Nonenhanced CT AND contrast-enhanced CT for suspected appendicitis?!

[kdburton]

In the ED that I did an EM elective in (and most of the other hospitals in that system and surrounding area according to the attendings I've worked with) it is common practice to do a nonenhanced CT followed by a contrast-enhanced (oral+IV) for patients with suspected appendicitis or "undifferentiated abdominal pain." All of the literature I've seen says that a single contrast-enhanced CT has a high sensitivity, specificity, + predictive value, and - predictive value (leading to an overall accuracy in the mid-to-high 90%ile). If you can be so sure with just the one CT, then what is the point of doing a nonenhanced in addition to the accurate contrast-enhanced CT as a standard practice? I'm just trying to figure out how common this practice is and to see if anyone can point me in the direction to literature that says it is the way things should be done. If any attendings, residents or students who have done an EM rotation can chime in and tell me if this is standard practice where they are ti would be much appreciated... Also if anyone else has asked themselves the same question that I'm asking and knows of some literature to point me to, please do. Thanks in advance.

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[Seaglass]

Some studies suggest that with current 64 slice scanners that an unenhanced CT is as good as enhanced. In all the places I've worked we did it with at least IV contrast unless there was some extenuating circumstance. The rationale I can see for this is: Hey, I think this person REALLY has appendicitis, but I know the surgeon won't operate without a CT. I'll do a quick non-contrast to prove it to them and give them a call. --- then if the non-contrast is negative and you need to PROVE whether or not they have appendicitis you get the contrasted study. It's worth pointing out that contrasted studies aren't 100% sensitive either.

 

[deleted109597]

What about the chances of picking up renal stones on patients with RLQ pain with tenderness? I don't know if that is their rationale, but it may work in their favor.

 

[Hawkeye Kid]

What about the chances of picking up renal stones on patients with RLQ pain with tenderness? I don't know if that is their rationale, but it may work in their favor.

I just did this yesterday in a young guy with an ileostomy due to Crohn's disease. He came in with about a day of right sided abd pain that sounded/looked more like ureteral colic than anything else, but obviously was at risk for other abdominal problems, and appy was a close second on the DDx. I discussed with him the potential problem of a non-con CT--but that if he had stones that's the test we needed--and that he may need another CT after that. He agreed to it and ended up having obvious obstruction without contrast. Of course, the surgery resident gave me a hard time about not having contrast, but I still think that approach was the best in that situation (though usually you can sort it out with H&P).

 

[kdburton]

What about the chances of picking up renal stones on patients with RLQ pain with tenderness? I don't know if that is their rationale, but it may work in their favor.

Thats possible, but how often does that happen? Probably not that often. Current literature shows that the amount of ionizing radiation in a abdominal CT is equivalent to 100-250 chest X-rays (and very few EM doctors, let alone radiologists, are aware of this). So the discussion I'm trying to get going is why would you subject the patient to twice the radiation by using two CT scans if you only need to do one to confirm suspected appendicitis? I asked the original question to see how common it is for EM docs to order two CTs right off the bat for suspected appendicitis because I'm not sure how many people actually do it and I'm having a hard time finding literature that tells me

 

[USCDiver]

The real answer is that it takes 2-3 hours for PO contrast protocols. Doing a non-con scan speeds that process up considerably. This is important for patient care (a ruptured appendix vs unruptured) and for patient flow through the ED.

 

[deleted109597]

I have learned in my first 3 shifts at my new hospital that our radiologists do, in fact, give the patient contrast and follow up a non-contrasted study with a contrasted study, if there is nothing on the renal study. I was somewhat shocked by this. However, it became second nature after the 4th or 5th one. I guess our sarcoma rate will be higher in 20 years.

 

[Apollyon]

I guess our sarcoma rate will be higher in 20 years.

Actually, lymphomas are much more likely. [/nerd alert]

 

[WilcoWorld]

I am appalled, but not surprised, that there are doctors practicing out there who would intentionally order two abdominal CT scans to r/o appy. There are certainly many clinical scenarios in which a second scan may be needed (order a non-contrast scan for stone, see a large AAA, and then have to rescan with contrast to evaluate for a leak), but those are specific situations. Now, the data suggests that a non contrast exam in your average patient (who has some adipose & thus periappediceal fat) is almost as good as an enhanced scan, so I think the reasoning behind the conrast needs to be reconsidered. However, I know there are plenty of radiologists who demand contrast to make a call, and if that's how your radiologists are going to be, then you'll have to play ball. That's the way they did it in my ED, so if I suspected appi I'd order contrast. However, sometimes people report an allergy / are puking too much / or have some other reason to not get contrast so I would get a non contrast scan. In those cases if the appendix does not appear distended / inflamed, then I'll reasses the patient. If they are comfortable & the belly is non-tender, then they are very unlikely to have appendicitis, so there's no need to rescan. If they have persisting pain & the exam has progressed then I'll call up the surgeon & tell them that we have a clinically diagnosed appi for them to see (and then I get to have this argument over rescanning with the surgeons, but that's anther story).

