This past Friday I had yet another CT scan. It's become almost a familiar routine now, but I try to pay attention when the technicians and nursing staff rehearse all the precautions, ask all the questions, and comment on all the possible side effects. The nurse performing the scan was especially kind, telling me everything she was doing and explaining every phyiscal symptom I would have moments before experiencing the sensation.
Last December, when I had my most recent CT scan, the barium cocktail left me feeling quite ill all afternoon. You know, the typical diarrhea, etc. This time, I was cautious about the barium, asking the technician if there was anything I could do to alleviate the after effects. Normally, the patient takes about 8 ounces of an orange-flavoured barium cocktail and then another 8 ounces about 20 minutes before the CT scan is performed and the intravenous iodine solution is injected into a vein in the arm. But because I had mentioned the after-effects, the technician substituted my second drink with gastrografin, a water-based iodine cocktail. It didn't taste any better, but I have to admit that I felt better Friday afternoon than I would have expected. The CT scan technician also mentioned that the culprit was probably not the barium itself, but the sorbitol that is added to sweeten the mixture.
The radiocontrast agent in the first cocktail is barium sulfate, a suspension of fine particles in an aqueous solution usually with sorbitol to make it sweeter. It is because the barium sulfate is so insoluble that this otherwise extremely toxic metal can be used for radiocontrast agents for the GI tract. If is was more soluble, then the body would absorb the toxins. But the relatively large nuclei of barium's high atomic number make it especially good at absorbing X-rays. So we get the best of both worlds - lower toxicity and higher absorption of X-rays.
The sweetening agent, sorbitol, on the other hand metabolizes very slowly in the body. Although it is often listed as an inactive ingredient, if my nurse/technician is correct, it is very active indeed. The medical community is quickly becoming aware that too much sorbitol causes severe GI-related problems. In my case, the caution now associated with sorbitol was dead on in December - abdominal pain, gas, and fairly severe diarrhea.
Gastrografin, otherwise known as diatrizoic acid, can be administered intravenously (I'm reasonably confident this is what is used for the CT scan) or orally. Like most other medications, there are contraindications associated with iodine sensitivity, but those don't seem to apply to me.
So, like most other things in my unwanted journey, getting a routine CT scan provides yet another opportunity for learning something new. This time it was a new cocktail - gastrografin. If I could have been given a choice, my preference would have been the same as James Bond in Casino Royale for a Vesper instead:
"Three measures of Gordon's, one of vodka, half a measure of Kina Lillet. Shake it very well until it's ice-cold, then add a large thin slice of lemon peel. Got it?"
Too bad they don't give patients a choice.
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