicitis, labs support it, you call surgery, they get their appendix taken out, no imaging tests needed there.

Then there's this larger middle where the fall into an intermediate range of a Pediatric Appendicitis Score that we have called between 4 and 7. If they have that score, you do an ultrasound scan first. Boy, when it shows the appendix and it shows it's normal or it shows the appendix and it shows it's not normal, that's really helpful. Then you can make your decision based off of that, but if it doesn't see the appendix, what do you do then.

The patient still has some tenderness, you're still a little uncertain. Do you just go stick them in the CT scanner to get your answer? That's what I think historically has been done, when the ultrasound fails to give you the answer you want, we go and scan them. We work with our surgeons to say, "You know what? We've observed this patient for a couple of hours here in the ER. Their pain is not really getting worse. It's not a clear cut appendicitis. Why don't we have them come see you tomorrow morning in clinic?"

So if it's Sunday night between Sunday night or Thursday night where they could go the next morning, that being between Monday and Friday, they can show up at about 7:30, 8:00 a.m., come into surgery clinic, get their belly pushed on, be examined, get lab tests repeated if they need to, perhaps do another ultrasound if necessary and find themselves in the hands of another expert the next morning also with not a second ER charge, which is nice, but being able to come into the clinic.

We thought, "Are we going to go and be doing surgery clinic follow up now? Are people going to just be like all the time overrunning the surgery clinic the next morning?" Actually it's only about one patient every ten clinic days that utilizes this resource. But the fact that you can offer it to them in the emergency department the families love and the docs love because in the faces of uncertainty, it gives them a plan. That's been the magic of the approach.

Looking Ahead at Screening Appendicitis in Kids

Interviewer: What's the next iteration then of this research? Where do we go from here?

Dr. Glissmeyer: We've been pleased with what we've been able to achieve at Primary Children's Hospital. It's to take it to other hospitals within Intermountain Healthcare, University Healthcare, having the support of surgeons at those other hospitals is key and radiologists as well, we're working on that. But only half of the appendix case present to the tertiary children's hospital here, Primary Children's Hospital. We want to address that other important half and that's where we're going next.

Interviewer: Getting that feedback from the surgeon afterwards for the patients that didn't get the imaging but had the operation and you find out how successful you've been or haven't been. Have these tools proven to be pretty successful?

Dr. Glissmeyer: That's a great question. You wouldn't want to be going and admitting to the surgery service a lot of patients who you as the ER doc are convinced have appendicitis and then they go in there to take it out and then, "Uh-oh, it looks normal." That happens on a rare occasion. Nationally about 5% is the rate of negative appendectomy. You go in and, "Oh, we thought it was appendicitis and it's not."

Our rate here is about 2-3% and it's not increased since the use of the protocol. So going in and taking out patients' appendix without ultrasound test or any imaging test, it still is successful and doesn't increase that negative appendectomy rate.

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