I just think that routinely scanning twice for the purpose of facilitating patient flow is a seriously poor prioritization. CT scans are safe when used judiciously, but when we start doubling our patients' radiation exposure because it helps us "move the meat" or because we're too damn lazy/stupid/apathetic to differentiate our abdominal pain (OK, sometimes you just can't make a good guess, I'll admit that, but it shouldn't be routine.) then we are doing our patients a serious disservice.

Don't get me wrong. I do think that decisions in the ED do need to consider patient flow, and I will change certain practices as a result (admit the hypoglycemic pt who is on oral hypoglycemics rather than watching them in the ED, do a urine HCG on every woman with any sort of abdominal complaint before a doctor has a chance to decide if it's indicated, etc) but I am not convinced that the benefit of routinely scanning abdominal pain patients twice outweighs the risk of double CT radiation exposure (especially in younger patients).

Umm, can someone help me get off this horse...it's a bit high.

 

[USCDiver]

Umm, can someone help me get off this horse...it's a bit high.

I'm not going to get you off your high horse, but a lawsuit for missed appy might.

If I order a non-con CT to rule out appy and the radiologist gives me an equivocal reading, you bet your ass I'm ordering a contrasted CT. In contrast (haha), if there is an obviously normal appendix and no stone on the non-con then I'm done.
Also, we're not talking about ruling out appy on the patient who comes in with belly pain on a weekly basis. We're talking about the patient you have a real suspicion of appendicitis on.

 

[WilcoWorld]

My point is that if you are suspecting appendicitis, and the radiologists at your institution require contrast to rule out appendicitis, then why would you ever order a non-contrast scan (contraindications to contrast withstanding)?

Now, if the patient presents like a stone, but on scan there is no stone, and there's equivocal evidence of appi, and the clinical scenario doesn't elucidate the situation, then I don't think it's wrong to get another scan with contrast.

I don't object to rescanning someone when the circumstances require it. I DO object to making two scans for the purpose of convenience a routine practice.

Additionally, I do not think that I would be found guilty of malpractice if I missed an appi in the clinical scenarios I described (patient with a negative non-con CT who was discharged after reevaluation showed resolution of pain / no progression of exam, or a patient on who I got a surgical consult & then complied with sugical recs).

 

[kdburton]

What if a patient presents to the ED and says "I'm getting my kidney stones again. It feels just like last time" etc... If you dip their urine and its positive for blood, but they're not in a ridiculous amount of pain do you still order a scan? Or do you just tell the patient to drink a bunch of water and give them some pain killers?

 

[deleted109597]

What if a patient presents to the ED and says "I'm getting my kidney stones again. It feels just like last time" etc... If you dip their urine and its positive for blood, but they're not in a ridiculous amount of pain do you still order a scan? Or do you just tell the patient to drink a bunch of water and give them some pain killers?

It may help you decide on the "will pass" or "won't pass" pathway, thus necessitating a urologist.

 

[Seaglass]

If they've had previous uncomplicated stones and I don't think they're a drug seeker then yes, I send them on their way. If it's a repeat visit for the same stone they will likely get scanned. I will also do a bedside US and look for hydro - if there's significant hydro I will scan them looking for a large stone.

 

[emergiQ]

Thats possible, but how often does that happen? Probably not that often. Current literature shows that the amount of ionizing radiation in a abdominal CT is equivalent to 100-250 chest X-rays (and very few EM doctors, let alone radiologists, are aware of this). So the discussion I'm trying to get going is why would you subject the patient to twice the radiation by using two CT scans if you only need to do one to confirm suspected appendicitis? I asked the original question to see how common it is for EM docs to order two CTs right off the bat for suspected appendicitis because I'm not sure how many people actually do it and I'm having a hard time finding literature that tells me

Are you kidding? very MANY EM doctors (and radiologists) are VERY AWARE of the radiation issues.

