Renal Biopsy

Updated: May 19, 2017
  • Author: Charbel E Chalouhy, MD; Chief Editor: Edward David Kim, MD, FACS  more...
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Overview

Background

A renal biopsy is a procedure used to obtain a segment of renal tissue, usually through a needle or another surgical instrument. Analysis of this tissue is then used in the diagnosis of an underlying renal condition.

In native kidneys, renal biopsy is used to identify various renal diseases especially glomerular or interstitial pathologies. It can also aid in the diagnosis of renal masses and malignancies, the most common being  renal cell carcinoma.

On a transplanted kidney, renal biopsy is indicated anytime when graft dysfunction ensues with a raise in serum creatinine. Renal biopsy aids in diagnosing graft rejection and helps guide treatment, as well as the response to treatment in some cases.

 

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Indications

Renal biopsy is typically performed by a radiologist under CT or ultrasonographic guidance. However, a urologist can also perform renal biopsy during renal surgery.

There are multiple indications to perform renal biopsy, including the following:

Paripovic et al [1] and Printza et al [2] both performed retrospective studies to determine indications of pediatric renal biopsy. Both found that nephrotic syndrome was the most common indication (32.9%). Paripovic et al found that other indications included asymptomatic hematuria (23.4%), urinary abnormalities in systemic diseases (15.8%), and proteinuria (11.4%). Both studies found that glomerular disease was most prevalent.

Paripovic et al found that the most common causes of glomerular disease included focal segmental glomerulosclerosis (20.9%), mesangioproliferative glomerulonephritis (14.6%), immunoglobulin A (IgA) nephropathy (8.9%), minimal change disease (13%), lupus nephritis (6%), and Henoch-Schönlein nephritis (4%).

Printza et al found that the most common findings included focal segmental glomerulosclerosis (15%), IgA nephropathy (13.5%), minimal change disease (10%), various stages of lupus nephritis (8.5%), Henoch-Schönlein nephritis (7.5%), membranous glomerulonephritis (7.5%), mesangioproliferative glomerulonephritis (6%), postinfectious glomerulonephritis (6%), hemolytic uremic syndrome (5%), tubulointerstitial nephropathies (3.5%), and acute tubular necrosis (2.5%).

The image below depicts a micrograph of focal segmental glomerulosclerosis.

Histology slide. Histology slide.

Biopsy of renal transplant allograft 

A recent survey by UNOS (United network for organ sharing) showed great disparities in practice across US transplant centers regarding the timing and performance of surveillance kidney transplant biopsies for diagnosing subclinical graft rejection. The most common timeframe for surveillance biopsies were 3 and 12 months post-transplant. The 1 and 3-year graft survival were similar among centers performing biopsies vs. those not performing biopsies. Obviously, the survey results showed the controversies around surveillance biopsies and the management of sub-clinical rejection. [3]

Rush et al from the Manitoba Adult Renal Transplant Program were the first to report the finding of subclinical rejection within the first 3 months post transplantation. [4] Subclinical rejection can be broadly defined as lymphocytic infiltration of a renal allograft with normal function. Rush et al further classified subclinical rejection as a serum creatinine increased by more than 10% 2 weeks before the protocol biopsy and a histological Baniff score (system used for scoring renal allograft histology) of “ai2at2” (type 1A acute rejection) or greater. [5] The controversy regarding this topic is whether detecting subclinical rejection from a specific biopsy protocol can guide early successful treatment of renal allograft pathology, ultimately improving long-term graft function.

A study analyzed a 10-year follow-up of their patient population diagnosed with subclinical rejection at 14 days post transplantation. [6] Their results showed a significant decrease in graft survival over the 10-year period, concluding that subclinical rejection can predict transplant outcomes. Another study attempted to determine the benefit of early detection of subclinical rejection and subsequent treatment with corticosteroids. [7] The study featured 72 patients randomized to 2 biopsy groups, one receiving biopsies at 1, 2, 3, 6, and 12 months (biopsy arm) and the other receiving biopsy at 6 and 12 months (control group). Patients in the biopsy group showed a decrease in acute rejection, reduced chronic tubulointerstitial score at 6 months, and a lower serum creatinine at 24 months compared with patients in the control group.

On the other hand, when renal transplant dysfunction is suspected as evidenced by rise in serum creatinine level, or clinical signs, such as fever, edema, hypertension, oliguria, and proteinuria, the allograft biopsy is mandatory for adequate histological diagnosis . [8]  Some studies went on analyzing the accuracy of clinical prediction of allograft pathology related to diagnosis found after renal biopsy. [9] Findings revealed 43% of clinical predictions were totally correct and of the 57 % of cases where predictions were not accurate, 26% of those cases were completely incorrect, clarifying the necessity of renal biopsy for accurate diagnosis of allograft pathology.

Renal allograft biopsy is very useful in identifying acute rejection in the transplant allograft and guide the treatment of antibody-mediated rejection or acute cellular rejection. Once the correct treatments are initiated, a repeat biopsy helps confirm adequate response to treatment.

In high risk transplant i.e. ABO or HLA incompatible kidney transplants, allograft interval biopsy schedule remains the mainstay for surveillance in this particular category of patients in whom the graft might be compromised by silent immunological processes. [10]

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Contraindications

Absolute contraindications to renal biopsy include the following:

  • Uncorrectable bleeding diathesis
  • Uncontrollable severe hypertension
  • Active renal or perirenal infection
  • Skin infection at biopsy site

The following are relative contraindications to renal biopsy:

  • Uncooperative patient
  • Anatomic abnormalities of the kidney which may increase risk
  • Small kidneys
  • Solitary kidney
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Technical Considerations

The following factors may make renal biopsy difficult for the radiologist:

  • Small kidneys
  • Solitary kidney
  • Retrorenal colon
  • Highly vascularized tumors (increased risk of bleeding)

Other considerations include the possibility of infection, injection into a muscle (creating a hematoma), and the possibility of the biopsy needle inadvertently piercing other organs in close proximity to the kidney, such as the colon, spleen, and liver.

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