Renal biopsy - Investigations and procedures

Renal biopsy

Renal biopsy is indicated when glomerular disease is suspected, and in unexplained acute renal failure. It may also be performed in cases of deterioration of renal function in patients with known kidney disease, to help guide treatment, for example in systemic lupus erythematosus, and relatively frequently in renal transplant patients particularly to look for rejection.

The biopsy can be performed percutaneously, or at open surgery (unusual unless the other method is not possible, or contraindicated, e.g. single kidney). Ultrasound guidance is used, and usually two cores are obtained using a springloaded biopsy needle. These are examined under light microscopy, electron microscopy and immunofluoresence or immunoperoxidase staining.

Complications include haematuria, bleeding under the renal capsule and bleeding out into the retroperitoneal space, arteriovenous aneurysm formation (if very large may need treatment) and discomfort. In up to 3% of individuals, blood transfusion is required for bleeding, and in 0.1–0.4% surgery or interventional radiology (artery embolisation using coils) is needed to stop the bleeding. Nephrectomy or death occur rarely.

Contraindications to percutaneous renal biopsy:

·        Clotting abnormality or low platelets (unless corrected).

·        Small kidneys (<9 cm), as this indicates chronic irreversible kidney damage.

·        Uncontrolled hypertension.

·        Multiple bilateral cysts or tumour. Active urinary tract infection.

·        If there is hydronephrosis, then obstruction should be corrected, and renal biopsy reconsidered and performed if there is still an indication.

Relative contraindications include obesity (technically difficult), single kidney (except of a transplanted kidney) and pregnancy, as this carries special risks, but biopsy may be necessary if urgent diagnosis and treatment are needed.