Kidney Biopsy : Indications, Preparation and Procedure

Pace Hospitals

Kidney biopsy is also called renal biopsy is a procedure during which a small piece of kidney tissue is removed and examined under microscope with a variety of stains to identify the underlying disease which is affecting the kidney function. The procedure of kidney biopsy is generally safe and can provide valuable information regarding the underlying kidney disease and helps in treatment.

Kidney Biopsy : Indications, Preparation and Procedure

Indications for kidney biopsy

Kidney biopsy is recommended in people with kidney disease. Based on the results of urine and blood tests nephrologist will advice the kidney biopsy. The most common reasons for kidney biopsy are as follows. More than one reason may be present in a given patient.

Blood in the urine (called haematuria)
Protein in the urine (called proteinuria)
Problems with kidney function (if the kidneys function declines slowly or suddenly and the cause is not clear)

Uses of kidney biopsy

Diagnosing a kidney problem which cannot be identified by any other way
Helps is developing treatment plan
Determines the extent of kidney damage
Can tell us how well the treatment is working
Can tell us if any treatment is going to work or not based on the damage already occurred

Preparation for kidney biopsy

If there is an indication to do a kidney biopsy following checks are done to prevent bleeding complications.

Adequate blood pressure control in patients who are already hypertensive preferably below 140/90mmHg
Blood tests are done to check if the patient has adequate haemoglobin and clotting capacity
Tests done are- complete blood count, PT-INR, APTT, Bleeding and clotting time
Urine tests are done to rule out any infection
Ultrasound kidneys to see if the kidneys are in normal position and size of kidneys are checked
Medications are reviewed to see if the patient is on blood thinners like Aspirin, clopidogrel, warfarin, rivaroxaban, dabigatran, heparin etc
Blood thinners like aspirin and clopidogrel are stopped 7 days before procedure

Procedure for kidney biopsy

During the procedure patient will lie on his abdomen with back facing the roof and will be awake. For patients who are renal transplant recipient’s biopsy is done with patient lying on back. Kidney biopsy procedure included following steps

Using an ultrasound machine probe, size of the kidneys and position of the kidneys are assessed first and then a site is identified to insert the kidney biopsy needle
Skin over the back where the site of entry is marked is cleaned with antiseptic
A local anaesthetic medication is injected with a syringe with needle at the site of entry to numb the area
Using the ultrasound probe as a guide, a biopsy needle (a spring-loaded instrument) is inserted and sample of kidney is collected
Patient is asked to hold the breath while collecting the sample and patient hears a pop sound or sharp clicking sound or feel some pressure
Biopsy needle maybe inserted few times to get adequate sample
Once the procedure is completed a bandage is placed over the biopsy site

Post procedure care

Patient is admitted in hospital over night after the biopsy to monitor for complications. Immediately after the procedure biopsy site is compressed and patient lies on his back. His pulse rate and blood pressure are monitored every 30 minutes for 6 hours. Patient is given transparent containers to collect urine each time he passes so that if any bleeding happens will be identified. After 6 hours patient can move in bed to sides but strict bed rest is advised overnight. Next day morning his blood pressure and pulse rate is checked and if there is no complication (like blood in urine) patient is discharged.

Contraindications of kidney biopsy

Kidney biopsy is avoided when the risk to patient is more than the benefit of procuring the kidney tissue.The following are the contraindications for kidney biopsy

Skin infection over site of needle insertion
Infection of kidney (pyelonephritis)
Uncontrolled hypertension (systolic BP > 140 mmHg)
Small hyperechoic kidneys (suggestive of advanced irreversible chronic kidney disease)
Patients with increased bleeding risk
Low platelet counts, elevated INR
On blood thinners and anti-blood clotting medications (need to be stopped before procedure)
Horse shoe kidney
Multiple cysts in kidneys
Hydronephrosis (obstruction to urine outflow from kidney)

Possible complications of kidney biopsy

Serious complications are not common after kidney biopsy but can rarely happen. Less serious complications are common like pain, bleeding and development of an abnormal connection between two blood vessels (a fistula).

Bleeding

Bleeding is the most common complication of renal biopsy.
Many people may notice blood in their urine after biopsy which resolves spontaneously
Some times blood may clot in urinary bladder and requires Foleys catheter insertion to clear the clot
Severe bleeding into the kidney or urine requiring blood transfusion is uncommon
Very rarely, it may become life threatening and possibly require a procedure or surgery to stop the bleeding.

Pain

Pain can occur after a renal biopsy
Pain generally responds to pain killers and resolves

Aretriovenous fistula

The biopsy needle can rarely injure the walls of a nearby artery and vein, and this can lead to the development of a fistula (a connection between the two blood vessels).
These are benign and generally intervened only when they cause bleeding which is persistent, resistant hypertension and heart failure or kidney dysfunction