When Mom and I interviewed dialysis patients for our KidneySteps book, we were surprised at the number who told us they ended up on dialysis after receiving dye for a CT scan. As a nurse, I also see patients who believe their kidneys were damaged by contrast dyes given during lab imaging tests. These people aren’t imagining the damage. Contrast agents, commonly used for coronary procedures, are known to be toxic to kidneys. The kidney damage they cause is called contrast-induced nephrology (“CIN”).
People who already suffer reduced kidney function are particularly susceptible to CIN. Those in stage 3 or 4 of kidney disease have the greatest risk. Other risk factors for developing CIN include being diabetic, dehydrated, over age 70, having congestive heart failure, or using NSAIDs (aspirin and other pain relievers) at the time of the test.
You have CIN from contrast dye if your serum creatinine (kidney patients know what this is) increases by 25% from baseline (e.g. creatinine increases from 2 mg/dL to 2.5 mg/dL) within 2 to 3 days after receiving the dye.
CIN is usually temporary, with kidney function returning to normal within a couple of weeks. However, just developing CIN is a hazard. It is associated with a significantly higher risk of death while in the hospital and within a year thereafter. In those with kidney disease, CIN can be permanent and can propel someone into end stage and dialysis.
Unfortunately, many physicians ordering CT scans with contrast dye are not fully informed about the CIN risk. If the patient is diabetic and/or has a creatinine level greater than 2 or 3, CIN can result up to 50% of the time, studies indicate, which sharply increases risk of death and permanent kidney damage and dialysis.
What to do: If your doctor orders a test that includes contrast dye, express your concern about your diabetes or kidney function. Ask about an alternative (such as an MRI), and see if the test is urgent. I have told my mother, the recipient of my kidney, to avoid contrast imaging. Transplantation does not cure kidney disease, and avoiding contrast dyes where at all possible is a reasonable precaution.