Why, when and how to perform percutaneous renal biopsies - DVM
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Why, when and how to perform percutaneous renal biopsies
Can you assess when this diagnostic procedure is best indicated?


DVM360 MAGAZINE



Figure 6: A schematic illustration of a biopsy of the renal cortex using a Tru-Cut biopsy needle. Note that the needle has not traversed the corticomedullary junction.
Renal size should be considered when evaluating the risks of needle biopsy of the kidney. Reduction in the thickness of the renal cortex as a consequence of chronic progressive renal disease increases the likelihood of needle damage to larger intrarenal vessels such as the arcuate arteries.

Because excessive hemorrhage is a potentially serious complication of this procedure, patients with a hemorrhagic tendency should not be undergo a biopsy unless abnormalities in hemostasis can first be adequately controlled. Likewise, hypertension has been associated with an increased incidence of hemorrhage and arteriovenous fistulas in humans after renal biopsy. Therefore, hypertension should be controlled before needle biopsy of the kidney.

How should renal biopsy samples be handled?


Figure 7: A photograph illustrating a linear infarct in the renal cortex of a dog's right kidney. A needle biopsy sample taken from this region one week previously contained only tissue from the renal cortex.
If a decision to perform a renal biopsy is deemed to be in the patient's best interest, before performing the procedure, contact a laboratory familiar with evaluation of kidney biopsy samples, and ask for specific directions on how to process the sample. For example, request information about how to process samples for standard light, immunofluorescent and electron microscopy, as well as immunohistochemical techniques.

Now what's your opinion?


Figure 8: A photograph illustrating a large, healed infarct in the caudal pole of the right kidney of an adult female miniature schnauzer. A Tru-Cut biopsy needle was used to obtain a sample containing cortex and medulla from this region six months previously.
Key point: Since renal biopsy procedures are associated with significant risks, they should not be performed unless the associated benefits are likely to outweigh those risks for the patient's welfare. After considering this information, how would you respond to the question: Are the probable benefits associated with needle biopsy of this cat's kidney likely to outweigh the risks associated with this procedure?

In formulating your answer, consider the following:

1. What diagnostic, prognostic or therapeutic goals are likely to be achieved by evaluation of kidney biopsy samples?

2. Will the benefits associated with the technique of ultrasound-guided kidney biopsy be sufficient to justify the associated risks and costs?

Dr. Osborne, a diplomate of the American College of Veterinary Internal Medicine, is professor of medicine in the Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Minnesota.


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Source: DVM360 MAGAZINE,
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