Kidney transplant risks and complications

Kidney transplantation is a big operation with a lot of potential side-effects and risks to consider. Your child’stransplant team will carefully monitor your child and check for signs of complications. They will discuss thesewith you in detail.

Complications immediately after operation

Your child’s transplant team will minimise these risks and monitor for any warning signs, so problems can be treated as soon as possible.

  • Bleeding – occasionally, children bleed more than usual during the surgery and lose a large amount of blood. Some children need a blood transfusion to receive new blood from a donor; some may need to go back to the operating theatre to stop the bleeding.
  • Difficulty breathing – occasionally, children are unable to remove the large amounts of fluid given during the surgery, and this may cause problems breathing. These children are usually treated in the paediatric intensive care unit.
  • Infection may occur in one of the ‘lines’, in the urine, in the chest or in the wound. Steps are taken to reduce the risk of an infection, but if an infection does occur, children can take medicines that treat the infection.
  • Seizures (also called fits or convulsions): very rarely, children have seizures after transplantation, though this is more likely in those who had them before. If this happens, children can take medicines that treat the cause of the seizure.
  • Thrombosis (blood clot) – occasionally, if a blood clot is large, it can block the blood flow to the kidney.
  • Sometimes the ureter (the tube between the kidney and bladder) is damaged and urine may leak.
  • Delayed bowel function (not doing a poo) – sometimes, children will not be able to empty their bowels (do a poo) for a short time after surgery. This is because their bowels might ‘go to sleep’ during the surgery. If this happens, the bowels will usually ‘wake up’ naturally. The transplant team will check for signs of delayed bowel function, and treat it if needed.
  • Operation – like all surgery, kidney transplantation has a risk of death; however this is extremely unlikely.

Delayed graft function

The transplanted kidney may take a few hours or a few days – or sometimes longer – before it starts working. This is called delayed graft function. We often say the kidney is ‘asleep’ and that we expect it to ‘wake up’ after it has recovered. This happens to 1 in 12 kidneys overall, but is more likely in children with a transplant from a deceased donor, especially if it is from a donor where the kidney was removed after the heart had stopped beating. (See the topic Deceased donors for more information.) Your child’s transplant team will check the kidney function and blood supply after the operation. Some children need dialysis before the new kidney starts working.

When kidney transplant does not work

Sometimes, the kidney transplant does not work properly. Your child’s transplant team will look for any signs that the kidney is not working properly. This may happen for several reasons, which are described below. If the kidney transplant fails, this is called graft loss.

Primary non-function (no function after the operation)

A few kidney transplants do not work because there is too little blood going into the new kidney. As with all organs, the new kidney needs plenty of blood flowing into it. This may be due to a blood clot (when the blood forms clumps). Smaller children are at higher risk of a blood clot. A medicine called heparin or asprin is used to stop the blood forming clots and reduce this risk. Other kidneys may never work because they have been starved of oxygen for too long. This can be because of the events leading to donation or because there is too much time between taking the kidney from the donor to implanting it.

Complication of medicines

The anti-rejection medicines, or immunosuppressants, which need to be taken to reduce the risk of rejection may also cause problems. In particular, two medicines – tacrolimus and ciclosporin – can cause long-term effects on the kidney in some children, and may cause a condition known as interstitial fibrosis and tubular atrophy (IFTA). If this happens, your child’s doctor may change his or her medicines.

Original disease comes back

Occasionally, the original disease that caused kidney failure comes back in the transplanted kidney. This may be the case with specific diseases, including:

Sometimes, the disease in the transplanted kidney is less serious than before, though your child will need to be monitored and may need further treatment. It does not always affect the kidney function. Occasionally, it can cause graft loss.


When a kidney – or any other body tissue – is transplanted from a donor to a recipient, the recipient’s body recognises it as ‘foreign’ and tries to reject or destroy it. This happens because of the immune system, which protects the body against disease and infection. Parts of the immune system can find, and destroy, foreign things, such as germs or other people’s cells, which are the tiny living parts of the body. This is called rejection, and is the major complication of kidney transplantation.

To reduce this risk, your child’s transplant team will have tried to find a close match between your child and the donor, and your child will take a combination of medicines that is right for him or her. If children forget or choose not to take the anti-rejection medicines, their bodies are likely to reject the transplanted kidney. Adolescents or teenagers have the highest rates of kidney transplant loss of all age groups (including adults) – this is thought to be due to not taking the medicines as prescribed.

Rejection may be sudden (acute) – there may be one or more episodes, or it may occur over a longer period of time.

Symptoms and signs

Many children do not have symptoms of rejection.

Occasionally children experience:

  • fever
  • pain or tenderness around transplanted kidney
  • blood in their urine (haematuria)
  • reduced urine output
  • tiredness/feeling unwell.


Your child will have blood and urine tests after the operation to check how well the new kidney is working. The amount of creatinine in his or her blood will be measured. This is a waste product in the blood, which the kidneys filter. A high amount of creatinine may be a sign of rejection. Some children will need an ultrasound scan and a biopsy of the transplanted kidney, to confirm the problem.


Early rejection can generally be successfully treated by changing medicines.

Rejection that occurs after 6 months or more since the transplant is much more difficult to treat, particularly if the rejection is due to your child not taking his or her medicines correctly.

