Although rates of serious complications have fallen sharply in the last few decades, kidney transplants – like any other type of surgery – are not risk-free.
The risks of a kidney transplant include:
- risks related to the procedure itself
- risks related to the use of immunosuppressant medications (which reduce the activity of your immune system)
- risks related to something going wrong with the transplanted kidney
Most complications occur in the first few months after a transplant, but can develop after many years.
Some of the main short-term and long-term complications of a kidney transplant are outlined below.
Blood clots can develop in the arteries that have been connected to the donated kidney. This is estimated to occur in around 1 in 100 kidney transplants.
In some cases, it may be possible to dissolve the blood clots using medication, but it's often necessary to remove the donated kidney if the blood supply is blocked.
Narrowing of an artery
Narrowing of the artery connected to the donated kidney, known as arterial stenosis, can sometimes occur after a kidney transplant. In some cases, it can develop months, or even years, after the transplant.
Arterial stenosis can cause a rise in blood pressure. The artery often needs to be stretched to widen it, and a small metal tube called a stent may be placed inside the affected artery to stop it narrowing again.
The ureter (the tube that carries urine from the kidney to the bladder) can become blocked after a kidney transplant. It can be blocked soon after the transplant – by blood clots, for example. It can also be blocked months or years later, usually due to scar tissue.
It may be possible to unblock the ureter by draining it with a small tube called a catheter. Sometimes surgery may be required to unblock the ureter.
Occasionally, urine may leak from where the ureter joins the bladder after surgery. This usually occurs during the first month after the procedure. The fluid may build up in the tummy or leak through the surgical incision.
If you develop a urine leak, you'll usually need to have further surgery to repair it.
Acute rejection means the immune system suddenly begins to attack the donated kidney because it recognises it as foreign tissue.
Despite the use of immunosuppressants, acute rejection is a common complication in the first year after a transplant, affecting up to 1 in 3 people.
In many cases, acute rejection does not cause noticeable symptoms, and is only detected by a blood test.
If it does occur, it can often be successfully treated with a short course of more powerful immunosuppressants.
Immunosuppressant side effects
Immunosuppressants prevent your body's immune system from attacking the new kidney, which would cause the transplanted kidney to be rejected.
A combination of 2 or 3 different immunosuppressants is usually taken long term.
These can cause a wide range of side effects, including:
- an increased risk of infections
- an increased risk of diabetes
- high blood pressure
- weight gain
- abdominal pain
- extra hair growth or hair loss
- swollen gums
- bruising or bleeding more easily
- thinning of the bones
- mood swings
- an increased risk of certain types of cancer, particularly skin cancer
The doctor in charge of your care will be trying to find the right dose that is high enough to "dampen" the immune system to stop rejection, but low enough that you experience very few or no side effects.
Finding the optimal dose to achieve both goals is often a difficult balancing act. It may take several months to find the most effective dose that causes the least amount of side effects.
Side effects should improve once the right dosage is identified. Even if your side effects become troublesome, never suddenly stop taking your medication because your kidney could be rejected. Speak to your GP or transplant team for advice.
Diabetes is a common complication of having a kidney transplant.
Diabetes is a lifelong condition that causes a person's blood sugar level to become too high. Some people develop it after a kidney transplant because, as they no longer feel unwell, they eat more and gain too much weight. Some types of immunosuppressants can also make you more likely to develop diabetes.
Symptoms of diabetes include:
- feeling very thirsty
- going to the toilet to urinate a lot, especially at night
Diabetes can often be controlled using a combination of lifestyle changes, such as alterations to your diet, and medication.
Read more about treating diabetes.
High blood pressure
High blood pressure is also a common long-term complication of a kidney transplant.
Many people who need a kidney transplant already have an increased risk of developing high blood pressure, and taking immunosuppressants can make the condition worse.
Because of the risk of high blood pressure, you'll have your blood pressure checked at your follow-up appointments. You can also check your own blood pressure at home with a simple device available from most pharmacies. Read more about testing your blood pressure.
The long-term use of immunosuppressants also increases your risk of developing some types of cancer, particularly types known to be caused by viruses (as you will be more vulnerable to the effects of infection).
- most types of skin cancer – including melanoma and non-melanoma
- Kaposi's sarcoma – a type of cancer that can affect both skin and internal organs
- lymphoma – a cancer of the lymphatic system
You can reduce your risk of skin cancer by avoiding exposure to the sun during the hottest part of the day and by applying sun cream to your lips and all exposed areas of your skin every day.
Your care team can give advice on your individual risks, whether you need regular check-ups, and any early signs to look out for.