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Acute Kidney Failure

What is acute kidney failure?

Acute kidney (renal) failure is the sudden shutdown of the kidneys. This problem is also called acute renal failure or acute renal insufficiency.

Your kidneys are located on each side of your spine above your waist. They make urine by filtering waste and extra water from your blood. They also control the balance of salt and water in your body and help regulate your blood pressure. As long as you have at least one kidney that is working, your body can filter enough blood and make enough urine to keep you healthy.

When you have kidney failure, the kidneys are no longer able to make urine, rid your body of harmful wastes, or keep a healthy balance of chemicals such as sodium and potassium.

Acute kidney failure is different from chronic kidney failure or insufficiency. Chronic kidney failure happens gradually over months or years due to a medical condition such as high blood pressure or diabetes.

How does it occur?

Tiny blood vessels in the kidneys filter the blood that flows through them. The kidneys need good blood flow to work properly. Acute kidney failure can happen when the kidneys are not getting enough blood flow. It can also happen when they are injured by disease, drugs, or poisons.

People who have been badly burned, have had a heart attack, have lost a lot of blood, are dehydrated, or are otherwise very ill may go into shock. Shock lowers blood flow to the kidneys. This means that the kidneys get less oxygen. The lack of oxygen may damage the kidneys.

Problems in the kidneys that can cause sudden failure are:

  • kidney stones
  • severe burn injury
  • loss of a lot of blood (hemorrhage)
  • dehydration
  • infection in the kidneys or blood
  • inflammation of one or both kidneys (nephritis)
  • injury from drugs, solvents, insecticides, or other poisons

Sometimes blockage of urine flow causes or contributes to acute kidney failure. This can happen, for example, when the prostate gland is enlarged.

What are the symptoms?

Some of the symptoms of acute kidney failure are:

  • urinating less or not at all even when you are drinking fluids
  • swelling all over the body or swelling of just the legs, feet, or ankles
  • confusion
  • drowsiness and tiredness
  • loss of appetite
  • nausea and vomiting
  • seizures
  • skin or breath that smells like urine.

How is it diagnosed?

Your healthcare provider will ask about your symptoms and examine you. You will have urine and blood tests to see how well your kidneys are working. A catheter (tube) will be placed in your bladder to keep track of the amount of urine being made.

Your healthcare provider will look for the cause of the kidney failure. You may have special X-rays and ultrasound scans to show the size of your kidneys and to look for blockages. You may need to have a kidney biopsy to look for the cause of the kidney failure. When you have a biopsy, you are given anesthesia and then a tiny piece of kidney is removed and examined in the lab.

How is it treated?

Your kidneys may work normally again when the problem causing the kidney failure is treated. For example, if you have an infection, you will be given antibiotics. To help your kidneys work better as they are healing, you may be given diuretics (“water pills”) to help the kidneys make urine. The amount of liquids put into your body, both by drinking and from IV (intravenous) fluids, will be carefully limited and measured until your kidneys are working again. Likewise, your diet will be limited to foods with nutrients that are easier for your kidney to process. For example, proteins (meat, eggs, dairy) break down into nitrogen. If the kidney is unable to process the nitrogen and filter it out of the blood, the nitrogen can build up and cause other serious problems.

If your kidneys don’t start working again soon, you may need kidney dialysis until they do start working.

The use of dialysis depends on:

  • whether your kidneys are working at all
  • why your kidneys stopped working
  • your other health conditions
  • your overall health.

For many people, dialysis can extend life, and improve quality of life. For others whose condition is extreme, dialysis may seem a burden that only prolongs suffering. Discuss this with your healthcare provider.

Dialysis is a mechanical way to do the work your kidneys normally do. It removes waste and extra water from the blood and can be life-saving. After several weeks the kidneys may begin to work again and dialysis can be stopped. Sometimes chronic (long-lasting) kidney failure develops, which requires long-term dialysis or a kidney transplant.

You may need to change your diet. Follow your healthcare provider's guidelines for the amount of salt in your diet. Also, the amounts of liquids you drink must be balanced against how much you urinate. You may need to have less protein in your diet. You may also need to limit potassium because it may be hard for your body to get rid of extra potassium. (Too much potassium can cause heart rhythm problems.) With the right diet, you can reduce the work your kidneys must do.

How long will the effects last?

The kidneys usually start working normally again when the condition causing the kidney failure is treated. Acute kidney failure can last for days or weeks. It may take the kidneys many months to regain full function. There is a risk your kidneys could be permanently damaged.

In some cases acute kidney failure can lead to chronic kidney failure or even death.

How can I take care of myself?

  • Carefully follow your healthcare provider's instructions for treating your kidney failure, including taking any medicines exactly as prescribed.
  • Follow your provider's instructions for balancing your fluids through the day.
  • Make changes in your diet as recommended by your healthcare provider. Ask your provider for written diet instructions or for a referral to a dietitian.

For more information, contact The National Kidney Foundation. The toll-free number is 1-800-622-9010. The Web site address is

Developed by RelayHealth.
Published by RelayHealth.
Last modified: 2011-08-11
Last reviewed: 2011-02-01
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2011 RelayHealth and/or its affiliates. All rights reserved.
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