This guide explains in plain language what the kidneys do, what can damage them, how kidney failure is found and how it is treated. It does not replace the advice of your own doctor.
What do the kidneys do?
The kidneys are a pair of bean-shaped organs in the abdomen, near the back. Each is slightly smaller than a clenched fist. They filter the blood, removing waste products and extra fluid, which leave the body as urine. Urine passes from each kidney down a tube called the ureter to the bladder, and out through the urethra.
What is kidney failure?
Kidney failure means the kidneys are no longer working well enough. It can come on very quickly, over a few days, which is called acute kidney failure. More often it develops slowly, over weeks, months or years, which is called chronic kidney failure.
What causes kidney failure?
- High blood pressure that is not controlled: blood reaches the kidneys with too much force and slowly damages them. Without treatment it is one of the most common causes
- Diabetes that is not controlled: high sugar levels damage the small blood vessels inside the kidneys
- Infections: an infection in the kidneys, or an infection elsewhere in the body that is not treated properly, such as a bad sore throat, can damage the kidneys
- Some medicines: painkillers such as diclofenac and ibuprofen can harm the kidneys when they are taken on your own, in large amounts or for a long time. Please take medicines only as advised
- Some herbal preparations, which can damage the kidneys either through the herb itself or the way it is prepared
Warning signs
Early kidney failure often causes no symptoms at all. Later, signs can include:
- Getting tired easily
- Swelling of the feet and legs, or of the whole body
- Passing urine less often, or not at all
- High blood pressure
- A low blood count (anaemia)
- Weakness of the bones
How is kidney failure found?
It is diagnosed with a kidney function test, a blood test that measures waste products such as urea and creatinine and gives a figure called the eGFR, which shows how well the kidneys are filtering. When the kidneys are failing, waste products are high in the blood and the eGFR is low. If your result is below normal, see a kidney specialist for follow-up so that it does not get worse.
Your doctor may also request other tests depending on your situation, for example a chest X-ray, an ECG, an echocardiogram (a heart scan), and for men a PSA blood test.
How can kidney failure be prevented?
The causes of kidney failure can often be prevented or controlled, which is much easier than treating kidney failure once it is established.
- Control high blood pressure: take your medicines as prescribed and keep your regular check-ups. High blood pressure becomes more common as we grow older, especially after the age of 35, and it is usually defined as 140/90 mmHg or above
- Keep diabetes under control if you have it
- Have infections treated properly, including sore throats
- Avoid taking painkillers and other medicines on your own for long periods
- Be careful with herbal products
- Have your kidney function checked if you have diabetes, high blood pressure or a family history of kidney disease
How is kidney failure treated?
Kidney failure is treated in two main ways: dialysis and kidney transplant.
Dialysis
Dialysis does part of the work of the failed kidneys, filtering waste products out of the blood. There are two types.
- Peritoneal dialysis (tummy dialysis): a soft tube is placed into the abdomen and a special solution is passed through it. The solution collects the waste products and is then drained away
- Haemodialysis (blood dialysis): blood is taken through a tube or a fistula to a dialysis machine, which removes the waste products and returns the cleaned blood to the body
Haemodialysis is the most common form. Each session lasts about 3 hours, and two to three sessions a week are usually needed. For most people, dialysis is needed for the long term. Our dialysis service and the procedures that make dialysis possible are described on their own pages.
Kidney transplant
In a kidney transplant, one healthy kidney from a donor is placed in a patient whose kidneys have failed. The donor can live a normal life with the one remaining healthy kidney. The person who receives the kidney needs medicines for the long term to help the new kidney to keep working. A transplanted kidney can work for many years. If it eventually stops working, the person goes back on dialysis.
When to see a specialist
- You have diabetes, high blood pressure or a family history of kidney disease
- Your legs, feet or face are swollen, or you are passing less urine
- You are tired all the time and cannot say why
- A kidney test from another clinic was abnormal
- You have been taking painkillers or herbal products for a long time
Learn more about our Nephrology service →
This article gives general information and does not replace advice from a doctor. To discuss your own situation, please book a consultation.