 

[southerndoc]

Are you kidding? very MANY EM doctors (and radiologists) are VERY AWARE of the radiation issues.

Actually you'd be surprised:

Lee CI, Haims AH, Monico EP, Brink JA, Forman HP. Diagnostic CT scans: assessment of patient, physician, and radiologist awareness of radiation dose and possible risks. Radiology, 231(2):393-8.

PURPOSE: To determine the awareness level concerning radiation dose and possible risks associated with computed tomographic (CT) scans among patients, emergency department (ED) physicians, and radiologists. MATERIALS AND METHODS: Adult patients seen in the ED of a U.S. academic medical center during a 2-week period with mild to moderate abdominopelvic or flank pain and who underwent CT were surveyed after acquisition of the CT scan. Patients were asked whether or not they were informed about the risks, benefits, and radiation dose of the CT scan and if they believed that the scan increased their lifetime cancer risk. Patients were also asked to estimate the radiation dose for the CT scan compared with that for one chest radiograph. ED physicians who requested CT scans and radiologists who reviewed the CT scans were surveyed with similar questions and an additional question regarding the number of years in practice. The chi(2) test of independence was used to compare the three respondent groups regarding perceived increased cancer risk from one abdominopelvic CT scan. RESULTS: Seven percent (five of 76) of patients reported that they were told about risks and benefits of their CT scan, while 22% (10 of 45) of ED physicians reported that they had provided such information. Forty-seven percent (18 of 38) of radiologists believed that there was increased cancer risk, whereas only 9% (four of 45) of ED physicians and 3% (two of 76) of patients believed that there was increased risk (chi(2)(2) = 41.45, P <.001). All patients and most ED physicians and radiologists were unable to accurately estimate the dose for one CT scan compared with that for one chest radiograph. CONCLUSION: Patients are not given information about the risks, benefits, and radiation dose for a CT scan. Patients, ED physicians, and radiologists alike are unable to provide accurate estimates of CT doses regardless of their experience level.

 

[emergiQ]

Actually you'd be surprised:

Lee CI, Haims AH, Monico EP, Brink JA, Forman HP. Diagnostic CT scans: assessment of patient, physician, and radiologist awareness of radiation dose and possible risks. Radiology, 231(2):393-8.

PURPOSE: To determine the awareness level concerning radiation dose and possible risks associated with computed tomographic (CT) scans among patients, emergency department (ED) physicians, and radiologists. MATERIALS AND METHODS: Adult patients seen in the ED of a U.S. academic medical center during a 2-week period with mild to moderate abdominopelvic or flank pain and who underwent CT were surveyed after acquisition of the CT scan. Patients were asked whether or not they were informed about the risks, benefits, and radiation dose of the CT scan and if they believed that the scan increased their lifetime cancer risk. Patients were also asked to estimate the radiation dose for the CT scan compared with that for one chest radiograph. ED physicians who requested CT scans and radiologists who reviewed the CT scans were surveyed with similar questions and an additional question regarding the number of years in practice. The chi(2) test of independence was used to compare the three respondent groups regarding perceived increased cancer risk from one abdominopelvic CT scan. RESULTS: Seven percent (five of 76) of patients reported that they were told about risks and benefits of their CT scan, while 22% (10 of 45) of ED physicians reported that they had provided such information. Forty-seven percent (18 of 38) of radiologists believed that there was increased cancer risk, whereas only 9% (four of 45) of ED physicians and 3% (two of 76) of patients believed that there was increased risk (chi(2)(2) = 41.45, P <.001). All patients and most ED physicians and radiologists were unable to accurately estimate the dose for one CT scan compared with that for one chest radiograph. CONCLUSION: Patients are not given information about the risks, benefits, and radiation dose for a CT scan. Patients, ED physicians, and radiologists alike are unable to provide accurate estimates of CT doses regardless of their experience level.

Yeah, I've seen this. But the data was collected 6 years ago even though the paper didn't get published till later. I would submit that it doesn't reflect the emphasis we now place in modern training programs.

 

[kdburton]

Yeah, I've seen this. But the data was collected 6 years ago even though the paper didn't get published till later. I would submit that it doesn't reflect the emphasis we now place in modern training programs.

