Doc: General guidelines for living with one kidney
Dear Dr. Roach: I had a kidney removed eight months ago due to a kidney tumor, and since then have had bloodwork done numerous times. My GFR fluctuates from 38-44, and my creatinine and BUN levels are high (creatinine level is about 1.7 and BUN around 27; before surgery, my creatinine was 1.2). As of this date, there is no cancer, as I have had several CT scans WITHOUT contrast. They have not shown any sign of metastasis. I have had both bloodwork and urinalysis, and the BUN and creatinine levels have stayed pretty much the same. Is my GFR low because I have only one kidney? No one seems to answer the question when asked. I would appreciate any guidance regarding my situation. I now have only one kidney, so I am pretty careful about treating it well!
Dear M.K.: BUN (blood urea nitrogen) and creatinine are waste substances removed by the kidney, so they are high when kidney function is poor. Removing one kidney always will cause an increase in these levels, even though the other kidney works harder to partially compensate. Since your creatinine level hasn’t changed much since the surgery, that suggests that there has been no decline in your kidney function since then. So, whatever you are doing is working.
You want to help keep your kidney working well, and eating more plants and less meat has been shown to protect the kidneys. You also should maintain good control of blood sugar and pressure, if appropriate. I would recommend that you avoid kidney-toxic drugs, such as ibuprofen and other NSAIDs; keep up a good but not excessive fluid intake; and let all of your doctors know about the one kidney and your creatinine level so they can adjust doses of any new medications that you may (but hopefully won’t) need.
Dear Dr. Roach: I have an ICD, which means I can’t have an MRI. I wasn’t aware of this issue when my ICD was implanted, though I didn’t have many options. I wonder how many people who have or need an ICD (or pacemaker) are aware of this restriction. What is the outlook for people like me?
Dear J.O.: Implantable cardioverter defibrillators are used in people who are at very high risk of a dangerous heart rhythm, especially people who have had a life-threatening arrhythmia before, and in people with very advanced heart failure, who are known to be at high risk. Newer ICDs also can act as pacemakers for people who need both functions. It is true that MRI scans, which utilize powerful magnetic fields to take pictures of the soft tissues of the body, generally are not used in people with pacemakers or ICDs. This is because the metals usually used to make these devices can move in the powerful magnetic field of an MRI scanner, but they also can heat up and damage surrounding tissue.
You certainly should have been told this when the ICD was put in. However, there are some situations in which MRI scans still may be used. A case series from Germany in 2009 showed that in people who did not need the pace-making function of the ICD, the device could be turned off, and the MRI could be performed safely (with the MRI power turned low). A careful evaluation found no damage to the pacemaker, no change in placement of the wires and no damage to the heart. However, this is still not the standard of care, and it usually is possible to find another test, such as a CT scan, for imaging needs.
Readers may email questions to ToYourGoodHealth@med.cornell.edu.