Percutaneous Renal Biopsy

Background and indications

Ultrasound-guided percutaneous kidney biopsy is the reference technique for diagnosing glomerular, tubulointerstitial, and vascular nephropathies. It is also indicated for characterizing indeterminate renal tumors on imaging and monitoring kidney transplants (rejection biopsy).

Main nephrological indications include: significant proteinuria, nephrotic syndrome, glomerular hematuria, renal insufficiency of undetermined etiology, and lupus nephritis.

Pre-procedure assessment

Assessment includes renal ultrasound (kidney size, cortical thickness, absence of obstruction), complete coagulation panel (PT, aPTT, platelets > 80,000/mm³, bleeding time), verification of anticoagulant and NSAID discontinuation, and blood pressure control (< 140/90 mmHg).

Procedure

The patient is positioned prone. Under local anesthesia and real-time ultrasound guidance, an automatic biopsy needle (16G) is inserted into the cortex of the left (or right) kidney lower pole. 2 to 3 cores are obtained. Sample adequacy is verified immediately (number of glomeruli visible to the naked eye). The procedure takes 15 to 20 minutes.

Results and scientific evidence

Ultrasound-guided percutaneous kidney biopsy offers over 95% diagnostic yield when a minimum of 10 glomeruli is obtained (standard recommendation). Major complication rate (requiring transfusion or intervention) is 1-2% in large published series. It remains essential for diagnosing many nephropathies, as diagnosis by biology or imaging alone is insufficient.

Risks and complications

Perirenal hematoma (5-10%, generally asymptomatic and self-resolving), gross hematuria (3-5%, spontaneously resolving), local pain (20-30%). Bleeding requiring transfusion (< 1%), arteriovenous fistula (< 1%, generally asymptomatic and self-resolving). Nephrectomy for uncontrolled hemorrhage is exceptional (< 0.01%).

Recovery

Strict bed rest for 4-6 hours in supine position with blood pressure, pulse, and urine monitoring. Relative rest for 48 hours, no sports for 1 week. Histological results within 5-10 days.

Practical information

The procedure is performed as an outpatient or short inpatient stay depending on the case. It is performed by an interventional radiologist or nephrologist, in an environment allowing post-procedural monitoring.