CT [un]necessary?

[kdburton]

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I posted this in the allo student forum a few days back but realized I may get better response here. I'm between MS1 and MS2 and doing a lit review on the use of CT scans on ED patients who present with undifferentiated abdominal pain. I'm curious what conditions would present like this and would normally trigger an order for a CT scan, but for which there may be other (probably less specific and sensitive) diagnositc tests that could be done. Right now I'm thinking acute appendicitis and possibly abdominal aortic aneurysm. Can anyone comment for me please?

 

[Rendar5]

MS4 here, only 1 month of EM clinical experience. Probably depends on the place. But I've only used ultrasounds to look for AAA's, never CTs. Biliary issues were evaluated with u/s and HIDA. I've heard appendicitis can be looked at with u/s but CT is more standard. Havent' had a case this month. This month I've used CT for trauma patients, to look for kidney stones (was told that despite what I learned as an MS2, most kidney stones are not radio-opaque on plain abdominal films), evaluating possible pancreatitis, and in one patient with biliary colic symptoms 4 months s/p lap chole (turned out to be a retained stone).

 

[southerndoc]

U/S for gallbladder pathology, AAA, appy (in thin patients/pediatric patients), ovarian pathology (torsion, TOA, etc.), and that's about it (other than transvaginal U/S for vaginal bleeding in pregnancy).

I use U/S for renal colic. My criteria for CT in renal colic is first stone, significant hydro on U/S in somebody with a history of stones, history of sickle cell disease or a clotting disorder (hypercoagulation state), unable to get pain relief, or somebody who presents for a second visit for the same renal colic.

I've been surprised at the number of times I've CT'd "renal colic" only to find renal vein thrombosis, renal infarction, etc. It's not very common, but it does occur. That's why I CT first time renal colic patients.

 

[kungfufishing]

To me, the scary double edge of that sword is both the number of people with a history of prior renal colic AND something worse wrong with them this time as well as the overall quantity of radiation provided daily on a national scale for people with known renal colic. I like your approach and would say that is about how I think about it, too.

For the OP, I think the problem with using other modalities vs. CT for lots of undifferentiated abdominal pain is that you are talking about diagnoses that carry significant M&M and given the choice the more accurate test is often the one to pick. I like ultrasound as much as the next guy (unless he is the son of the CT scanner salesman, then I probably like it better).

 

[roja]

there are a few studies that look at this and basically don't show much of anything because they are horribly done.

No one really has 'undifferntiated' belly pain. Your h&p, physical exam (+/- pelvic/testicular exam) plus a urine dip/rectal exam will start to 'narrow' down your differential.

So, things that will generally trigger CT's? appy, obstructions, diverticulitis (some places only in sicker older patients, others for any suspected diverticulitis), acute mesenteric ischemia.

plus or minus triggers (depends on the attending) renal colic (kidney stone)

Ultrasound is good for: gallbladder, AAA, ovarian masses, ectopics, PID, TOA.

I rarely do scans for kidney stones. (several years of extensive research in renal colic and having read all the literature 2-3 times, teaching etc) I have boiled it down to this, in pts with suspected kidney stone:

-people with one kidney
-people with signs of infected stone
-intractable pain (meaning >2 doses of adequate analgesia)
-history of cancer
-age >55-60 with first time presentation

 

[GeneralVeers]

to this, in pts with suspected kidney stone:

-people with one kidney
-people with signs of infected stone
-intractable pain (meaning >2 doses of adequate analgesia)
-history of cancer
-age >55-60 with first time presentation

I'd also add to the above pain greater than 3 days duration. If it hasn't resolved by then, I worry about a large stone that won't pass on its own. They get a renal scan.

 

[southerndoc]

I've actually seen a couple large SBO's on ultrasound. However, the number I've ultrasounded that I didn't see, but turned out to have SBO diagnosed by CT, is rather large. (So is the number of SBO's by CT that were not diagnostic by 3-way X-rays.)

 

[TysonCook]

Also remember that some diagnostic testing (including CT's), while not being clinically indicated, sometimes are done to "move the meat" when other diagnostic modalities are not available, time consuming, equivocal, or delay treatment that could have serious M+M.

A poor example would be trauma pts with abd pain (serial exams vs CT's etc). I'm sure there is lit for both, but the reality of the ED vs the literature version leaves quite a bit of gray.

 

[Whisker Barrel Cortex]

there are a few studies that look at this and basically don't show much of anything because they are horribly done.

No one really has 'undifferntiated' belly pain. Your h&p, physical exam (+/- pelvic/testicular exam) plus a urine dip/rectal exam will start to 'narrow' down your differential.

So, things that will generally trigger CT's? appy, obstructions, diverticulitis (some places only in sicker older patients, others for any suspected diverticulitis), acute mesenteric ischemia.

plus or minus triggers (depends on the attending) renal colic (kidney stone)

Ultrasound is good for: gallbladder, AAA, ovarian masses, ectopics, PID, TOA.

I rarely do scans for kidney stones. (several years of extensive research in renal colic and having read all the literature 2-3 times, teaching etc) I have boiled it down to this, in pts with suspected kidney stone:

-people with one kidney
-people with signs of infected stone
-intractable pain (meaning >2 doses of adequate analgesia)
-history of cancer
-age >55-60 with first time presentation

Pleeeeeeeease come to my hospital and lecture to our ED docs. I've seen too many 20-40 year olds with >10 scans for renal colic over a relatively short period of time. The worst one was a 22 year old with 15 scans over 5 years! I usually put in my report this fact and give the alternative of US or x-ray and talk to the requesting provider, but it still happens. I do keep a close eye out for any enlarging lymph nodes that could indicate radiation induced lymphoma though. 😉

 

[roja]

Pleeeeeeeease come to my hospital and lecture to our ED docs. I've seen too many 20-40 year olds with >10 scans for renal colic over a relatively short period of time. The worst one was a 22 year old with 15 scans over 5 years! I usually put in my report this fact and give the alternative of US or x-ray and talk to the requesting provider, but it still happens. I do keep a close eye out for any enlarging lymph nodes that could indicate radiation induced lymphoma though. 😉

😍

Oh lord. You are kidding me. That is horrible. I would be happy to send you my 'faculty development' document that outlines exactly why the above is completely appropriate and not some 'rebel' thing. I have read 98% of the literature on kidney stones

 

[Rendar5]

😍

Oh lord. You are kidding me. That is horrible. I would be happy to send you my 'faculty development' document that outlines exactly why the above is completely appropriate and not some 'rebel' thing. I have read 98% of the literature on kidney stones

Could I take a look at that too if you have a chance? Very interested in seeing it.😀

 

[bartleby]

I've seen too many 20-40 year olds with >10 scans for renal colic over a relatively short period of time.

It is easier to order a CT than think. The recurrent "I have a kidney stone and I need dilaudid" patients who have tiny punctate non-obstructing stones on their last few CT's get a bedside ultrasound. If they don't have any evidence of hydronephrosis (i.e. ureteral obstruction), urinary infection or likely alternate diagnosis, they get motrin, instructions for urology f/u, and pointers on finding the waiting room.