Common Pitfalls/Complications: Performing A Renal Biopsy Under Sub-Optimal Conditions

OVERVIEW

This page is dedicated to discussing an important pitfall that is experienced often in the field of radiology: performing a renal biopsy under sub-optimal conditions. Read this page for more information on how to conduct an ultrasound guided non-focal renal biopsy.

A renal biopsy, while a relatively benign procedure,, should be done in the correct clinical setting (image source)

While the evidence base in some cases in anecdotal/limited, there are a few clinical contexts under which a renal biopsy should NOT be performed.

  • High blood pressure
  • Hydronephrosis
  • Elevated INR
  • Low platelets
  • Low hemoglobin (anemia)
  • Recent usage of “blood thinning” medications 
AVOIDING A RENAL BIOPSY IN PATIENTS WITH HYPERTENSION

Why should it be avoided?

The kidneys of a patient with elevated blood pressure can be though of as a high pressure system. Given that a large amount of a patient’s blood will perfuse the parenchyma of the kidney, puncturing this organ in the setting of elevated pressure may lead to excessive bleeding.

What do I look for before performing the biopsy?

Vital signs (unsurprisingly the blood pressure of the patient). Recent values, in addition to the pressure right before the procedure can be informative. Generally speaking, a systolic blood pressure of 160 mm Hg or above is a risk factor for serious bleeding during a kidney biopsy. 

AVOIDING A RENAL BIOPSY IN PATIENTS WITH HYDRONEPHROSIS

Why should it be avoided?

In the setting of hydronephrosis, the collecting system of the kidneys can be thought of as an over-distended balloon (and is a high pressure setting). In such a setting, if a biopsy needle was to puncture the collecting system the risk of developing a urinoma is high.

What do I look for before performing the biopsy?

Signs of hydronephrosis reported on imaging in the patient’s recent past. Whats more, when imaging the kidneys with the ultrasound probe/CT scanner prior to conducting the biopsy the kidneys should be evaluated for signs of hydronephrosis BEFORE the biopsy is conducted.

AVOIDING A RENAL BIOPSY IN PATIENTS WITH AN ELEVATED INR

Why should it be avoided?

Given that a large amount of an individual’s blood circulates through the kidneys, any patient who has compromised coagulation should not be subjected to a kidney biopsy due to the risk of excessive bleeding. Generally speaking, an INR of 1.5 or higher is a risk factor for serious bleeding during a kidney biopsy. 

What do I look for before performing the biopsy?

An INR should be ordered and evaluated on all patients before biopsy.

AVOIDING A RENAL BIOPSY IN PATIENTS WITH LOW PLATELETS

Why should it be avoided?

Given that a large amount of an individual’s blood circulates through the kidneys, any patient who has an impaired ability to stop bleeding should not be subjected to a kidney biopsy (due to the risk of excessive bleeding).

What do I look for before performing the biopsy?

A CBC should be conducted before a renal biopsy. Generally a patient with platelets below 50 x 10³/µl of blood can be concerning for a serious bleed due to a biopsy. 

AVOIDING A RENAL BIOPSY IN PATIENTS WITH LOW HEMOGLOBIN (ANEMIA)

Why should it be avoided?

Given that a large amount of an individual’s blood circulates through the kidneys, any patient with anemia should not be subjected to a kidney biopsy due to the risk of excessive bleeding. A moderate amount of bleeding in the setting of anemia may be enough to bring about serious complications, and may even require a blood transfusion.

What do I look for before performing the biopsy?

A CBC should be conducted before a renal biopsy. Generally speaking, a Hg of below 9.0 mg/dLis a risk factor for serious complications after a kidney biopsy. 

AVOIDING A RENAL BIOPSY IN PATIENTS WITH THE RECENT USAGE OF “BLOOD THINNERS”

Why should it be avoided?

Given that a large amount of an individual’s blood circulates through the kidneys, any patient who has their ability to stop bleeding compromised by recent medication usage (i.e “blood thinners:) should avoid having a renal biopsy performed.

What do I look for before performing the biopsy?

A patients medication history is important to evaluate prior to the procedure. Special attention should be paid to the usage of medications such as warfarin, aspirin or NSAIDs. Generally speaking anticoagulation/anti-platelet therapy that was stopped less then 7 days prior to the biopsy is a risk factor for serious bleeding occurring after the kidney biopsy. 

 

Page Updated: 06.22.2017