While the possible risks of radiation have been heavily research and well-documented (especially in surgery and radiology journals) the question of awareness of these possible risks have not been. The article that was cited earlier is still the most recent and the only literature (barring one article from the UK) that I've found on the topic after extensive searching and I highly doubt that this article single-handedly changed EM and rads residency programs across the US. Furthermore if it had done that then we're still only taking about recent grads or those in later years of residency, so awareness as a whole for those ordering CT scans wouldn't be affected. As much as you may be aware of the amount of radiation in an abdominal CT scan I think you'd be surprised if you asked your colleagues.

 

[WilcoWorld]

kdburton: Just curious, I saw "Ulnar deviant" on your avatar & wondered if you have rheumatoid arthritis. Sorry to pry, but inquiring minds want to know...

 

[bulgethetwine]

While the possible risks of radiation have been heavily research and well-documented (especially in surgery and radiology journals) the question of awareness of these possible risks have not been. The article that was cited earlier is still the most recent and the only literature (barring one article from the UK) that I've found on the topic after extensive searching and I highly doubt that this article single-handedly changed EM and rads residency programs across the US. Furthermore if it had done that then we're still only taking about recent grads or those in later years of residency, so awareness as a whole for those ordering CT scans wouldn't be affected. As much as you may be aware of the amount of radiation in an abdominal CT scan I think you'd be surprised if you asked your colleagues.

With all due respect, I think the OP is going to know a little more about what the colleagues think then what a medical student thinks the OPs colleagues think

I agree with EmQ. At my institution, everytime I want a CT PE study for my patient, I have to argue with radiology about the issue of radiation so as to get the study I want instead of the inferior V/Q scan... which often ends up being indeterminate.

Same thing when I want a CT when it is indicated for a peds patient -- call and waste valuable time arguing with radiology (who hasn't seen the patient) the risk reward of a timely study vs. delay to get an ultrasound first. Which may or may not be interpreted by someone with expertise in peds ultrasound. Notice I said when it is "indicated" for a peds patient lest you think I am haphazard in this regard about attempting to avoid radiation in peds (or any patient).

The current climate is such that ED physicians and radiologists have a great deal of collective consideration regarding the issues of radiation exposure on a day-to-day basis. No study a medical student can/can't find is gonna change this fact.

 

[kdburton]

kdburton: Just curious, I saw "Ulnar deviant" on your avatar & wondered if you have rheumatoid arthritis. Sorry to pry, but inquiring minds want to know...

Haha no it was just a joke from gross anatomy.

 

[kdburton]

With all due respect, I think the OP is going to know a little more about what the colleagues think then what a medical student thinks the OPs colleagues think

I agree with EmQ. At my institution, everytime I want a CT PE study for my patient, I have to argue with radiology about the issue of radiation so as to get the study I want instead of the inferior V/Q scan... which often ends up being indeterminate.

Same thing when I want a CT when it is indicated for a peds patient -- call and waste valuable time arguing with radiology (who hasn't seen the patient) the risk reward of a timely study vs. delay to get an ultrasound first. Which may or may not be interpreted by someone with expertise in peds ultrasound. Notice I said when it is "indicated" for a peds patient lest you think I am haphazard in this regard about attempting to avoid radiation in peds (or any patient).

The current climate is such that ED physicians and radiologists have a great deal of collective consideration regarding the issues of radiation exposure on a day-to-day basis. No study a medical student can/can't find is gonna change this fact.

Actually I am the OP, but to address your comment... Just because I'm a medical student doesn't mean that I haven't asked this question of residents and attending physicians at the hospitals my school is affiliated with. I've asked these same questions and I've been surprised to find that even some attending physicians who are training the residents don't even know that ultrasound (as an alternative in some cases) doesn't use ionizing radiation and that most literature says an abdominal CT scan is the equivalent of 100-250 chest X-rays in terms of radiation. So while the person who respoded to my post earlier may be at an institution where the ER docs are on the higher end of the awareness curve I don't think it was laughable, as you've put it with your smiley face, to say that he'd probably be surprised if he asked his colleagues about it (because I, N=1, was pretty surprised when I did). Furthermore, radiology departments don't have standard protocols across the country. At one hospital I did an EM elective at saw them scan a young patient without and then with contrast in one sitting for suspected appendicitis because the radiologist argued that if they are unable to confirm appendicitis on the enhanced scan then they will have a non-enhanced one for a better chance of picking up on the real problem. So, again, while you may be aware of radiation risks, not everyone else is. The point of this conversation is not to say that CTs are bad or good, etc, I just wanted to see how prevalent it is for people to do two scans for suspected appendicitis.