Unfortunately, sometimes kidney transplants stop working because of rejection. If the new kidney does not work – or stops working after time – your child may need to start dialysis. Your child will be considered for another transplant.


All transplant recipients need to take anti-rejection medicines (called immunosuppressants), which make the immune system less active. This means they are at higher risk of getting infections caused by germs such as bacteria and viruses. Some of these are minor, but may need treatment with antibiotic or antiviral medicines. Others may be more serious. 

CMV and EBV 

Cytomegalovirus (CMV) and Epstein–Barr virus (EBV) are viruses that each cause a glandular fever-like illness in people with healthy immune systems. These people may have symptoms of glandular fever, such as a fever (temperature above 38°C), sore throat and tiredness, but they often get better after a few weeks. The virus does not leave the body, but rather stays in a dormant state – which means it is not active. These people are now ‘immune’ to the virus, and so cannot get re-infected with the virus. In people whose immune system has been suppressed – such as when taking anti-rejection medicines – these viruses can cause more serious illness. Your child will be tested to find out if whether they have already been infected with CMV and/or EBV. If your child has not previously been infected with these viruses, he or she may be at a higher risk of getting ill if he or she receives a kidney from a donor who had been exposed to CMV and/ or EBV. If your child has become ‘immune’ to CMV and/or EBV from a previous infection, then he or she is at a lower risk of getting ill from these viruses.

  • Cytomegalovirus (CMV): for CMV, your child may be given a low dose of an antiviral medicine to protect him or her against getting this infection. If your doctor thinks that your child may be ill, he or she may be tested for CMV infection. Your child may be given a higher dose of an antiviral medicine that will kill the virus.
  • Epstein-Barr virus (EBV): there is no effective antiviral treatment for EBV. Your doctor will test for EBV infection during your child’s routine blood tests for a period after the kidney transplant. If your doctor thinks that your child may be infected with EBV, he or she may need to reduce the dose or stop some of the anti-rejection medicines. This will help your child’s immune system to fight the infection.


The BK virus (BKV) is a commonly occurring virus. It is thought that over 80% of the population have been infected with the BK virus. However, it is very rare for these people to have any symptoms. People with healthy immune systems can show some symptoms – known as primary BK infections – including mild chest infections or fever (temperature above 38°C). After a primary BK infection, the virus tends to hide itself in the kidneys or urinary tract, where it stays for the rest of a person’s life. For most people this virus will remain there in a dormant state – which means it is not active.

In people whose immune system has been suppressed – such as when taking anti-rejection medicines – this virus  can activate and may cause serious complications (BKV nephropathy or BKVN), including loss of graft (kidney) function and, in a small number of individuals, graft loss (failure of the new kidney).

Your child will have a blood test and a urine test if their transplanted kidney is not working properly, and a BKV infection is suspected. Some centres screen transplant patients for this infection, with regular urine tests. At present, there are some treatments that have been used with variable success but no specific antiviral treatment for a BKV infection. If your child has a BKV infection, he or she will probably need to reduce the dose of anti-rejection medicine (immunosuppressant), or may also need to change the type of immunosuppressant. This will help the immune system to fight the infection.

Other long-term complications

Obstruction to flow of urine

Sometimes there is blockage that affects how urine is drained.

Problems with blood vessels

Transplant renal artery stenosis (TRAS) may happen some time after transplantation. It means that the renal artery, the blood vessel that carries blood into the kidney, becomes narrower. This means that less blood can get into the kidney, and may cause high blood pressure and increase the risk that the kidney does not work.

High blood pressure

Some children have high blood pressure (hypertension) after transplantation, even if they did not have it before the surgery. This may happen because of TRAS or medications such as steroids. If this happens, your child may need to take medicines that control his or her blood pressure.

More in the infoKID topic: Hypertension

Cancer – including skin cancer

There is a slightly increased risk of cancer. Very occasionally, this is through the donor – however, this is very rare, as the medical histories of all prospective donors are carefully checked.

Transplant recipients have a much higher risk of skin cancer than the rest of the population. Protect your child’s skin from strong sunlight by dressing them in long-sleeved tops and trousers and a hat, and using high-factor sunscreen (at least SPF 30).

PTLD – a type of cancer

Post-transplant lymphoproliferative disorder (PTLD) is a type of cancer that happens in about 3 in 100 kidney transplants in children. Your child’s healthcare team will check for signs of PLTD at follow-up appointments. These include symptoms of nausea (feeling sick), diarrhoea or weight loss. If PTLD is suspected, your child may need a biopsy to help with the diagnosis. A tiny piece of an affected organ or lymph node is removed from the body with a needle and examined under microscopes.

Reducing or stopping the immunosuppressants often successfully treats PTLD. A few children need chemotherapy – much stronger medicines, to treat the cancer.

This is often related to EBV virus. Sometimes donors have this virus in their blood because they previously had an infection. It can also reactivate in a child who has previously had EBV, although many children have not yet been exposed to the virus.


Diabetes is a disease in which the body is not able to remove sugar in the blood after a meal. This is a rare side effect of treatment with tacrolimus and prednisolone, medicines that need to be taken after transplantation. Sometimes, this can be successfully treated by changing the medicines. Occasionally, children need to take insulin, a medicine that is injected under the skin, for a long time.