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Great Ormond Street Hospital for Children NHS Trust UCL Institute of Child Health
 

Children and families

Kidney biopsy - 2nd edition

This leaflet explains what happens when your child needs to come to Great Ormond Street Hospital for a kidney biopsy.

Contents

What is a kidney biopsy?

A kidney biopsy is a procedure to remove a very small piece of kidney tissue to examine under a microscope.

Why does my child need this procedure?

A kidney biopsy is usually carried out to determine or confirm a diagnosis. It could also be useful in assessing how the kidneys are responding to treatment. It may become necessary when blood and urine tests, ultrasound scans and other radiology imaging have not been able to give the cause of your child’s kidney problem or whether are specific treatment is needed.

Some of the problems that might need a kidney biopsy include: recurrent episodes when blood can be seen in the urine, the presence of large amounts of protein in the urine and when kidney function has deteriorated rapidly and the cause is not known. In children who have had kidney transplants, it can identify why the transplanted kidney is not working well and what treatment is needed.

What happens before a kidney biopsy?

We need to be sure that your child’s blood clots properly so we will take a small blood sample for testing. This is because healing after the procedure relies on blood clotting. We also check your child’s blood group so that if we need to give your child blood, we can organise this.

We will discuss with you whether or not you need to come in the night before or very early on the day of the biopsy. An anaesthetist will visit you to discuss the best form of anaesthetic for your child. Anaesthesia can either be with a full general anaesthetic or the use of Entonox®, which the ‘gas and air’ women have during childbirth, or a local anaesthetic.

What does the biopsy involve?

The biopsy will take place in the Radiology department on the ground floor of the hospital. Your child will usually be able to walk or be carried there with you but he or she will return to the ward on a bed. When in the department, your child will lay on their left side if his or her own kidney (native kidney) is being biopsied. If the biopsy is on a transplanted kidney, your child will lie on his or her back, as this makes it easier to feel the transplanted kidney. The exact position of the kidney, whether native or transplanted, is confirmed using an ultrasound scan, which also identifies the best place to take the biopsy. This is usually at the lower and outer part of the kidney.

Local anaesthetic is injected under the skin at the biopsy site. When this is numb, the needle is inserted more deeply to numb the path between the skin and the kidney. The only cut that is made is a tiny nick in the skin to allow the biopsy needle to enter more easily. This nick is 2 to 3mm long and is so small that it does not need a stitch afterwards.

When the radiologist had identified the right position for the biopsy, he or she will insert the needle while your child holds his or her breath and then quickly withdraw it again. The process may need to be repeated if the sample if small.

The biopsy needle has a hollow centre, and when it is removed, it brings a very fine core of kidney with it. This is about the size of a piece of thick cotton and is approximately 1 to 2cm long. This tiny piece of kidney will take away between ten and 50 glomeruli, which are the little filtering units within the kidney. This will not affect kidney function as each kidney contains about a million glomeruli.

The sample of kidney tissue is given to the histopathology technician who looks at it under the microscope to make sure the sample is adequate. If the sample is too small, a second will be taken during the same procedure. If the sample is just right, the technician will take it for processing.

The incision site will be closed by steristrips®, which are like strong sticky plasters, and then covered with a dressing. The area usually bleeds slightly straight after the procedure, but this will stop when pressure is applied to the site. Your child will then return to the ward where they need very frequent observations of their heart rate, breathing and blood pressure. This is because very rarely a child can bleed after a kidney biopsy as we rely on natural blood clotting for it to heal. For this reason, we need your child to lie still for at least four hours afterwards.

Are there any risks involved?

Some children may get a little bit of pain over the biopsy site, but this is not usually serious. Paracetamol is usually enough to help this.

Another potential complication is bleeding so that your child’s urine may look red. This is because the kidney has a lot of blood flowing through it all the time. The nurse will check your child’s blood pressure and pulse so that if any bleeding occurs, it can be picked up quickly. Very rarely it is necessary to give a blood transfusion, and every more rarely, it has been reported that kidneys have been lost due to bleeding.

Another rare complication is that if the blood causes clots in the urine, a bladder catheter may be needed if the clots are stopping urine being passed. Another complication is the creation of a join between a small artery and a small vein, called a fistula, which can very occasionally cause bleeding and blood pressure problems.

Over the last two years, we have taken 72 kidney biopsies from transplanted kidneys and 155 from native kidneys. Of these, one child had bad pain over the biopsy site and one child has blood in the urine severe enough to require a blood transfusion.

Going home

If your child’s blood pressure, pulse and breathing remain satisfactory, the biopsy site looks fine and he or she has passed urine (peed) that is not heavily blood stained on two occasions, we will let you and your child go home about six hours after the biopsy. However, if the biopsy took place late into the afternoon, your child may need to stay overnight.

When your child goes home

  • Keep the dressing dry and in place for a day or two after the procedure. This helps the biopsy site to heal and reduces the risk of scarring. The dressing can then be removed. The steri-strips® used to seal the wound may fall off of their own accord – otherwise, you can gently peel them off three days after the biopsy.
  • Your child may feel uncomfortable for a couple of days afterwards and may experience a dull ache in the area where the biopsy was taken. It is fine to give your child paracetamol (given according to the instructions on the bottle) unless you have been advised otherwise.
  • Your child’s urine may look slightly pink afterwards due to a small amount of bleeding. This will usually settle down within 72 hours.
  • When you get home your child should take it easy and not run around or ride a bike for two weeks. We advise that he or she stay off school for two days after the biopsy. Your child should avoid horse riding and contact sports such as rugby for the next four weeks to allow the kidney to heal properly.

You should call the ward if:

  • Your child has blood-stained urine;
  • The biopsy site is still painful more than three days after the biopsy was taken and normal pain relief is not helping;
  • There is any oozing or bleeding from the biopsy site;
  • Your child develops a fever.

When will I get the results?

The biopsy is processed in three different ways. First of all, we look at it under a microscope. This may give us some information within a day or two. We then do special stains on the sample, which takes a bit longer, and electron microscopy, which takes longer again. We may have some results available while you are still in hospital, but would need to allow six weeks to be sure that the others are back. You need to make sure that when you leave the hospital, you have an appointment for six weeks or sooner if you are asked to do so.

If you have any questions, please call Great Ormond Street Hospital on 020 7405 9200 and ask to be put through to the ward from which your child was discharged.

Ref: 07F144 © GOSH Trust March 2008
Compiled by the Nephrology department in collaboration with the Child and Family Information Group

This information does not constitute health or medical advice and will not necessarily reflect treatment at other hospitals. If you have any questions, please ask your doctor. No liability can be taken as a result of using this information.

This page was last updated on 8 August, 2008