kidney damage caused by ct scan dye, whilst taking metformin.

[rosylea]

Was booked in for a CT scan with A and E, to be had 3 days later (was bank holiday). No one told me I shouldn't take my metformin (for diabetes) on the day. Saw a doctor, nurse, had all the usual checks. When I was lying on the table, about to be injected with dye for the scan, the radiologist asked if I'd taken metformin. When I told him I had, he said my kidney function was already a bit low, (which I hadn't known) but just within the boundaries. That the dye can sometimes react with the metformin and cause "problems". He said he was happy to go ahead but gave me the choice of whether to stop metformin for a few days and come back? The scan was for a slight risk of clot on the lung so I had the scan which turned out to be fine thankfully (no clot). Checked on the internet later and found that the dye with metformin could have caused kidney failure!! I now have to go for regular blood tests as kidney function has dropped significantly. No metformin now for 6 weeks, (luckily diabetes not too bad at the moment) Have now been told my kidneys are damaged, function might never go back to normal. Obviously, I'm devastated! Hospital and GP quite blasé. Anyone else have this problem please? So upset, angry and worried.

You were warned though OP, and had the opportunity to ask "what kind of problems?"

Shit that sounds horrible OP. No advice but I really feel for you.

Maybe he could have been clearer in what the problems were, or you could have asked, but you were given the option not to go ahead so I don't think you can be annoyed with the doctors really

It is not quite correct that metformin and the dye interact. The dye used in CT scans can cause kidney damage in a small proportion of people. Metformin is only excreted by the kidneys. The reason for stopping metformin 24-48hrs before is that - if you do end up with kidney damage after the scan - it can lead to a build-up of metformin and lactic acid. They will be monitoring this (and your kidney function) with blood tests.

It sounds as if you had an element of kidney "damage" already - perhaps due to diabetes? This is probably quite minor, which is why no-one has mentioned it before. The truth is that kidney function declines a bit with age and no-one really knows at what level we should say that "damage" has occurred. Your kidneys might have been normal but borderline for being abnormal, which is what spooked the person who was administering the dye.

Although they have said that your kidney function might never go back to normal, the kidney damage caused by the dye is usually temporary. Obviously if your kidneys weren't working at 100% before, this would still be the case afterwards as well, and so you might not be back to "normal".

I hope all goes well and suspect that it probably will.

Thank you so much for replies. I think at the time, I was worrying more about the risk of blood clot because the doctor had (very tactfully) told me the clot could travel to my brain and cause brain bleed!! Was concentrating more on that. Thanks also JohnHunter, that makes it more clear in my mind and gives me hope.

Agree with JohnHunter. The combo of metformin and dye isn't an interaction as such, it's that if the dye does cause a kidney wobble the metformin is more likely to cause side effects. If the dye does cause the kidneys to deteriorate it is usually a temporary thing. If your kidneys weren't normal before the scan unfortunately they're never going to go back to normal.

There's a balance of risk and benefit with everything in hospital (and perhaps that could have been explained a bit better, but you were given an opportunity to bail and find out more about the risks) - the options, from what I can see in your post, were
a) not doing the scan (which may have delayed diagnosis and treatment for a PE)
b) doing the scan without dye (in which case the results would probably not have been useful)
c) doing the scan in the knowledge that the kidneys may deteriorate a little, but the benefits of diagnosing and starting treatment for a PE may offset that risk (the serious risk of a big PE being sudden death).

Fortunately for you the scan was negative, but unfortunately that means that all you experience is the side effects. Had the scan returned a positive diagnosis of a PE is suspect you'd be less worried about the fact that your kidneys were a little worse because the scan result may have saved your life. Fortunately there's quite a bit of redundancy built into our kidneys (or they wouldn't allow living donation for kidney transplant) so hopefully this deterioration in the numbers won't cause any real problems in terms of causing other symptoms or problems and things will get back to your 'normal' in their own time.

It’s risk of using contrast dye to end up with deranged kidney function . We tend to delay scans of people’s U&Es aren’t the best but in the case of ruling out PE or something life threatening a lot of the time me have to go ahead . There is still a chance is your kidney function will improve over time , ask consultant to go over with you .

Thankyou, guys. Is there anything I can do naturally apart from drinking 2 litres water per day?

Thanks again all. Have stopped panicking now Enjoy the bank holiday (for those not working).