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Kidney Diseases

Kidney Biopsy

07/27/2009

Question:

I am a 70-year-old white male, slightly overweight, with long-standing proteinuria (+1 30 years ago, to +4 now). I also have fairly well controlled hypertension for the last 20 years. My doc suggests a kidney biopsy. However, I am taking Plavix and aspirin because of a stroke 4 years ago and she told me this would have to be stopped 2 weeks before and 2 weeks after the biopsy. Also, I was on prednisone 4 years ago because of a mild bout of dermatomyositis, which seems to be cleared up. While on the prednisone, there was a drastic drop in the amount of proteinuria. Question – would the biopsy be important and risky?

Answer:

It does sound like a biopsy would be helpful in establishing why your kidneys are leaking so much protein.  The drastic decrease in proteinuria on prednisone suggests several categories of disease, particularly those called "autoimmune" diseases, including dermatomyositis, in which the body appears to attack itself and produce antibodies that can damage multiple organ systems.  Therapy to suppress the immune system can be very helpful in this class of diseases, but this is not a therapy to be undertaken lightly, so a biopsy could help to establish whether it is helpful worthwhile to give a drug like prednisone (which does have its own side effects and risks that must be carefully weighed against its benefits).  However, before having the biopsy, you should have an ultrasound exam to determine whether you have two kidneys, whether their size is normal, and whether the kidney tissue is "echogenic" or scarred.  If there is a lot of scar tissue, or small-sized kidneys, then a biopsy may not yield useful information.  However, if your kidney function (as measured by blood tests for BUN and creatinine) is normal or nearly so, and if your kidneys are of normal size, then a biopsy should yield a helpful diagnosis.

If you stop the Plavix (as well as aspirin and nonsteroidal meds such as Motrin and Aleve) ahead of time as recommended, and if you are not terribly overweight, the biopsy should be a simple and safe procedure (which is almost always performed as an outpatient).  Good luck: I would be interested for you to write again and let us know how things turned out.

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Response by:

Mildred   Lam, MD Mildred Lam, MD
Associate Professor of Medicine
School of Medicine
Case Western Reserve University