What do kidneys do?

Kidneys do more than one task. The main one is to clean your blood and the waste products in your urine. In addition the kidneys keep your blood pressure stable and maintain the proper balance of salts in your blood (without which your heart and brain cannot function). The kidneys are also involved in the production and activation of hormones. This is necessary for proper growth, keeping bones strong and making new red blood cells.

What is kidney failure?

Kidney failure is when the kidneys cannot do these tasks properly. Kidney function is measured by the amount of blood that the kidneys clean per minute (also called GFR). In an adult, the kidney cleans about 80 – 100 ml of blood per minute. Kidney failure is defined as a GFR below 80 ml/min. Fortunately, our kidneys have a lot of reserve capacity, so you can live even with impaired kidney function, although usually medications are needed to help the kidneys. This is called chronic kidney failure. However, once kidney function is down to about 10 ml/min or less, the symptoms can become very dangerous. This is called end-stage kidney disease.

What causes kidney failure?

Most children with kidney failure are born with a problem affecting their kidneys and/or the drainage system of the kidneys (ureters/bladder/urethra). Less common reasons in children are kidney infections and certain medicines or poisons. Losing blood in an accident or severe dehydration can also cause kidneys to fail. This is called acute renal failure. Fortunately, most of the time the kidneys can recover from this.

What are the key warning signs?

There are no clear warning signs for kidney failure. Depending on how the kidneys are affected, you might either have very high or very low blood pressure. Urinating a lot more, or a lot less, can also be a warning sign. There may be blood in your urine and you might get swollen hands and feet.

How is kidney failure diagnosed?

If doctors think you may have kidney failure they will probably test your blood, your urine and your blood pressure. You may be given a kidney scan (like an x-ray) or a kidney biopsy to determine what causes the kidney failure. A biopsy is where they take a tiny piece of tissue so they can test it and look for damage. You can carry on as normal with just one kidney. But if the other kidney gets damaged or stops working, you will need treatment.

How can kidney failure be treated?

Chronic kidney failures can usually be treated with medications. The doctor will need to see you regularly and will probably take some blood to make sure everything is stable. You may need to take some special vitamins, salt supplements or an injection to help you make new red blood cells.

End-Stage Kidney failure can be treated by dialysis. This cleans and filters your blood. It gets rid of harmful waste products and extra fluid. You can have dialysis in hospital three times a week for about three to four hours. Some dialysis you can do at home. Kidney failure can also be treated with a transplant to give you a new kidney. For this the hospital would have to find a kidney to match yours. This is to lower the chances of your body rejecting the kidney. You would also have to take medication every day to protect against rejection.

What about my future health?

You can have dialysis for many years. In between dialysis sessions, you can enjoy a normal life as long as you take your medication every day.  If you’re given a new kidney, this can last for many, many years.

For more help and information

UK National Kidney Federation

Last reviewed by Great Ormond Street Hospital: 22 February 2007

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