Posted on 05/06/2023 7:16:30 AM PDT by ConservativeMind
Upon an arrival to the emergency department for abdominal pain of unknown cause, most non-pregnant adult patients receive a CT scan with IV contrast to diagnose the source of the pain.
However, IV contrast can be a risk in patients with severe kidney disease or at risk for an allergic reaction from the dye. When scans are performed without IV contrast, though, they are usually less accurate, which can lead to misdiagnosis.
And recent research from the University of Michigan now confirms this: a study found choosing to withhold IV contrast from certain types of abdominal CT scans can decrease the accuracy of the scan by about 30%.
"The decrease in accuracy means there is a higher chance of misdiagnosis," said Matthew Davenport, M.D., senior and corresponding author. "Non-contrast scanning can lead to confusion about what the source of the pain is, resulting in a misdiagnosis or missing the problem entirely."
Contrast is used in these general abdominal scans to create an image contrast between the normal and abnormal parts of the body. Clear distinction of abnormalities in the body gives emergency department doctors the most accurate real-time answers to make a quick diagnosis.
The results of the study provide a much clearer understanding of the risk-benefit tradeoffs involved in patients with borderline kidney function or a questionable contrast allergy. We now know that the diagnostic penalty of withholding IV contrast is large, and this needs to be considered when attempting to avoid the risks of giving IV contrast.
"Our goal is to maximize benefit and avoid harm," said Davenport, a clinical professor of diagnostic radiology and urology. "We now have a clearer understanding of how to do that in patients undergoing CT scanning in the emergency department for abdominal pain."
(Excerpt) Read more at medicalxpress.com ...
Would you like to know how to mitigate this? Apparently, a lot of researchers and doctors still don’t know how to use CT contrast, despite better practices coming out years ago. I can vouch for this in a local hospital, where I got the practices permanently changed.
It appears the main problem with CT contrast is that the viscosity (thickness) is above the safe zone, according to prior published, and trained, information. This seems to create what one writeup once called “micro-tears” in sensitive tissues, like the kidneys, leading to part of what is then called a “contrast allergy.” Additionally, as the next post will show, we can’t be allergic to iodine, but can be to the rest of the compound(s) in the specific contrast.
Pharmacists should have been trained on this, but CT techs and doctors, haven’t, seemingly.
I’ll next post the PowerPoint slides from a 2016 pharmacist conference presentation that points to the problem and the practices to prevent it. In sum, it is making sure your CT tech is pre-heating the contrast to body temperature, reducing viscosity by 50%, if using a higher concentration (such as with chest or brain scans), and using a better contrast agent option (use a low-osmolality contrast agent like Isovue, Optiray, or Omnipaque).
Do note I am not a doctor, but I can read and pass on what makes sense, to me, from what doctors and researchers provide.
“Best Practices in the Use of Iodinated Contrast Media in the Clinical Setting: What the Pharmacist Needs to Know” (February 2016)
https://ashpadvantagemedia.com/contrastmedia/files/handout-contrastmedia.pdf
My wife is allergic to contrast dye. When this first happened and her throat was closing up, the nurses ran around not prepared until a doctor finally came up with an antihistamine and luckily she could still swallow it.
No idea why they didn’t prepare for this.
Just ran into this problem myself. They wouldn’t use contrast because my gfr is 29 (it fell from 36 from a previous test result just a few months earlier- I had a test with contrast back then- then needed another due to another problem, but they said they couldn’t use it for the reason stated above)
Wow- that’s pretty bad. They absolutely should, have emergency meds on hand- I know when I get tests done that they often have trainees doing the job, maybe a trainee wasn’t fami,iar with everything yet.?
(Love when I get trainees for it placement- that’s always good for a fun time of bleeding profusely lol... not actually that bad, but they do botch the job more often than not and have to bring in a real nurse)
Thanks, I will pass this along. One of the times I took contrast dye I had Nausea for several hours. That should have been a wake up on my part. The last time I had it, it rushed immediately to my crotch area. I now have a section of my penis that is about an inch and a half long turned to rock. I also coincidentally have stage 3 kidney disease. I now wonder about that.
Mild Symptoms (self‐limiting)
Treatment: Observation and reassurance (minimize patient anxiety)
Symptoms: Nausea, mild vomiting, urticaria, itching
Moderate Symptoms (potential to be severe)
Treatment: Responds to symptomatic treatment.
Continue to treat and monitor to ensure symptoms abate.
Symptoms: Severe vomiting, marked urticaria, bronchospasm, facial/laryngeal edema, and vasovagal symptoms
Severe Symptoms (potential morbidity/death)
Treatment: CPR/code cart, usually hospitalization
Symptoms: Hypotensive shock, respiratory arrest, cardiac arrest or severe arrhythmia, convulsion
Contrast wrecked my kidneys. Between 2013 and 2020, I had more than a dozen procedures.
My second cat scan triggered a shellfish allergy. It took me a year to figure out why it was “everybody out of the pool..... NOW” every time I ate shrimp, and then I discovered it by researching on the internet. When I asked my Dr he said “oh yeah, that happens sometimes”. Sheesh. Thanks a lot!
My husband had surgery to repair an abdominal aortic aneurysm last July. The surgery went longer than average, 4.5 hours, which used a lot of contrast dye. He went in to surgery with Stage 3 Chronic Kidney disease and the right kidney atrophied. We had no idea he even had kidney disease or that the right one had shrunk (He went to appointments alone, not sure if it was said to him and he didn’t comprehend it or what). Every month since the surgery his kidneys got worse until he was in kidney failure with a gfr of 11. We are now doing peritoneal dialysis at home, I am giving it to him. A lot of work but of course he’s worth it.
Good luck to you folks.
No thanks. I’m a kidney transplant recipient, and this little puppy has been on the brink of death more than once. I’d rather have a less accurate scan than wind up back on dialysis.
I also have bad reactions to iodine and betadine, so... No thanks.
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