Introduction to Renal Biopsy

Renal biopsy is not a commonly performed procedure in medical practice but it is sometimes indicated when it has diagnostic value in certain kidney diseases. Most cases of acute renal failure are due to pre renal causes or acute tubular necrosis and recovery of renal function typically occurs over a course of few weeks. Renal biopsy should only be performed if knowing the histology will help in the management. Once chronic renal failure is established, the kidneys are small, may be hard to biopsy, and theresults are usually unhelpful.

Indications

• To determine the cause of unexplained renal failure.
• Persistent Heavy proteinuria >1gm/24hrs
• Investigating the cause of adult nephritic syndrome with persistent hematuria.
• Childhood nephritic or nephrotic syndrome that are unresponsive to treatment.
• Systemic disease with renal involvement like sarcoidosis, amyloidosis.
• Post transplant renal dysfunction.

Contraindication

• Underlying disorder of coagulation.
• Thrombocytopenia.
• Uncontrolled hypertension.
• Solitary kidney (except in transplanted kidneys).
• Small contracted kidneys i.e < 60% of expected bipolar length because it is technically difficult, histology is hard to interpret and prognosis cannot be altered.
• Uncooperative patient.

Procedure

1. All the basic investigations including CBC, coagulation screen, bleeding time, blood group and ultrasound of the kidneys is done.

2. A full explanation of procedure is given to the patient and informed consent is taken.

3. Biopsy is done under ultrasound guidance with the patient lying in the prone position and the breath held.

4. Local anaesthetic is injected along the biopsy track.

5. A pressure dressing is applied to the biopsy site and the patient rests in bed for 24 hrs.

6. The pulse and B.P and urine color are monitored regularly.

7. The request form sent for histology should clearly indicate why the test is performed.

Complications

• Pain
• Infection
• Bleeding.