A B C D E F G H I J K L M N O P R S T U V W

RENAL BIOPSY

Why is a Renal Biopsy performed ?

The two kidneys are situated in the back of the abdomen. They remove waste products and excess water from blood to make urine. The urine then passes down the ureter on each side into the bladder. When the kidneys do not function properly, the cause for this may only be found out in some cases by taking a piece of tissue from one kidney. The test is done when a patient is thought to have the conditions of glomerulonephritis or nephrotic syndrome. A renal biopsy is also sometimes done to find the cause of acute kidney failure.

Preparations needed for Renal Biopsy

You will need to come to hospital only on the day of the biopsy. A sample of blood is taken to check that there is no tendency to excessive bleeding. After the biopsy, rest in bed is needed for only 24 hours and return home is then possible. Depending on what is involved, you can return to work immediately. However, it is advisable to avoid any strenuous exercise for 2 to 3 days after the biopsy to reduce the risk of any bleeding.

What Happens during Renal Biopsy

Usually the renal biopsy is performed in an x-ray department. The kidneys lie close to the back. You will therefore be asked to lie on your stomach. The position of the kidneys is then traced using ultrasound or a kidney x-ray (intravenous pyelogram: IVP, intravenous urogram: IVU). Ultrasound equipment produces a type of radar picture using sound waves. For an IVP, x-rays are taken after an injection of a special dye into an arm vein. These show up the kidneys. The biopsy is done only if two normal, equal-sized kidneys are seen. If there is any abnormality of any sort, it is not safe to proceed. Having decided to go ahead with the biopsy, the position for the biopsy is marked on the skin. Local anaesthetic is injected into the area. The biopsy needle is passed through the skin into the kidney and the biopsy taken. The doctor will tell you when he is about to move the needle into the kidney. It is important for you to hold your breath and keep absolutely still. This will prevent the needle from damaging the kidney. Usually, two or three separate biopsies will be taken. Sometimes it is difficult to find the kidney, even when the position has been marked on the skin. This means that a few attempts at passing the needle may be needed before a biopsy is obtained.

Possible Complications during Renal Biopsy

The major risk is bleeding. Often the urine may be pink for the first day because of a little bleeding. Rarely (l in l00 biopsies), the urine may be heavily bloodstained and a blood transfusion may be needed. If the bleeding is very heavy and does not stop, a special foam may need to be injected down the artery supplying that part of the kidney. This is necessary in only 1 out of 1000 biopsies. Even more rarely, the kidney may need to be removed. This is why renal biopsy is only done when both kidneys have been clearly seen to be normal.

After a Renal Biopsy

You may feel as if you have been kicked in the back for the first day or two! Simple painkillers such as paracetamol may be needed. Any discomfort should then gradually disappear. A renal biopsy normally causes no damage to the kidney and does not affect its function.

If a Renal Biopsy is not performed

The exact diagnosis of the particular kidney disease may not be possible. However, sometimes other blood and urine tests may help to make the diagnosis.